C. Durandet

Measurement of J / psi, psi-prime and upsilon total cross-sections in 800-GeV/c p - Si interactions

Abstract We report on the analysis of Charmonium and Bottomium states produced in p-Si interactions at s =38.7 GeV . The data have been collected with the open geometry spectrometer of the E771 Experiment at the FNAL High Intensity Lab. J ψ , ψ′ and γ total cross sections as well as the ratio B(ψ′ → μμ)σ(ψ′) (B( J ψ → μμ)σ( J ψ )) have been measured. Results are compared with theoretical predictions and with results at other energies.

A combination drift chamber/pad chamber for very high readout rates

Details of the construction of high-rate, mid-sized (1-m*2-m) pad chambers, intended for use in Fermi National Accelerator Laboratory (FNAL) experiment E-771, are described. Each gas volume module represents a chamber doublet: two identical anode wire planes, two transverse strip planes, and two pad planes. Wire signals, from 8-mm square cells, are recorded via TDCs; corresponding stripe and pad image signals are latched. Pad sizes range from 0.8 cm*3.6 cm to 3.2 cm*35 cm. In addition to facilitating pattern recognition, pad signals are also used as inputs to an online, high transverse momentum trigger processor.<<ETX>>

The Fermilab E771 spectrometer: A large aperture spectrometer to study charm and beauty states as detected by decays into muons

This paper describes the final incarnation of the Fermilab High Intensity Lab spectrometer which operated for ten years in the Proton West Area of Fermilab in the execution of two experiments (E537 and E705) which studied hadroproduction of high mass dimuon pairs. The version of the spectrometer used in E771 differed from earlier versions of the spectrometer by the addition of a silicon microstrip detector, pad chambers and resistive plate counters. These additions were implemented to give the spectrometer the capability of detection of secondary decay vertices from B → μ or B → Jψ → μμ decays. As discussed, the spectrometer in a short data taking period was able to address many kinds of physics, other than beauty decays.

Hadroproduction of theχ1andχ2states of charmonium in 800-GeV/cproton-silicon interactions

The cross sections for the hadroproduction of the Chi1 and Chi2 states of charmonium in proton-silicon collisions at sqrt{s}=38.8 GeV have been measured in Fermilab fixed target Experiment 771. The Chi states were observed via their radiative decay to J/psi+gamma, where the photon converted to e+e- in the material of the spectrometer. The measured values for the Chi1 and Chi2 cross sections for x_F>0 are 263+-69(stat)+-32(syst) and 498+-143(stat)+-67(syst) nb per nucleon respectively. The resulting sigma(Chi1}/sigma(Chi2) ratio of 0.53+-0.20(stat)+-0.07(syst), although somewhat larger than most theoretical expectations, can be accomodated by the latest theoretical estimates.

Effects of high energy protons on the E771 silicon microstrip detector

Abstract A silicon strip detector (SSD) system for use in very high rate experiments has been operated in Experiment E771 (Cox, 1989) at the Fermi National Accelerator laboratory. The detector electronics were designed (Swoboda, 1990; Bowden, 1990; Zimmerman, 1989; Christian, 1991) to meet the specific needs of Fermilab experiment E771 using ASIC chip sets where commercial circuits were not suitable. The electronics for the SSD were designed to operate at rates up to 60 Mhz and were operated at interaction rates up to 10 7 interaction/sec (beam rates of 2 × 10 8 proton/sec). In addition to being very fast, the detector for the 1991 run was very compact with 10000 channels of active detector in a volume fo 5cm × 5cm × 10cm. An expansion of the system to 16000 channels is planned for the next Fermilab fixed target run. The strip pitch ranged from 25 μ m in the center of the detector near the target to 100 μ m pitch at the most downstream, outer edges of the detector. The readout is a latch design with pipelined readout and appears to have single strip efficiencies of ≈ 75% even in the presence of a high radiation dose (∽ 10 14 protons/cm 2 ) and high leakage currents(≈ 1 nA/strip). The detector and associated amplifier electronics has presently been operated at 17° C and is designed to operate as low as 8° C.

B physics at FNAL E771

Abstract The short-term prospects for Fermilab experiment E771 - devoted to the hadroproduction of beauty - are described as well as the major characteristics of the spectrometer. Expectations for detection and reconstruction of exclusive B decay channels are discussed.