Implementation of target mass corrections and higher-twist effects in the xFitter framework

Muhammad Goharipour,S Rostami

doi:10.1103/physrevd.101.074015

Abstract

Knowledge of parton distribution functions (PDFs) at large momentum fraction $ x $ is not only important to study the flavor and spin dynamics of quarks in the nucleon, but also to search for signals of new physics at collider experiments. It is well known now that the nonperturbative QCD effects generally play a more significant role at such kinematic regions. In this work, we present an open-source QCD analysis of PDFs considering target mass corrections (TMCs) and higher-twist (HT) effects which are necessary when the analysis includes also data points from deep inelastic scattering (DIS) with larger values of $ x $ and smaller values of photon virtuality $ Q^2 $. To this aim, we use the xFitter package, as a comprehensive and powerful tool for studying PDFs. We report and discuss our recent activities on the implementation of TMCs and HT effects in the xFitter framework in a user-friendly way, so that the user can switch on or off them, and also choose between different options. We check the validity of the modifications by performing sample analyses of PDFs considering TMCs and HT effects and using a wide range of DIS data.

Highlights

Thanks to the high-energy scattering data from various accelerator facilities worldwide, significant advances have been made toward the internal structure of the nucleon using the framework provided by the quantum chromodynamics (QCD)
It should be noted that we impose kinematic cut Q2 > 1.69 GeV2 on all deep inelastic scattering (DIS) data and W2 > 3.0 GeV2 on all fixed target data, since we are going to study the impact of target mass corrections (TMCs) and HT effects on extracted parton distribution functions (PDFs)
The results obtained clearly show that considering TMCs solely can include the nonperturbative effects to a large extent and HT helps to improve results even further. We found that such a situation is established if one first turns on HT and includes TMCs, which indicates that considering HT effects solely can include the nonperturbative effects to a large extent

Summary

Introduction

Thanks to the high-energy scattering data from various accelerator facilities worldwide, significant advances have been made toward the internal structure of the nucleon using the framework provided by the quantum chromodynamics (QCD). To analyze this huge amount of data, concerted efforts are being made to improve information about the parton distribution functions (PDFs) of the proton [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15].

Objectives

Results

Conclusion