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Recent QCD results in {nu} - N deep-inelastic-scattering at CCFR/NUTEV

Description: We present recent QCD results in {nu}-N scattering at the Fermilab CCFR/NuTeV experiments. We present the latest Next-to-Next-Leading order strong coupling constant, {alpha}{sub s}, extracted from Gross-Llewellyn-Smith sum rule. The value of {alpha}{sub s} from this measurement, at the mass of Z boson, is {alpha}{sub s}{sup NNLO}(M{sub Z}{sup 2})=0.114{sub -0.012}{sup +0.009}. We also present a preliminary result of the CCFR F{sub 2} at large-x. This measurement of F{sub 2} is compared to other experiments and various models that provide nuclear effects. We discuss the previous strange sea quark measurement from the CCFR experiment and the prospects for improvements of the measurement in the NuTeV experiment.
Date: August 1, 1998
Creator: Yu, Jaehoon
Partner: UNT Libraries Government Documents Department

W/Z + jets production at the tevatron {bar p}p collider

Description: Both the D0 and CDF experiments at Fermilab Tevatron collider at {radical}s = 1.8TeV have accumulated over 13pb{sup {minus}1} of data during the 1992--1993 collider run. Each experiment collected more than 10,000 W {yields} l + {nu} and 1,000 Z {yields} l + {bar l} candidates for each lepton species (e and {mu}). Using this large data sample of W and Z candidates, the two experiments are actively testing perturbative QCD predictions. Among the studies that are in progress, preliminary results of Z+jets characteristics, multiplicity distributions of associated jets, and a determination of the strong coupling constant using the ratio of the +ljet to W + Ojet cross sections are presented.
Date: June 1, 1995
Creator: Yu, Jaehoon
Partner: UNT Libraries Government Documents Department

Gas Electron Multiplier (GEM) Chamber Characteristics Test

Description: Gas Electron Multipliers (GEMs) have been used in many HEP experiments as tracking detectors. They are sensitive to X-rays which allows use beyond that of HEP. The UTA High Energy group has been working on using GEMs as the sensitive gap detector in a DHCAL for the ILC. The physics goals at the ILC put a stringent requirement on detector performance. Especially the precision required for jet mass and positions demands an unprecedented jet energy resolution to hadronic calorimeters. A solution to meet this requirement is using the Particle Flow Algorithm (PFA). In order for PFA to work well, high calorimeter granularity is necessary. Previous studies based on GEANT simulations using GEM DHCAL gave confidence on the performance of GEM in the sensitive gap in a sampling calorimeter and its use as a DHCAL in PFA. The UTA HEP team has built several GEM prototype chambers, including the current 30cm x 30cm chamber integrated with the SLAC-developed 64 channel kPiX analog readout chip. This chamber has been tested on the bench using radioactive sources and cosmic ray muons. In order to have fuller understanding of various chamber characteristics, the experiments plan to expose 1-3 GEM chambers of dimension 35cm x 35cm x 5cm with 1cm x 1cm pad granularity with 64 channel 2-D simultaneous readout using the kPiX chip. In this experiment the experiments pan to measure MiP signal height, chamber absolute efficiencies, chamber gain versus high voltage across the GEM gap, the uniformity of the chamber across the 8cm x 8cm area, cross talk and its distance dependence to the triggered pad, chamber rate capabilities, and the maximum pad occupancy rate.
Date: January 11, 2011
Creator: Yu, Jaehoon; White, Andy; Park, Seongtae; Hahn, Changhie; Baldeloma, Edwin; Tran, Nam et al.
Partner: UNT Libraries Government Documents Department