The physics of heavy quark distributions in hadrons: Collider tests

Abstract

We present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron wavefunctions -the "intrinsic" quarks, is reviewed. The determination of heavy-quark parton distribution functions (PDFs) is particularly significant for the analysis of hard processes at LHC energies. We show that a careful study of the inclusive production of open charm and the production of γ/Z/W particles, accompanied by the heavy jets at large transverse momenta can give essential information on the intrinsic heavy quark (IQ) distributions. We also focus on the theoretical predictions concerning other observables which are very sensitive to the intrinsic charm contribution to PDFs including Higgs production at high x F and novel fixed target measurements which can be tested at the LHC.

Hard production of a Z boson plus heavy flavor jets at LHC and the intrinsic charm content of a proton

“…Hard production of vector bosons accompanied by heavy flavor 1 jets (V + HF) in pp collisions at LHC energies can be considered as an additional tool to study the quark and gluon PDFs compared to the deep inelastic scattering of electrons on protons. In these processes, in the rapidity region |y| < 2.5, which corresponds to the kinematics of ATLAS and CMS experiments, one can study these PDFs not only at low parton momentum fractions x < 0.1 but also at larger x values [1]. Therefore, such V + HF processes can give us new information on the PDFs at large x > 0.1, where the non-trivial proton structure (for example, the possible contribution of valence-like intrinsic heavy quark components) can be revealed [2][3][4][5].…”

“…Intense studies of an intrinsic charm (IC) signal in the production of vector (Z and W ) bosons or prompt photons γ accompanied by heavy-flavor jets in pp collisions at LHC energies were made in [1,[6][7][8][9]. It was shown that the contribution of IC to the proton PDFs can be visible in the transverse momentum spectra of γ/Z/W or c/b-jets in the forward rapidity region of the ATLAS and CMS kinematics, 1.5 < |y| < 2.5, at large p T > 100 GeV.…”

“…Up to now there is a long-standing debate about the w IC value [9][10][11][12] (see also [1] and references therein). A first estimate of the intrinsic charm probability in the proton was carried out in [13] utilizing recent ATLAS data on the production of prompt photons accompanied by c-jets at √ s = 8 TeV [14].…”

Collider test of proton intrinsic charm in γ ( Z )+ c ( b ) production by pp collisions

“…The hypothesis of the intrinsic (or valence-like) heavy quark component, the quark Fock state |uudQQ [1]- [4] in a proton suggested by Brodsky with coauthors [1,2] (BHPS model) is intensively discussed in connection with an opportunity to verify it experimentally, see [5] and the review [6] and references there in. Below we perform the calculations in two ways.…”

IC at IC: IceCube can constrain the intrinsic charm of the proton

“…Most calculations of the prompt neutrino spectrum from charm hadroproduction are based within perturbative QCD (pQCD) gluon splitting g → cc alone [63-71, 73-81, 85-87]. Inclusion of nonperturbative effects, for e.g., intrinsic charm [88][89][90][91], have received much less consideration [61,62]. Recently attention has been drawn to forward production of charm hadrons by Refs.…”