强子对撞中测量J/Ψ极化的方法(英文)  

A Method for Measuring J/Ψ Polarization in Hadron Collisions

作　　者：胡震[1] 郭爽[1] Eric James 钱思进[1] 

机构地区：[1]核物理国家重点实验室,北京大学,北京100871 [2]Fermi National Accelerator Laboratory, Batavia IL 60510

出　　处：《北京大学学报（自然科学版）》2011年第3期397-403,共7页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：国家自然科学基金(10099630);国家重点基础研究发展计划(2007CB816101)资助

摘　　要：描述测量J/Ψ介子极化的方法,该方法能够测量质心能量为10 TeV(或以上)的质子对撞中产生的J/Ψ介子的极化参量随其横向动量的变化,LHC上的CMS探测器收集到的前50 pb-1的数据就可以完成这项测量。研究了用于提取极化参量α的拟合过程的误差,并分析了相应的测量精度。该方法的测量精度受到统计误差和系统误差的影响,其量级为Δαstat<0.13,Δαsyst<0.01。在费米实验室的CDF实验上曾进行过J/Ψ极化的测量,其结果与非相对论QCD理论预言不符,在CMS上进行的再次测量将为这项研究提供更充足的信息。The authors describe a method for measuring the polarization of prompt J/Ψ mesons produced in proton-proton collisions at the center of mass energy s=10 TeV（and above）as a function of the J/Ψ transverse momentum.This measurement can be made with -50 pb-1 of data to be collected by the CMS detector during the first period of LHC operations.The authors study potential biases in the fit procedure used to extract the polarization parameter α,and to determine the expected measurement sensitivity.The precision of the method is limited by statistics and systematic uncertainties,and is estimated about Δαstat0.13,Δαsyst0.01.This measurement is expected to provide some insight into the currently observed disagreement between the non-relativistic QCD theory and the recent J/Ψ polarization measurements by CDF on the Tevatron collider at Fermilab.

关 键 词：极化 J/Ψ B强子 CMS 模板 非相对论QCD 

分 类 号：O572.33[理学—粒子物理与原子核物理]