5,827 research outputs found
Measurement of the charge asymmetry of electrons from the decays of W bosons produced in p p ¯ collisions at s =1.96 TeV
Publisher Copyright: © 2021 authors. Published by the American Physical Society.At the Fermilab Tevatron proton-antiproton (pp¯) collider, high-mass electron-neutrino (eν) pairs are produced predominantly in the process pp¯→W(→eν)+X. The asymmetry of the electron and positron yield as a function of their pseudorapidity constrain the slope of the ratio of the u- to d-quark parton distributions versus the fraction of the proton momentum carried by the quarks. This paper reports on the measurement of the electron-charge asymmetry using the full data set recorded by the Collider Detector at Fermilab in 2001-2011 and corresponding to 9.1 fb-1 of integrated luminosity. The measurement significantly improves the precision of the Tevatron constraints on the parton-distribution functions of the proton. Numerical tables of the measurement are provided.Peer reviewe
Single Top Quark Production as a Probe for Anomalous Moments at Hadron Colliders
Single production of top quarks at hadron colliders via fusion is
examined as a probe of possible anomalous chromomagnetic and/or chromoelectric
moment type couplings between the top and gluons. We find that this channel is
far less sensitive to the existence of anomalous couplings of this kind than is
the usual production of top pairs by or fusion. This result is
found to hold at both the Tevatron as well as the LHC although somewhat greater
sensitivity for anomalous couplings in this channel is found at the higher
energy machine.Comment: New discussion and 10 new figures added. uuencoded postscript fil
Search for low-mass WIMPs in a 0.6 kg day exposure of the DAMIC experiment at SNOLAB
We present results of a dark matter search performed with a 0.6 kg day
exposure of the DAMIC experiment at the SNOLAB underground laboratory. We
measure the energy spectrum of ionization events in the bulk silicon of
charge-coupled devices down to a signal of 60 eV electron equivalent. The data
are consistent with radiogenic backgrounds, and constraints on the
spin-independent WIMP-nucleon elastic-scattering cross section are accordingly
placed. A region of parameter space relevant to the potential signal from the
CDMS-II Si experiment is excluded using the same target for the first time.
This result obtained with a limited exposure demonstrates the potential to
explore the low-mass WIMP region (<10 GeV/) of the upcoming DAMIC100, a
100 g detector currently being installed in SNOLAB.Comment: 11 pages, 11 figure
Measurement of differential production cross section for bosons in association with jets in collisions at TeV
Differential cross sections for the production of bosons or off-shell photons in association with jets are measured in proton-antiproton collisions at center-of-mass energy TeV using the full data set collected with the Collider Detector at Fermilab in Tevatron Run II, and corresponding to 9.6 fb of integrated luminosity. Results include first measurements at CDF of differential cross sections in events with a boson and three or more jets, the inclusive cross section for production of and four or more jets, and cross sections as functions of various angular observables in lower jet-multiplicity final states. Measured cross sections are compared to several theoretical predictions
Construction of Precision sMDT Detector for ATLAS Muon Spectrometer Upgrade
This paper describes the small-diameter monitored drift-tube detector
construction at the University of Michigan as a contribution to the ATLAS Muon
Spectrometer upgrade for the high-luminosity Large Hadron Collider at CERN.
Measurements of the first 30 chambers built at Michigan show that the drift
tube wire position accuracy meets the specification of 20 microns. The
positions of the platforms for alignment and magnetic field sensors are all
installed well within the required precision. The cosmic ray test measurements
show single wire tracking resolution of 100 +- 7 microns with an average
detection efficiency above 99 %. The infrastructure, tooling, techniques, and
procedures for chamber production are described in detail. The results from the
chamber quality control tests of the first 30 constructed chambers are
reported.Comment: 35 pages, 41 figure
Measurement of the p\bar{p}\sqrt{s}$ = 1.8 TeV
We update the measurement of the top production cross section using the CDF
detector at the Fermilab Tevatron. This measurement uses decays to
the final states +jets and +jets. We search for quarks from
decays via secondary-vertex identification or the identification of
semileptonic decays of the and cascade quarks. The background to the
production is determined primarily through a Monte Carlo simulation.
However, we calibrate the simulation and evaluate its uncertainty using several
independent data samples. For a top mass of 175 , we measure
pb and pb using
the secondary vertex and the lepton tagging algorithms, respectively. Finally,
we combine these results with those from other decay channels and
obtain pb.Comment: The manuscript consists of 130 pages, 35 figures and 42 tables in
RevTex. The manuscript is submitted to Physical Review D. Fixed typo in
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