Production of light flavor and single-charmed hadrons in $pp$ collisions at $\sqrt{s}=5.02$ TeV in an equal-velocity quark combination model

Abstract

We apply an equal-velocity quark combination model to study the production of light-flavor hadrons and single-charmed hadrons at midrapidity in pp collisions at √ s = 5.02 TeV. We find experimental data for pT spectra of Ω and φ exhibit a quark number scaling property, which is a clear signal for quark combination mechanism at hadronization. Experimental data of p , Λ, Ξ, Ω, φ and K * 0 are systematically described by the model. The non-monotonic pT dependence of Ω/φ ratio can be naturally explained using only combination mechanism and we find it is closely related to the concave/convex shape of the logarithm of strange quark pT spectrum. Using pT spectra of light-flavor quarks extracted from light-flavor hadrons and a charm quark distribution which is consistent with perturbative QCD calculations, the differential cross-sections of D 0,+ , D + s and Λ + c as the function of pT are systematically described. We predict the differential cross-sections of Ξ 0,+ cand Ω 0 c . The ratio Ξ 0,+ c /D 0 in our model is about 0.16 and Ω 0 c /D 0 is about 0.012 due to the cascade suppression of strangeness. In addition, ratios Ξ 0,+ c /D 0 and Ω 0 c /D 0 exhibit the non-monotonic dependence on pT in the low and intermediate pT range.

Signals of quark combination at hadronization in $pp$ collisions at $\sqrt{s}=200$ GeV

“…On the other hand, compared with fragmentation mechanism, quark combination mechanism is conceptually more suitable to describe the hadronization of QGP and actually works well in relativistic heavy-ion collisions. Interestingly, our recent works [32][33][34][35][36][37] suggest that an equal-velocity quark combination mechanism at hadronization can systematically describe the momentum spectra of hadrons in pp collisions at LHC energies. Therefore, signals of quark combination found in pp collisions at √ s =200 GeV in current study, which indicate the stochastic combination of quarks and antiquarks at hadronization, inspire us to consider the possibility of mini-QGP creation in pp colli-sions at RHIC energies!…”

“…The detailed derivation of coefficient κ h in the EVC model can be found in Refs. [33,34,37]. In Fig.…”

“…This attracts intensive theoretical studies from different aspects [25][26][27][28][29][30]. Our recent studies [31][32][33][34][35][36][37] found that an equal-velocity combination (EVC) mechanism of constituent quarks and antiquarks can systematically describe p T spectra of light-flavor and single-charm hadrons. Compared with the traditional viewpoint that fragmentation mechanism is often applied to small parton system and usually successful, our studies indicate the new feature of hadron production in pp and pA collisions at LHC energies.…”

“…Experimental data were usually compared with calculations of event generators such as PHTHIA with tuned parameters. In view of our findings in pp collisions at LHC energies [31][32][33][34][35][36][37], it is interesting to study the performance of quark combination in pp collisions at √ s =200 GeV so as to find the similarity or difference in hadron production in pp collisions at two collision energy scales. The study of p T spectra of identified hadrons in this paper gives a surprising indication.…”