W. Yang

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.