Particle Coalescence Production And Isospin Dynamics In Relativistic Heavy-ion Collisions

What is the basic element of matter,what is law of matter,how universe evolve?These kinds of questions which have been pursued by many philosophers,great thinkers and genius scientists,now can be largely answered by the modern particle physics which is based on the principle of relativity and quantum theory.Matter can be created from pure energy,and energy can be released by annihilation of matter and anti-matter.The evolution of universe is driven by the distribution of matter.Relativistic heavy-ion collisions can create a form of matter,ex-isting in the very early universe after big bang,which is called Quark-Gluon Plasma with a temperature as high as 175 MeV.Besides,it provides a unique place for us to understand the production mechanism of hadrons,(anti-)light nucleus and(anti-)hypernucleus.In this the-sis,the binding energy effect in the production of light nucleus,the multi-freeze-out between ?particle and nucleons in the production of hypernucleus,the production of exotic hadrons are studied.We also give a new analytical formula for covariant coalescence model.Furthermore,we investigate isospin effect on elliptic flow of quarks in the dynamical evolution of fireball.Fi-nally,we calculate the phase transition of asymmetric nuclear matter by developing a numerical algorithm.In the first part,I will mainly discuss the production of particles within coalescence model mainly for RHIC and LHC energies.First,we develop a numerical multi-dimension integration method to calculate coalescence model.The advantage of exact numerical method is that it can not only describe the total multiplicity but also the momentum spectrum which is hard for analytical formula.In the study of light nucleus,we propose that the binding energy effect of(anti-)4He can enhance its yields.In the study of hypernucleus,we propose that A particle freezes out earlier than nucleons,we find this can increase the yield ratio?3,H/3He and solve the puzzle of experiment result of RHIC and LHC.In the study of ??,we point out that if it is a six-quark states,its yields is around the experiment upper-limits.Second,standing on the shoulder of predecessors,we develop an improved analytical formula for covariant coalescence model.This new formula can be applied to investigate the production of hadrons,(anti-)light nucleus and(anti-)hypernucleus.We demonstrate that the previous formula fails to account the measured yield ratio ?3H/3 He because of over simplification,while the new formula does not possess this problem.Further more,we give corrections of multiplicity from relativity and finite size of fireball.The new formula can describe the experiment results of normal hadrons,(anti-)light nucleus and(anti-)hypernucleus.In summary,coalescence model can help us to understand particle production in relativistic heavy-ion collisions.In the second part,we discuss the dynamics of isospin in heavy-ion collisions.We adopt a chiral model(NJL model)to study isospin effect.We find that isospin interaction can lead to a split of the elliptic flow of uw,d quarks and this split can survive after hadronization.We calculate the elliptic flow of ?+,?-,the split is close to that at quark level.In order to understand NJL model,we investigate the phase transition of extended NJL model.On one hand,we develop a program to calculate liquid-gas phase transition,on the other hand,we also try to understand the chiral phase transition from theoretical perspective.In the limit of zero chemical potential,we give a relation between the temperature T,of chiral restoration and mass of nucleon in vacuum,that is Tc = Mvac/2?Furthermore,we find this relation not only holds at level of nucleons but also at the level of quarks.In this sense,this relation is quite general.