ABM news and benchmarks

TL;DR

This paper updates the ABM global fit framework for unpolarized nucleon PDFs with new collider data, improving accuracy at small x and analyzing the impact on the gluon distribution and _s.

Contribution

It provides an updated set of PDFs incorporating recent experimental data and theoretical improvements, with minimal impact observed from top-quark production cross sections.

Findings

Updated PDFs with improved accuracy at small x

Minimal impact of top-quark data on gluon distribution

Determined _s(M_Z)=0.1133(8) from the fit

Abstract

We report on progress in the determination of the unpolarised nucleon PDFs within the ABM global fit framework. The data used in the ABM analysis are updated including the charm-production and the high-Q2 neutral-current samples obtained at the HERA collider, as well as the LHC data on the differential Drell-Yan cross-sections. An updated set of the PDFs with improved experimental and theoretical accuracy at small x is presented. We find minimal impact of the t-quark production cross section measured at the Tevatron and the LHC on the gluon distribution and the value of the strong coupling constant \alpha_s determined from the ABM fit in the case of the t-quark running-mass definition. In particular, the value of \alpha_s(M_Z)=0.1133(8) is obtained from the variant of the ABM12 fit with the Tevatron and CMS t-quark production cross-section data included and the MSbar value of m_t(m_t)=162 GeV.