# Jet shape modification at LHC energies by JEWEL

• Jet shape measurements are employed to explore the microscopic evolution mechanisms of parton-medium interaction in ultra-relativistic heavy-ion collisions. In this study, jet shape modifications are quantified in terms of the fragmentation function $F(z)$, relative momentum $p_{T}^{\rm rel}$, density of charged particles $\rho(r)$, jet angularity $girth$, jet momentum dispersion $p_{T}^{\rm disp}$, and $LeSub$ for proton-proton (pp) collisions at 0.9, 2.76, 5.02, 7, and 13 TeV, as well as for lead-lead collisions at 2.76 TeV and 5.02 TeV by JEWEL. A differential jet shape parameter $D_{girth}$ is proposed and studied at a smaller jet radius $r<0.3$. The results indicate that the medium has the dominant effect on jet shape modification, which also has a weak dependence on the center-of-mass energy. Jet fragmentation is enhanced significantly at very low $z<0.02$, and fragmented jet constituents are linearly spread to larger jet-radii for $p_{T}^{\rm rel}<1$. The waveform attenuation phenomena is observed in $p_{T}^{\rm rel}$, $girth$, and $D_{girth}$ distributions. The results obtained for $D_{girth}$from ${\rm pp}$ to ${\rm Pb+Pb}$, where the wave-like distribution in ${\rm pp}$ collision is ahead of ${\rm Pb+Pb}$ collisions at small jet-radii, indicates a strong medium effect.
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Ren-Zhuo Wan, Lei Ding, Xi Gui, Fan Yang, Shuang Li and Dai-Cui Zhou. Jet shape modification at LHC energies by JEWEL[J]. Chinese Physics C, 2019, 43(5): 054110. doi: 10.1088/1674-1137/43/5/054110
Ren-Zhuo Wan, Lei Ding, Xi Gui, Fan Yang, Shuang Li and Dai-Cui Zhou. Jet shape modification at LHC energies by JEWEL[J]. Chinese Physics C, 2019, 43(5): 054110.
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Revised: 2019-02-24
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• 1.

沈阳化工大学材料科学与工程学院 沈阳 110142

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## Jet shape modification at LHC energies by JEWEL

###### Corresponding author: Dai-Cui Zhou, dczhou@mail.ccnu.edu.cn
• 1. Nano Optical Material and Storage Device Research Center, School of Electronic and Electrical Engineering, Wuhan Textile University, Wuhan 430200, China
• 2. College of Science, China Three Gorges University, Yichang 443002, China
• 3. Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079, China

Abstract: Jet shape measurements are employed to explore the microscopic evolution mechanisms of parton-medium interaction in ultra-relativistic heavy-ion collisions. In this study, jet shape modifications are quantified in terms of the fragmentation function $F(z)$, relative momentum $p_{T}^{\rm rel}$, density of charged particles $\rho(r)$, jet angularity $girth$, jet momentum dispersion $p_{T}^{\rm disp}$, and $LeSub$ for proton-proton (pp) collisions at 0.9, 2.76, 5.02, 7, and 13 TeV, as well as for lead-lead collisions at 2.76 TeV and 5.02 TeV by JEWEL. A differential jet shape parameter $D_{girth}$ is proposed and studied at a smaller jet radius $r<0.3$. The results indicate that the medium has the dominant effect on jet shape modification, which also has a weak dependence on the center-of-mass energy. Jet fragmentation is enhanced significantly at very low $z<0.02$, and fragmented jet constituents are linearly spread to larger jet-radii for $p_{T}^{\rm rel}<1$. The waveform attenuation phenomena is observed in $p_{T}^{\rm rel}$, $girth$, and $D_{girth}$ distributions. The results obtained for $D_{girth}$from ${\rm pp}$ to ${\rm Pb+Pb}$, where the wave-like distribution in ${\rm pp}$ collision is ahead of ${\rm Pb+Pb}$ collisions at small jet-radii, indicates a strong medium effect.

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