Impact of Beauty and Charm H1-ZEUS Combined Measurements on PDFs and Determination of the Strong Coupling

TL;DR

This paper analyzes how recent charm and beauty cross section measurements from HERA influence the determination of parton distribution functions and the strong coupling constant, leading to reduced uncertainties and improved fit quality.

Contribution

It introduces a comprehensive QCD analysis incorporating recent heavy-flavor data to refine PDFs and the strong coupling, demonstrating the impact of charm and beauty measurements on these parameters.

Findings

Including charm and beauty data reduces gluon distribution uncertainty.

Fit quality improves by up to 4.1% at NLO with heavy-flavor data.

Uncertainty decreases by up to 1.7% when including heavy-flavor data at NLO.

Abstract

In this QCD analysis, we investigate the impact of recent measurements of heavy-flavor charm and beauty cross sections data sets on the simultaneous determination of Parton Distribution Functions (PDFs) and the strong coupling, $\alpha_s(M^2_Z)$. We perform three different fits based on Variable-Flavour Number Scheme (VFNS) at the Leading Order (LO) and Next-to-Leading Order (NLO) and choose the full HERA run I and II combined data as a new measurement of inclusive Deep Inelastic Scattering (DIS) cross sections for our base data set. We show that including charm and beauty cross sections data reduces the uncertainty of gluon distribution and improves the fit quality up to 4.1\% from leading order to next-to-leading order and up to 1.7\% for only NLO without and with beauty and charm data contributions.