Study On Influence Of Conventional Effects In Higher Moments Of Net-proton In Relativistic Heavy Ion Collisions

In the past century, Professor T.D.Lee pointed out that a matter with high tem-perature and density would be produced and the hadron matter transit to a new physic form called quark gluon plasma(QGP), through high energy heavy ion colli-sion. Study about QGP is the foreland of physics,in experiment, relativistic heavy ion collider (RHIC) is the main method of observing QGP and published lots of work; in theory, Quantum Chromodynamic(QCD) that describes the strong interaction be-tween quark and gluon explains and predicts many phenomenons. Phase transition from hadronic phase to QGP can be demonstrated by QCD phase diagram, which plot with parameters temperature(T) and baryon chemical potential(μB). Lattice QCD calculations predict a cross-over transition at high temperature and low μB from hadronic phase to QGP; while at low temperature and highμB is a first phase transition. Between the line of first phase transition and cross-over region is a end point-QCD Critical Point(QCP). Locating this point, which exist second phase tran-sition, is the key to QCD phase diagram. Recently, lots of work about phase diagram and locating QCP have be done, the properties of QCP become more clearly.In21th century, The Relativistic Heavy Ion Collider (RHIC) at Brookhcavcn National Lab(BNL) collide gold nuclei to center of mass energy (?)=200GeV. Many results, such as the hydrodynamic behavior and number of quarks scaling of the elliptic flow(u2), high Pt particle suppression-jet quenching, arc as the evidences of the strongly coupled QGP has been generated. The QGP was formed at collider provide opportunity for studying the QCD phase diagram and locating the critical point. In the year2010, RHIC has run its Beam Energy Scan program and tuned Au-Au collision with energy from (?)=7.7GcV to200GeV. Recently, theorists calculations found that the higher moments of the distribution of conserved quantum, such as net-baryon, net-charge and net-strangeness, are sensitive to the singularity of critical point and probably to change their signs. However, the uncharged particles like neutron is undetected in at experiment. Recently, theory calculations pointed out that the higher moments of distribution of net-proton can reflect that of net-baryon, so the higher moments of distribution of net-proton are suggested to probe the location of QCD phase diagram.Using the A Multi Phase Transition(AMPT) default and String Melting model, we study the influence of traditional effects on the measurement of higher moments of distribution of net-proton, we found that the statistical fluctuations will dominate its behavior and suggested the dynamical higher moments. We also study the de-pendence of net-proton higher moments and dynamical higher moments on detection efficiency and measurements such as the different definitions of centrality, transverse momentum(pr) and rapidity(y) cut. We found that both net-proton higher moments and dynamical higher moments are independent on detection efficiency. While dy-namical higher moments show a dependence on the definition of centrality, especially in periphery collisions. Meanwhile, we study its centrality dependence at seven ener-gies, which are run at RHIC Beam Energy Scan. This is helpful to know more about net-proton higher moments to locating the QCD critical point.