intrepid young physicists from 20 auditorium at the Plaza of America. countries, including The Flying Cir­ This specially-commissioned work cus of Physics' from Copenhagen featured scientifically accurate lyric and Amsterdam, began their dra­ verse by French astrophysicists Jean matic demonstrations of physics prin­ Audouze and Michel Cassé, music ciples. Thousands of visitors partici­ by Graciane Finzi, and a dance alle­ pated in the fun, which showed how gory of the Big Bang and the creation fascinating science can be. Interac­ of the Universe with choreography by tive video stations, with programmes Jean Guizerix, Wilfride Piollet and specially developed at CERN in col­ Jean-Cristophe Paré from the Opéra laboration with Olivetti, helped visi­ de Paris. (The sound track, featuring tors explore science. film star Michel Piccoli, has been re­ The carnival continued with scien­ corded by Radio-France.) For more tists and gymnasts, disguised as par­ mundane tastes, a CERN scientist ticles, printed circuits, atoms and Ein­ Latino funk band jammed on the cen­ stein clones, dancing around a tral Expo 92 stage until late into the float. Throughout night. the day CERN's glamorous 'Les Tired but happy, the scientists pre­ Horribles Cernettes' belted out their pared to return to their laboratories. special brand of 'hardronic' rock with 'Genius, Originality and Participa­ songs about the hassles of science tion the scientists from CERN life and how making it with physicists showed the public that physics can is tough. be really interesting,' applauded the The day finished on a more serene Expo 92 Information Bulletin. Maybe The CERN Day at Seville finished with the note with the première of a 'Universe physics should go to the ball more of­ première of a specially-commissioned of Light' ballet playing to a packed ten. 'Universe of Light' ballet.

DESY focuses on HERA

On 1 October, a special 'Fest- years of presenting news bulletins of grated, overall economic integration Kolloquium' at DESY marked the offi­ HERA construction progress, was was not proceeding so smoothly. cial start of the research programme proud to announce the start of opera­ After Vice-Chairman of the DESY at the new HERA - tions. Research Council Gustav Kramer collider, which began operations ear­ Leonhard Hajen, Senator for Sci­ congratulated the HERA team on lier this year (July, page 2). The tim­ ence and Research of the City of their accomplishments, keynote ing could not have been better, as , reflected his city's pride in speaker Christopher Llewellyn Smith, HERA performance had improved by being home to a major world Labora­ long a proponent of the benefits of a factor of ten during the two weeks tory. Hinrich Enderlein, Minister of electron-proton experimentation, beforehand. More than 600 guests Science, Research and Culture of painted a picture of the HERA experi­ assembled in one of the big halls pre­ Land reported the suc­ mental objectives which was well il­ viously used for assembly of major cessful integration of the lustrated with appealing analogies. components for HERA experiments. (formerly East ) Laboratory into Gus Voss covered the HERA ma­ Introducing the ceremony, Volker an enlarged DESY infrastructure. chine and its most recent perform­ Soergel, Chairman of the DESY Di­ While similar research institutions ance. The machine is behaving as rectorate since 1981, after many were also being successfully inte­ expected and Voss felt confident that

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CERN Courier, December 1992 9 On 1 October, a special 'Fest-Kolloquium' at DESY marked the official start of the research programme at the new HERA electron-proton collider, which began operations earlier this year. Christopher Llewellyn Smith of Oxford (left) covered the new physics HERA will at­ tack, while G us Voss of DESY described the HERA machine itself. Llewellyn Smith has been proposed as the next Director General of CERN, in which case he would take office on 1 January 1994. (Photo P. Waloschek)

In July, maximum intensity per pro­ ton bunch had been restricted to about 20 per cent of the 750 microamp design value because of difficulties in the proton supply up­ stream. After sorting out some mag­ netic problems in the DESY III proton , the proton level in­ creased, only to run into another bot­ tleneck in the intermediate PETRA ring. However this is being worked on and the proton should soon improve. With careful beam centering and tune adjustments, the proton beam can be kept for about a day, the elec­ tron beam being refreshed several times during this period. The HERA superconducting magnets are per­ forming well, and, last but not least, ugly 'persistent' eddy current prob­ lems widely expected to plague pro­ it would reach its design objectives luminosities increased from the 6 x ton injection have not materialized, (luminosity) within one or two years. 1028 per sq cm per s achieved in July thanks to the special monitoring sys­ First results from the experiments to above 1029. Already ten times the tem based on reference magnets. (which had also been aired several luminosity provided during June/July Running has used about ten days before at the DESY Theory has been delivered, the improve­ Workshop - see -below) were re­ ments coming mainly from better sta­ 600 guests were at the HERA 'Fest- ported by Sergei Levonian (Moscow) bility of the proton beam and from Kolloquium'at DESY. for the experiment and Matthias increased reliability. (Photo K. Desler) Kasemann (DESY) for Zeus. Finally Bernd Neumann, Parliamen­ tary State Secretary of the Federal Ministry of Research and Technol­ ogy, assured the audience that his Government will fulfil all its obliga­ tions for high energy physics, where 's annual expenditure is cur­ rently running at about 500 million deutschmarks, mainly for CERN and DESY. The goal, he said, is now op­ timum utilization of existing resources and facilities.

HERA back on

After a short shutdown following its initial production run in July, the new HERA electron-proton collider re­ started on 20 August. Maximum

10 CERN Courier, December 1992 bunches per beam. The design figure at low frequency (S-band) with con­ their public debut at the International is 210 bunches in both beams, but ventional cavities and lower fre­ Conference on High Energy Physics efforts to push more current into the quency TESLA (superconducting) in Dallas in August (October, electron ring are currently coming up schemes. However with having to page 6). against problems. These are not look after the nine DESY machines These initial presentations show avoided by the powerful bunch-to- currently operating, DESY's machine dramatically how HERA probes deep bunch damping system, based on a specialists already have a lot on their inside interesting and hitherto very design successfully used in the plate. remote new kinematical regions, now PETRA ring, which has already dem­ called 'deep diffractive' in the trade. onstrated how well it can counter co­ and theory with flavour As well as charting photoproduction herent instabilities in both PETRA rates at higher energies, results al­ and HERA beams. The problem can With first results from the HERA elec­ ready given at Dallas, the analyses be partially overcome by careful orbit tron-proton collider now emerging, had subsequently sharpened to pro­ steering, but this is treating the symp­ this year's traditional Theory Work­ duce evidence for photoproduction toms rather than the cause. A special shop at DESY could change gear. jets, confined sprays of hadrons sig­ positron run planned for November This annual event has become a fo­ nalling constituent interactions deep could reveal more. cus for the large theory community in inside the target . With the luminosity per bunch al­ DESY and even further afield. Under After this foretaste of HERA physics ready running at about 30% of the the theme 'Flavour Physics', the to come, attention turned to the main design level, the electron and proton meeting set the scene for HERA's business of the meeting. Today's intensities are the main obstacle to appearance, and looked at the poten­ Standard Model uses six fla­ more HERA collisions. tial impact this new experimental vours, grouped pairwise with three The design energy of the electron venture could have. flavours. A number of talks beam is 30 GeV and has already For the experiments, G. Bernardi of covered the phenomenology of been reached in precommissioning Paris and S. Bhadra from Toronto heavy , a domain where tests. However current running pre­ spoke for H1 and Zeus respectively. HERA will help to plug empirical fers 26.67 GeV, which leaves some These results were based on the holes in the Standard Model. The radiofrequency flexibility and allows three inverse nanobarns of luminosity picture is still clouded by the non­ spin polarizations studies to continue. received during July, and had made appearance of the sixth ('top') quark. The recent polarization achievements (October, page 35) open the door to the HERMES proposal for a gas jet target in the HERA electron ring for measurements of proton spin struc­ ture. For the future, DESY machine physicists are playing a major role in the international effort to develop the next generation of electron-positron linear colliders (November, page 23). With a wide range of technology to exploit, DESY is looking particularly

The DESY Theory Workshop in September assessed at the impact HERA could make on physics. J.D. Bjorken (right) ofSLAC looked at what could happen in the new kinematical region opened up by HERA. He is seen here in discussion with Workshop organizer E.A. Paschos of Dortmund. (Photo P. Waloschek)

CERN Courier, December 1992 11 As one speaker said, 'everybody lation of all solar neutrino results sug­ shop provided an excellent snapshot knows where to expect the , gests that the deficiency between the of some of today's physics frontiers, but nobody knows where it is'. observed and expected signals in all interesting to physicists from all Heavy quark business dominated solar neutrino channels (the 'solar walks of life, not just theorists. A the meeting. There are several ap­ neutrino problem') is due to neutrino graduate student remarked 'these proaches to heavy quark calcula­ oscillation resonance. Doing the cal­ were three wonderful days where tions, and both were covered at the culations identifies two small allowed many new ideas were discussed. DESY meeting. A technique becom­ regions, with implications for neutrino You could feel the excitement at ing increasingly popular is an expan­ masses. DESY with the^expectation of new sion in the reciprocal of the quark These implications were seized by results from HERA'. mass. For heavy quarks, such a se­ neutrino specialist Lincoln ries should become rapidly conver­ Wolfenstein - It is still not clear gent. The fourth (charm) quarks can whether neutrinos have masses or begin to be considered in this way, not'. Neutrino mass limits from labo­ the fifth (beauty) is better, but the ratory experiments are still being at­ idea should really come into its own tacked but are unlikely to improve with top, the heaviest quark. At the drastically. But there is indirect evi­ international conference in Dallas in dence, said Wolfenstein, that neutri­ August, after several speakers nos are much lighter. pointed out the potential of this ap­ The solar neutrino problem is really proach, the message was underlined the solar neutrino opportunity', by Steven Weinberg in his Dallas claimed Wolfenstein, one of the ar­ summary. chitects of the neutrino oscillation The second approach to quark cal­ resonance mechanism. He went on culations is field theory to describe how improved solar neu­ supercomputer calculations on a hy­ trino measurements could help fix pothetical lattice. As well as compu­ neutrino mass parameters and help ter power, many improvements are probe the role, possibly very consid­ being incorporated into the calcula­ erable, that neutrinos played and tions. continue to play in the large scale On the final day of the workshop, structure of the Universe. the spotlight turned from quark to Finally J.D. Bjorken of SLAC, who lepton flavours. W. Hampel of has been looking at new possibilities Heidelberg gave an excellent review using parton dynamics at the ener­ of solar neutrino measurements, gies which will be opened up at the which this year have been boosted next generation of proton colliders, by the first sightings of neutrinos from adapted these ideas for HERA con­ the proton-proton fusion mechanism sumption. This deep diffractive be­ which provides the bulk of the sun's haviour should extrapolate smoothly thermonuclear power. from today's elastic (diffractive) scat­ The results from the Gallex experi­ tering, dominated by the 'Pomeron' ment in the Italian underground Gran mechanism, whatever this might be. Sasso Laboratory had been first an­ Bjorken suspected it could be of nounced in June at the Grenada origin. Electron-proton colli­ Neutrino 92 meeting (September, sions, with their reduced complexity page 1), while an updated number compared with traditional proton-pro­ from the SAGE Russian/US collabo­ ton approaches, should provide a ration emerged at Dallas (October, valuable new window. page 6). Ably organized by E.A. Paschos of Hampel pointed out that the compi­ Dortmund, the DESY Theory Work­

12 CERN Courier, December 1992