Identification of charm jets at LHCb
Identification of charm jets at LHCb
复制标题
LHCb 魅力喷流的识别
DOI：
10.1088/1748-0221/17/02/p02028
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发表时间：
2022
影响因子：
1.3
通讯作者：
Aidala, C.A.
中科院分区：
文献类型：
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作者：
Aaij, R.;Abdelmotteleb, A.S.W.;Abellán Beteta, C.;Abudinen Gallego, F.J.;Ackernley, T.;Adeva, B.;Adinolfi, M.;Afsharnia, H.;Agapopoulou, C.;Aidala, C.A.
识别魅力喷流，即那些起源于魅力夸克强子化的喷流，在标准模型(SM)过程的研究和新物理的探索中都是有意义的。例如，在前沿区域产生包含𝑍玻色子和𝑐喷流的事件，可以直接探测大部分子动量分数时质子的魅力含量[1，2]。这样的研究依赖于能够区分魅力喷流与美丽喷流和光部分子喷流的算法。LHCb探测器重建的识别魅力和美丽喷流的算法已用于对2011-2012年记录的数据集的研究(第1轮)[3]。然而，2015-2018年(运行2)数据中较高的粒子多重性被发现会降低其性能[4]。此外，对于只涉及Charm喷注的测量，使用专门的Charm标记算法可以获得更好的性能。Charm喷流被定义为那些在喷流锥体内具有迅速产生的、具有横向动量𝑐强子的弱衰变𝑝T(𝑐Hadron)>；5GeV的强子。因此，𝑐喷注的标记是使用由这种𝑐强子衰变形成的位移顶点(DV)来执行的。选择使用DVS而不是单道或其他不基于DV的喷注属性，例如喷流中的粒子数量，是因为需要在LHCb𝑐-JET分析中对丰富的轻部分子喷注有较小的误判概率。此外，来自𝑐-强子的DV的性质也在衰变
Identification of charm jets, ie those originating from the hadronisation of a charm quark, is of interest in both the study of Standard Model (SM) processes and the search for new physics. For example, the production of events containing a 𝑍 boson and a 𝑐 jet in the forward region provides a direct probe of the charm content of the proton at large parton momentum fractions [1, 2]. Such studies rely upon algorithms capable of distinguishing charm jets from beauty and light-parton jets. An algorithm for identifying both charm and beauty jets reconstructed by the LHCb detector has been used for studies of the dataset recorded in 2011–2012 (Run 1)[3]. However, the higher particle multiplicity of 2015–2018 (Run 2) data has been found to degrade its performance [4]. Furthermore, for measurements that only involve charm jets, it is possible to achieve better performance using a dedicated charm-tagging algorithm.Charm jets are defined as those that have a promptly produced and weakly decaying 𝑐 hadron with transverse momentum 𝑝T (𝑐 hadron)> 5GeV within the jet cone. Therefore, the tagging of 𝑐 jets is performed using displaced vertices (DVs) formed from the decays of such 𝑐 hadrons. The choice of using DVs and not single-track or other non-DV-based jet properties, eg the number of particles in the jet, is driven by the need for a small misidentification probability of the copious light-parton jets in LHCb 𝑐-jet analyses. In addition, the properties of DVs from 𝑐-hadron decays