Physics monitor

Graham Ross of Oxford - looking beyond the

ty) is not conserved (spontaneously Looking for violated) so that even the lightest new physics supersymmetric particle, stable un­ der R parity conservation, becomes unstable. The problem with the Standard Such processes could provide Model of is that novel signatures at LEP and/or at a while it is very successful, its pre­ tau factory (July/August, page 13), dictive power has run out of steam. and the underlying physics could A major objective now is to look help in understanding the long­ beyond this Model - the twin pic­ standing deficit of observed solar ture of particle physics in terms of neutrinos. the electroweak unification of elec- In the neutrino sector, the claims tromagnetism and the weak force and counter-claims for a 17 keV on one hand and the quantum particle (April, page 9) were reex­ chromodynamics theory of inter- amined, but no conclusions can yet forces on the other - to find be drawn. The solar neutrino ses­ out why it works so well. sion was enlivened by new results Thus the implications of recent from the American Germanium Ex­ accelerator and underground exper­ periment (SAGE), given by Tom iments came under scrutiny at a re­ Bowles of Los Alamos. He pre­ Corpuscular (IFIC) and sponsored cent International Workshop on El­ sented a series of measurements by Universidad Internacional Men- ectroweak Physics Beyond the carried out this year with 50 tons endez Pelayo (UIMP-Valencia) and Standard Model held in Valencia, of gallium. Taken at face value, other Spanish agencies. Spain. these results support the classic is the most pop­ deficiency of solar particles seen From Jose. W.F. Valle ular way to extend the electroweak by the Kamiokande and Homestake sector for a deeper understanding. detectors. At Valencia, this was reviewed by The implications of solar neutri­ Electron-positron Graham Ross (Oxford) and by Luis no results were explored by spe­ Ibanez (CERN). Ross argued that cialists John Bahcall of Princeton colliders: looking at the minimal supersymmetric unified and Alexei Smirnov of Moscow future physics models are remarkably consistent (currently at Valencia). Taking the with precision low energy and LEP 17 keV neutrino seriously, organ­ data (April, page 3). izer Jose Valle showed how it With research and development This consistency underlines the could be reconciled with the solar work underway throughout the need to search for signs of super- neutrino observations. The out­ world towards high energy elec­ symmetry, where LEP has already come should be testable in the tron-positron linear colliders (April, contributed in several ways. One is next generation of solar neutrino page 10), interest turns to the new the search for supersymmetric experiments and laboratory physics these machines would Higgs bosons, a subject discussed searches for neutrino conversions. open up. by Spanish theorist M. Quiros, who The meeting concluded by look­ The first International Workshop stressed the importance of includ­ ing at the physics which will be on Physics and Experiments with ing radiative corrections in the ex­ opened up by increased energy at Linear Colliders was held recently perimental analyses. CERN's LEP electron-positron col­ in Saariselka in Finnish Lapland - There was also an interesting lider, by CERN's proposed LHC some 300 kilometres north of the presentation by Portuguese theorist proton collider, and by the Tau- Arctic Circle. The consensus was Jorge Romao on the rare decays Charm Factory now being dis­ that a compelling programme of expected in supersymmetric mod­ cussed in Spain. physics would be opened up by els where the conventional super- The Valencia meeting was colliders reaching 300-500 GeV, symmetry quantum number (R pari­ organized by Instituto de Fisica the major topics being precision

20 CERN Courier, December 1991