标题： 高能下γ/π^0簇射的分离 显示英文标题

标题： Separation of γ/π^0 showers at high energies

摘要： 我们设计并进行了针对30到150 GeV能量范围内的\pi ^0簇射与\gamma 簇射分离的双层 Shower Maximum Detector 对角偏移（SMD-dos）的仿真研究。对于90%的\gamma 接受度，SMD-dos在30、50和150 GeV入射能量下分别给出了92+-4%、87+-4%和32+-2%的\pi ^0 排除效率。我们发现，在50到150 GeV能量范围内，SMD-dos比具有相同粒度的传统几何结构单层或多层Shower Maximum Detector（SMD）平均优越约1.5倍。我们还发现，对于相同数量的通道，SMD-dos的\pi ^0 排除效果优于SMD。在强子-强子对撞机上，检测质量范围为120到160 GeV的希格斯粒子的最佳特征是通过衰变 H-->\gamma \gamma 来实现的。 在大型强子对撞机计划的探测器中添加一个SMD-dos，将显著减少来自丰富产生 \pi ^0 的背景对 \gamma 信号的影响。 显示英文摘要

摘要： We have designed and carried out simulation studies of a two layer Shower Maximum Detector diagonally off-set (SMD-dos) optimized for the separation of \pi^0 showers from \gamma showers in the 30 to 150 GeV energy range. For 90% \gamma acceptance the SMD-dos yields \pi^0 rejection efficiency of 92+-4%, 87+-4% and 32+-2%, respectively, for 30, 50 and 150 GeV incident energies. We find that the SMD-dos is superior to a conventional geometry single-layer or mutiple-layer shower maximum detector (SMD), of equal granularity, by an average factor of ~1.5 over the 50 to 150 GeV energy range. We also find that the SMD-dos gives better \pi^0 rejection, for the same number of channels, than a SMD. At hadron - hadron colliders the signature of choice for the detection of the Higgs particle, in the mass range of 120 to 160 GeV, is via the decay H-->\gamma\gamma. The addition of a SMD-dos to the planned detectors at the LHC would significantly reduce the background to the \gamma-signal coming from prolific \pi^0 production.