Hadrons In Relativistic Heavy Ion Collisions And Deuteron Elliptic Flow

Since the operation of Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) in 2000, many important progresses have been made in studying microscopic material. The new properties of hadrons which were observed in experiment have shown that the quark gluon plasma (QGP) in high energy nucleus-nucleus collisions has been obtained. In theory, as the deconfined, there is no rigorous theoretical framework that is reliable for describing heavy-ion collisions. We have to study the properties of QGP indirectly through the properties of final hadrons with the hadronization model. Currently there are two more successful hadronization models: one is the parton fragmentation mechanism model, the other is the quark combination model.RHIC energy of nuclear-nuclear collisions produce a large number of solutions quark confinement material, its internal thermal pressure led to the expansion evolution of the hot and dense quark matter. The collective expansion of the hot and dense quark matter of the hadronic final state have very obvious effects can be observed, for example, the hadrons directed flow v₁, elliptic flow v₂, a higher level of v₄ flow and so on. Especially, elliptic flow can reflect more the properties of the hot and dense quark matter's collectivity for the initial stage of the collision system. Recently, the elliptic flows of hadrons have been made a fine measurement at RHIC, and the results shown that the elliptical flows have a significant phenomenon, constituent quark number scaling at the intermediate transverse momentum, which means that the collective property of hadrons orginate in the initial stage of the part of the collective sub-stage, as well as quark combination mechanism is probably the major hadronic mechanisms. In the framework of quark combinations, Qubing Xie of Shandong University proposed Shandong quark combination model in the eighties, and has successfully explained a series of experimental phenomenon at e⁺e^- collision. With the development of RHIC, the quark combination model has been applied to RHIC by Shao Fenglan, and also successful explained a series of experimental phenomenon., such as hadrons yield and multi-ratio, charged particles pseudo-rapidity distribution at different energy and centrality bins, the fine structure of hadrons elliptic flow at low p_T range as well as the energy and centrality dependence of p_T spectrum at RHIC and so on. In this paper, based on the above work, we use the Shandong quark combination model system to study the elliptic flows of hadrons, especially the strange hadrons elliptic flows, as they have small effects of hadrons re-scattering, better reflect nuclear-nuclear collision early stage of the evolution of information.Recently, the elliptic flow of deuteron has been measured at RHIC, the measured results showed that the elliptic flow of deuteron follows the same laws of constituent quark number scaling, the elliptic flow of deuteron with the same phenomenon as hadrons has caused a great interest in the emergence of mechanisms of deuteron and its collective origin. In this paper, based on the study of hadrons elliptic flow, we give a naive combination model, calculate the p_T spectrum and elliptic flow of deuteron and compare them with the experiment data.The work contains two aspects as follows:(Ⅰ) With the Shandong quark combination model, we calculate the elliptic flow of hadrons in Au + Au collisions at (?) = 200GeV. We separate calculate the elliptic flow of p⁺ + p^-, k_s⁰, (?) ,Ω⁺ +Ω^-,Ξ⁺ +Ξ^- ,Φin the centrality of 0-10%, 10 - 40%, 40 - 80% , 0 - 80% , and compare them with the experimental data. The results show that our model provides a good description of hadron's elliptic flows.(Ⅱ) Under the above calculated results, we calculate the elliptic flow of deuteron. We give a naive combination model, and study the p_T spectrum and elliptic flow of deuteron in the centrality of 20 - 60%. The calculated results show that our theoretical predictions and experimental results are in well agreement in error. This means that not only the elliptic flow of hadrons but also the elliptic flow of deuteron originates in the part of the collective sub-phase.