论文标题
$ \ sqrt {s _ {\ rm nn}} $ = 5.02 TEV
Jet fragmentation transverse momentum distributions in pp and p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV
论文作者
论文摘要
喷气碎片横向动量（$ j _ {\ rm t} $）分布在质子 - 普罗顿（PP）和质子潜水（p-pb）碰撞中测量$ \ sqrt {s _ {\ rm nn}} $ = 5.02 $ = 5.02 tev the lhc lhc the lhc。使用抗$ k _ {\ rm t} $算法的Alice跟踪探测器和电磁热量计重建喷气机，其分辨率参数$ r = 0.4 $ r = 0.4 $ r = 0.4 $ in pseudorapitive范围$ | |hη| <0.25 $。 $ j _ {\ rm t} $值是针对重建的射流轴周围带有半径$ r = 0.4 $的固定锥体内的带电粒子计算的。将测量的$ j _ {\ rm t} $分布与各种党派模型进行了比较。 Herwig和Pythia 8的模型很好地描述了较高$ j {\ rm t} $区域的数据，而它们低估了较低的$ j _ {\ rm t} $ region。 $ j _ {\ rm t} $分布的进一步特征是将它们与较高的$ j _ {\ rm t} $ valuts组成的函数拟合，以使$ j _ {$ j _ _ _ rmm t} commountion（称为“宽组件”）（称为“宽组件”）（称为“宽组件”），与较低的零件相关。连接到强调过程。高斯的宽度仅对射流横向动量的依赖性较弱，而反伽马功能的宽度随着射流横向动量的增加而增加。对于狭窄的组件，除了Herwig以外，所有模型都成功地描述了测得的趋势。对于较宽的组件，基于Herwig和Pythia 8的模型略微低估了较高的喷射横向动量区域的数据。这些测量值对射流碎片化和强调模型设定了限制。
Jet fragmentation transverse momentum ($j_{\rm T}$) distributions are measured in proton-proton (pp) and proton-lead (p-Pb) collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV with the ALICE experiment at the LHC. Jets are reconstructed with the ALICE tracking detectors and electromagnetic calorimeter using the anti-$k_{\rm T}$ algorithm with resolution parameter $R=0.4$ in the pseudorapidity range $|η|<0.25$. The $j_{\rm T}$ values are calculated for charged particles inside a fixed cone with a radius $R = 0.4$ around the reconstructed jet axis. The measured $j_{\rm T}$ distributions are compared with a variety of parton-shower models. Herwig and PYTHIA 8 based models describe the data well for the higher $j_{\rm T}$ region, while they underestimate the lower $j_{\rm T}$ region. The $j_{\rm T}$ distributions are further characterised by fitting them with a function composed of an inverse gamma function for higher $j_{\rm T}$ values (called the "wide component"), related to the perturbative component of the fragmentation process, and with a Gaussian for lower $j_{\rm T}$ values (called the "narrow component"), predominantly connected to the hadronisation process. The width of the Gaussian has only a weak dependence on jet transverse momentum, while that of the inverse gamma function increases with increasing jet transverse momentum. For the narrow component, the measured trends are successfully described by all models except for Herwig. For the wide component, Herwig and PYTHIA 8 based models slightly underestimate the data for the higher jet transverse momentum region. These measurements set constraints on models of jet fragmentation and hadronisation.
