论文标题
5.02 TEV PB+PB碰撞与Atlas检测器的核修饰系数的测量$ B $ -JET
Measurement of the nuclear modification factor of $b$-jets in 5.02 TeV Pb+Pb collisions with the ATLAS detector
论文作者
论文摘要
本文介绍了$ b $ -JET在PB+PB中的生产和$ PP $ Collisisions $ \ sqrt {s _ {_ \ textrm {nn}}} = 5.02 $ TEV，lHC的ATLAS检测器。该测量使用260 $ \ textrm {pb}^{ - 1} $ $ pp $ collisions在2017年收集的碰撞和PB+PB碰撞的1.4 $ \ textrm {nb}^{ - 1} $ 2018收集的PB+PB碰撞。 $ b $ - 喷气式飞机是从包含$ b $ QUARKS半衰减的Muons的样本中鉴定出来的，使用MUON动量的模板拟合相对于喷气轴。在$ pp $碰撞中，$ b $ jets是半径参数重建的$ r = 0.2 $和$ r = 0.4 $，只有$ r = 0.2 $ jets在PB+PB碰撞中使用。为了进行比较，还使用1.7 $ \ textrm {nb}^{ - 1} $ pb+pb碰撞和2018年收集的$ pp $碰撞数据与$ b $ -JET-JET-JET-JET MEATUREMENT一起测量了包含$ r = 0.2 $喷气机。核修饰因子$ r_ \ textrm {aa} $是针对$ b $ - 喷气机和包含喷气式飞机计算的，$ r = 0.2 $在80--290 GEV的横向动量范围内。 $ b $ - 日志的核修饰因子从外围碰撞降低到中央碰撞。还提出了$ b $ -jet $ r_ \ textrm {aa} $与包容性喷气$ r_ \ textrm {aa} $的比例，并暗示$ r_ \ textrm {aa} $ for $ b $ -jets比中央pb+pb+pb collisions中的$ b $ - jets大于包含式jets。将测量值与理论计算进行了比较，并提出了质量和颜色荷利效应在重离子碰撞中的党能量损失中的作用。
This paper presents a measurement of $b$-jet production in Pb+Pb and $pp$ collisions at $\sqrt{s_{_\textrm{NN}}}=5.02$ TeV with the ATLAS detector at the LHC. The measurement uses 260 $\textrm{pb}^{-1}$ of $pp$ collisions collected in 2017 and 1.4 $\textrm{nb}^{-1}$ of Pb+Pb collisions collected in 2018. In both collision systems, jets are reconstructed via the anti-$k_{t}$ algorithm. The $b$-jets are identified from a sample of jets containing muons from the semileptonic decay of $b$-quarks using template fits of the muon momentum relative to the jet axis. In $pp$ collisions, $b$-jets are reconstructed for radius parameters $R= 0.2$ and $R= 0.4$, and only $R= 0.2$ jets are used in Pb+Pb collisions. For comparison, inclusive $R= 0.2$ jets are also measured using 1.7 $\textrm{nb}^{-1}$ of Pb+Pb collisions collected in 2018 and the same $pp$ collision data as the $b$-jet measurement. The nuclear modification factor, $R_\textrm{AA}$, is calculated for both $b$-jets and inclusive jets with $R= 0.2$ over the transverse momentum range of 80--290 GeV. The nuclear modification factor for $b$-jets decreases from peripheral to central collisions. The ratio of the $b$-jet $R_\textrm{AA}$ to inclusive jet $R_\textrm{AA}$ is also presented and suggests that the $R_\textrm{AA}$ for $b$-jets is larger than that for inclusive jets in central Pb+Pb collisions. The measurements are compared with theoretical calculations and suggest a role for mass and colour-charge effects in partonic energy loss in heavy-ion collisions.
