Purdue Physics Colloquium

	General Colloquium August 24 - 4:00pm Phys 223 (Coffee at 3:30p.m. in room 242) Laszlo Gutay Professor of Physics Purdue University Title: "Precision Measurement of Electroweak Z, W Parameters and Search for Higgs at the New e⁺e^- Collider's Energy Frontier"
Abstract: To circumvent excessive energy loss of the accelerated e⁺e^- beams via bremsstrahlung, the worlds largest radius circular accelerator was built 100m underground at CERN, Geneva Switzerland. The 27km circumference made possible the construction of a =100 GeV electron positron collider using conventional RF cavities. This permitted high precision scan of the mass region of Z⁰ resonance, the 91 GeV massive weakly interacting photon, and thus the high precision measurement of the electroweak parameters in the Z⁰ region. The development and gradual installation of super conducting resonance cavities made it possible to double the energy of the e⁺e^- collider beyond the 200 GeV energy threshold. This permits the exploration of W⁺-W^- and Z⁰- Z⁰ pair production threshold regions and search for Higgs and Supersymmetric Particles.
Brief Bio: Professor Gutay joined the Purdue Physics Department in 1965. He became a member of the synchrotron nuclear group, then in transition to establish the Purdue High Energy Group. At that time, the group was involved in a large construction effort to build one of the world's most powerful bubble chamber analysis facility under the leadership of Professor Tautfest. One of the high crossection reaction which was measured by this bubble chamber film analysis facility was the reaction +p ++n. Early stages of experimental high energy physics consisted of finding p, and K resonances and the interaction was the testing ground of the newly developing theories of strong interactions. Thus Professor Gutay developed the technique to extract the S - P wave pion-pion scattering amplitude in the newly (1961) discovered resonance region. With these amplitudes Professor Gutay could test Weinberg's off-mass-shell - scattering amplitude, Sakurai's vector dominance hypothesis ( is similar to gamma), the Venziano model and measured the Ball's invariant amplitude. In general he proved that pion exchange dominates the single pion production amplitude in p and Kp reactions. His work initiated a series of international conferences on this subject. In 1970 Professor Gutay joined the multiparticle detector group at Brookhaven National Laboratory to develop wireplanes with high multiparticle track efficiency in magnetic field. They succeeded to construct the first electronic detector which was equivalent to a bubble chamber. With this newly developed multiparticle spectrometer, high multiplicity events were detected which emerged from then high energy (pc = 28GeV) p-p collisions. Using this data Professor Gutay isolated the centrally (y=0) produced hadronic matter (CPHM) just predicted by Frazer, Feynman, Hagedorn, and DeTar. He measured the size, lifetime, and limiting temperature of this system. In 1975 Professor Gutay and Professor Scharenberg established at Purdue the High Energy Nuclear Counter group to study Gamow-Teller nuclear transitions and study further the properties of Hadron Thermodynamics in CPHM. Acting on the intuitive argument that the l =1 absorption by JI=00 nuclei gives JI = 11 nuclear state. Using the p + Cn + N (1) it was demonstrated for the first time that Gamow-Teller transitions, initiated on isoscaler targets, are dominated by exchange and that the g coupling constant is related by PCAC to the ft value of N (1). This discovery created an upsurge in international interest in GT transition, induced on isoscaler targets. The new High Energy Nuclear group built an Internal Target Laboratory at Fermilab whereby a supersonic Xenon jet intersected the circulating 400 GeV proton beam inside the vacuum pipe. Since their detectors were inside the vacuum, they could measure fragment yields from proton to aluminum. From the data they deduced conclusively that fragments are produced at the critical point, thereby establishing the validity of Hadron Thermodynamics and Hadronic Phase Transition. The Purdue Group ( Bujak, Carmony, Gutay, Hirsch, Porile, Scharenberg and Stringfellow) was joined by Fermilab and several Midwestern Universities. They converted the Internal Target laboratory into the CØ - collidor region at Fermilab. At the suggestion of Hagedorn, Van Hove and Weisskopf, the Purdue group proposed, with Professor Gutay as the spokesman, to search for hadron quark-gluon deconfinement transition. A decade later the importance of this experiment can be measured by the number of heavy ion experiment at CERN and the development of heavy ion colliders at CERN and Brookhaven National Laboratory. They have been all built to search for QGP. It was an unexpected twist of nature that although strongly interacting p-p and -p collisions were the initial driving force in the development of High Energy Physics, yet it was the electromagneticly interacting lepton pair production and weak interactions (neutrino scattering) which gave the first clues which led to the ultimate description of the elementary particle interactions: The Standard Model. Thus Professors Carmony and Gutay joined the Large Electron - Positron Collider experiment L3 to study electroweak interactions. The L3 spokesman is Nobel Laurate S. Ting. During 12 years of operation, the L3 group has shown the validity of lepton number conservation, counted the number of quark-lepton families, made a precision measurement of the mass and width of Z and of other electroweak parameters and predicted the top mass. The first measurement of -oscillation was a Purdue thesis topic (Banicz). By converting LEP into a superconducting accelerator, the LEP energy has been increased above the Z-Z and W-W pair production threshold. Thus students of Professors Carmony and Gutay are working on determination of the energy dependence of the Z and W pair production and the magnitude of the anomalous Z - W-W and - W-W couplings. Note that and do not exist. To increase further the collision energy one has to switch from e-e to the p-p collider. CERN approved both the construction of the 14 TeV proton - proton collider and the CMS detector of which Professors Carmony and Gutay have been members since approval. Professor Gutay and Professor Carmoney have been responible for the development of robotics based CMS muon chamber quality control and construction. Professor Gutay's accomplishments have their roots in the coherent work of several members of the experimental and theoretical groups at the beginning of his career at Purdue, which is gratefully acknowledged.