Measurement of jet production in deep inelastic scattering and NNLO determination of the strong coupling at ZEUS

TL;DR

This paper presents a precise measurement of jet production in deep inelastic scattering at HERA, using NNLO QCD analysis to determine the strong coupling constant and demonstrate its running across different energy scales.

Contribution

It provides a new, high-precision determination of the strong coupling constant using NNLO QCD analysis of jet data from ZEUS, improving accuracy over previous measurements.

Findings

Measured jet cross sections as a function of Q^2 and p_T in the Breit frame.

Determined alpha_s(M_Z^2) = 0.1142 with reduced uncertainties.

Confirmed the running of the strong coupling across different energy scales.

Abstract

A new measurement of inclusive-jet cross sections in the Breit frame in neutral current deep inelastic scattering using the ZEUS detector at the HERA collider is presented. The data were taken in the years 2004 to 2007 at a centre-of-mass energy of $318\,\text{GeV}$ and correspond to an integrated luminosity of $347\,\text{pb}^{-1}$. Massless jets, reconstructed using the $k_t$-algorithm in the Breit reference frame, have been measured as a function of the squared momentum transfer, $Q^2$, and the transverse momentum of the jets in the Breit frame, $p_{\perp,\text{Breit}}$. The measured jet cross sections are compared to previous measurements and to perturbative QCD predictions. The measurement has been used in a next-to-next-to-leading-order QCD analysis to perform a simultaneous determination of parton distribution functions of the proton and the strong coupling, resulting in a value of $\alpha_s(M_Z^2) = 0.1142 \pm 0.0017~\text{(experimental/fit)}$ ${}^{+0.0006}_{-0.0007}~\text{(model/parameterisation)}$ ${}^{+0.0006}_{-0.0004}~\text{(scale)}$, whose accuracy is improved compared to similar measurements. In addition, the running of the strong coupling is demonstrated using data obtained at different scales.