Hadron Production And Jet-Medium Interaction In Light Of High Energy Multi-Production

The internal structure of hadron and its related problems have always been the hot field of the theoritical and experimental research of particle physics, which need to be further explored. A large number of exotic hadron states have been found in experiments of recent years, such as XYZ particles. The production mechanism of such new states is closely related to their structures. The investigation of the production mechanism of these hadrons, including exotic hadronic states, in light of different high energy reactions is crucial to further understanding the hadron structures, and is also a nature way to study QCD deeply.Relativistic heavy ion collisions improve the understanding of new matter states, hadronization mechanism and jet-medium interaction, and open up a new area for the strong interaction. In particular, the experimental measurements such as inclusive jet suppression phenomenon, di-jet asymmetry and isolated-photon+jet correlations ob-served in relativistic heavy ion collisions at the LHC provide opportunities and chal-lenges to further investigation of QGP. The research of jet-medium interaction mecha-nism is an effective way to explore the nature of the QGP. Its theorical research includes two aspects, the one is to study the characteristics of the jets after the influence of medi-um directly, the other is to study the reaction of the jets on the medium.It cannot be separated with high energy multi-production for studying hadron struc-ture and its production in high energy reactions as well as jet-medium interaction in high energy heavy ion collisions. In this thesis, we study two problems above in light of high energy multi-production, and the main research contents are as follows,We investigate the production of doubly heavy bayon and tetraquark in high energy e+e-annihilation. Firstly, we discuss the special color connections of four-heavy-quark system cccc in e+e--â†'ccccâ†'(?)cc+X process according to the SU(3) group. Only one of such special color connections can lead to the production of doubly heavy bayon and tetraquark. Then, we analyze the typical 3-jet event shape triggered by the special color connections at parton level, and calculate the production rate of double heavy bayon (or tetraquark Tcc). Finally, we investigate the hadronization of the special color connection with Lund string fragment model and quark combination model, the string effect of the special color connection does not depend on the specific hadronic model by comparing the results of the two models.We investigate the production of exotic hadron bound states in high energy hadronic colliders. We firstly review the non-relativistic wave function framework for the ex-otic hadron bound states production and decay. Then, we investigate the high energy hadronic production of some exotic hadrons which are observed in various experiments recently, and illustrate the crucial information of the production cross section of the hadron bound states, the invariant amplitudes of the ingredient hadrons in bound s-tates can not be calculated directly with quantum field theory. Hence we calculate the production cross sections of hadron bound states via the extrapolations of two particles correlation with event generators. The results of the rapidity distributions and transverse momentum distributions in high energy process ppâ†'H(A. B)+X are shown finally. The yields and the characteristics of dynamic distribution are of great reference value for studying the production of hadron bound states and exotic hadron states in high en-ergy multi-production process. These two works which can be reference to each other are beneficial supplement for studying currently exotic hadrons and hadron bound states in the decay process.We investigate the production of forward Ï€0 in high energy hadronic colliders. The measurement and analysis of forward Ï€0 production rate in high energy pp colliders can help to understand the UHECR phenomenon, which is very sensitive to the details of forward Ï€0 particle production. The development of the cosmic ray experiments is also very sensitive for the selection of hadron interaction models. We calculate the distribution of transverse momentum of forward Ï€0 in the rapidity range larger than y=8.9 in pp collision at (?)=7 TeV with quark combination model. The calculation results agree well with the LHCf experimental data. We extract the quark distribution information at forward rapidity region from the production process of forward Ï€0. It shows that quark combination mechanism is also good to describe the hadron production at forward rapidity range in hadronic colliders. This work provides the useful reference for the measurement of UHECR phenomenon.We investigate the jet-medium interaction in high energy heavy ion collisions. An even-t generator model named jet-embedded quark combination model is constructed. We firstly describe the production of initial jets in high energy heavy ion collisions em-ploying PYTHIA. According to the nuclear modification factor of the inclusive jets, a simple model of jet energy loss is selected. The lossing energy of jets is transformed into newborn quarks. Finally, the two cases hadronization of quark gluon matter with jets and quark gluon matter without jets are described with quark combination model, and the results of the two cases are compared. We calculate some observables such as average multiplicity, average scalar pt sum of charged particles and the neustral strange hadrons wrt the jets at (?)=2.76 TeV in the most central Pb+Pb collision with the model. The results show that jet-medium interaction leads to jets energy lossing, simultaneously, the medium is also influenced by jets so that the properties of such final particle observables wrt jets are changed. Background fragment functions of the jets in the most central Pb+Pb collision at (?)=2.76 TeV with the model are inves-tigated. The longitudinal momentum fractions and transverse momentum fractions of charged particles are calculated. These works provide an practical platform for further investigation of jet-medium interaction.