Study On The Transverse Momentum Spectra Of Strange Hadrons In 13TeV Pp Collisions On LHC

Most of the final hadrons produced in high energy reactions are called soft hadrons because of their small transverse momentum.The production of soft hadrons is dominated by various Non-Perturbative Quantum Chromodynamics(QCD)processes.Hadronization,process of the final quark and gluon transforming into hadron produced in the high energy reaction is a complex QCD Non-Perturbative process.Due to the difficulty of Non-Perturbative QCD,peoples can only use various phenomenological models to describe hadronization at present.Quark combination model is a phenomenological model of hadronization.Since the model was proposed in the 1980s,it has successfully explained hadron production in the early e+e-pair annihilation and p+p(collision energy is tens of GeV)reactions.In relativistic heavy ion collisions,quark combination model has been widely used to describe hadronization of quark gluon plasma(QGP).It has successfully explained a series of striking features of hadron production observed by RHIC and LHC experiments,e.g.,quark number scaling of hadronic elliptic flow and high baryon-meson ratio in the intermediate transverse momentum region,strangeness-related hierarchy,etc.Recently,ALICE collaboration reported the preliminary data of transverse momentum spectra of identified hadrons at midrapidity in inelastic events in pp collisions(?)=13 TeV.We show that the data of transverse momentum pT spectra of multi-strange baryon ?-and meson(?)exhibit a constituent quark number scaling property,which is a clear signal of quark combination mechanism at hadronization.In this paper,the strange hadrons yield and its transverse momentum spectra in pp collision at(?)=13 TeV are systematically studied by using a quark combination model under equal velocity combination approximation.Model results are compared with the latest experimental data of ALICE collaboration.The main contents and conclusions of this paper are as follows:(?)Study of PT spectra of identified strange hadrons in inelastic events in pp collisions at(?)=13 TeV Firstly,we show the constituent quark number scaling property for the data of PT spectra of ?-and(?).The PT spectra of strange s quark at hadronization are extracted.The midrapidity data of pT spectra of proton,?,?-,?-,(?)and K*0 in inelastic events are calculated by using the quark combination model under equal velocity combination approximation.It is found that the model results are in good agreement with the experimental data.The transverse momentum spectra of u/d quarks are also extracted during hadronization,and the differences between u/d quark and s quark are analyzed.The data of transverse momentum spectrum of p/(?)ratio is calculated and show a strong PT dependence for it,which is in agreement with the experimental data.It suggests that the production of two hadrons with similar masses is mainly determined by their quark contents,not the hadron mass,which is obviously different from the statistical thermal model.(?)Study of yield and pT spectra of strange hadrons in different multiplicity classes in pp collisions at(?)=13 TeV.Based on the preliminary data of pT spectra of proton and(?)in different multiplicity classes from ALICE collaboration,the pT spectra of u/d quark and s quark in different multiplicity classes are extracted by using quark combination model.pT spectra of other strange hadrons(???-??-?K*0??*and ?*in different multiplicity classes are predicted.The dependence of yield ratio ?/?,?-/? and ?-/? as the function of midrapidity density of charged particle multiplicity has been systematically studied and compared with the experimental data,and a good agreement has been found.Strangeness-related hierarchy exhibited by the production of strange hadrons are naturally understood by quark combination mechanism.