论文标题
\ pp碰撞中的修饰喷气子结构的测量$ \ sqrt {s} = 200 $ gev with star with star
Measurement of Groomed Jet Substructure Observables in \pp Collisions at $\sqrt{s} = 200$ GeV with STAR
论文作者
论文摘要
在这封信中,对SoftDrop Algorihm中定义的共享动量分数($ z {\ rm {g}} $)和修饰的喷气半径($ r _ {\ rm {g}} $),如softdrop algorihm中所定义的,在$ \ s coltives中在$ \ s colltion中报告了$ \ sqrt colltions pp collection。这些子结构可观察值是针对不同分辨率参数的射流差异测量的,从$ r = 0.2-0.6 $的横向动量范围$ 15 <p _ {\ rm {t,jet}} <60 $ gev $/c $。这些研究表明,在$ p _ {\ rm {t,jet}} $范围内可在$ \ sqrt {s} = 200 $ gev上访问,并且随着喷气分辨率参数和喷气横向动量的增加,$ z _ {\ z {\ rm {g rm {g}} $ groply ysympts y groply asymptotical asmptotily asmptotily gromist y to dgla kern glu kernel glu kernel a qual a qur a dgul a qul a qur a qul a g rad kernel a n a kernel a n a kernel。修饰的喷射半径测量结果反映了给定分辨率参数喷射的射流结构的动量依赖性狭窄,即$ p _ {\ rm {t,jet}} $越大,首先拆分的较窄。将这些完全校正的测量值与具有领先顺序的QCD矩阵元素并在Parton淋浴中引导日志的蒙特卡洛发生器,并将其最新的理论计算以近代型木材的准确性进行比较。我们观察到,使用调用以重现RHIC测量的参数的参数能够定量描述数据,而Pythia 8和Herwig 7被调用以复制LHC数据,无法同时提供两种$ z _ {\ rm {g}} $ rm _ {这些模型在rhic能量处发生\ pp碰撞。我们还发现,没有非扰动校正的理论计算能够在高$ p _ {\ rm {t,jet}} $上定性地描述大分辨率参数的数据趋势,但在小型喷射分辨率参数和低射流横向动量时失败。
In this letter, measurements of the shared momentum fraction ($z_{\rm{g}}$) and the groomed jet radius ($R_{\rm{g}}$), as defined in the SoftDrop algorihm, are reported in \pp collisions at $\sqrt{s} = 200$ GeV collected by the STAR experiment. These substructure observables are differentially measured for jets of varying resolution parameters from $R = 0.2 - 0.6$ in the transverse momentum range $15 < p_{\rm{T, jet}} < 60$ GeV$/c$. These studies show that, in the $p_{\rm{T, jet}}$ range accessible at $\sqrt{s} = 200$ GeV and with increasing jet resolution parameter and jet transverse momentum, the $z_{\rm{g}}$ distribution asymptotically converges to the DGLAP splitting kernel for a quark radiating a gluon. The groomed jet radius measurements reflect a momentum-dependent narrowing of the jet structure for jets of a given resolution parameter, i.e., the larger the $p_{\rm{T, jet}}$, the narrower the first splitting. For the first time, these fully corrected measurements are compared to Monte Carlo generators with leading order QCD matrix elements and leading log in the parton shower, and to state-of-the-art theoretical calculations at next-to-leading-log accuracy. We observe that PYTHIA 6 with parameters tuned to reproduce RHIC measurements is able to quantitatively describe data, whereas PYTHIA 8 and HERWIG 7, tuned to reproduce LHC data, are unable to provide a simultaneous description of both $z_{\rm{g}}$ and $R_{\rm{g}}$, resulting in opportunities for fine parameter tuning of these models for \pp collisions at RHIC energies. We also find that the theoretical calculations without non-perturbative corrections are able to qualitatively describe the trend in data for jets of large resolution parameters at high $p_{\rm{T, jet}}$, but fail at small jet resolution parameters and low jet transverse momenta.