[en] The AGS's prime function when RHIC comes on line will be as a heavy ion injector, free time will exist for unique operation that can be tailored and dedicated to users. Many of the next generation of experiments require RF time structure in the spill as it is extracted to time events or assure no background during decay times. Two methods have been developed to meet these needs. Micro-bunching where the beam is forced between empty buckets producing bursts at arbitrary integer harmonics of rotation period [1], and mini-bunching where the beam is kept bunched to provide high extinction between bursts [2]. With an RF dipole the period may be increased to three times the rotation period of the beam. Further modeling and test results with beam will be presented. At high beam currents above transition, tight clusters of beam form causing severe random spike structure in the spill. Forcing the beam between empty buckets before extraction breaks up these clusters with minimal modulation of the spill at the RF frequency. Results of spill structure and loss reduction will be given

No abstract available

[en] To study the primary composition at energies greater than several thousand TeV, an array of four individual calorimeters, together with eight shower detectors, is being operated at sea level. The experiment studies energetic hadrons delayed with respect to air shower fronts. Each calorimeter is of area 1.5 m²; two independent timing measurements are made of the hadron cascade in each calorimeter

[en] We present the results of an experimental search for energetic particles which arrive at sea level delayed with respect to the shower front, with an order of magnitude greater exposure than previous experiments. The experiment was sensitive to showers from cosmic rays between 10⁵ and 10⁷ GeV per nucleus. Events with signals greater than 20 equivalent particles and delayed more than 20 ns were observed and studied. A four-dimensional Monte Carlo simulation of cosmic-ray showers combined with accelerator calibration data showed that the observed events as well as previously reported observations of this type can be accounted for by rare fluctuations in signals from low-energy hadrons in the air shower. No evidence for the existence of heavy long-lived particles in air showers was found. We set an upper limit to the flux of these particles at the 90% confidence level of 1.4 x 10^-12 cm^-2sr^-1s^-1

[en] The results of an experimental search for energetic particles which arrive at sea level delayed with respect to the shower front, with an order of magnitude greater exposure than previous experiments are presented. The experiment was sensitive to showers from cosmic rays between 10 to the 5th power and 10 to the 7th power Gev per nucleus. No evidence for the existence of heavy long lived particles in air showers was found. An upper limit to the flux of these particles was set at the 90% confidence level of 1.4 x 10 to the minus 12th power cm(-2) sr(-1) s(-1)

[en] The existence of particles with mass > 5 GeV c² and lifetime > 10^-7 sec has been suggested by the presence of energetic hadrons arriving delayed with respect to air shower fronts. Three events with E > 30 GeV and delay > 30 ns have been reported at mountain level. Here we report on a new experiment to search for such events at sea level

[en] Detector cells consisting of fast lead-tungstate crystals viewed by avalanche photo-diodes were designed, built and bench-tested. It was found that cooling the crystals to -20 C, using two avalanche photo-diodes per crystal, and using fast pulse shaping provided the light yield, low noise, and fast response needed for use in 100 MeV calorimetry at high beam rates. The achieved stochastic term coefficient is 0.8% and the time response is characterized by a single decay term of 24 ns.

[en] Detector cells consisting of fast lead-tungstate crystals viewed by avalanche photo-diodes were designed, built and bench-tested. It was found that cooling the crystals to -20 C, using two avalanche photo-diodes per crystal, and using fast pulse shaping provided the light yield, low noise, and fast response needed for use in 100 MeV calorimetry at high beam rates. The achieved stochastic term coefficient is 0.8% and the time response is characterized by a single decay term of 24 ns.

[en] This paper examines the relative merits of several methods for determining the number of neutrino generations with the SLD at the Stanford Linear Collider. The authors conclude that in the limit of large statistics, the most precise technique is a measurement taken at a collision energy of 96 GeV of the ratio of the cross sections for the processes e⁺e- → γ to e⁺e- → - vγ, for which errors smaller than 0.10 N_v should be achievable. Alternatively, if 10⁶ Z⁰ events are collected at the Z⁰ resonance peak, this measurement will provide a precision of about 0.15 N_v. The authors give a summary of the relative performance of the experimental methods examined in this paper as a function of the size of the available data sample

[en] A search for the decay of the charmed meson D⁰→ bar K⁰e⁺e^- is presented, based on data collected at the ψ(3770) resonance with the Mark III detector at the SLAC storage ring SPEAR. No evidence for this process is found, resulting in an upper limit on the decay branching ratio of 1.7x10^-3 at the 90% confidence level