论文标题
核核碰撞核中最高夸克的证据
Evidence for top quark production in nucleus-nucleus collisions
论文作者
论文摘要
使用$ 1.7 \ pm 0.1 \，\ mathrm {nb^{ - 1}} $的铅铅（$ a = 208 $）的碰撞数据，由CMS实验记录在5.02 tev的Nucleon-Nucleon质量中心能量中，为5.02 tev，我们报告了Top Quark Pair的证据（$ \ MATHRM）的证据（$ \ MATHRM BARM {t \ bar} $ { $ \ mathrm {t \ bar {t}} $交叉部分（$σ_\ mathrm {t \ bar {t}} $）是在Dilepton最终状态和两种方法中使用Lepton Kinematic变量的多变量歧视器中提取的。一种方法仅依赖于松性信息，而第二种方法还利用了底部夸克的存在。测量的$σ_\ MathRm {t \ bar {t}} $是$ 2.54^{+0.84} _ { - 0.74} $和$ 2.03^{+0.71} _ { - 0.64} \ 0.64} \，μ\，μ\ Mathrm {b} $，在两个情况下，均一定的量子相应地，均一定范围。我们首次证明，可以识别出顶级夸克衰减产品（衰减的w实量和底部夸克），无论与夸克 - 果糖等离子体的任何最终状态相互作用如何。
Using $1.7 \pm 0.1\,\mathrm{nb^{-1}}$ of lead-lead ($A = 208$) collision data recorded by the CMS experiment at a nucleon-nucleon center-of-mass energy of 5.02 TeV, we report evidence of top quark pair ($\mathrm{t\bar{t}}$) production. The $\mathrm{t\bar{t}}$ cross section ($σ_\mathrm{t\bar{t}}$) is extracted from likelihood fits to a multivariate discriminator using lepton kinematic variables in dilepton final states and two methods. One method relies on the leptonic information alone, and the second one exploits, in addition, the presence of bottom quarks. The measured $σ_\mathrm{t\bar{t}}$ is $2.54^{+0.84}_{-0.74}$ and $2.03^{+0.71}_{-0.64}\, μ\mathrm{b}$ in the two cases, respectively, consistent with predictions from perturbative quantum chromodynamics. We demonstrate, for the first time, that top quark decay products (leptonically decaying W bosons and bottom quarks) can be identified, irrespective of any possible final-state interactions with the quark-gluon plasma.
