论文标题
使用pp，p $ - $ pb $ - $ pb $ - $ pb collisions $ \ sqrt {s _ {\ rm nn}} = 5.02 $ 5.02 $ pb collisions的事件拓扑中的高$ p _ {\ rm t} $的收费粒子生产研究
Study of charged particle production at high $p_{\rm T}$ using event topology in pp, p$-$Pb and Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV
论文作者
论文摘要
这封信报告了pp，p $ - $ - $ - $ PB和PB $ - $ PB碰撞的基础事件（$ |η| <0.8 $）与硬质量中的硬散射相关的测量值。测量结果是在LHC处用爱丽丝进行的。根据在正向速度上测得的事件活动定义了不同的多样性类别。硬散射是由定义为具有最大横向动量的带电粒子（$ p _ {\ rm t} $）的，并具有$ 8 <p _ {\ rm t} <15 $ gev/$ gev/$ gev/$ c $。相关粒子的$ p _ {\ rm t} $光谱（$ 0.5 \ leq p _ {\ rm t} <6 $ gev/$ c $）是在针对领先的粒子方向定义的不同方位角区域测量的：朝向，横向和远方。横向区域中相关的带电颗粒的产量是从外出和向区域的。剩余的喷气样产量报告是在横向区域中测得的多样性的函数。与最小偏见的PP碰撞相比，测量结果表明，与最小偏见的PP碰撞相比，高$ p _ {\ rm t} $相关粒子的高$ p _ {\ rm t} $相关粒子的抑制作用。这些观察结果与以前使用两粒子相关性的测量结果一致，并且与高密度夸克Gluon血浆中的Parton能量损失有关。这些收益率修改在外围PB $ - $ PB碰撞中消失，并且在高质量PP或P $ - $ PB碰撞中均未观察到。
This letter reports measurements which characterize the underlying event associated with hard scatterings at mid-pseudorapidity ($|η|<0.8$) in pp, p$-$Pb and Pb$-$Pb collisions at centre-of-mass energy per nucleon pair, $\sqrt{s_{\rm NN}}=5.02$ TeV. The measurements are performed with ALICE at the LHC. Different multiplicity classes are defined based on the event activity measured at forward rapidities. The hard scatterings are identified by the leading particle defined as the charged particle with the largest transverse momentum ($p_{\rm T}$) in the collision and having $8 < p_{\rm T} < 15$ GeV/$c$. The $p_{\rm T}$ spectra of associated particles ($0.5 \leq p_{\rm T}<6$ GeV/$c$) are measured in different azimuthal regions defined with respect to the leading particle direction: toward, transverse, and away. The associated charged particle yields in the transverse region are subtracted from those of the away and toward regions. The remaining jet-like yields are reported as a function of the multiplicity measured in the transverse region. The measurements show a suppression of the jet-like yield in the away region and an enhancement of high-$p_{\rm T}$ associated particles in the toward region in central Pb$-$Pb collisions, as compared to minimum-bias pp collisions. These observations are consistent with previous measurements that used two-particle correlations, and with an interpretation in terms of parton energy loss in a high-density quark gluon plasma. These yield modifications vanish in peripheral Pb$-$Pb collisions and are not observed in either high-multiplicity pp or p$-$Pb collisions.
