122023821
Measurement of the double-spin asymmetry ALL for inclusive multi-γ pair production with 200 GeV/c polarized proton beam and polarized proton target
The invariant double-differential cross section, E1E2d6 delta/dp(1)3dp(2)3, and the double-spin asymmetry, A(LL), for inclusive multi-gamma pair production in which gamma-rays came from neutral mesons were measured with a 200 GeV/c longitudinally-polarized proton beam and a longitudinally-polarized proton target. Most of the multi-gamma pairs comes from two-jet type events which are sensitive to partonic interaction. The A(LL) values were found to be consistent with zero. The invariant double-differential cross section for inclusive pi0pi0 production was also measured. These measured cross sections are consistent with LUND Monte Carlo simulations. Using the LUND Monte Carlo simulation package with the Carlitz-Kaur model of spin dependent distribution functions of valence quarks, the A(LL) values have been compared with theoretical predictions of gluon polarization, DELTAG/G. The results put restrictions on the size of DELTAG/G in the region of 0.05 less-than-or-similar-to x less-than-or-similar-to 0.35.
124083721
SOME ASPECTS OF TARGETING SYSTEMS FOR A SLOW EXTRACTED BEAM AT THE AGS.
126003037
The Meson Area at 1000-GeV
123662576
Observation of a likely example of the decay of a charmed particle produced in a high energy neutrino interaction
Abstract In a study of neutrino interactions occurring in nuclear emulsion, an event has been found that is most readily interpreted as the decay of a charmed particle with lifetime a few times 10 −13 s.
124689502
A POSSIBLE SPECTROMETER FOR ACCOMPLISHING A SECONDARY BEAM SURVEY AT NAL.
121757543
Measurement of single spin asymmetry for direct photon production in pp collisions at 200 GeV/c
The single spin asymmetry for inclusive direct-photon production has been measured using a polarized proton beam of 200 GeV/c with an unpolarized proton target at −0.15 < xf < 0.15 and 2.5 < pt < 3.1 GeV/c at Fermilab. The data on the cross section for pp → γX at 2.5 < pt < 3.8 GeV/c are also provided. The measurement was done using lead-glass calorimeters and photon detectors which surrounded the fiducial area of the calorimeters. Background rejection has been done using these surrounding photon detectors. The cross section obtained is consistent with the results of previous measurements assuming a nuclear dependence of A1.0. The single spin asymmetry, AN, for the direct-photon production is consistent with zero within experimental uncertainty.
12181544
PROTOTYPE TESTS FOR A VERTEX CHAMBER
We describe the design parameters for a pressurized drift chamber under construction for use with the MAC detector at PEP to operate within 3 cm of the beam line. The chamber is constructed of 7 mm diameter tubes of aluminized mylar with wall thickness of 0.10 mm. The tracking device incorporating these tubes is particularly simple to construct and can be configured so that any malfunctioning tube cau be remotely disconnected without affecting overall og erations. Resolution studies made in a SLAC test beam with a prototype over a wide range of gases and operating conditions are reported. The resolutions obtained were in the 10-40 micron range. It was found that the chamber could be operated satisfactorily, using heavily quenched gases, at high pressures (~4 atm) and operating voltages of ~4 kV in a mode for which saturated streamers were initiated with high efficiency by single electrons. Single electron gains for this mode were -108. The streamers were confined to a region of the wire with dimension of the order of a few hundred microns and count rates in excess of lo4 Hz/cm could be sustained with low dead-times. Further studies are in progress on chamber lifetimes with a variety of gas Elliogs. For our specific application this is of particular importance as the vertex chamber is expected to run in regions of high radiation backgrounds. As was expected for a chamber with extended cathodes, lifetimes were good. Actual lifetimes observed to date with our tube configurations have ranged from 0.05 coul/cm integrated current on the anode for 50:50 argon-isobutane to ~1 coul/cm for a mix of 49% A: 50% CO2: 1% C&. The results of these tests show our design goals to be achievable. Additionally they provide a basis on which to design high precision tracking devices particularly in applications where the device is to be operated in regions of difficult physical access or high ambient radiation levels.
111306611
Prototype design, construction and test of a Pb/scintillator sampling calorimeter with wavelength shifter fiber optic readout
A prototype for the new DELPHI luminosity monitor has been built and tested. The scope of this prototype is to measure the response of the proposed calorimeter in the region which is most critical for the luminosity measurement, i.e., at the inner edge of the acceptance. The aim of the new luminosity monitor is to measure the LEP (Large Electron Position Collider) luminosity with per mill systematic uncertainty. This requires experimental biases at the level of 50 mu m or less in the definition of the fiducial volume. The technique used ensures good energy resolution and high spatial uniformity. With the prototype, better than 2% uniformity in response and an energy resolution of 3% at 45 GeV have been achieved. >
122512473
Linear interpolation of histograms
A prescription is defined for the interpolation of probability distributions that are assumed to have a linear dependence on a parameter of the distributions. The distributions may be in the form of continuous functions or histograms. The prescription is based on the weighted mean of the inverses of the cumulative distributions between which the interpolation is made. The result is particularly elegant for a certain class of distributions, including the normal and exponential distributions, and is useful for the interpolation of Monte Carlo simulation results which are time-consuming to obtain. ( 1999 Elsevier Science B.V. All rights reserved.
110699804
The small angle tile calorimeter project in DELPHI
The new Small Angle TIIe Calorimeter (STIC) covers the forward regions in DELPHI. The main motivation for its construction was to achieve a systematic error of 0.1% on the luminosity determination. This detector consists of a “shashlik” type calorimeter, equipped with two planes of silicon pad detectors placed respectively after 4 and 7.4 radiation lengths. A veto counter, composed of two scintillator planes, covers the front of the calorimeter to allow ϱ − γ separation and to provide a neutral energy trigger. The physics motivations for this project, results from extensive testbeam measurements and the performance during the 1994 LEP run are reported here.
108830204
A CMOS charge sensitive amplifier for silicon strip detectors: Design criteria and test results
Abstract A low noise charge sensitive amplifier has been developed with a commercial CMOS process. We present measurements of the amplifier's performance when used to read out a silicon strip detector exposed to a particle beam. A few prototypes have been exposed to large doses of radiation in order to study the radiation hardness.