-~-2------NEVVS------N_ATU__ RE__ v_o_L_.~_3_1_6_Ju_N_E_I_~_3 High-energy physics in high-energy physics from the United States. He also says that the net cost of SF50 million could be brought down to Another flavour of quark? SF20-30 million by using some of the con­ HARD on the heels of the discovery of the duced the Zs, Ws and possibly top. There is tribution from the new member, Spain Z0 particle by the UA1 group at CERN a proposal for a SF50 million (£15 million) (which wished to support mostly lower (European Organization for Nuclear development of the collider to improve its energy physics at CERN). And the money Research), rumours were rife that the luminosity (production rate of events such would be spread over three years, he pleads. group has also discovered the "top" quark as Ws and Zs) tenfold. This would take But members are more likely to require - the sixth flavour in the family. This three years and could thus be just ahead of that if the collider is to be improved, it development has not been confirmed, Fermilab (see below). The snag is that the should be within a constant CERN budget. however. The position seems to be that member governments of CERN are not That might entail a delay in the LEP pro­ among its harvest of possible W± and zo flush with cash just now. gramme - which is itself in competition events, the UA1 group has a few events that Even so, Dr Erwin Gabathuler, CERN's with an American proposal, the SLAC are "consistent with" the existence of top. director for colliding beams, is hopeful. He linear collider. The ball thus seems likely to The difficulty is that, hitherto, the criteria argues that member states should acknow­ end up right back in the physicists' court. used for selecting for analysis record.s of ledge that the collider has wrested the lead Robert Walgate proton-antiproton collisions have been biased towards putative heavy-meson us particle accelerators events. Nevertheless, the data to sustain a search for the top quark exist, but the search will not be started until the data on Fermilab poised to leapfrog theWs and zo have been tidied away. Chicago discovery of the W and Z particles. Fer­ Meanwhile, the UA1 group is rushing THE Fermi National Accelerator milab is now building the antiproton ac­ out a paper on the intermediate vector Laboratory is jubilant over its achievement cumulator and other machinery necessary to bosons giving the latest estimates of their of a long-sought goal, the operation of the use the Tevatron as a collider, but it is not ex­ masses as follows: world's first large superconducting particle pected to operate until 1985-86. accelerator. The machine is called the According to Chris Quigg, head of the UAI estimate Salam-Weinberg theory energy doubler/saver, for its twin goals of theory group at Fermilab, intense beams of z 95.2 ± 2.5 94 ± 2.5 doubling the maximum energy of Fcr­ secondary particles such as neutrinos and w 81 ±2 83 ± 3 milab's proton beams to I ,000 GeV- one muons produced by the Tevatron will be teravolt - and of using electrical power ideally suited to study the quark structure of The measurements are clearly consistent more efficiently. For several years, Fer­ nucleons. The fixed-target accelerator will with the theory. Moreover, the UA1 group milab has been able to afford power for its also be unsurpassed for studying short-lived has also measured the "Weinberg angle" accelerator for only about half the year. particles that contain charmed and bottom 8w, an essential parameter of the unified Beams in the superconducting ring, also quarks. The tau neutrino, expected as a theory of electromagnetism and the weak called the Tevatron, were circulated at 100 companion of the tau lepton, is also a can­ nuclear interaction. The value quoted in GeV (I GeV = 10 9 electron volts) for the didate for discovery. the paper from the UAl group is sin28w = first time this month. Experiments with the But Quigg says that qualitatively new 0.226 ± 0.011, again consistent with earlier new beam arc scheduled for October at 400 physics is expected to appear at Fermilab in estimates of 0.236 ± 0.030. GeV, and beams approaching I TeVareex­ 1985, when the Tevatron is first used as a Meanwhile, CERN has had success of pected early next year. Development of the collider. If all goes as planned, the machine another kind. The French Government at superconducting accelerator began at Fer­ will produce collisions four times as the end of last month gave its formal bles­ milab in 1972, while the conventional 400 energetic as CERN's and with as much as ten sing to the construction of LEP, the large GeV accelerator was still being broken in. times the luminosity. One prize in conten­ electron-positron collider due to be com­ The machine was the idea of Fermilab's tion between Fermilab and CERN will be pleted by 1989. Armed with the govern­ builder and first director, Robert R. the top quark, the sixth and perhaps the last ment's blessing (a declaration d'utilite Wilson, who reasoned that the cheapest way quark flavour (see above), as well as a deter­ publique, an environmental requirement to increase that accelerator's energy was to mination of the total number of neutrino for big constructions), CERN is now pur­ build a new ring of powerful supercon­ species in the Universe (by measurements of chasing the land it requires around the ring ducting magnets in the same tunnel. the energy width of the Z) and the for surface buildings. The technology of superconducting mechanism of the rare Centauro events There has been strong local opposition magnets was not then as advanced as some hitherto seen only in cosmic rays. to these buildings, particularly in the had hoped. The US Government compli­ Of CERN's recent successes, Quigg says, village of Echenevex - where villagers cated matters by reducing funds for high­ "The European strength in high-energy claim the buildings are far too close and energy physics, which prompted Wilson's physics is healthy for the field as long as we noisy. The opposition to LEP now has no resignation in 1977. While Fcrmilab and keep up our end of it. In two years it will be further legal line of resistance, but the legal another American accelerator projector, our turn again. As long as we keep alter­ owners of the land could have some in­ Brookhaven Laboratory's ISABELLE, nating the big new machines this way, the fluence by refusing to sell at the price were bogged down on the frontier of super­ competition between CERN and Fermilab CERN offers, when a judge would have to conductivity, the European Organization will be a good thing". By 1986, Fermilab's arbitrate. CERN officials say, however, for Nuclear Research (CERN) moved in 2Tc V collider will be the most powerful of its that the farmers who own the land at 1979 into the different technology of col­ kind". But in 1989, CERN hopes to com­ Echenevex are accepting the offers. Con­ liding beams of protons and antiprotons, mission LEP, the most powerful electron­ struction is now expected to begin in July, making available much more energy in positron accelerator. Whether the United with injection of electrons and positrons inter-particle collisions than can be had States will then be able to look forward to its beginning in late 1988 and first experiments from fixed targets. next turn depends in large part on the recom­ in mid-1989. With the I ,000 GcV Tcvatron beam, mendations to be made this month by The pace of development may, however, only 45 GeV will be available to create new physicists meeting at Woods Hole, Massa­ be affected by the interests of the UA1 particles, far less than the 540 GcV chusetts, to discuss the next generation of physicists and others in improving the available from CERN's 270 GeV beam, US accelerators. antiproton-proton collider which has pro- which has made possible the recent Larry Arbeiter

U02H-OH36/R3/24U562-Ui.$01.1XJ ICJ 1983 Macmillan Journals Ltd