The Study Of The Hadron Transverse Momentum P_T Spectrum In Pp And P-Pb Collisions In The LHC Energy Region

Hadronization,the process of formation of observable hadrons out of final-state quarks and/or gluons created in high energy reactions,is currently described by the phenomenological models closely interacting with experiments,since the Non-Pertuibative Quantum Chromo Dynamics?QCD?has difficulties in dealing with it directly.In recent years,the Large Hadron Collider?LHC?has successfully increased the central collision energy to TeV magnitude,and has obtained the rich experimental data of pp,p-Pb and Pb+Pb collisions,which provides an unprecedented opportunity for the studying of hadron production mechanism.Lately,the ALICE and CMS experiments have found a series of new properties of hadron production in the small parton systems created in high multiplicity events of pp and p-Pb collisions,e.g.,long-range angular correlations and collectivity,enhanced strangeness and high-enhanced baryon to meson ratios at soft transverse momentum,which in heavy ion collisions of RHIC and LHC are typically attributed to the formation of a strongly interacting QGP.Does this imply that the small parton systems in high-energy collisions has also been deconfined or mini-QGP created?Therefore,the search of new properties or signals involving the mini-QGP,deconfinement and new features of hadronization is a hot topic of theoretical research in high-energy reaction at LHC.Quark combination mechanism can successfully explain many experimental phenomena of identified hadrons production in heavy-ion collisions of LHC and RHIC.This paper adopts the quark combination mechanism to systematically study the yield and transverse momentum spectrum of identified hadrons in pp and p-Pb collisions at LHC.The study focuses on whether these small parton systems are deconfined or not,and puts particular emphasis on the discussion of new possible signals of deconfinement from the aspect of the hadronization,thereby gains deep insights into the new property and hadronization.This article is organized as follows:???Study of hardonic yield and transverse momentum spectrum in pp collisions at???= 7TeV.The LHC experiments have revealed a series of new features of hadron production in high multiplicity events of pp collision.We apply quark combination mechanism with the parametrized up?down?quark spectrum and strange quark spectrum at hadronization to systemically study the hadron yield and transverse momentum spectrum of p????????^-???K?892?^*0?????1530?^*0,the average transverse momentum<p_T)of light hadrons,strange hadrons and resonance particles,the hadrons ratios of ???/???/???/????K/? as the function of p_T.The results calculated from quark combination reproduce the data quite well and we compare with the other hadronization models.We further make predictions for the p_T distributions of other hadrons for the future test,and propose the possible existence of two scaling behaviors among the p_T spectra of decuplet baryons and vector mesons as the effective probe of hadron production mechanism at such high collision energies.These results suggest that the quark combination mechanism also plays an important role for hadron production in such small systems at LHC energy.???Study of quark number scaling of hadronic transverse momentum spectrum and constituent quark degree of freedom in p-Pb collisions at LHC.Recently,ALICE and CMS collaborations have observed many new striking features for high multiplicity events at Large Hadron Collider?LHC?such as long range angular correlations,enhanced strangeness which is an indication of the possible deconfinement or mini-QGP creation in such small parton systems.In this work,we systemically analyze the LHC data on p_T spectra of light hadrons,strange hadrons and resonance particles in p-Pb collisions at???= 5.02TeV,and,for the first time,we find that the p_T-spectra data exhibit an explicit quark number scaling.The scaling behavior is a direct consequence of quark combination mechanism of quarks and antiquarks with independent momentum distributions under"equal velocity combination".In this way,we can get the up?down?quark spectrum and strange quark spectrum by quark combination mechanism.We further study the p_T-spectra of p,?,???-,?^-,?,K?892?^*0,????1530?^*0,??1385?^*+ hadrons in the different multiplicity classes of p-Pb collisions,and the results calculated from quark combination reproduce the data quite well.This result is a strong evidence that constituent quark degree of freedom plays an important role in hadronization also in such"small system"and may be considered as a signature of formation of the deconfined system in p-Pb collisions at such high energies.