Lisbon Conference

Lisbon Conference Braganca Gil, President of the Portuguese Physical Society, addresses the Lisbon conference. (Photo A. Amor) Although no major physics discover of experiments is emerging to test erators and storage rings. ies were announced, the European the predictions of these broader the Another pointer to the future ca me Physical Society's International ories. Some experimentalists are on the first day of the conference, Conference on High Energy Physics, turning away from their traditional when CERN Director General Her- held in Lisbon from 9-15 July, was haunts at high energy accelerators wig Schopper, in a talk on the future significant in that it showed the to mount new 'passive' experiments development of European particle emerging pattern of physics for the deep underground to search for new physics, indicated the initial success 1980s. phenomena. Theoreticians are striv of tests with antiprotons in the SPS With the electroweak theory ade ing to use the new insights on the (see page 2&9). He proudly empha quately explaining almost all of lep- structure of matter to aid cosmolo- sized that this remarkable achieve tonic physics and with quantum gists in their bid to reconstruct the ment had been accomplished just chromodynamics (QCD) emerging early history of the universe. Gravity three years, almost to the day, since as the theory of inter-quark forces, too is being fed into the new unifica the antiproton project had been for physicists are confidently looking to tion schemes. mally approved at CERN. broaden their horizons. However the Apart from specialized work The next day saw the arrival of comparison of QCD predictions with shops, Lisbon was the first example Carlo Rubbia hotfoot from CERN experiment still looks sometimes of a major international meeting where only hours before, some evi more like an art than a science, and which included substantial coverage dence for proton-antiproton colli there is a lot of ground to be covered of passive experiments looking for sions had been picked up in the before any QCD textbooks can be new behaviour, notably proton de forward telescope of the U A1 detec written. cay. Although it is too early for con tor in the SPS ring. This announce Putting QCD problems to one side, fident new results to be available, the ment was greeted with spontaneous new unifications are being sug international effort under way in this applause, and conference chairman gested to merge the electroweak sector reflects how physicists are Giuliano Preparata rushed mes and QCD pictures, and a new breed beginning to look away from accel sages of congratulation to CERN on CERN Courier, September 1981 283 The conference opened with R. Barloutaud speaking on the search for evidence of baryon number violation. (Photo A. Amor) The measurement of this parameter This initial talk was supplemented in the collider would be a major later in the conference by a session breakthrough and would have im on proton decay searches, chaired portant implications. by Abdus Salam, who has provided For the possible future develop significant motivation for these ment of the collider, Rubbia men experiments. In his introductory tioned the use of polarized protons, remarks, Salam emphasized the already being actively investigated long-term implications of this work. at other machines. Higher luminosi Rather tffan being an ad hoc series of ties, if achieved, would increase the short-term studies, he advocated chances of uncovering more new that this type of physics should particles, in particular the Higgs develop into a regular long-term bosons, which are just as fundamen effort, and indicated in no uncertain tal to the underlying theory as the way that funding arrangements weak bosons. For the longer term, should take this into account. If the Rubbia touched on the possibility of proton is indeed found to be unsta building a proton-antiproton collider ble, then its exact decay modes in the proposed LEP tunnel at could have serious implications for CERN. the future of high energy physics While Rubbia could not report any machines. Certain decays, because collider physics, experiments at the of the mass-scale involved, could Intersecting Storage Rings (ISR) mean that this new physics would be have already had their first look at inaccessible to conventional high proton-antiproton collisions, albeit energy machines. at a lower energy (see June issue, In the proton search session, the page 196). In the early sessions, results from the Japan/India colla this 'spectacular success'. Martin Block presented first results boration at the Kolar Gold Fields By next year's conference season, from experiment R211 (a Louvain/ were presented (see July/August passive experiments and the CERN Northwestern collaboration) which issue, page 253). However no new studies of 540 GeV proton-antipro- uses the 'Roman Pot' technique. events could be reported to supple ton collisions might have a lot of With meagre statistics and using ment the three proton decay candi fascinating new material to report. instrumentation resurrected from dates recorded up to the end of April. Rubbia's talk at Lisbon centred on some of the first experiments carried Another detector, weighing 31 tons, the objectives of the new physics out at the ISR ten years ago, a first has begun operation 2000 feet opening up at the collider. Spotting shot at the proton-antiproton total underground at the Soudan site in heavier quark flavours by looking cross-section gives 46 millibarns. Minnesota. Embarrassingly quickly, directly for new quark-antiquark Although the errors are, in Block's this detector has recorded an event bound states might no be easy, and words, 'still obscene', this suggests which could be interpreted as proton alternative flavour mechanisms that the proton-antiproton reaction decay. However the group prefers at would have to be exploited. Assum rate, like that of proton-proton, is this stage to explain it away as ing of course that they exist at the still rising, but might be approaching multiple scattering. predicted masses, the long-sought the proton-proton figure from above. Another feature of the conference intermediate bosons of weak inter Other ISR experiments also reported was that, unlike the more recent actions should not present such pro initial antiproton results. European biennial particle physics blems. High on the experimental In the new department of passive meetings, Lisbon included parallel agenda is the job of fixing their experiments, the conference in fact sessions. With a total of some 700 masses as accurately as possible. If opened with a talk by R. Barloutaud, participants (significantly less than it could be measured, the width of who described the motivation be the conferences held in recent years the neutral Z boson would give infor hind the range of studies under way in Madison, Geneva and Tokyo), the mation on the number of species of or being mounted to search for signs parallel sessions were fairly compact neutrino which exist in the universe. of baryon number violation. and gave a workshop feel to the first 284 CERN Courier, September 1981 Herwig Schopper spoke on the future of European high energy physics, and was able to reveal the first successes at CERN with tests at the high energy proton-antiproton collider. (Photo A. Amor) few days, with plenty of opportunity for discussion, public and private. On the other hand, the physics which had to be covered ranged over a wide field, so that the parallel sessions included valuable 'mini- rapporteur' talks which brought together results from several experi ments. For the plenary sessions, the organizers had included two types of talks - review papers presented after the appropriate parallel sessions, and invited speakers deemed to be worth hearing. Despite this imagina tive organization, there were a few topics, like the structure of the weak current, which slipped off the map during the plenary sessions. Another praiseworthy feature was the reappearance of sessions on experimental instrumentation. Once a regular adjunct to these inter national meetings, this important corner of particle physics has had no regular international forum in recent years. At Lisbon, these parallel ses sions covered particle detectors and A not altogether unexpected con be a good test bed for QCD, and in data handling. While contributions frontation was the disagreement certain cases agreement between on particle detectors were naturally between two experiments using the theory and experiment is quite good. well covered by the experimental Split Field Magnet at the CERN ISR. However devil's advocate argu physicists, data handling has be While Antonino Zichichi's Bologna / ments can be proposed which chal come something of a speciality, and CERN / Frascati group sees signs of lenge this. The behaviour seen in despite some brave attempts, the a beauty baryon at 5.5 GeV, an gluon jets seems to be similar to that coverage of this sector was not Annecy / CERN / College de France of quark jets, although there could be really representative. / Dortmund / Heidelberg / Karls a systematic broadening. Baryon As a European meeting, it was ruhe / Warsaw collaboration sees production in electron-positron anni only natural to encouter a prepon nothing (see June issue, page 207). hilation seems to be unexpectedly derance of European data, domi After much debate, the issue re high. nated by results from CERN and mained unresolved. After the discovery of the upsilon DESY. Nevertheless, the scarcity of In the high energy electron-posi at Fermilab and the subsequent US contributions was a bit disap tron sector, it was DESY's PETRA investigation of upsilon fine struc pointing. A notable exeption was the ring which dominated, with lumino ture at DORIS, the energy region nice talk by P. Franzini on the results sities at record levels and with data covered by the CESR ring has en obtained at Cornell's CESR electron- from JADE, PLUTO, TASSO and abled the CLEO and CUSB experi positron collider.

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