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/Innovative n n o v a t i Vacuum Technology A Degussa Company ii CERN Courier, June 1993 Volume 33 Advertising enquiries No. 5 Europe June 1993 Micheline Falciola Covering current developments in high energy Advertising Manager CERN physics and related fields worldwide CH-1211 Geneva 23, Switzerland Editor: Gordon Fraser (COURIER @ CERNVM)* Tel.: +41 (22) 767 4103 Production and Advertisements: Fax: +41 (22) 782 1906 Micheline Falciola (FAL @ CERNVM)* Advisory Board: E.J.N. Wilson (Chairman), E. Lillestol, Rest of the world H. Satz, D. Treille; with W. Hoogland, Tim Serpico HJ. Miettinen Gordon and Breach Science Publishers *(Full electronic mail address... @ CERNVM. CERN. CH) 820 Town Center Drive Langhorne, PA 19047 Tel.:+1 (215) 750 2642 Fax: +1 (215) 750 6343 Distributed to Member State governments, institutes and laboratories affilliated with CERN, and to their personnel. Around the Laboratories CORNELL: CLEO discovers B meson penguins General distribution 1 Alternative route for heavy quark decays Jacques Dallemagne CERN, 1211 Geneva 23, Switzerland CERN: Materials science from radioactive isotopes

J> Exploiting exotic beams m In certain countries, copies are available on request from: 7_ SUPERCOLLIDER: Testing muon chambers Texas style China BERKELEY: ALS ring Dr. Qian Ke-Qin 8 Commissioning Advanced Light Source Institute of High Energy Physics P.O. Box 918, Beijing, RUTHERFORD/STANFORD: First physics from novel detector People's Republic of China 9^ Pixel-based tracking techniques Germany FERMILAB: Main Injector Gabriela Heessel 10. Replacing the Main Ring

DUBNA: Update DESY, Notkestr. 85, 2000 Hamburg 52 13 Italy Mrs. Pieri or Mrs. Montanari Physics monitor INFN, Casella Postale 56 00044 Frascati, Roma Neutrinos, atoms and gravity United Kingdom 14 Stimulating physics at Moriond workshop Su Lockley Mass-producing B mesons Rutherford Appleton Laboratory, 16 Potential for heavy quark physics Chilton, Didcot, Oxfordshire OX11 0QX Physics and astrophysics of quark-gluon plasma USA/Canada 18 Calcutta meeting Cyndi Rathbun (B90904 @ FNALVM) Fermilab, P.O. Box 500, Batavia The genesis of unified gauge theories Illinois 60510 22 by Tom Kibble

CERN COURIER is published ten times yearly in English and French editions. The People and things views expressed in the Journal are not 27 necessarily those of the CERN management. Reader service form, page 30. Printed by: Drukkerij Lannoo nv 8700 Tielt, Belgium Published by: European Laboratory for Particle Physics CERN, 1211 Geneva 23, Switzerland tel.: +41 (22)767 61 11, telex: 419 000 CERN CH, telefax: +41 (22) 767 65 55 CERN COURIER only: tel. +41 (22)767 41 03, Cover photograph: The vivid channeling of emitted alpha particles in telefax+41 (22) 782 19 06 diamond shows the location of an implanted lithium-8 nucleus. A recent workshop at CERN (see page 6) demonstrated the benefits that on-line USA: Controlled Circulation isotope sources like CERN's ISOLDE can bring for solid state science. Postage paid at Batavia, Illinois

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41 Circle advertisement number on reader service form VI CERN Courier, June 1993 Around the Laboratories

CORNELL CLEO discovers B meson penguins

The CLEO collaboration at Cornell's CESR electron-positron storage ring has discovered a rare type of B meson decay in which only a high energy photon and a K* meson are produced. These decays provide the first unambiguous evidence for an alternative route for heavy quark decay that has been given the whimsical name "penguin diagram". In the mid-1970s penguin diagrams were proposed to explain the puz­ zling strangeness quantum number selection rules in the decay of K mesons. At the same time it was realized that penguin diagrams could also be important in the CP violation seen in neutral K meson decay. CP violation, an asymmetry between matter and antimatter, is an essential ingredient in understanding why there is much more matter than antimatter in the universe. CP violation introduces a definite direc­ tion to the arrow of time, which could otherwise point equally forwards or backwards. In addition, penguin decays are very sensitive to some extensions of the Standard Model of B mesons contain beauty (b) Computer display of a CLEO event in which all weak decay. quarks, with charge -1/3, which of the particles produced in the decays a B meson pair have either been observed or Although penguin diagrams were ordinarily decay to charm (c) or up inferred. One B decayed in an electromagnetic first proposed to explain an effect in (u) quarks with charge +2/3. So far penguin mode; the other decayed convention­ K meson decay, the K system gives there has been no evidence for ally. The curved tracks in the large inner circle no unique signature for them, and "flavour changing neutral currents" are the tracks of the charged particles in a drift chamber in the 1.5 T magnetic field. The outer verification of penguin processes which would result in quark transfor­ region with its radial-angular segments is the meant looking elsewhere. mations without changing electric "barrel" portion of the CLEO II cesium iodide In the Standard Model, quarks charge. In a penguin process, a b electromagnetic calorimeter. Each segment represents a counter as it would appear in decay under the influence of the quark can also decay to an s quark perspective if one were looking down the weak force, emitting a W boson. via a one-loop process (2nd order barrel. The photons in the event are indicated; Since the W is charged, the charge effect) in which a W boson is emitted the other black segments are due to charged of the initial quark differs from that of and then reabsorbed. Since the b particles in the counter or usual background the final quark, so the charge of the and s quarks have the same charge, signals from stray particles from other sources. quark changes as well as its flavour. this process is an effective flavour

CERN Courier, June 1993 1 Penguins at work. When a quark transforms The distribution of masses reconstructed from under the influence of the weak force, it K, pi, and photon candidates for 'penguin' necessarily changes its electric charge as well decay of B mesons seen by the CLEO as its quark 'flavour'. In so-called 'penguin' detector at Cornell's CESR electron-positron processes, two such quark transformations collider. The 13 events in the peak between couple back-to-back, providing an additional, 5.274 and 5.286 GeV is the signal for the but very rare route for quark transformation. In decay. Events at lower mass are due to the process seen at Cornell an emitted photon random combinations of particles from other is seen accompanied by a K* meson, formed processes. by the strange quark emerging from the penguin mechanism combining with a spectator up or down quark.

changing neutral current. Accompa­ nied by the emission of a high energy photon, the decay is known as an electromagnetic penguin decay. B meson decays which result in only a K* meson and a high energy photon are a striking and unambiguous signature for this type of process. Events in which a B meson decays to only a K* and a photon are rare - approximately one per 20,000 de­ cays. Taking into account the ineffi­ K and pi meson. If a number of other the B meson mass, 5.280 GeV, ciencies of even the best detector, selection criteria are satisfied, the K shows that many of the candidates more than a million B mesons are and pi are checked to see if they are actually resulted from the decay of a needed to obtain an unambiguous consistent with their being the prod­ B meson. Of the 13 events in the signal. During the last two years, ucts of the decay of a K*. If so, the peak, only about two are attributable over 3 million B mesons were re­ reconstructed K* is combined with to background. corded in CLEO. At CESR, B the high energy photon, and the total These decays establish the exist­ mesons are produced in pairs without energy of these particles is compared ence of the electromagnetic penguin additional particles, so the events are to the energy of the CESR electron decay process, but theoretical very clean and the energy of the B and positron beams. This constraint understanding is not yet sufficient to mesons is fixed - a good environment on the energy of the decay products make accurate calculations of spe­ for studying rare B decays. eliminates nearly all background due cific processes. However reliable Both the B and K* mesons decay to random combinations of K calculations can be made for the total much too quickly to be observed mesons, pi mesons, and photons that rate including all electromagnetic directly in the CLEO detector, so they come from other processes. penguin decays, and these calcula­ must be reconstructed from their Once these three candidate parti­ tions are sensitive to the existence decay products. The search for cles have been selected, the mass of and masses of the sixth (top) quark these penguin decays starts with the parent particle that might have and a hypothetical charged Higgs identification of a high energy photon produced them can be calculated. boson, neither of which have been in the detector in coincidence with a The peak in the mass spectrum at observed. Now that the existence of

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CERN Courier, June 1993 electromagnetic penguin processes a new era when the facility began lengthy isotope menu. has been established, conclusions operations last year in its new home Thus whole new classes of semi­ derived from measurements of the at the 1 GeV Booster synchrotron conductors become accessible for rate of inclusive decays are substan­ (July 1992, page 5). Nuclear solid PACS, yielding information on the tially more significant. state physics accounts for about 30% annealing of radiation damage after The CLEO collaboration has also of ISOLDE beam time, other re­ heavy ion implantation and on the searched for electromagnetic pen­ search highlights being nuclear hydrogen passivation of acceptor guin decays by looking for photons in physics, atomic physics, nuclear dopants. Emission channeling has an energy region where these de­ astrophysics, and biophysics. been used to Investigate the lattice cays should dominate. The number The achievements so far and site location of implanted lithium-8 of photons observed is not signifi­ ongoing goals of nuclear solid state (see front cover). cantly larger than the number ex­ research were covered in a recent Radioactive isotopes also open up pected from background electron- workshop - 'Materials Science with new techniques, for example the positron annihilation processes in Radioactive Isotopes' - held at CERN Conversion Electron Spectroscopy of which no B mesons are produced. from 5-7 April. This carried on from Valence Electron Configurations The resulting upper limit, 5.4 x 104, where the 'Radioactive Implants in (CESVEC), where the detection of for the rate of inclusive electromag­ Materials Science' meeting in Bad conversion electrons by a high netic penguin decays rules out a Honnef left off in January 1992. resolution beta spectrometer gives large class of models that include The main aims of the CERN meet­ the energy state density of the probe charged Higgs bosons with masses ing were: atom's valence electrons. in the 100 GeV range. This result - to show the outstanding possibili­ Participants at meeting also heard sharpens the focus of ongoing Higgs ties offered by ISOLDE for solid state how combining standard techniques searches. experiments using short-lived iso­ like Deep Level Transient Further elucidation of the role of topes; Spectroscopy (DLTS) with radioac­ penguin diagrams in heavy quark - to stimulate discussion between tive isotopes can overcome other­ decay requires much larger samples physicists using nuclear techniques wise inherent 'chemical blindness' - of B mesons. Cornell is currently and those employing other methods; the decay rate of the radioactive upgrading the luminosity of CESR by and implant identifies the chemical at least a factor of five (December - to look for collaboration opportuni­ species and gives the energy levels 1992, page 17). Cornell also has an ties between present ISOLDE users of chemical impurities. This trick can asymmetric B Factory proposed as a and other researchers: small teams also be applied to optical techniques further CESR upgrade (July/August could be strengthened to provide a like photoluminescence or electric 1991, page 8). very cost-effective way of exploiting methods like the Hall Effect. ISOLDE beams. Summarizing at the end of the Nuclear solid state physics at CERN workshop, R.C. Newman of ISOLDE is mainly focused on the the Interdisciplinary Centre for CERN investigation of defects and impuri­ Semiconductor Materials Research ties in semiconductors, but will also at London's Imperial College pointed Materials science with be used for metals, surfaces and out that more collaboration between radioactive isotopes interfaces, using nuclear techniques the nuclear and conventional tech­ such as radiotracer diffusion, emis­ nique communities would be useful, from ISOLDE sion channeling, and Môssbauer or while non-nuclear techniques should Perturbed Angular Correlation exploit the advantages of radioactive Among the major physics objectives Spectroscopy (PACS). isotopes to get additional information. at CERN's ISOLDE on-line isotope The hitherto serious limitation of 'The conference has made us aware separator is the growth field of many nuclear methods due to a of new possibilities,' he concluded. nuclear solid state physics, where the restricted range of chemically differ­ goals are both technological and ent suitable radioactive probe atoms (See front cover illustration) scientific. ISOLDE research entered can be easily overcome by ISOLDE'S

6 CERN Courier, June 1993 *• The next issue wiil include a description of the GEM proposal for a second major detector at the SSC.

SSC Laboratory physics research staff and some of the GEM collaborators who are using the big Texas Test Rig' to study prototype muon chambers.

SUPERCOLLIDER Testing muon chambers Texas style

Encouraging performance is being achieved for large muon chambers at the Superconducting Supercollider Laboratory (SSCL) in Ellis County, Texas. As part of the R&D effort for the muon system of the GEM detec­ tor*, a cosmic ray test stand known as the Texas Test Rig (TTR) has been built for studying chamber response. The triggerable volume of the TTR is large, with a surface area of 1.2 m x 5 m and a height of 3 m, allowing performance studies of as many as six different chambers simultane­ ously. All chamber types tested to date have shown excellent perfor­ mance, with resolutions better than the 75-micron GEM design goal. Comprehensive testing has yielded unanticipated and important knowl­ edge on chamber operation. The planes of 1-cm pitch larocci cham­ 32 tubes wide. Using gas pressures TTR has become the first user facility bers can be used to select the higher up to 5 atmospheres, the PDTs give at the SSCL, with more than 100 momentum component of the muon 50-90 micron resolution. An LSDT participating physicists from 19 spectrum, effectively raising the from MIT, operating at atmospheric universities and national laboratories threshold to 10 GeV/c. pressure, gave similar results. in China, Mexico, Russia, and the The state-of-the-art data acquisition CSC systems were developed United States. (DAQ) system developed at the independently by Brookhaven, At the TTR, a metre of steel ab­ SSCL accommodates a wide variety Dubna, and Houston. In a CSC, sorbs cosmic rays with less than of contributions from visiting groups. image charge induced on the cath­ about 1.3 GeV momentum. Remov­ Four types of detectors have been ode strips is typically shared among ing this "soft" component makes tested. Pressurized drift tubes several adjacent strips, and the hit resolution studies less susceptible to (PDT), limited-streamer drift tubes position is estimated from the pulse misleading multiple scattering effects, (LSDT), and cathode strip chambers heights. Different mechanical de­ and reduces the trigger rate to about (CSC) were candidates for position signs addressed issues of construc­ 60 Hz. Scintillator hodoscopes with measuring detectors, with resistive tion, alignment (GEM tolerances are timing resolution of about 300 ps plate chambers (RPC) for triggering tight), and manufacturability. Several above and below the steel provide and bunch tagging. chambers were tested, the largest the fast trigger. The steel can be Two separate PDT systems were approximately 1 m x 2 m. The three magnetized to 15 kG by solenoidal built at Dubna and Michigan State systems have shown 50-80 micron coils. With the magnet on, a finer using staggered layers of tubes 3- resolution. position measurement with four 4 cm in diameter, 4 m long, stacked A 1.2 m x 2.4 m RPC from a

CERN Courier, June 1993 7 Advanced Light Source (ALS) management (standing) ALS Director Brian Kincaid, LBL and staff met with Lawrence Berkeley Director Director Shank, Accelerator Group Leader Director Charles Shank to discuss successful Alan Jackson, Electrical Group Leader Henry storage-ring commissioning. Left to right are Lancaster, Head of Operations Ben Feinberg, (seated) accelerator physicists Hiroshi and Accelerator-physics Section Leader Rod Nishimura and Malika Meddahi, operator Keller. ALS Project Manager, Ron Yourd, was Cheryl Hauck, and Jay Marx, who guided the not present. ALS construction project until last October;

Livermore-MIT group uses plastic doped with conducting polymer as a low-cost alternative to scintillator for large area counting. Tests with a radioactive source indicate rate capability to 1 kHz/cm2, substantially higher than bakélite RPCs currently in use. GEM groups working with PDTs and CSCs had been con­ cerned that their chambers would pick up spurious signals from the RPCs, but TTR tests show clearly this is not the case. Such excellent and rapid results were possible because of advances in chamber design, a sophisticated DAQ system, and the TTR's size and flexibility, despite its being limited to cosmic rays.

BERKELEY Once injected, the electron beam superperiods with a total of 36 decays quasi-exponentially primarily gradient magnets, 72 focusing ALS ring because of interactions with residual quadrupoles, and 48 sextupoles, with gas molecules in the storage-ring horizontal and vertical orbit correction Everybody at Lawrence Berkeley vacuum chamber. Eventually, when by auxiliary windings on the Laboratory's Center for Beam Phys­ the pressure in the vacuum chamber sextupoles and by 46 dedicated ics is pleased with the rapid with beam decreases toward the corrector magnets. progress in commissioning LBL's expected operating level of 1 The first successful attempt to inject Advanced Light Source (ALS) elec­ nanoTorr, it will only be necessary to beam into the storage ring came on tron storage ring, the foundation for refill the storage ring at intervals of 19 January when, just before mid­ this third-generation synchrotron- four to eight hours. At present the night, a jubilant accelerator crew radiation facility. Designed for a vacuum is improving rapidly as successfully guided an electron maximum current of 400 mA, the surfaces are irradiated (scrubbed) by beam around the storage ring for the ALS storage ring reached 407 mA the synchrotron radiation itself. At first time. In subsequent days, the just 24 days after storing the first 100 mA, beam lifetime was about number of turns was gradually raised beam on 16 March. one hour (9 April). beyond 400, nearly the maximum ALS construction as a US Depart­ To generate high-brightness VUV possible without the radiofrequency ment of Energy (DOE) national user and soft x-ray synchrotron radiation, system to replenish energy lost to facility to provide high-brightness the ALS electron storage ring is synchrotron radiation. vacuum ultra-violet and soft x-ray designed to have very low emittance. By mid-March, the 500-MHz stor­ radiation began in October 1987. The calculated natural emittance of age-ring rf system was ready. On 16 One technical requirement marking the ring is 3.5 nm-rad at the normal March, with a little fine tuning, the project completion was to accumu­ operating energy of 1.5 GeV. How­ ALS crew was gratified to see the late a 50-mA current in the storage ever, the ring is capable of operating number of turns on the beam-position ring. The ALS passed this milestone over the range 1 -1.9 GeV. monitors increasing dramatically from on 24 March, a week ahead of the The triple-bend achromat (TBA) several hundred to several million. official deadline. magnet lattice contains 12 Beam started to accumulate immedi-

8 CERN Courier, June 1993 ately. The de current transformer machine studies until they were sure available beginning around August. reported a stored current of 6 mA In that no ring component could be Over the summer, the ALS accelera­ four bunches, and the vacuum overheated by spilled photons or tor crew will attack the problem of gauges shot up from about 10 beam-induced effects. Occasional operating with first one and then nanoTorr to 1 microTorr as a result of attempts to raise the current were multiple undulators in the storage desorption induced by synchrotron permitted during continuing machine ring with their gaps closed to the radiation. refinements, and the maximum maximum magnetic-field value. After carefully tuning the rf cavities current at the time of writing was 407 and optimizing rf power and phase, mA. another try on 19 March resulted in a As a third-generation source of VUV current of 42 mA in four bunches. and soft x-ray synchrotron radiation, RUTHERFORD/ This exceeded a performance goal of the ALS emphasizes insertion de­ STANFORD 7.6 mA in a single bunch, a specifica­ vices in the straight sections between tion that will be useful when operat­ the 12 arcs of the ring. Ten sections First physics from ing in a single- or few-bunch mode are available for undulators and novel detector for time-resolved experiments. wigglers up to 4.5 m in length. Of the March 24 saw the passing of the two remaining, one is occupied by Pixel-based tracking detectors are milestone known as the "DOE Project injection hardware and the other by making their mark. The first such Plan Technical Baseline" requirement two rf cavities. In addition, each arc detector used for high energy physics of 50 mA, a figure well below the of the storage ring is fitted with four was a twin charge coupled device maximum current of 400 mA but ports for access to bend-magnet (CCD) assembly at the front end of chosen in recognition that accelera­ radiation. the CERN fixed target experiment tors seldom reach full design per­ Completion of the initial accelerator NA32, completed in 1986. Measur­ formance levels without extensive studies early in May is followed by a ing space points on the particle commissioning and extended operat­ three-month shutdown for installation tracks with five-micron precision and ing time. To surpass the 50-mA of the first two undulators and front- having unprecedented track resolu- figure, the ALS accelerator crew end hardware for the two undulators, further optimized the rf power, phase, as well as one undulator and three The vertex detector for the SLD experiment at and cavity tunes, adjusted the verti­ bend-magnet photon beamlines. Stanford's SLC linear collider, prior to cal closed orbit, and shifted to a more One of the bend-magnet beamlines assembly round the beam pipe. The inner­ uniform multi-bunch filling pattern. is designated for machine diagnos­ most of the four concentric barrels has a These improvements took the current tics. It is hoped that completed radius of 29 mm. The detector consists of 60 to 67 mA and brought a congratula­ ladders, each fitted with 8 CCDs. Each CCD beamlines for synchrotron-radiation comprises 250,000 independently digitized tory letter from Secretary of Energy research will gradually become pixels. Hazel O'Leary. The accelerator crew kept pushing and boosted the stored current to 90 mA the next day after carefully adjusting most of the available corrector magnets and a subset (QFA) of the horizontally focusing quadrupole magnets in the storage- ring TBA lattice. At this point, the beam decayed from 90 to 20 mA in 16 minutes. A week later, the peak current reached 290 mA, and the accelerator crew decided to limit the current temporarily to 200 mA for further

CERN Courier, June 1993 9 tion, this detector enabled a large variety of charm particle lifetimes to be measured accurately, including the only determination to date of the lifetime of the neutral charmed xsi, which lives for only 0.8 x 1013 sec­ onds. Following that experiment, the group from the Rutherford Appleton Laboratory and Brunei University in the UK, joined by several Stanford- based physicists, extended this technology to a collider environment (the SLD detector at Stanford's SLC linear collider). Achieving good solid angle cover­ age round a 25mm-radius beam- pipe meant increasing the number of CCDs from two to 480. The detector, consisting of 120 million independent elements, started running in May 1992, giving tracking quality as precise as in the earlier fixed target experiment. The combination of the very small and stable SLC beam spot (just 2 microns across), the small beam pipe, the precise measurement of space points from the vertex detec­ tor, and a high quality central drift chamber, is now bringing SLD some Environmental work ('wetlands mitigation') for Fermi lab's planned Main Injector. clean physics for Z decays into heavy FERMILAB flavour quarks. One advantage of CCDs for track­ Main Injector ing detectors is that since they are widely used, new developments are The Fermilab Main Injector (FMI) continually being made. Since the fixed target experiments and in linear project is the centerpiece of the design phase of the SLD vertex colliders. Laboratory's Fermilab III programme detector, the technology has ad­ For the high luminosity conditions of for the 1990s. Designed to support a vanced to the point where one of the the next generation of hadron luminosity of at least 5x1031 cm2s1 in ladders' of eight CCDs could be colliders, a number of groups are the Tevatron collider, it will also constructed with a single device, developing 'smart pixel' devices with provide new capabilities for rare which furthermore could be read out a micrologic controlled silicon matrix neutral kaon decay and neutrino ten times faster. array (January 1990, page 19). oscillation studies. Such developments will allow even These have demonstrated detector The Fermilab Main Injector 8-150 more powerful vertex detectors to be feasibility over small surfaces (half a GeV synchrotron is designed to constructed in the future. The main square centimetre) en route to the replace the existing Main Ring which areas of possible application in high much larger areas needed for actual seriously limits beam intensities for energy physics will continue to be in experiments. the Tevatron and the antiproton

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34 Circle advertisement number on reader service form CERN Courier, June 1993 11 Characteristics (beta and dispersion functions) for a portion of the Fermilab Main Injector cell design. Shown here (left to right) are a normal cell, a dispersion suppressing cell, a disper­ sion-free straight cell, a dispersion suppress­ ing cell and a normal cell. The horizontal blocks represent bending magnets while the vertical blocks signify focussing or correction magnets.

current of 9375 A, and peak power of 75 kW. The poletip gap is 5 cm, and the good-field region exceeds ± 4.4 cm at injection. At the peak field (1.72 T) there is significant saturation producing a sextupole field which determines the required strength of the chromatigty-controlling sextupole magnets. Twelve production proto­ type dipoles are to be built in this year before magnet production gets underway. Four new beamlines will link the FMI to Fermilab's accelerator com­ plex: a 760-m 8 GeV line from the Booster injector, two 260-m beamlines to connect to the Tevatron (one for protons and one for antiprotons), and a beamline to transport 120 GeV protons to the production target. The lattice features two types of antiproton production target or to the The project has passed several cells: normal (34.6 m) cells in the experimental areas. This latter significant milestones and is now arcs and straight sections, and beamline will utilize a remnant of the proceeding rapidly towards construc­ dispersion-suppressor (25.9 m) cells Main Ring. tion. The project received a $11.65M adjacent to the straight sections to The two 150 GeV lines to transfer appropriation in 1992 and has been reduce the dispersion to zero in the beams to the Tevatron will be almost given $15M for the current fiscal straight. mirror images of one another, utiliz­ year. Through the Energy Systems Tighter focussing and smaller ing Main Ring magnets for all of the Acquisition Advisory Board (ESAAB) dispersion give smaller beams than dipoles and quadrupoles. Beam process, the US Department of in the Main Ring, and over three transfers to the Main Ring remnant Energy (DoE) has authorized funds times the acceptance. The standard will utilize the same beamline as for construction of the underground cell consists of a FODO lattice proton transfers to the Tevatron. The enclosure and service building where containing two 6-metre dipoles in Lambertson magnets at the Tevatron the Main Injector will touch the each half-cell. Straight section cells will be turned off, allowing the beam Tevatron, and to the preparation of are the same length as normal ones. to continue upwards. bids for remaining project construc­ The dispersion suppressor cells R&D work in support of the project tion. require special length quadrupoles is also well advanced. In addition to Last year, work began on filling and dipoles; again, the lattice is a the dipole effort, R&D for the twelve some six acres of wetlands. Permis­ simple FODO array with two 4-m 1000V/10,000A supplies required to sion had been granted by the US dipoles between quadrupoles. power the dipoles has also begun. Army Corps of Engineers contingent The dipole magnet has been Finally, significant progress has been upon the creation of nine acres of designed and two prototypes con­ made on the project's 200 kW new wetlands close by. Earth moving structed and measured. Both mag­ radiofrequency power amplifier. is complete. nets give field quality well described Eighteen such units will be required. The new accelerator will use 344 by computer models and within the Much work has been accomplished new conventional dipole magnets, performance specification. The in technical design, in project man­ together with quadrupoles, accelerat­ magnets have four 2.54 cm x agement and in permit applications. ing radiofrequency cavities and 10.16 cm turns per pole of conductor Fermilab was awarded a State of instrumentation from the Main Ring. (for rapid ramping), with a peak Illinois grant, with which the architect/

12 CERN Courier, June 1993 engineering firm Fluor-Daniel pro­ The FOBOS multiple event bers of JINR Scientific council in­ vided advance conceptual design spectrometer mounted in the heavy clude Ugo Amaldi and Lucien work for the civil construction and site ion beam of the U-400M cyclotron is Montanet from CERN, Claude Detraz mitigation. The state money was also designed to record the products of (IN2P3, Paris), Friedrich Dydak used for environmental impact nuclear reactions in the high mass (Munich), Guido Piragino (Italy), studies. All other construction permits and charge region with high effi­ George Trilling (Berkeley), Herwig have been secured construction of ciency. New experiments are envis­ Schopper (Germany) and Norbert the MI-60 underground enclosure aged. Kroo (Hungary). began in March. At the IBR research reactor a Earlier this year saw the 80th cryogenic moderator has been put birthday of Venedikt Dzhelepov, into operation. Physics goals include Honorary Director of JINR's Labora­ generation of an impulse flux of cold tory of Nuclear Problems. DUBNA neutrons. The neutron Fourier high resolution diffractometer was com­ Update missioned for polycrystal studies. Meanwhile an imaginative scheme At the annual session of the Plenipo­ to establish an International Univer­ tentiaries Committee of the Joint sity using JINR research facilities and Institute for Nuclear Research highly qualified personnel is being (JINR), Dubna, near Moscow in implemented. March, Institute Director Vladimir G. New appointments include Alexei Kadyshevsky reported on important Sissakian and Tzvetan Vylov as recent achievements. Vice-Directors, Nikolai Russakovitch The Nuklotron superconducting as Chief Scientific Secretary, accelerator has now been completed Vladislav Sarentzev as Chief Engi­ and is in operation. (A report will neer and Alexandre Lebedev as feature in a forthcoming edition of the Administrative Director. CERN Courier.) Western physicists elected mem­

At the annual session of the Plenipotentiaries Committee of the Joint Institute for Nuclear Research (JINR), Dubna, near Moscow in March.

CERN Courier, June 1993 13 Physics monitor Neutrino oscillations at work. Shown in black are the regions of the two parameters (difference of squares of neutrino masses, vertical axis, and lepton mixing angle, horizontal axis) required to fit solar neutrino observations. The top diagram is for vacuum oscillations, the lower for resonant neutrino mixing (the 'MSW Effect'). The figures are from P.I. KrastevandS.T. Petcov.

± 0.06 tsyst) of the Bahcall- Neutrinos, atoms and Pinsonneault Standard Solar Model (SSM) prediction. For the new gravity gallium-based experiments, GALLEX, from the first 15 runs, gives A interesting overview of ongoing 82 ±17 ± 8 solar neutrino units developments in neutrino physics (SNU), while SAGE sees 58 +17/-24 and recent advances in atomic and ± 14 SNU, to be compared with the optical physics and in gravitation SSM predictions of 125-132 SNU. emerged from the recent 'Moriond' Michel Spiro presented simulation Workshop on Perspectives in Neutri­ results (performed in collaboration nos, Atomic Physics and Gravitation with Jim Rich) which show that the Theory, held from January 30 to three radiochemical experiments' February 6 at Villars sur Ollon in the data (Davis et al., GALLEX, and Swiss Alps. SAGE) are statistically selfconsistent. Neutrino physics is a Moriond Moreover, given the few events tradition, and the Workshop began registered so far by the SAGE and with presentations of new measure­ GALLEX collaborations (25 and 75, ments of the tritium beta spectrum by respectively), the results of these two the Livermore and Mainz groups, gallium experiments, although setting limits on the mass of electron different, are still statistically compat­ (anti)neutrino of 8 eV and 7.2 eV ible. Thus, Spiro felt justified in respectively. combining the two gallium results to It is puzzling that the five most yield a weighted average of 72 ±17 advanced experiments setting upper ±14 SNU. limits on the electron (anti)neutrino Marc Pinsonneault showed that the mass (Livermore, Los Alamos, SSMs generally reproduce measured Mainz, Tokyo and Zurich) report solar parameters quite well, an negative best-fit values for the exception being the abundances of square of the neutrino mass, with a lithium, beryllium, and CNO isotopes weighted average of -59 ±177 ± 26 at the Sun's surface. Inclusion of eV2. This corresponds to an excess rotational mixing may resolve these of counts near the tritium endpoint, differences, and initial calculations in rather than a deficit which would this framework show lower rates in indicate a nonzero neutrino mass. the chlorine experiments by 7% at soiar neutrinos, ana soiar neuinno most and in the gallium experiments Gerry Stephenson presented a transitions induced by neutrino by less than 1%. possible explanation, invoking a very flavour changing neutral current light (or massless) scalar boson Pinsonneault also looked at possi­ interaction), as discussed by Serguey coupled only to neutrinos. Perhaps ble astrophysical solutions of the Petcov, the nonadiabatic MSW more plausibly, a systematic effect solar neutrino problem proposed so (Mikheyev-Smirnov-Wolfenstein) may be the cause, and further far and concluded that all of them transitions provide an especially studies are underway. Nonetheless, have problems (either not self- attractive particle physics solution. the limits are unlikely to change consistent or incompatible with the Given the gallium results midway significantly, and the results exclude observations). This reinforces the between the SSM predictions and a electron neutrinos as the possible case for an elementary particle clear signature for a particle physics dominant component of dark matter. solution. solution, only the next generation of The solar neutrino problem persists. While many possible mechanisms solar neutrino detectors (SNO, The event rate in the Kamiokande are not ruled out (as vacuum oscilla­ SuperKamiokande, Borexino, and experiment is now 0.49 ± 0.04 (stat) tions and spin-flavour precession of IP.API IQ\ \A/MI alln\A/ tho nrrvhlom tr» ho

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CERN Courier, June 1993 13a Circle advertisement number on reader service form 15 resolved definitively. MACHOs (MAssive Compact Halo quark) has emerged from the detec­ The relative deficit of muon to Objects) have seen nothing so far, tors ARGUS (at the DORIS ring, electron atmospheric neutrinos but only a small fraction of the data DESY, Hamburg) and CLEO (at the observed by the Kamiokande and has been analysed. A new genera­ Cornell CESR ring) as well as from 1MB collaborations is confirmed by tion of cryogenic detectors should CERN's LEP electron-positron recent data from Soudan II experi­ soon be able to probe the region collider and the proton-antiproton ment, albeit with large uncertainties. predicted for a supersymmetric dark colliders at CERN and Fermilab. While the Kamiokande results are matter candidate - the lightest But the mosj challenging goal of consistent with neutrino oscillations, neutralino. this physics is to explore the mystery 1MB collaboration does not make Gravitation sessions concentrated of CP violation, so far only seen in such a claim, due to much larger mainly on current tests of the equiva­ neutral kaon decays. This subtle systematic uncertainties (attributed lence principle, and the theoretical mechanism - a disregard for the mostly to simulations). significance of this effort. A special combined symmetry of particle- An experiment at a test beam at the section reviewed the development of antiparticle switching and left-right Japanese KEK Laboratory is being the STEP project for a satellite test of reflection - possibly moulded the set up in a joint IMB-Kamiokande the principle. Theoretical talks under­ evolution of the Universe after the effort using a 1-kiloton water lined the challenge of measuring the Big Bang, providing a world domi­ Cherenkov detector. This should extremely small effects of any such nated by matter, rather than one provide important information about violation. where matter and antimatter play electron-muon separation at low Covering such a wide range of comparable roles. energies, crucial for correct interpre­ different but interrelated areas of To fully explore CP violation in the tation of the Kamiokande and 1MB physics was a challenge. However in laboratory needs a dedicated ma­ data. the informal Moriond atmosphere chine - a particle 'factory' - to mass The Moscow-Heidelberg group participants could ask even 'elemen­ produce B mesons. Only when this searching for neutrinoless double tary' questions, increasing the scope, full picture of CP violation has been beta decay of germanium-76 using as well as the depth, of their physics revealed will physicists finally be able an enriched sample detector now knowledge. to solve its mysteries. has, as reported by Piepke, a lower The workshop was organized by As well as major proposals in the limit on the isotope lifetime of 1.6 x J. Tran Thanh Van and his col­ US and Japan, several ideas have 1024 yrs, implying an upper limit on a leagues with the financial support been launched in Europe. Over the Majorana mass of the electron from CNRS, CEA, NSF and the years, many working groups have neutrino of 1.2-1.4 eV (a Majorana Observatoire de Paris. accumulated an impressive amount particle is its own antiparticle - a of data and knowledge on the phys­ Dirac particle has a distinct antiparti­ Information from T.J. Bowles and ics as well as on the machine and cle). P.S. Joshi detectors. Although an excess of events below The spearheads of experimental B the endpoint is seen, the shape of physics are the ARGUS and CLEO the electron spectrum rules out Mass-producing B collaborations. Highlights include the Majoron emission for a Majoron- determination of the parameters of neutrino coupling greater than 1.8 x mesons the (Cabibbo-Kobayashi-Maskawa, 10~4. This makes it rather unlikely that CKM) quark mixing matrix, testing the excess of events in other experi­ Since the discovery of the upsilon the consistency of the Standard ments is due to Majorons. resonances in 1977 the physics of Model with six quarks and three Dark matter was covered by Larry the fifth quark - beauty - has played a leptons, and giving the first indirect Krauss and David Caldwell. The vital role in establishing and consoli­ hint that the as yet unseen sixth COBE and IRAS satellite data is best dating today's Standard Model of ('top') quark is very heavy, together fitted by a mix of hot and cold dark particle physics. with initial indications of how it should matter containing 30% of 7 eV (tau?) In recent years, a wealth of data on decay. neutrinos. Two groups searching for B particle (containing the beauty Valuable complementary informa-

16 CERN Courier, June 1993 A recent sighting at the Aleph experiment at CERN's LEP electron-positron collider was this beautiful fully reconstructed formation of a Bs meson and its subsequent decay into a psi prime (subsequently giving a muon pair) and a phi meson (giving a kaon pair). The Bs mass is 5.3746 GeV, in accord with theoretical predictions.

tion has come from proton-antiproton violation in kaon decays to constrain on charmed particles, and in the collider data and particularly from the the Standard Model. However, there limiting case of an infinitely heavy LEP experiments at the Z resonance. are still large uncertainties, especially quark system, both of which have Experiments at LEP have measured the top quark mass, which to the best been studied by lattice techniques. average and individual lifetimes of of our knowledge is somewhere These methods are well on their way the various B hadron species as well between 91 and 180 GeV. to providing fully quantitative predic­ as the weak neutral current proper­ Top quark particles will hopefully tions for many aspects of B decays. ties of the b quark, while both elec­ soon be found at Fermilab's Tevatron Awaiting experimental determina­ tron-positron and proton-antiproton collider. However determination of tion of several important quark studies have been able to establish a the various quark couplings and form couplings, recent measurements of significant signal for neutral B mixing. factors needs a reliable theoretical the Ds meson (strange antiquark and

The Bs-meson (containing a strange framework. Here lattice gauge theory charmed quark) by the WA75 col­ antiquark and a b quark) and calculations are promising. Although laboration at CERN provide a useful lambda-b baryon have been seen by the present lattice-volumes are not check on a number of theoretical experiments at CERN. sufficient to simulate B physics models and strengthen confidence in B physics information can be directly, reliable methods have been lattice results. combined with results from CP developed in extrapolating the results To match the precision and reach of

CERN Courier, June 1993 17 experiments at a B factory needs mesorrs to transform into each other further development of theoretical provide another possibility, while the Physics and tools. A particular goal is to perfect interference of this effect with direct the lattice techniques needed to B decay gives a third. In the Stand­ astrophysics of quark- compute B decays with a precision of ard Model, this latter class might gluon plasma 10% or better. exhibit large CP violating effects, In the same vein, the discovery of much larger than those seen in kaon heavy quark symmetry by Isgur and decays. The quark gluon plasma - matter Wise in 1989 and its subsequent While the bulk of analysis so far too hot or dense for quarks to crystal­ consolidation has opened up reliable uses a Standard Model context, B lize into particles - played a vital role predictions for B decays. This ap­ decays also provide a scenario for in the formation of the Universe. proach exploits the big difference physics beyond the Standard Model. Efforts to recreate and understand between quark masses, revealing With high production rates for tau this type of matter are forefront powerful symmetries in heavy quark leptons, a B factory will allow physics and astrophysics, and systems which facilitate computa­ searches for many decays at levels progress was highlighted in the tions. The approach has already paid at least two orders of magnitude Second International Conference on handsome dividends, but data from B more sensitive than present limits. Physics and Astrophysics of Quark factory experiments would increase The wide diversity of B decay Gluon Plasma (ICPA-QGP 93), held its usefulness. channels needs to be exploited to in Calcutta from 19-23 January. (The Flavour changing neutral current improve our understanding of weak first conference in the series was transitions in B decays creep in as decays. Present measurements and held in Bombay in February 1988). higher order (rare) processes and are theoretical analyses support the Although primarily motivated to­ dominated by virtual top quark Standard Model, but consistency is wards enlightening the Indian physics contributions. Measurements would not yet complete. Experiments at a B community in this new and rapidly provide valuable constraints on the meson factory will pin this down. evolving area, in which India now top quark mass and its inter-quark In particular, the possibility of plays an important role, the confer­ couplings. The recent observation by observing CP violation in B decays is ence also catered for an international the CLEO collaboration at Cornell's an outstanding opportunity to finally audience. Particular emphasis was CESR electron-positron collider of get to grips with a fundamental placed on the role of quark gluon the decay of a B meson into a K* and physical phenomenon vital to our plasma in astrophysics and cosmol­ a photon provides a good check of understanding of the evolution of ogy. the strength of so-called 'penguin' universe. While Charles Alcock of Lawrence processes (see page 1 ) and opens a Last but not least, there is the Livermore looked at a less conven­ new chapter in the study of weak general dissatisfaction with the tional picture giving inhomogeneous decays. However exploiting the full Standard Model, where masses and ('clumpy') nucleosynthesis, David potential of the B sector with its many mixing patterns have to be put in by Schramm (Chicago) covered stand­ rare decay possibilities requires a B hand. Understanding this is one of ard big bang nucleosynthesis. The factory. Precision measurements on the major challenges facing physi­ abundances of very light elements do all these B decays would provide full cists today, and a B factory could not differ appreciably for these and stringent tests of the quark provide the long-sought clue to what contrasting scenarios; the crucial mixing matrix and probe any loop­ makes the Standard Model tick. difference between them shows up holes indicative of new physics. for heavier elements like lithium-7 CP violation in B decays is ex­ From RoyAleksan (Saclay) and and -8 and boron-11. pected to happen through three Ahmed Ali (DESY) Richard Boyd (Ohio State) high­ mechanisms. The interference of two lighted the importance of accurate Feynman diagrams with different measurements of the primordial weak and strong phases gives so- abundances of these elements for called direct CP violation. The un­ clues to the cosmic quark hadron equal probabilities for neutral B- phase transition. B. Banerjee (Bom-

18 CERN Courier, June 1993 WHEN I WANT TO TALK VACUUM

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while Thomas Peitzmann (also WA80) presented results on pion- pion interferometry, claiming a two component structure of the pion source, with one component substan­ tially bigger than the original target. Preliminary proton-proton correlation measurements, he reported, show no such effect. Chris Voltolini (Strasbourg) gave the strangeness measurements of the NA36 collaboration. J. Dodd (Columbia) showed preliminary NA44 data on on two-particle correlations in proton and sulphur beam experi­ ments. Johanna Stachel (Stony Brook) reviewed the results from the bay) argued, on the basis of lattice NA38 at CERN. Hans-Ake Brookhaven AGS experiments. calculations, for only slight supercool­ Gustafsson (Lund) discussed WA80 Soren Sorensen (Knoxville and Oak ing in the cosmic quark phase transi­ (CERN) data on charged particle Ridge) discussed measurements of tion - an assertion which runs counter distributions for sulphur-32 beams. to the inhomogeneous Karl-Heinz Kampert (Munster) nucleosynthesis scenario. focussed on WA80 data on thermal CERN Director General designate Chris Jes Madsen of Aarhus reviewed the photon and neutral meson production Llewellyn Smith at the Calcutta quark-gluon role of (meta)stable strange quark for oxygen and sulphur projectiles plasma meeting. matter in astrophysics and cosmol­ ogy, discussing the prospects for distinguishing between neutron stars and quark stars (where the neutron matter is compressed into a cold version of quark-gluon plasma). P. Bhattacharya (now at Bangalore) reported the results of recent calcula­ tions by the Calcutta group with a colour flux tube model giving evapo­ ration from quark nuggets formed in the cosmic phase transition. With conservative estimates of baryon number above which such nuggets would be stable, they are a viable candidate for dark matter. However self-consistency conditions require these nuggets to be of supernuclear density, in contrast to those of normal density postulated by Ed Witten some time ago. On the experimental side, Albert Romana (Palaiseau) reported the recent analysis of dimuon data by

20 CERN Courier, June 1993 transverse and forward energies. LHC energies, the lifetime of the on the future directions of CERN The consensus was that although reaction seems unaffected by activities, where he welcomed SPS (CERN) and AGS experiments whether the hadronic phase is greater involvement of Indian scien­ clearly indicate the formation of hot treated as only massless pions, or tists. dense nuclear matter, on the other pions and massive resonances. It In all it was a stimulating week for hand one does not necessarily need thus seems that photons continue to the 220-odd participants. Civil unrest to invoke QGP formation to explain be viable QGP signals, assuming in India at the time made the organiz­ any of the observations, including the preequilibrium photon production is ers' work difficult, but those who did key suppression of J/psi or strange­ neglected. It was however pointed attend could vouch for excellent ness enhancement. out that preequilibrium photon pro­ organization by Santanu Pal and his What then happened to the confi­ duction could indeed play havoc with team. Several participants felt it dent predictions of some years ago the electroweak signals, an observa­ should not be as long as five years that at energy densities of a few tion made by the same group over before the next conference in the GeV/fm3, QGP must be formed? This two years ago. Detailed analysis of series. is closely linked to the estimation of photon and dilepton signals, taking stopping in nuclear collisions, as into account all these effects at all pointed out by Franz Plasil (Oak energies, are eagerly awaited. Ridge) in his experimental overview. Rajiv Gavai (Bombay) and Sean We do not as yet have an universally Gavin (Brookhaven) discussed J/psi accepted criterion for estimating production and related matters. J.Y. stopping, and the evaluation of initial Ollitrault (Saclay) proposed energy density depends, noted Plasil, anisotropy in transverse momentum quite sensitively on this estimate. distributions as a signature of trans­ Many experimental talks looked verse collective flow. Klaus Werner forward to new experimental possi­ (Heidelberg) reviewed the status of bilities and new machines - new various event generators in the beams at CERN's SPS, new energy market for the simulation of domains from RHIC at Brookhaven ultrarelativistic nucleus-nucleus and LHC at CERN. collisions. There were no talks on In the theory talks, Sibaji Raha lattice calculations due to a couple of (Calcutta) reviewed the status of last minute cancellations. Arthur electroweak probes for possible QGP Poskanzer (Berkeley) and Bikash signals. Summarizing the work of the Sinha (Calcutta) respectively summa­ Calcutta group, he showed that rized experiment and theory. photons can indeed be a viable QGP The conference was inaugurated by signal, contrary to the apprehension P.K. Iyengar, then Chairman of the resulting from recent work which Atomic Energy Commission of India, suggested that massive resonances who pointed out that with ICPA-QGP make a hadron gas 'shine' as brightly 1988 having initiated the younger as QGP. generation of Indian physicists, there The other important Calcutta result, was now a responsibility to nurture reported by Raha and J. Alam, is the them. He noted with satisfaction that transverse expansion in nuclear Indian participation in experimental collisions at SPS, RHIC and LHC QGP studies had matured remark­ energies. They showed that with ably in the intervening five years and transverse expansion, the impor­ urged scientists to broaden their tance of including higher mass horizons through these and other resonances in the hadronic phase collaborative efforts. This was under­ 'pales' with increasing energy, and at lined by CH. Llewellyn Smith's talk

CERN Courier, June 1993 21 The genesis of unified gauge theories by Tom Kibble

Abdus Salam in Munich, 1947.

The theoretical physics group at London's Imperial College in 1959 From 8-12 March, at a had three permanent faculty: Abdus 'Salamfest' at the International Salam, his erstwhile thesis supervi­ Centre for Theoretical Physics in sor Paul Matthews, and John Trieste, Italy, friends, colleagues, C.Taylor. I joined as a lecturer the admirers and former students paid following year. tribute to the Institute's founder In those early days we had lots of and director Abdus Salam, and his visitors, both long- and short-term - contributions to science. Presenta­ Murray Gell-Mann, Ken Johnson, tions centred around the develop­ John Ward, Lowell Brown, Gordon ment of today's Standard Model of Feldman and Steven Weinberg. particle physics and attempts to go About a year after I arrived we were beyond it, and the parallels be­ transferred from the Mathematics to tween the physics of condensed the Physics Department under the matter and elementary particles. formidable Patrick (P.M.S.) Blackett. During the week, Salam was Having been brought up in the awarded the honorary degree of Cavendish Laboratory tradition under Doctor of Science by the Rector of Lord Rutherford, Blackett was rather St. Petersburg University, Acad­ scornful of theoretical physicists, but emician S. Merkuriev. he knew a good thing when he saw states of a single fundamental entity, While in recent years Salam has one and had persuaded Salam to join the nucléon. The symmetry was mainly been identified with the the rapidly expanding Physics De­ generalized to include Yukawa's Centre which he established in partment. mesons in an important paper by 1964, many of his important In 1960 field theory was widely Nick Kemmer in 1938, which is contributions to physics came regarded as very passé. It had had incidentally perhaps one of the first when he resided permanently at its triumphs: renormalization theory papers to suggest the need for a London's Imperial College. At the had made sense of divergences, and neutral current. Trieste Salamfest, Tom Kibble, quantum electrodynamics had been Kemmer was very influential in formerly Head of Physics at magnificently vindicated. British theoretical physics in the Imperial and a longtime colleague But field theory didn't seem to work immediate post-war period. He was of Salam, described Salam's role for anything else, particularly not for Paul Matthews' supervisor in Cam­ at Imperial in the quest for a the strong interactions, and was bridge and when I was a student in unification of electromagnetism definitely out of fashion. There were, Edinburgh he was my Head of and the weak force. In 1979 however, a few places in the world Department, having succeeded Max Salam, Sheldon Glashow and where field theory was still studied Born in 1953. Steven Weinberg shared the unashamedly. Imperial College was In the forties and fifties, as new Nobel Physics Prize for the new one. Harvard was certainly another; particles proliferated, it was natural to synthesis, one of the major many of our visitors over the next few try to bring some order into this achievements of 20th-century years were Julian Schwinger's chaos by enlarging the symmetry physics. students. group beyond the SU(2) of isospin, (This is an abridged version of At Imperial there were two dominant especially after the discovery of the the talk, the complete version theory themes: symmetries and new quantum number, strangeness. being available on request from gauge theories. Both had their Salam had students working on Tom Kibble at the Blackett Labora­ origins in the concept of isospin. every conceivable symmetry group. tory, Imperial College, London, The isospin symmetry between One of those students was Yuval SW7). protons and neutrons had shown Ne'eman, who had the good fortune how two apparently disparate parti­ and/or prescience to work on SU(3). cles might be regarded as different From that work, and of course from

22 CERN Courier, June 1993 The International Centre for Theoretical Physics, Trieste, Italy was founded byAbdus Salam in 1964. the independent work of Murray Gell- Mann, stemmed the Eightfold Way, with its triumphant vindication in the discovery of the omega-minus in 1964. Salam himself made many impor­ tant contributions to these symmetries, but I believe this was not his first love. His real goal was to find the ultimate theory to describe the weak, electromagnetic and strong interactions, and even gravity - what we would now call a Theory of Everything. From an early stage, certainly well before I joined Imperial, Salam was convinced that the ultimate theory would be a gauge theory. The starting point was the epoch- making paper of Yang and Mills in 1954. There may be others who deserve some of the credit - Weyl, hard to make progress because and Feynman and Gell-Mann Klein, Shaw, Utiyama - but Yang and calculations were difficult. With such showed how the weak interaction Mills articulated very clearly the a strong coupling, perturbation theory should be written down. This sug­ 'gauge principle' - sometimes para­ would not work, and the asymptotic gested that weak interactions could phrased as 'Nature abhors a rigid freedom of quarks was unknown. be mediated by a charged vector symmetry'. So the weak interactions emerged boson, the W. Yang and Mills argued that a rigid, as a better bet. There were certainly The seemingly insuperable difficulty global isospin symmetry is incompat­ tantalizing hints of a structure very was the large W mass. If the interac­ ible with relativistic field theory. Their similar to electrodynamics. While tion were of the same strength as point was that once isospin symmetry Fermi's classic recipe with four electromagnetism, the W mass would has been accepted, it is arbitrary particles interacting at a point was have to be about 40 GeV. But which component is identified with obviously non-renormalizable, it was putting a mass term in the the proton and which with the neu­ probably a shorthand way of writing Lagrangian would destroy the gauge tron. But it then seems odd that an effective interaction due to the invariance, and the heavy vector making this choice should automati­ exchange of a heavy boson. particle would make the formalism cally fix the convention throughout all Progress was held up while people blow up and become unrenorm- space for ever. So they looked at searched for the correct space-time alizable. what needed to be done to make symmetry of the weak interaction. As early as 1958, Salam and John isospin a local symmetry. The breakthrough came with another Ward proposed a unified gauge The gauge principle provided a suggestion of Yang's, working this theory of weak and electromagnetic natural basis for electromagnetic time with T.D. Lee, that mirror sym­ interactions, involving a charge triplet interactions, and after the work of metry (parity) is not conserved in of vector mesons, with the neutral Yang and Mills people began to look weak interactions. After the fall of component identified with the photon. for gauge theories of the strong and parity in 1957, Salam was one of the They placed the electron, neutrino weak interactions. first to point out the connection and positron too in a triplet. This was The first goal was strong interac­ between left-handedness and a zero ingenious, but of course they could tions; that is what Yang and Mills mass neutrino. only obtain the parity-conserving part themselves were after. But it was Meanwhile Marshak and Sudarshan of the weak interaction. Parity

CERN Courier, June 1993 23 Abdus Salam at Stockholm in 1979 - the first Pakistani to receive the Nobel Award. violation was artificially imposed, and Guralnik and Dick Hagen, both at the W mass put in by hand. Imperial that year, and I had also Two years later they proposed a realized the Goldstone theorem unified theory of weak, electromag­ doesn't apply to gauge symmetries, netic and strong interactions, based others were there too. The result on the gauge group SO(8), a paper was published independently in 1964 well ahead of its time, foreshadowing by Englert and Brout and by Peter later ideas of grand unification. Higgs. But these theories did not really So by 1963*64 the problem of the work; nor did similar ones proposed origin of mass was solved, at least in by Glashow and others. The major principle. But there was still another obstacle remained the vector meson major hurdle, to unify weak interac­ mass. This was essential to make tions, which are parity-violating, with the interaction weak and short-range, electromagnetism, which is not. It but apparently incompatible with both took another three years to realize gauge invariance and that for the photon to coexist with the renormalizability. The only way parity violation of weak interactions, anyone knew to make a vector- the gauge group had to be extended meson theory renormalizable was to from SU(2) to SU(2)xU(1), with two use zero-mass gauge bosons. neutral particles rather than one. As often happens, progress was Actually the solution, or something delayed by a 'folk theorem'. Theo­ very like it, was already there in retical physicists sometimes quote Sheldon Glashow's 1961 paper 'theorems' that everyone believes but forces. But the theorem seemed to which had proposed SU(2)xli(1) with eventually turn out not to be true. rule out this mechanism for relativis­ mixing between the neutral particles, One such folk theorem was that the ts theories. but this was before the key concepts photon is massless because of An important 1963 paper by Phil of spontaneous symmetry breaking gauge invariance, considered one of Anderson showed how Schwinger's and the Higgs mechanism had been the predictive successes of the suggestion of a heavy gauge field developed. gauge principle. In 1961 Julian could work. One example was the At Imperial, Salam kept plugging Schwinger said this theorem might plasmon: in a high-density plasma away at the problem, especially in be false, although he was thinking the photon acquires a non-zero collaboration with John Ward. In more about strong interactions at the 'mass' - the plasma frequency. But autumn 1967, Salam gave a series of time. Anderson also pointed out, using the lectures at Imperial in which he Another folk theorem came in when example of superconductivity, how described the SU(2)xU(1) theory. people began edging towards spon­ Goldstone bosons could 'become Meanwhile the same model had been taneous symmetry breaking to tangled up with Yang-Mills gauge found independently by Steven explain the heavy gauge mesons. bosons and, thus, do not in any true Weinberg. Here the Goldstone theorem appar­ sense have zero mass'. He con­ When Weinberg's paper appeared I ently predicted unobserved massless cluded 'the Goldstone zero-mass was at Rochester, where Bob spin-zero particles. difficulty is not a serious one, be­ Marshak asked me to give a talk to When Steven Weinberg came to cause we can probably cancel it off his weekly discussion group. Imperial College in 1961-62, he and against an equal Yang-Mills zero- I mentioned that Salam and Ward Salam, collaborating at long range mass problem'. This is exactly what had been working on very similar with Jeffrey Goldstone, spent a lot of is now known as the Higgs mecha­ ideas, and focused on the problems time confirming this theorem. In nism. in constructing a unified theory of condensed-matter physics, This should have cleared everything weak and electromagnetic interac­ counterexamples to the Goldstone up, but these new ideas were difficult tions and how ingeniously the new theorem were known for long-range to understand. By the time Gerry model avoided them. However I

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CERN Courier, June 1993 25 described it as a wonderful toy - First crumb of research without any connection to the real world! While I was myopic, in a sense I In 1964, Abdus Salam introduced only to a privileged few. was right. The whole thing seemed Paul Matthews' inaugural lecture at Later, his PhD complete, Matthews much too ad hoc and ugly, with its London's Imperial College. It was a left a research 'crumb', as Salam put curious built-in asymmetry between poignant moment. Salam, who had it. The agreement was that Salam the left- and right-handed fermions taken his first steps in theoretical would look at a continuing problem in and its large number of independent physics at Cambridge under meson field fenormalization while parameters. If it is part of the final Matthews' watchful eye, had become Matthews took a few months off theory, it is ugly; surely the Creator Imperial's first professor in Theoreti­ before starting work at Princeton in was having an off day! But that is not cal Physics. Now he was overseeing the fall. If Salam had made no the right way to look at it. Seen the promotion of his former supervi­ progress, Matthews would repossess merely as one step towards a still sor. the problem. undiscovered final theory, the intri­ Salam recalled his 1949 research Characteristically, Salam's first act cate way the electroweak picture fits debut at Cambridge, where, because as a research student was to phone together does have a remarkable of impressive examination results, he Freeman Dyson (his 'hero'), then beauty. had initially been directed towards visiting Birmingham, and ask for an It is sad that Paul Matthews, who the laboratory. interview. The discussion continued died tragically six years ago, could 'Soon, I knew the craft of experi­ on the train to Southampton, where not have given this tribute. For many mental physics was beyond me, ' Dyson was to embark for the US. years, Imperial was Salam and wrote Salam later. It was the sublime The seeds of the solution were sown Matthews. They made a superb quality of patience which I lacked.' and soon the 'crumb' problem was team, exactly complementing each Looking towards theory, he had gone solved. It was the start of a meteoric other's strengths and abilities. to Nicholas Kemmer (in the front row career. at Matthews' inaugural). Kemmer had said he had enough students already Paul Matthews (1919-1987). Abdus Salam's and did not want another. Salam had first mentor. pleaded, and fortunately Kemmer had relented. 'All theoretical problems in quantum electrodynamics have been solved by Schwinger, Feynman and Dyson, ' Kemmer had told Salam. 'Paul Matthews has applied their methods to meson theories. He is finishing his PhD. Ask him.' At Imperial in 1964, Salam recalled that first meeting with Matthews in 1950. What are you reading?' Matthews had asked. 'Heitler's Quantum Theory of Radiation, ' had come the reply. It was the only standard text at the time. Matthews quickly recommended instead the new work by Schwinger, Feynman and Dyson, then known

26 CERN Courier, June 1993 People and things

This model twin-aperture superconducting magnet from the research and development programme for CERN's LHC proton-proton collider recently achieved a magnetic field of 10.25 tesla at 2K.

LHC magnets

External In the research and development correspondents programme for CERN's LHC high energy proton-proton collider to be built in the 27-kilometre LEP tunnel, a Argonne National Laboratory, (USA) D. Ayres model twin-aperture superconducting Brookhaven, National Laboratory, (USA) magnet recently achieved a magnetic P. Yamin field of 10.25 tesla after being cooled CEBAF Laboratory, (USA) to2K. S. Corneliussen The magnet used new wide-cable Cornell University, (USA) niobium-titanium conductor, with up D. G. Cassel to 27,000 5-micron filaments. DESY Laboratory, (Germany) Meanwhile on 23 April an agree­ P. Waloschek ment was signed between CERN, Fermi National Accelerator Laboratory, (USA) Helsinki University of Technology J. Cooper, J. Holt and Uppsala University for the GSI Darmstadt, (Germany) development of prototype LHC G. Siegert superconducting magnets. CERN INFN, (Italy) LHC superconducting magnetdevel- A. Pascolini opment work already involves col­ IHEP, Beijing, (China) laborations with partners in Austria, Qi Nading France, Germany, Holland, Italy, JINR Dubna, (USSR) Spain and the UK. B. Starchenko KEK National Laboratory, (Japan) S. Iwata Physics cinema Lawrence Berkeley Laboratory, (USA) B. Feinberg Physics cineast Lynn Silverman's 53- Los Alamos National Laboratory, (USA) minute film Anatomy of an Experi­ C. Hoffmann ment' about the Aleph collaboration Novosibirsk, Institute, (USSR) at CERN's LEP electron-positron V. Balakin collider had peak time showing on Gerhard 'Gerry' Fischer 1929-93 Orsay Laboratory, (France) the Franco-German Arte' channel in Anne-Marie Lutz May. Gerhard 'Gerry' Fischer of the PSI Laboratory, (Switzerland) Stanford Linear Accelerator Center R. Frosch (SLAC) died on 7 February. After Rutherford Appleton Laboratory, (UK) Oxford accelerators Jacky Hutchinson research at Columbia and Harvard, he became convinced of the impor­ Saclay Laboratory, (France) Elisabeth Locci Oxford Instruments are combining tance of electron-positron colliders. skills from their Synchrotron and IHEP, Serpukhov, (USSR) He moved to SLAC for the design Yu. Ryabov Cyclotron groups into an Accelerator and construction of the SPEAR ring. Stanford Linear Accelerator Center, (USA) Technology Group under Martin As well as being responsible for M. Riordan Wilson. Principal activities are manu­ SPEAR's injection system, he also Superconducting Super Collider, (USA) facture of compact superconducting designed the solenoid magnet for the N. V. Baggett synchrotrons and cyclotrons, to­ famous Mark I experiment. Subse­ TRIUMF Laboratory, (Canada) gether with development and design quently he went on to assume a M. K. Craddock work for new accelerator applications major role in the development of and research equipment. Stanford's SLC Linear Collider.

CERN Courier, June 1993 27 HEAD OF FACILITES DEPARTMENT University of Lancaster NATIONAL SUPERCONDUCTING CYCLOTRON LABORATORY School of Physics and Materials MICHIGAN STATE UNIVERSITY

The National Superconducting Cyclotron Laboratory at Michigan TWO RESEARCH ASSOCIATE POSITIONS State University is seeking to fill the position of Head of the Facilities Department. The NSCL has a staff of approximately 130 people and it is funded by the National Science Foundation Applications are invited for two postdoctoral Research Associate for research in basic nuclear physics, accelerator physics, and Positions in the Particle Physics Group. The successful candidates related instrumentation R&D. The Head of the Facilities Depart­ will work in one of the following activities of the group. ment will be responsible for directing approximately 10 technical 1. Studies of electroweak interactions in ALEPH at LEP at CERN. professional staff in the disciplines of ion source operation and related R&D superconducting magnet design and fabrication, and 2. Deep Inelastic Scattering in the H1 group at HERA at DESY. cryogenic and mechanical engineering. The department is responsible for the continued reliable operation of the experimen­ 3. Detector development for the inner tracking detector for the tal facilities including the ion cources ? K1200 superconducting ATLAS collaboration at the LHC at CERN. cyclotron, and associated beam transport systems. The department is also expected to initiate and/or participate in R&D projects Both posts are supported by the SERC in the UK. Applications consisting of a CV together with the names of two referees aimed at improving present operations. should be sent to: The candidate must have a demonstrated ability to manage in a Professor T Sloan technical research environment. Previous experience in accelera­ School of Physics and Materials tor laboratories is highly desirable. A bachelor's degree or University of Lancaster equivalent in mechanical engineering'electrical engineering, or Lancaster LA1 4YB UK physics with at least five years professional experience is required. (e-mail: [email protected]). Positions in the NSCL Continuing Appointment system parallel from whom further details can be obtained. The closing tenure system ranks at MSU. Applicants should send resume to date for applications is 30 June 1993. Ms. Chris Townsend, Laboratory Administrator, Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824- 1321 by July 12, 1993, Michigan State University is an affirma­ tive action/equal opportunity institution. Women and minorities are especiallyt encouraged to apply.

University of South Carolina ORGANISATION EUROPEENNE Faculty Position in POUR LA RECHERCHE NUCLÉAIRE High Energy Physics EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH

The Department of Physics at the University of South Carolina invites applications for a tenure-track posi­ tion in the area of experimental high energy physics MOVING? to begin on January 1, 1994. The position is at the assistant professor level although appointment at a higher level may be considered for an exceptionally qualified candidate. The South Carolina high energy Please remember to let us know group currently pursues e+e~ collider physics at in good time. All notices of KEK's TRISTAN ring using the AMY detector and two change of address must be experiments at Fermilab, E789 on two-body B° de­ accompanied by old and new cays and E687 on charm photoproduction. The ongo­ addresses. (Include label from ing programs would welcome new members, but magazine wrapper.) candidates with other research interests will also be considered. Applicants should submit a curriculum vitae and publications list, a statement of research Any enquiries regarding subscriptions interests, and the names of professional references should be addressed to: to Prof. Frank T. Avignone, III, Chairman, Depart­ ment of Physics and Astronomy, University of Jacques DALLEMAGNE South Carolina, Columbia, SC 29208. The Univer­ CERN COURIER/CERN sity of South Carolina is an Affirmative Action / Equal Opportunity employer and solicits applications espe­ 1211 Geneva 23 Switzerland cially from qualified women and minorities.

28 CERN Courier, June 1993 1992 Physics Nobel Georges Charpak (right) tours the successful 'La France au CERN' trade expo held at CERN from 30 March to 2 April.

of physics processes into a wealth of A Guide to Radiation and handy formulae and tables as well as Radioactivity Levels Near High almost 100 graphs. Energy Particle Accelerators, by This data enables those with Anthony H. Sullivan, Nuclear minimal knowledge in this field to find Technology Publishing, Ashford their own answers to many of the TN231JW UK (ISBN 1-870965-18-3) radiation protection questions which arise in accelerator design, such as The design of shielding and the the dose rate as a function of shield­ prediction of the induced radioactivity ing thickness, the shape and dimen­ for high energy accelerators have sions of access chicanes, skyshine usually been considered by most from weak spots in roof shielding, the accelerator builders as a somewhat level and decay rate of induced mysterious subject for which they radioactivity during a machine shut­ were largely dependent on the down, etc. wisdom of a few specialists. Alexander S. Davydov (1912-1993) There was clearly a strong need for This has changed dramatically for such a handbook, and I am con­ A.S.Davydov died in February of a people with a do-it-yourself mentality vinced Sullivan's book will save a lot disease induced by a heart attack. In after the publication of this delightful of time for people involved in radia­ the early 1940s simultaneously and book by Tony Sullivan of CERN, tion protection around accelerators. independently of Rarita and which will stand as his 'scientific Schwinger he proposed a relativistic testament', condensing the knowl­ Bastiaan de Raad equation for spin 3/2 particles. Later edge from a lifetime's work as a he shifted towards solid state theory, radiation protection physicist. European Physical Society nuclear physics, nonlinear phenom­ For each subject Sullivan gives a ena and biophysics. Such notions as short description of the physics After two years in office, Maurice "Davydov splitting", "Davydov- involved, after which he uses his Jacob of CERN steps down as Filippov model of nonaxial nuclei", extensive experience around CERN President of the European Physical "Davydov solitons" became wide­ accelerators to condense a diversity Society. His successor is Budapest spread. A popular author of brilliant books and manuals, his "Quantum Mechanics" is used worldwide as a basic text. He worked in Moscow, Kiev, Obninsk and Ufa. From 1973- 88 he headed the Institute for Theo­ retical Physics of the Ukrainian Academy of Science in Kiev, and remained as Honorary Director of the Institute.

From L.Jenkovszky and V.Loktev (Institute for Theoretical Physics, Kiev)

On 29 March CERN Research Director Walter Hoogland formally opened CERN's travelling exhibition in Prague, organized in collaboration with the Czech Academy of Sciences, with Czech Deputy Ministers P. Bratinka (left, Foreign Affairs) and V. Ludvik (right, Industry and Trade).

CERN Courier, June 1993 29 Physics Faculty Position READER SERVICE FORM Theoretical Accelerator Physics University of Houston CERN COURIER

The Department of Physics invites applications for a tenured, JUNE 1993 or tenure-track position which it expects to be open for Fall 1993, at a rank appropriate to the qualifications of the candi­ date. Applicants for the position are expected te have exten­ Please send information on items circled: sive experience in theoretical research on high energy accel­ 7c 7d 13a 13b 15 19b 19c 26 30 33a erators and storage rings. Involvement in operation of accel­ erators, and beam studies, are considered important. The 34 38 41 58 60 61 73 74 candidate is expected to have demonstrated outstanding excellente in research, and to have interest and-ability in teaching. Topics of research interest at UH include: beam dynamics in linacs, space charge effects in low energy proton Please send to: synchrotrons, optimization of synchrotron tunes in the pres­ ence of nonlinear multipole fields, self-consistent treatment of Judy Pray, CERN COURIER beam-beam interaction in hadron colliders, emittance dilution Gordon & Breach Science Publishers 820 Town Center Drive due to periodic crossings of nonlinear resonances, and the Langhorne, PA 19 047 optimum arrangement of magnets in superconducting rings. USA The group maintains active collaborations with Argonne, Brookhaven, Fermilab and SSCL. Students participate in theoretical investigations as well as various beam studies Name Title during residence at laboratories. Applicants should send a full resume and the names of at least references as early as Employer Dept. possible, to Prof. Roy Weinstein, Chairman of Search Address Comm., IBPD, Room 632 SR1, University of Houston, Hou­ ston, Texas 77204-5506. The University of Houston is an City State Zip equal opportunity/Affirmative Action Employer. Telephone ( ) Country

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33a Circle advertisement number on reader service form 30 CERN Courier, June 1993 European Physical Society and physics education. At the recent EPS Council meeting in Nice, Uppsala particle physicist G. Tibell (left), responsible with G. Marx of Budapest for the new EPS Forum on Education, talks with CM. Ferreira of Lisbon, who oversees education matters on the EPS Executive Committee.

559), INFN-Laboratori Nazionali di Frascati, cp 13, 00044 Frascati, Italy, decnet vaxlnf::nan93 bitnet nan93@irmlnf

Internal targets at HERA

At DESY an international workshop on 'Physics at HERA with internal condensed matter physicist Norbert Neutrino 94 - the XVI International targets' from September 21-23 will Kroo. Former CERN Director Gênerai Conference on Neutrino Physics and discuss the physics accessible with Herwig Schopper was reelected to Astrophysics - will be held from 29 both the 30 GeV electron and the the Executive Committee. May - 3 June 1994 in Eilat, Israel. 820 GeV proton beam of HERA. The Society's recent Council Contact Arnon Dar, Dept. of Physics, Special emphasis will be given to: the meeting in Nice also underlined the Technion, Haifa 32000 Israel. Fax physics accessible through scattering importance of EPS involvement in +972.4.221514, e-mail experiments with polarized/ physics education. phr 19ad@ technion unpolarized electrons and polarized/ unpolarized targets; Beauty Physics The second biennial workshop on and CP violation using the HERA nucleon-antinucleon physics will be proton beams; and the implications Meetings held at the Institute of Theoretical for proposed and planned experi­ and Experimental Physics (ITEP), ments and the accelerators. Partici­ This year's DESY Theory Workshop Moscow, from 13-18 September. pation is open to anybody interested. on "Quantum Chromodynamics" will Further information from Naja For further details from e-Mail be held in Hamburg (Germany) from Smorodinskaya, ITEP, B. [email protected] or fax: Sept.29 - Oct. 1, 1993. Further Cheremushkinskaya ul. 25, 117259 ++49 40 8994 4304. information from O.Nachtmann Moscow, Russia, fax +7(095) 123 (Chairman), Inst. Theor. Physik, 6584, e-mail Polarized beams at Stanford Universitaet Heidelberg, D-6900 nan93 @ vxitep. itep. msk. su. Or Silvia Heidelberg (Germany); e-Mail: C12 Giromini (fax +39 6 9403 243) or A marked increase in beam polariza­ at vm.urz.uni-heidelberg.de Donatella Pierluigi (fax +39 6 9403 tion and a recent doubling of the luminosity at Stanford's SLC linear collider have considerably increased physics potential. Story in the next issue.

L Jackson Laslett

Prominent Berkeley machine physi­ cist L. Jackson Laslett died on 7 May. A full tribute will appear in the next issue.

C de Witt (left), founder of the Les Houches Summer School over 40 years ago, and A. Nemoz, President of the University of Grenoble, at les Houches in April to discuss future les Houches programmes. During the meeting, the main auditorium was dedicated to the late Y. Rocard who served on the Les Houches Board for many years. C. de Witt was recently awarded the 'Prix du Rayonnement français'. (Photo M. Jacob)

CERN Courier, June 1993 31 Elementary Particle Physics The Particle Physics Department of the Rutherford Appleton Laboratory has a vacancy for an Elementary Particle Physicist to work on its experimental programme. The Department is engaged in research at CERN and DES Y and other Institutes abroad. The programme also includes non-accelerator experiments. The successful applicant will be expected to participate in one of the current projects and to plan future experiments for the next generation of accelerators. He or she will be required to work closely with other members of the Department and to collaborate with physicists from Universities and other Institutes in the UK and abroad. Communication skills and the ability to contribute effectively as a member of a team are therefore essential. He/she should be prepared to spend a significant fraction of his /her time working overseas, if required. The appointment will be made in the Higher Scientific Officer or Senior Scientific Officer grade, according to ability and experience. The salary ranges are: Higher Scientific Officer £\ 2,833 to £22,669 pa Senior Scientific Officer £15,929 to £28,687 pa Formal minimum entry qualifications required for the Higher Scientific Officer grade are a degree, HNC/HND or equivalent in a relevant subject together with at least 2 years Post Graduate experience with a first or second class honours degree or 5 years relevant experience with an ordinary degree, HNC/HND or equivalent. For the Senior Scientific Officer grade a first or second class honours degree plus at least four years post graduate experience is required. It is expected that the successful candidate should have several years of post-doctoral experience in the field of Elementary Particle Physics. We offer excellent working conditions and benefits include a non-contributory pension scheme and generous holidays. For an application form please contact the Recruitment Office, Personnel and Training Division, Science and Engineering Research Council, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 OQX. Tel: 0235-445435 for an application form, quoting reference number VN 1114. All applications must be returned by 25th June 1993

SERC is an equal opportunities employer and is working towards a smoke free work place.

SGRC — Rutherford Appleton Laboratory

Physicist - Silicon Detector Systems The LBL Physics Division is participating in the design design group has extensive experience in conven­ and construction of several major silicon detector tional and radiation-hard technologies. systems. The most demanding is the SDC Silicon Applicants must have participated in the technical Tracker, which requires a variety of novel techniques design, installation, and use of complex particle de­ in front-end electronics and electro-mechanical tector systems in high-energy or nuclear physics integration. experiments (not limited to silicon technology). The LBL is seeking a technically oriented physicist to tasks require a thorough understanding of electronic assume responsibility for the development of Silicon detectors and measurement techniques, coupled Tracker detector modules, which combine detec­ with experience in the conceptual design of small tors, integrated front-end electronics and cabling. mechanical systems. The ability to carry out research Low-mass hybrid and cabling technologies are criti­ independently and interact with a diverse group of cal components of this work, which requires close scientists and engineers is essential. Ph.D. in experi­ interaction with commercial vendors. Overall elec­ mental physics preferred. tronic and mechanical characteristics of modules This is a term appointment, with the possibility of will be measured and analyzed in detail to tailor the becoming a career appointment. Please send your design to the experimental environment. With a total resume, with references and salary history to: of 6.5 million channels, the Silicon Tracker requires Lawrence Berkeley Laboratory; Staffing Office, Job carefully developed procedures for quality control, #A/1305, One Cyclotron Road, Bldg. 90/1042, Berke­ reliability testing, installation, maintenance, and ley, CA 94720. We are an equal opportunity employer. operation.

LBL offers a wide range of technical expertise, includ­ LAWRENCE BERKELEY LABORATORY ing semiconductor device design and fabrication UNIVERSITY OF CALIFORNIA utilizing the LBL Microsystems Laboratory. Our IC LB U.S. Department of Energy

32 CERN Courier, June 1993 Giant Read-Out Boards?

Epoxy laminates FR-4 1300x4400 mm produced by

[DITRONr

have been chosen for the construction of the "Read- Out Board" of the hadron calorimeters of the ALEPH and DELPHI detectors.

Standard production: • FR-4, G-10, G-11 rigicHaminates for printed circuit boards • thin laminates and prepreg for multilayer boards

DITRON srl Via Mulino Vecchio, 85 - 28065 CERANO (NO) ITALY Tel.: 0321/772181 - Telex: 331565 PENCO I Telefax: 0321/721645

30 Circle advertisement number on reader service form Advertisements in CERN COURIER Format A4 Monthly publication All advertisements are published in both English and French edi­ n s $ tions. Second language versions accepted without extra charge.

Cost per insertion (Swiss Francs) Space Actual size (mm) (page) width by height 1 3 10 insertion insertions insertions UAP

7i 185 x 265 1980 1900 1830 1730 185 x 130 1/2 1170 1100 1040 960 90 x 265 1/4 90 x 130 690 630 590 550 BUTTLER MARINE S.A. These prices include no entitlement to special placing. Direction pour la Suisse Supplement for: — one additional colour 1500 SwF de la Branche Maritime et Transports — 1/2 page 900 SwF — Covers: GENÈVE Covers 2 and 3 (one colour) 2000 SwF Cover 4 (one colour) 2500 SwF Publication date 1 st of month of cover date Closing date for positive films and copy 1st of month preceding cover date The cost of making films and of translation for advertisements are charged in addition. Screen (offset) 60 or 54 Swiss (150 English) Advertisements cancelled after 1st of month preceding cover date will be invoiced. These rates are effective for the year 1993 54, route des Acacias - Case postale 41 Inquiries for Europe : Micheline FALCIOLA/CERN COURIER-CERN 1211 Genève 24/Acacias CH-1211 Geneva 23 Switzerland Téléphone 022/342 00 57-58-59 - Telephone: 022/767 41 03 Telex 419 000 CER CH Telefax 022/342 00 26 - Telefax 022/78219 06 Télex 422 215 buci Inquiries for the rest of the world: please see page III.

CERN Courier, June 1993 33 HAMAMATSU

256-Channel readout. Hamamatsu's Multi-Anode PMTs with 256-channel readout not only dramatically extend the conditions for SCIFI tracking and calorimeter measurement, they operate with 2 percent or less crosstalk. This ensures high performance and reliability in addition to decisive SCIFI readout. For detailed information on 256- Channel Multi-Anode PMTs, just contact Hamamatsu Photonics at the office nearest you.

HAMAMATSU HAMAMATSU PHOTONICS KK., Electron Tube Center 314-5, Shimokanzo, Toyooka-village, Iwata-gun, Shizuoka-ken, 438-01 Japan. TEL: 81-539-62-5248 FAX: 81-539-62-2205 TLX: 4289-625

U.S.A.: Hamamatsu Corporation. TEL: 1-908-231-0960 FAX:1-908-231-1218 North Europe: Hamamatsu Photonics Norden AB. TEL: 46-8-59032190 FAX: 46-8-59094567 Germany: Hamamatsu Photonics Deutschland GmbH. TEL: 49-8152-3750 FAX:49-8152-2658 Italy: Hamamatsu Photonics Italia S.Rib. TEL: 39-(02) 935 81 733 FAX: 39-(02) 935 81741 France: Hamamatsu Photonics France S.A.R.L. TEL: 33-(i) 49 75 56 80 FAX: 33-(i) 49 75 56 87 Spain: Hamamatsu Photonics Espana S.L. TEL. 34-3 699 65 53 FAX: 34-3 588 19 66 United Kingdom: Hamamatsu Photonics UK Limited. TEL: 44-81-367-3560 FAX: 44-81-367-6384

13b Circle advertisement number on reader service farm