Study Of The Production Of Non-prompt D~0 Meson In LHC/ALICE

Quantum chromodynamics predicts that under extreme conditions(high temperature and high energy density),matter will undergo the phase transition from quark confinement to quark deconfinement,namely Quark Gluon Plasma(QGP).This matter phase existed in the early evolution of the universe,so the study of quark gluon plasma is of great significance for exploring the properties of the material structure in the early universe.Experimentally,the Large Hadron Collider(LHC)at CERN can accelerate nucleons to extremely high energies and collide them.By measuring the information of the final particles produced after the collision,the properties of quark-gluon plasmas can be studied,which can provide a way to further study the interactions of matter at partonic free degree.Since the rest mass of the heavy quark is very large and most of the heavy quarks produced in the early stage of hard scattering and thus experience the whole evolution of QGP.Therefore,the heavy flavor quark is an excellent probe for high-energy heavy ion collisions.By measuring the yield of heavy-flavor hadrons in the final state,the properties of the medium can be studied.The LHC-ALICE experiment has been used to study heavy hadrons in pp,p-Pb and Pb-Pb collision systems.By measuring the invariant yield ratio of heavy hadrons in Pb-Pb collisions(Ds+/D⁰),we can explore how the hot environment of heavy ion collision affects particle production mechanism.The energy loss of heavy quarks in QGP can be studied by measuring the nuclear correction factor R_AA.This theis mainly analyzes the experimental data from Pb-Pb collisions at(?)=5.02 TeV collected by the ALICE detector in 2018.In this analysis,we reconstruction D⁰ meson D⁰?K-?+decay channel in 30-50%centrality,and measured the pT spectrum of non-prompt D⁰ meson and the nuclear modification factor R_AA distribution using machine learning method.The first part of this thesis introduces quark-gluon plasma,high-energy heavy ion collisions and the research background and significance of this analysis.The second part introduces the ALICE experimental detector and the sub-detectors related to this analysis.The third part mainly introduces the experimental scheme in detail,including event selection,single track selection,signal extraction and different modification processes.The fourth part analyzes and compares the experimental results obtained.The experimental results show that when comparing the non-promt D⁰ meson R_AA distribution in 30-50%centrality with the results of 0-10%centrality,in the range of pT>2 GeV/c,the suppression effect of the semi-central collision is less than that of the central collision.The distribution of non-prompt D⁰ meson R_AA in 30-50%centrality was compared with that of prompt D⁰ meson in 30-50%centrality,showing that the distribution of non-prompt D⁰ meson was always above the prompt D⁰ meson in the region of intermediate transverse momentum.This means that the b quark has a lower energy loss than the c quark during their traveling through QGP.Comparing with different related model,we have the further understanding of measured results.In other words,the R_AA distribution may be affected by shadowing effect in the low transverse momentum interval.In the interval of medium transverse momentum,it may be due to radial flow and recombination effect.