Comparative analysis of jet and underlying event properties across various models as a function of charged particle multiplicity at 7 TeV  

作　　者：Maryam Waqar Haifa I.Alrebdi Muhammad Waqas K.S.Al-mugren Muhammad Ajaz 

机构地区：[1]Department of Physics,Abdul Wali Khan University Mardan,Mardan 23200,Pakistan [2]Department of Physics,College of Science,Princess Nourah bint Abdulrahman University,P.O.Box 84428,Riyadh 11671,Saudi Arabia [3]School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Chinese Physics C》2024年第9期118-125,共8页中国物理C（英文版）

基　　金：Supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2024R106);Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia。

摘　　要：In this study,a comprehensive analysis of jets and underlying events as a function of charged particle multiplicity in proton-proton(pp)collisions at a center-of-mass energy of √s=7 TeV is conducted.Various Monte Carlo(MC)event generators,including Pythia8.308,EPOS 1.99,EPOSLHC,EPOS4_(Hydro),and EPOS4_(noHydro),are employed to predict particle production.The predictions from these models are compared with experimental data from the CMS collaboration.The charged particles are categorized into those associated with underlying events and those linked to jets,and the analysis is restricted to charged particles with|η|<2.4 and p_T>0.25 GeV/c.By comparing the MC predictions with CMS data,we find that EPOS4_(Hydro),EPOSLHC,and Pythia8 consistently reproduce the experimental results for all charged particles,underlying events,intrajets,and leading charged particles.For charged jet rates with p_T^(ch.jet)>5 GeV/c,EPOS4_(Hydro)and Pythia8 perform exceptionally well.In the case of charged jet rates with p_T^(ch.jet)→30 GeV/c,EPOSLHC reproduces satisfactorily good results,whereas EPOS4 Hydro exhibits good agreement with the data at higher charged particle multiplicities compared to the other models.This can be attributed to the conversion of energy into flow when"Hydro=on"leading to an increase in multiplicity.The EPOSLHC model describes the data better owing to the new collective flow effects,correlated flow treatment,and parameterization compared to EPOS 1.99.However,the examination of the jet p_T spectrum and normalized charged p_T density reveals that EPOS4_(Hydro),EPOS4_(noHydro),and EPOSLHC exhibit good agreement with the experimental results,whereas Pythia8 and EPOS 1.99 do not perform as well owing to the lack of correlated flow treatment.

关 键 词：Monte Carlo models underlying event jets charged particle multiplicity 

分 类 号：O572.2[理学—粒子物理与原子核物理]