Kaon quark distribution functions in the chiral constituent quark model

Abstract

We investigate the valence u ands quark distribution functions of the K þ meson, v KðuÞ ðx; Q 2 Þ and v KðsÞ ðx; Q 2 Þ, in the framework of the chiral constituent quark model. We judiciously choose the bare distributions at the initial scale to generate the dressed distributions at the higher scale, considering the meson cloud effects and the QCD evolution, which agree with the phenomenologically satisfactory valence quark distribution of the pion and the experimental data of the ratio v KðuÞ ðx;Q 2 Þ=v πðuÞ ðx;Q 2 Þ. We show how the meson cloud effects affect the bare distribution functions in detail. We find that a smaller SUð3Þ flavor symmetry breaking effect is observed, compared with results of the preceding studies based on other approaches.

Parton Distribution Functions from a Light Front Hamiltonian and QCD Evolution for Light Mesons

“…The parton distribution function (PDF), the probability that a parton (quark or gluon) carries a certain fraction of the total light front momentum of a hadron, encodes the nonperturbative structure of hadrons, attracting numerous dedicated experimental and theoretical efforts [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Since experimental results span a large range of momentum transfers, one must address the dependence of these results on the resolving power (scale) of the experimental probe, which is equivalent to addressing the physics of scale evolution based on quantum chromodynamics (QCD) [20].…”

“…The valence PDF of the kaon has been theoretically investigated in Refs. [9,11,[37][38][39][40][41][42][43][44]. Similar to the scale dependence of the angular momentum observables [45,46], addressing these two issues requires a unified approach, such as we describe here, that successfully encapsulates properties of both the pion and the kaon at their respective model scales, while the available data across various other scales are then modeled with reasonable precision after QCD evolution.…”

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

“…Explicitly, we evolve the input PDFs given in Eqs. (10) and (14) to the relevant experimental scale µ 2 = 16 GeV 2 using the higher order perturbative parton evolution toolkit (HOPPET) to solve the NNLO DGLAP equations [71]. While applying the DGLAP equations numerically, we impose the condition that the running coupling α s (µ 2 ) saturates in the infrared at a cutoff value of max α s = 1 [36,72].…”

“…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]. Quantum chromodynamics (QCD) is the underlying theory to explain the structure of hadrons in all energy regions.…”

“…[3,7,8], whereas the determinations of the light meson and the nucleon PDFs with associated uncertainties from the experiments have been reported in Refs. [6,9,10,11,12,13,14,15,16,17,18]. The first global QCD analysis of the pion PDF has been performed in Ref.…”