RICH/PHENIX相对论性重离子对撞实验中的μ子探测

PHENIX是BNL/RHIC上重离子对撞实验，除研究高温高密极端条件下强相互作用物质的性质，寻找夸克胶子等离子体外，还将研究质子自旋结构。PHENIXμ子测量的物理目标将涵盖夸克胶子的退禁闭相变、反夸克的极化和胶子的极化等。我们拟承担μ子鉴别方法的研究、事件重建软件、实验模拟、数据处理分析等。快速进入这一核物理前沿领域，共享物理成果。.

PHENIX is one of the two large experiments at RHIC(Relativistic Heavy Ion Collider) in BNL(Brookhaven National Laboratory). There are two main physics goals in the experiment: one is to search QGP(Quark Gluon Plasma) by studying the ultra high temperature and high density nuclear matter produced in AGeV Au+Au collision; second is to study the hadron spin structure via polarized proton - proton collision at GeV. The measurement of muon is one of the important probes for above physics goals. The di-muon production from J/Y and Y'decay plays an important role in studying deconfinement phase transition. Electron-muon coincidence is the indispensable to remove the background from semi-lepton decay in di-lepton measurement. In addition, the gluon polarization can be studied by tagging muons from heavy flavor quark production. One can easily understand that a clean and high efficient muon identification is the key issue for the PHENIX experiment. We have set up a small LINUX farm in Peking University and installed and tested CERN libraries, GEANT4, ROOT and etc, high energy physics related software, in the farm. Further more, PHENIX simulation and analysis software have also been installed and tested. With the complete of the farm with necessary software installed, we applied neural network to the PHENIX muon identification. The preliminary result shows that this new method is better than our current method - discriminant analysis method. More detailed study and comparision are in prosess.