Fluctuations Of The Two-pion Correlation Functions And Elliptic Flow Of Granular Sources

The purpose of doing experiment of high energy heavy iron collisions is to study the properties of nuclear matter.As the theory named Quantum Chromo Dynamics predicted,in the condition of high energy or high density,hadron would melt and a new kind of matter named quark-gluon plasma(QGP)would be born.Because of the fast longitudinal expansion of the system,QGP with high energy and high density with be pulled and looked like a tube.Due to some reasons like the perturbation of the system,asymmrtrically fast expansion,surface tension and so on,the system will fall apart,then a granular source formed.The size,shape and density of granular source fluctuate event by event.This kind of fluctuations will be passed to the elliptic flow and two-pion correlation functions.Because both elliptic flow and Two-pion correlation functions are sensitive to the source.The most important target of the article is to research the fluctuations of two-pion correlation functions and elliptic flow,in order to research the fluctuations of two-pion correlation functions,we use a parameter called f,f is equal to the result that the two-pion correlation functions of fluctuate initial condition source minus the the two-pion correlation functions of smooth initial condition source,then divede by the error of two-pion correlation functions.After doing that calculating and adding them together,you will get a distribution of f then,the width of the the distribution reflects the extent of fluctuations.As we know,after the collisions,the size,shape and density of granular source fluctuate event by event,in order to research the fluctions qualitatively,we research the fluctuations from four aspects: different numbers of droplets,different radius of droplets,different radius of source,different mixed degree of events.After calculating,we find that the fluctuations of two-pion correlation functions is inverse proportion to the numbers of droplets,radius of droplets and mixed degree of events while in proportion to the radius of source.