A systematic study on the impact of widely-used nuclear-modified parton distribution function(nPDF)parameterizations on the production of direct photons and charged hadrons is performed by employing a next-toleading o...A systematic study on the impact of widely-used nuclear-modified parton distribution function(nPDF)parameterizations on the production of direct photons and charged hadrons is performed by employing a next-toleading order Monte Carlo event generator JETPHOX in hadronic collisions at LHC energies.The nuclear modification factors of photon and charged hadron productions are studied in three types of collision systems,i.e.,small(p+p and p+Pb),medium(O+O),and large(Pb+Pb),in a wide rapidity acceptance.The results illustrate that the direct photon production process is a sensitive probe to decipher the difference of the nPDF parameterization implementations,which provides new insights for the experimental measurements to refine the nuclear modifications of the parton distributions.To provide a benchmark for searching for quark gluon plasma in the upcoming small system measurements at LHC energies,we carry out detailed studies on the cold nuclear matter effect in(O+O)collisions.Our outcomes show that the cold nuclear matter effects are negligible for the charged hadron production in(O+O)collisions,which can be used as a baseline to subtract the initial state contribution.展开更多
To measure the R value in an energy scan experiment with e＋e- collisions, precise calculation of initial state radiation is required in the event generators. We present an event generator for this consideration, whic...To measure the R value in an energy scan experiment with e＋e- collisions, precise calculation of initial state radiation is required in the event generators. We present an event generator for this consideration, which incorporates initial state radiation effects up to second order accuracy. The radiative correction factor is calculated using the totally hadronic Born cross section. The measured exclusive processes are generated according to their cross sections, while the unknown processes are generated using the LUND Area Law model, and its parameters are tuned with data collected at s = 3.65 GeV. The optimized values are validated with data in the range s = 2.2324--3.671 GeV. These optimized parameters are universally valid for event generation below the DIS threshold.展开更多
An exclusive event generator is designed for e＋e- scan experiments, including initial state radiation effects up to the second order correction. The generator is coded within the framework of BesEvtGen. There are sev...An exclusive event generator is designed for e＋e- scan experiments, including initial state radiation effects up to the second order correction. The generator is coded within the framework of BesEvtGen. There are seventy hadronic decay modes available, with effective center-of-mass energy coverage from the two pion mass threshold up to about 6 GeV. The accuracy achieved for the initial state radiation correction reaches the level achieved by the KKMC generator. The uncertainty associated with the calculation of the correction factor to the initial state radiation is dominated by the measurements of the energy-dependent Born cross section.展开更多
DJpsiFDC is an event generator package for the process gg → J/ψJ/ψ. It generates events for primary leading-order 2 → 2 processes. The package could generate a Les Houches Event （LHE） document and this could eas...DJpsiFDC is an event generator package for the process gg → J/ψJ/ψ. It generates events for primary leading-order 2 → 2 processes. The package could generate a Les Houches Event （LHE） document and this could easily be embedded into detector simulation software frameworks. The package is produced in Fortran code.展开更多
基金Supported by the National Key Research and Development Program of China(2018YFE0104700,2018YFE0104800)the National Natural Science Foundation of China(12061141008,12175085)the Fundamental Research Funds for the Central Universities(CCNU220N003)
文摘A systematic study on the impact of widely-used nuclear-modified parton distribution function(nPDF)parameterizations on the production of direct photons and charged hadrons is performed by employing a next-toleading order Monte Carlo event generator JETPHOX in hadronic collisions at LHC energies.The nuclear modification factors of photon and charged hadron productions are studied in three types of collision systems,i.e.,small(p+p and p+Pb),medium(O+O),and large(Pb+Pb),in a wide rapidity acceptance.The results illustrate that the direct photon production process is a sensitive probe to decipher the difference of the nPDF parameterization implementations,which provides new insights for the experimental measurements to refine the nuclear modifications of the parton distributions.To provide a benchmark for searching for quark gluon plasma in the upcoming small system measurements at LHC energies,we carry out detailed studies on the cold nuclear matter effect in(O+O)collisions.Our outcomes show that the cold nuclear matter effects are negligible for the charged hadron production in(O+O)collisions,which can be used as a baseline to subtract the initial state contribution.
基金Supported by National Natural Science Foundation of China(11175146,11375205,11575077,11335008,11565006)Large Science Setup of Joint Foundation(10979059)100 Talents Program of CAS
文摘To measure the R value in an energy scan experiment with e＋e- collisions, precise calculation of initial state radiation is required in the event generators. We present an event generator for this consideration, which incorporates initial state radiation effects up to second order accuracy. The radiative correction factor is calculated using the totally hadronic Born cross section. The measured exclusive processes are generated according to their cross sections, while the unknown processes are generated using the LUND Area Law model, and its parameters are tuned with data collected at s = 3.65 GeV. The optimized values are validated with data in the range s = 2.2324--3.671 GeV. These optimized parameters are universally valid for event generation below the DIS threshold.
基金Supported by National Natural Science Foundation of China(11079038,11235011,11375205)
文摘An exclusive event generator is designed for e＋e- scan experiments, including initial state radiation effects up to the second order correction. The generator is coded within the framework of BesEvtGen. There are seventy hadronic decay modes available, with effective center-of-mass energy coverage from the two pion mass threshold up to about 6 GeV. The accuracy achieved for the initial state radiation correction reaches the level achieved by the KKMC generator. The uncertainty associated with the calculation of the correction factor to the initial state radiation is dominated by the measurements of the energy-dependent Born cross section.
基金Supported by National Natural Science Foundation of China (10935012, 10928510, 10821063, 10775179)CAS Key Projects(KJCX2-yw-N29, H92A0200S2)100 Talents Program of CAS
文摘DJpsiFDC is an event generator package for the process gg → J/ψJ/ψ. It generates events for primary leading-order 2 → 2 processes. The package could generate a Les Houches Event （LHE） document and this could easily be embedded into detector simulation software frameworks. The package is produced in Fortran code.
