Measurement of high-Q^2 charged current deep inelastic scattering cross sections with a longitudinally polarised positron beam at HERA

TL;DR

This paper reports precise measurements of charged current deep inelastic scattering cross sections with a polarised positron beam at HERA, confirming Standard Model predictions and setting limits on hypothetical W boson masses.

Contribution

First measurement of CC DIS cross sections with a longitudinally polarised positron beam at HERA, providing new data for testing the Standard Model and constraining new physics.

Findings

Measurements agree with Standard Model predictions.

Set lower limit on right-handed W boson mass.

Provided detailed differential cross-section data.

Abstract

Measurements of the cross sections for charged current deep inelastic scattering in e+p collisions with a longitudinally polarised positron beam are presented. The measurements are based on a data sample with an integrated luminosity of 132 pb^-1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is presented at positive and negative values of the longitudinal polarisation of the positron beams. The single-differential cross-sections ds/dQ^2, ds/dx and ds/dy are presented for Q^2 > 200 GeV^2. The reduced cross-section is presented in the kinematic range 200 < Q^2 < 60,000 GeV^2 and 0.006 < x < 0.562. The measurements agree well with the predictions of the Standard Model. The results are used to determine a lower limit on the mass of a hypothetical right-handed W boson.