843 research outputs found
Measurement of Single-top Quark Production with ATLAS Data
Single-top production processes have been studied using 0.7 fb-1 of data from
7 TeV center-of-mass energy proton-proton collisions collected with the ATLAS
detector at the LHC. Single-top is electroweak top production and the standard
model includes three production modes. Each contains a Wtb vertex, allowing the
possibility of a direct measurement of the CKM matrix element |Vtb|. Single-top
could also be sensitive to new physics, such as flavor changing neutral
currents or heavy W' bosons. Using cut-based selections, a limit of < 39.1 pb
is set for dilepton Wt production and < 26.5 pb for s-channel production. For
the t-channel measurement, both cut-based and neural network analyses are
performed and the cross-section is measured to be 90 +32 -22 pb, where 65 +28
-19 pb is expected according to standard model.Comment: 3 pages, 2 figures, proceedings for XXXI Physics in Collision,
Vancouver, BC Canada, August 28 - September 1, 201
Foam-in-place materials for high voltage insulation in a space environment
Dielectric polyurethane foam materials tested for high voltage insulation in space environmen
Installation, commissioning, and testing of the HB650 CM at PIP2IT
The Proton Improvement Plan-II (PIP-II) is a major upgrade to the Fermilab
accelerator complex, featuring a new 800-MeV Superconducting Radio-Frequency
(SRF) linear accelerator (LINAC) powering the accelerator complex to provide
the world's most intense high-energy neutrino beam. This paper describes the
conversion of the PIP-II Injector Test Facility (PIP2IT) cryogenic system into
a test stand for PIP-II High-Beta 650 MHz (HB650) cryomodules at Fermilab's
Cryomodule Test Facility (CMTF). A description of the associated mechanical,
electrical, and controls modifications necessary for testing HB650 cryomodules
are provided. The cooldown and warmup requirements, procedures and associated
controls logic is described.Comment: 2023 Cryogenic Engineering Conference and International Cryogenic
Materials Conference (CEC/ICMC
Journal Staff
We present the first measurements of the differential cross section d sigma/dp(T)(gamma) for the production of an isolated photon in association with at least two b-quark jets. The measurements consider photons with rapidities vertical bar y(gamma)vertical bar < 1.0 and transverse momenta 30 < p(T)(gamma) < 200 GeV. The b-quark jets are required to have p(T)(jet) > 15 GeVand vertical bar y(jet)vertical bar < 1.5. The ratio of differential production cross sections for gamma + 2 b-jets to gamma + b-jet as a function of p(T)(gamma) is also presented. The results are based on the proton-antiproton collision data at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. The measured cross sections and their ratios are compared to the next- to- leading order perturbative QCD calculations as well as predictions based on the k(T)- factorization approach and those from the sherpa and pythia Monte Carlo event generators
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