G.A. Blair

The Snowmass points and slopes: Benchmarks for SUSY searches

Abstract. The ”Snowmass Points and Slopes” (SPS) are a set of benchmark points and parameter lines in the MSSM parameter space corresponding to different scenarios in the search for Supersymmetry at present and future experiments. This set of benchmarks was agreed upon at the 2001 ”Snowmass Workshop on the Future of Particle Physics” as a consensus based on different existing proposals.

The Design and construction of the ZEUS central tracking detector

Abstract The mechanical, electrical and electronic design and construction of the ZEUS central tracking detector are described, together with the chamber monitoring and environmental control. This cylindrical drift chamber is designed for track reconstruction, electron identification and fast event triggering in a high beam-crossing rate, high magnetic field application.

Superstring-inspired models

Abstract We discuss the structure of low-energy groups arising from compactified models based on the heterotic string. Particular regard is paid to the possibility of intermediate scale breaking which may change the low-energy gauge structure and may naturally lead to doublet-triplet splitting and the suppression of proton decay. We present an illustrative example of such a model with a low energy gauge group structure SU 3 c × SU 2 L × SU 2 R × U 1 B−L which may be compatible with low-energy phenomena including limits on neutrino masses and sin 2 θ W . Mechanisms leading to the minimal SU 3 c × SU 2 L × U 1 Y low-energy gauge group are also presented.

Reconstructing supersymmetric theories at high energy scales

We have studied the reconstruction of supersymmetric theories at high scales by evolving the fundamental parameters from the electroweak scale upwards. Universal minimal supergravity and gauge mediated supersymmetry breaking have been taken as representative alternatives. Pseudo-fixed-point structures require the low-energy boundary values to be measured with high precision.

The reconstruction of supersymmetric theories at high energy scales

Abstract. The reconstruction of fundamental parameters in supersymmetric theories requires the evolution to high scales, where the characteristic regularities in mechanisms of supersymmetry breaking become manifest. We have studied a set of representative examples in this context: minimal supergravity and a left-right symmetric extension; gauge mediated supersymmetry breaking; and superstring effective field theories. Through the evolution of the parameters from the electroweak scale the regularities in different scenarios at the high scales can be unravelled if precision analyses of the supersymmetric particle sector at e+e- linear colliders are combined with analyses at the LHC.

Analysis of Neutral Currents in Superstring Inspired Models

We fit existing neutral current data to (E6) models inspired by superstrings, concentrating on the case of diagonal neutral currents. Using a convenient parametrization (which includes all popular models as particular cases) we conclude that sin2θW ∼ 0.225 and MZ ∼ 92.5 GeV but we cannot exclude in a model independent way new gauge bosons with masses ∼ 100 GeV. We compare fits to different sets of data and discuss particular models.

Simultaneous measurement of KS and KL decays into π+π-γ

With the E731 apparatus at Fermilab, we have simultaneously collected 6859 [ital K][sub [ital L]] and [ital K][sub [ital S]] decays into [pi][sup +][pi][sup [minus]][gamma]. Using our sample of over 370 000 [pi][sup +][pi][sup [minus]] decays for normalization we have determined that the ratio [Gamma]([ital K][sup 0][r arrow][pi][sup +][pi][sup [minus]][gamma])/[Gamma]([ital K][sup 0][r arrow][pi][sup +][pi][sup [minus]]) is (23.0[plus minus]0.7)[times]10[sup [minus]3] for [ital K][sub [ital L]] and (7.10[plus minus]0.22)[times]10[sup [minus]3] for [ital K][sub [ital S]], for photon energies greater than 20 MeV in the kaon center of mass. After removing the inner-bremsstrahlung contribution, we find that the photon energy spectrum of the direct emission decay of the [ital K][sub [ital L]] is consistent with the presence of a vector meson propagator in the form factor.

New limits on KL,S--> pi 0e+e-

Data taken in a Fermilab experiment designed to measure to CP-violation parameter epsilon/epsilonfrom a study of K..-->..2..pi.. decays were used to look for the as yet unseen decay modes K/sub L//sub ,//sub S/..--> pi../sup 0/e/sup +/e/sup -/. The detector was optimized for the detection of kaon decays with four electromagnetic showers in the final state. The results (90% confidence) are branching ratios pi../sup 0/e/sup +/e/sup -/ and K/sub S/..--> pi../sup 0/e/sup +/e/sup -/, respectively.

Measuring gauge-mediated supersymmetry breaking parameters at a 500 GeV \(e^+e^-\) linear collider

Abstract. We consider the phenomenology of a class of gauge-mediated supersymmetry (SUSY) breaking (GMSB) models at a

Present status and first results of the final focus beam line at the KEK Accelerator Test Facility

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