为了在GeV能区开展核子核子相互作用中强子的产生和衰变的实验研究,将在HIRFL-CSR主环上建造一台兰州强子物理谱仪(HPLUS)。首先结合HPLUS的初步构型阐明了针对不同极角区域的粒子鉴别方法,接着介绍了在蒙特卡罗模拟中使用的Pluto事件产生器,并针对HPLUS上主要的反应道模拟研究了:Pluto产生的质子质子弹性散射的角分布和实验数据的符合程度;在产生K介子的反应道中,HPLUS前角区对K介子的接收度;强子衰变产生光子的最大能量和两个光子的最小夹角随极角区域的变化情况;不同的重建方法对核子激发态质量谱形状的影响。以上研究说明了Pluto事件产生器可以满足HPLUS模拟的需要。
Hadron Physics Lanzhou Spectrometer(HPLUS) is designed for the study of hadron production and decay from nucleon-nucleon interaction in the GeV region.The current formation of HPLUS and the particle identification methods for three polar angle regions are discussed.The Pluto event generator is applied to simulate the primary reactions on HPLUS, concerning four issues as followed: the agreement on pp elastic scattering angular distribution between Pluto samples and experimental data;the acceptance of charged K mesons in the strangeness production channels for the forward region of HPLUS;the dependence of the maximum energy of photons and the minimum vertex angle of two photons on the polar angle;the influence on the mass spectrum of excited states of nucleon with large resonant width from different reconstruction methods.It is proved that the Pluto event generator satisfies the requirements of Monte Carlo simulation for HPLUS.