High Q^2 Measurements from HERA

TL;DR

This paper presents new high Q^2 cross section measurements from HERA II, confirming Standard Model predictions and providing the most precise unpolarised data by combining HERA I and II results.

Contribution

It reports the first high Q^2 measurements with polarized beams from HERA II and combines them with previous data for enhanced precision.

Findings

Polarisation asymmetry matches Standard Model predictions

Charged current cross section depends on beam polarisation as expected

Combined data yields the most precise unpolarised measurements to date

Abstract

New measurements of neutral and charged current cross sections at large negative four-momentum transfer squared Q^2 have been performed by H1 and ZEUS, using up to the complete HERA II ep data, which was taken with polarised electron and positron beams. The data are compared to predictions of the Standard Model, based on various parton distribution function parameterisations. The polarisation asymmetry of the neutral current interaction is measured as a function of Q^2, as well as the polarisation dependence of the charged current cross section and both are found to be in agreement with the Standard Model expectation. The HERA II cross sections are also combined with previously published HERA I data to obtain the most precise unpolarised measurements.