In this paper,we describe a study of charged particle yield as a function of pT for K^(*)(892)0 and phgr(1020)mesons in proton–proton(pp)and Pb–Pb collisions at√S_(NN)=2.76 TeV in the central rapidity region of|y|&...In this paper,we describe a study of charged particle yield as a function of pT for K^(*)(892)0 and phgr(1020)mesons in proton–proton(pp)and Pb–Pb collisions at√S_(NN)=2.76 TeV in the central rapidity region of|y|<0.5,in a pT range of 0<pT<15 GeV c^(−1)in pp collisions and in a pT range of 0<pT<20 GeV c−1 in Pb-Pb collisions.We also investigated a very important ratio,the nuclear modification factor,to study the effects of the medium in the most central region,i.e.0%–5%centrality.For data simulation,we used the EPOS-LHC and EPOS-1.99 models.To check the validity of these models'simulations,we compared the data obtained from these Monte Carlo simulation programs with ALICE experimental data for√S_(NN)=2.76 TeV.It was concluded that the models'predictions for the phgr-meson in pp and for the most central Pb-Pb collisions disagreed with the ALICE data,and that the difference increased with pT.This may be connected with the essential role of collective parton behaviors which could not have been taken into account by the models.For K^(*)0 mesons,both programs gave almost the same predictions,and with pT in the interval pT>3 GeV c^(−1),the predictions were very close to the experimental data.Both models gave higher predictions for the soft pT interval and lower predictions for the hard interactions.The values of the RAA distributions were lower than unity and both models were very close to the ALICE data.It is very interesting that the models were not able to describe the pT distributions,but they gave good predictions for their ratios.This may possibly be due to parton collective behaviors.We observed some additional suppression of K^(*)0 at low values of pT with respect to phgr-mesons,which may be related to the role of the masses of the particles in soft interactions.The rising trend for R_(AA)in the region from pT=10 GeV c^(−1)to 20 GeV c^(−1) observed by the ALICE experiment was absent for theФ-mesons.展开更多
文摘In this paper,we describe a study of charged particle yield as a function of pT for K^(*)(892)0 and phgr(1020)mesons in proton–proton(pp)and Pb–Pb collisions at√S_(NN)=2.76 TeV in the central rapidity region of|y|<0.5,in a pT range of 0<pT<15 GeV c^(−1)in pp collisions and in a pT range of 0<pT<20 GeV c−1 in Pb-Pb collisions.We also investigated a very important ratio,the nuclear modification factor,to study the effects of the medium in the most central region,i.e.0%–5%centrality.For data simulation,we used the EPOS-LHC and EPOS-1.99 models.To check the validity of these models'simulations,we compared the data obtained from these Monte Carlo simulation programs with ALICE experimental data for√S_(NN)=2.76 TeV.It was concluded that the models'predictions for the phgr-meson in pp and for the most central Pb-Pb collisions disagreed with the ALICE data,and that the difference increased with pT.This may be connected with the essential role of collective parton behaviors which could not have been taken into account by the models.For K^(*)0 mesons,both programs gave almost the same predictions,and with pT in the interval pT>3 GeV c^(−1),the predictions were very close to the experimental data.Both models gave higher predictions for the soft pT interval and lower predictions for the hard interactions.The values of the RAA distributions were lower than unity and both models were very close to the ALICE data.It is very interesting that the models were not able to describe the pT distributions,but they gave good predictions for their ratios.This may possibly be due to parton collective behaviors.We observed some additional suppression of K^(*)0 at low values of pT with respect to phgr-mesons,which may be related to the role of the masses of the particles in soft interactions.The rising trend for R_(AA)in the region from pT=10 GeV c^(−1)to 20 GeV c^(−1) observed by the ALICE experiment was absent for theФ-mesons.
