Charmonium dissociation cross sections and - 曲阜

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Quark-Interchange Processes in Evolution of Mesonic Matter,Xiao-Ming Xu,1,1. Meson-meson scattering is crucial to chemical equilibration, kinetic equilibration, hadron flows and hadron yields. 2. Earlier decoupled mesons due to small cross sections can show relatively clear information on quark-gluon plasma.,Use master rate equations including inelastic meson-meson scattering to describe mesonic matter.,We concern about pions, rhos and kaons since experimental data show that , , K are dominant meson species in hadronic matter.,2,PHENIX results:,central Au-Au collisions, =200 GeV, mid-rapidity,STAR results:,peripheral Au-Au collisions, =200 GeV, mid-rapidity,most central Au-Au collisions, =200 GeV, mid-rapidity,3,BRAHMS results: rapidity dependence in central collisions,constant near midrapidity slowly decrease,in the other region,constant,in,PHENIX results: centrality dependence,constant,in the whole centrality range,increase with,centrality,4,inelastic meson-meson scattering:,resonant processes,;,quark-antiquark annihilation processes,;,quark-interchange processes,.,The cross section for an isospin channel consists of three parts:,for example,I=3/2,K*K c,res,=0,c,anni,=0,c,qi,=1,I=1/2,K*K c,res,=1,c,anni,=1,c,qi,=1,5,in master rate equations the unpolarized cross section for,i,(,S,1,I,1,),j,(,S,2,I,2,), i,(,S,3,I,3,),j,(,S,4,I,4,),6,resonant processes,resonances:,f,0,(1370),(1450),f,0,(1500),3,(1690),for,K,1,(1270),K,1,(1400),K,*,(1410),K,*,2,(1430),K,*,(1680),K,*,3,(1780),for,K,*,K,f,0,(980),(1020),f,2,(1270),f,0,(1370),(1450),f,0,(1500),f,2,(1525),3,(1690),(1700),f,0,(1710),f,2,(1810),f,4,(2050),for,cross section:,7,quark-antiquark annihilation processes,cross section:,for example,b=2.7 mb, c=0.76 for,b=0.4 mb, c=0.5 for,b=3.5 mb, c=0.38 for,G.E. Brown, et al., Phys. Rev. C 43, 1881 (1991),W. Cassing, et al., Nucl. Phys. A 614, 415 (1997),8,quark-interchange processes,for example,I,=2,I,=1,KK,K,K,*,I,=1,KK,*,K,*,K,I,=3/2,K,K,*,I,=3/2,K,*,K,*,I,=3/2,K,K,*,I,=3/2,K,*,K,Y.-Q. Li, X.-M. Xu, Nucl. Phys. A 794 (2007) 210,9,Prior form,: gluon propagation before quark interchange,10,Post form,: gluon propagation after quark interchange,11,I,=2,12,I,=1,KK,K,K,*,13,I,=1,KK,*,K,*,K,14,I,=3/2,K,K,*,15,I,=3/2,K,*,K,*,16,I,=3/2,K,K,*,17,I,=3/2,K,*,K,18,Cross sections for endothermic reactions,are parametrized as,are listed in Table 2 of Eur. Phys. J. A47 (2011) 65,19,master rate equations,(,n,u,)=,for pions,(,n,u,)=,for rhos,(,n,K,u,)=,K,for kaons,(,n,K*,u,)=,K*,for vector kaons,hydrodynamic equation,T,=0,meson number density,20,i,no,(,solid curves): without,K,K*,iqar,(dashed curves): with the qi, anni and res processes,i,qi,(,dotted curves): with only the quark interchange processes,21,mesonic matter in longitudinal expansion,depends on time,average over time,initial fugacities:,results:,Tables 6-8 in Eur. Phys. J. A47 (2011) 65 show that for 81 sets of initial fugacities most are above 0.2.,The quark-interchange processes are important in the contribution of the inelastic 2-to-2 scattering to the evolution of mesonic matter.,22,mesonic matter in longitudinal expansion with 2,1 processes,2,1 processes:,needs,needs,K,needs,K*,needs,About 96% of have values larger than 0.5 and 53% larger than 1.,The quark-interchange processes are important in the contribution of the inelastic meson-meson scattering to the evolution of mesonic matter.,23,mesonic matter in longitudinal and transverse expansion with 2,1 processes,four-velocity of the local reference frame,The left-hand sides of the master rate equations,initial fugacities:,results:,for most of the 81 sets of initial fugacities are larger than 1.,While the quark-antiquark annihilation processes and the resonant processes are taken into account, the quark-interchange processes must be included on an equal footing.,24,Summary,(1),We have established the master rate equations with the quark-interchange processes.,(2),If the number density of, is increased (reduced) by the quark-interchange processes, the number density of is reduced (increased) in the same amount. This relation also holds true for,K,and,K*,.,(3),Quark-interchange processes are shown to be important in the contribution of the inelastic meson-meson scattering to the evolution of mesonic matter. Therefore, all microscopic models involving hadronic matter must include the quark-interchange processes.,Y.-Q. Li, X.-M. Xu, H.-J. Ge, Eur. Phys. J. A 47 (2011) 65,25,