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Measurement of High-Q2 Neutral Current Cross-sections with Longitudinally Polarised Positrons with the ZEUS Detector

The cross sections for neutral current (NC) deep inelastic scattering (DIS) in e+p collisions
with a longitudinally polarised positron beam are measured at high momentum
transfer squared (Q2 > 185 GeV2) at the ZEUS detector at HERA. The HERA accelerator
provides e+-p collisions at a centre-of-mass energy of 318 GeV, which allows the
weak contribution to the NC process to be studied at high Q2. The measurements are
based on a data sample with an integrated luminosity of 135.5 pb-1 collected with the
ZEUS detector in 2006 and 2007. The single differential NC cross sections dsigma/dQ2,
dsigma/dx and dsigma/dy and the reduced cross section are measured. The structure function
xF3 is determined by combining the e+p NC reduced cross sections with the previously
measured e-p measurements. The interference structure function xF 3^gamma,Z is extracted at Q2 = 1500 GeV2.

The cross-section asymmetry between the positive and negative polarisation of the
positron beam is measured and the parity violation effects of the electroweak interaction
are observed.

The predictions of the Standard Model of particle physics agree well with the measurements.

Identiferoai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/34931
Date07 January 2013
CreatorsStewart, Trevor
ContributorsMartin, John
Source SetsUniversity of Toronto
Languageen_ca
Detected LanguageEnglish
TypeThesis

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