论文标题
在CERN大型强子对撞机上可用的能量下,PBPB碰撞中的底部抑制作用
Bottomonium suppression in PbPb collision at energies available at the CERN large hadron collider
论文作者
论文摘要
我们一直在逐步努力建立全面的Quarkonia抑制形式主义,以解释从重型离子碰撞实验中获得的所有3种Quarkonium抑制依赖性。我们在这里提出了Quarkonia抑制框架的改进版本。它假设在早期产生的底部尼亚由于颜色筛选,gluonic解离和碰撞阻尼而产生的底部尼亚除了阴影作为初始状态效应之外。假定在碰撞中形成的QGP培养基在($ 3+1 $)的基础下进化 - 尺寸相对论粘性流体动力学,该动力学是使用Echo-QGP建模的。这取代了Bjorken的流体动力学,我们在早期的工作中使用了中心性和横向动量依赖性抑制。相关的底部夸克和底部反夸克可能会在血浆中重新组合。采用了一个速率方程,其解决方案在分解和重组后的最终数量在$(3+1)$ - QGP培养基的尺寸膨胀下。阴影效应是LHC能量的主要冷核物质效应,现已通过采用从CT14全球分析和EPPS16阴影因子获得的最新Parton分布函数来修改。使用这种改进的形式主义,我们确定了$υ(1s)$的底部抑制依赖性的中心性,横向动量和速度,以及LHC的$ 2.76 $ TEV和$ 5.02 $ TEV的$υ(1s)$和$υ(2s)$。我们发现在两个能量的理论上计算的生存概率与测量的核修饰因子($ r_ {aa} $)之间找到了相当良好的一致性。
We had been gradually working towards building a comprehensive quarkonia suppression formalism to explain all 3 dependencies of quarkonium suppression obtained from heavy-ion collision experiments. We present here the improved version of quarkonia suppression framework. It assumes bottomonia produced in the early stage which dissociates due to color screening, gluonic dissociation, and collisional damping in addition to the shadowing as an initial state effect. The QGP medium formed in the collisions is assumed to evolve under ($3+1$)-dimensional relativistic viscous hydrodynamics which is modeled using ECHO-QGP. This replaces the Bjorken's hydrodynamics which we had used in our earlier work where we determined the centrality and transverse momentum dependent suppression. The correlated bottom quark and bottom anti-quark could recombine in the plasma. A rate equation is employed, whose solution gives the final number of bottomonium after dissociation and recombination under $(3+1)$-dimensional expansion of the QGP medium. The Shadowing effect, which is the dominant Cold Nuclear Matter effect at LHC energies, has now been modified by employing the most recent parton distribution functions obtained from CT14 global analysis and shadowing factors from EPPS16. Using this improved formalism we determine the centrality, transverse momentum, and rapidity, dependencies of bottomonium suppression for $Υ(1S)$, and $Υ(2S)$ at the LHC's energies of $2.76$ TeV and $5.02$ TeV. We find a fairly good agreement between theoretically calculated survival probability and the measured nuclear modification factor($R_{AA}$) at the two energies.