Combination and QCD Analysis of Charm Production Cross Section Measurements in Deep-Inelastic ep Scattering at HERA

TL;DR

This paper combines charm production measurements from HERA to perform a detailed NLO QCD analysis, studying heavy flavor schemes, determining charm mass, and assessing implications for LHC W/Z predictions.

Contribution

It introduces a combined dataset of charm production cross sections and uses it to analyze the impact of heavy flavor schemes on parton distribution functions and charm mass determination.

Findings

Optimal charm mass values obtained for different schemes

Implications for W and Z production cross sections at LHC

Running charm mass determined using fixed flavor scheme

Abstract

Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections sigma_red^{c\bar{c}} for charm production are obtained in the kinematic range of photon virtuality 2.5<Q2<2000 GeV2 and Bjorken scaling variable 0.00003<x<0.05. The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deep-inelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W^{\pm} and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined.