Pion-nucleus induced Drell-Yan cross section in models inspired by light-front holography

Jiangshan Lan,Chandan Mondal

doi:10.1016/j.physletb.2020.135613

Abstract

We evaluate the cross section for the pion induced Drell-Yan process in two different models of the pion light-front wave function, inspired by light-front holographic approaches. We obtain the valence quark distribution functions in those models, which after QCD evolution, are consistent with the experimental data from the E-0615 experiment at Fermilab. Supplemented by the parton distribution functions of the target nuclei, we obtain the cross section consistent with the experimental data for the π− Nucleus →μ+μ−X Drell-Yan process.

Highlights

The next-toleading order (NLO) analyses of this Drell-Yan process have been carried out in Refs. [3, 7, 8], whereas the determinations of the light meson and the nucleon parton distribution functions (PDFs) with associated uncertainties from the experiments have been reported in Refs. [6, 9, 10, 11, 12
We adopt the initial scale μ20I = 0.236 ± 0.024 GeV2 for the ModelI, which we determine by requiring the results after Quantum chromodynamics (QCD) evolution to fit the reanalysis of the FNAL-E0615 data for the pion PDF [9, 73]
We calculated the valence quark PDF of the pion using the pion light-front wave functions in two different models inspired by light-front holographic QCD

Summary

Introduction

The determination of parton distribution functions (PDFs) from the analysis of hard scattering processes has emerged as one of the main topics of hadron physics, attracting dedicated theoretical and experimental efforts [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]. The pion valence PDF at large-x shows a linear (1 − x) or slightly faster falloff, which is supported by the NJL model [28], the constituent quark model [29], and duality arguments [38] This observation is in discrepancy with perturbative QCD [39, 40, 41, 42] and the BetheSalpeter equation approach [11, 43], where the behavior has been predicted as (1 − x). With the dilaton profile of the soft-wall model, φ(z) = κ2z2, one can solve the holographic Schrodinger equation, which yields the meson mass spectrum, ple approach known as Bottom-Up allows to built the models that have some essential QCD features, such as counting rules and confinement.

Light-front holographic wave functions for the pion

Model-I

QCD evolution of the PDFs

Cross section in unpolarized Drell-Yan process

Summary