Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Jet quenching and its substructure dependence due to color decoherence

Xiang-Pan Duan, Lin Chen, Guo-Liang Ma, Carlos A. Salgado, Bin Wu

Abstract

Motivated by color coherence and decoherence effects in the QCD medium, we propose a theoretical framework that combines vacuum-like emissions and medium-induced radiation to study jet quenching and its dependence on jet cone sizes and substructure. In our approach, a jet produced at a hard scale $Q$ first undergoes vacuum-like evolution, as described by the well-established generating-function method in the double logarithmic approximation. These vacuum-like emissions generate subjets at an infrared momentum scale $Q_0$. Each subjet then experiences medium-induced energy loss as described by the BDMPS-Z formalism. By modeling the QCD bulk medium using OSU (2+1)-dimensional viscous hydrodynamics and treating $Q_0$ together with the jet-quenching parameters at the initial proper time of the hydrodynamic evolution as free parameters, our approach provides a very good description of the inclusive jet modification factor $R_{AA}$ for large-radius jets and its dependence on jet substructure in 0-10% PbPb collisions at $\sqrt{s_{NN}} = 5.02~\rm{TeV}$, as measured by the ATLAS experiment.

Jet quenching and its substructure dependence due to color decoherence

Abstract

Motivated by color coherence and decoherence effects in the QCD medium, we propose a theoretical framework that combines vacuum-like emissions and medium-induced radiation to study jet quenching and its dependence on jet cone sizes and substructure. In our approach, a jet produced at a hard scale first undergoes vacuum-like evolution, as described by the well-established generating-function method in the double logarithmic approximation. These vacuum-like emissions generate subjets at an infrared momentum scale . Each subjet then experiences medium-induced energy loss as described by the BDMPS-Z formalism. By modeling the QCD bulk medium using OSU (2+1)-dimensional viscous hydrodynamics and treating together with the jet-quenching parameters at the initial proper time of the hydrodynamic evolution as free parameters, our approach provides a very good description of the inclusive jet modification factor for large-radius jets and its dependence on jet substructure in 0-10% PbPb collisions at , as measured by the ATLAS experiment.
Paper Structure (20 sections, 38 equations, 8 figures)

This paper contains 20 sections, 38 equations, 8 figures.

Table of Contents

  1. Introduction
  2. Jet suppression with color decoherence
  3. Building blocks: vacuum-like emissions and medium-induced radiation
  4. The virtuality evolution of multiplicity distributions in jets
  5. Quenching weights within the BDMPS-Z formalism
  6. Jet quenching incorporating vacuum-like emissions and medium-induced radiation
  7. Initial states of jet cross sections in heavy-ion collisions
  8. Jet cross sections in heavy-ion collisions
  9. Jet quenching with color decoherence.
  10. Jet quenching as a single color charge.
  11. Jet energy loss with color decoherence
  12. Multiplicity distributions in QCD jets
  13. Mean medium-induced energy loss
  14. Suppression of jets reconstructed from subjets with different cone sizes
  15. Jet quenching parameter and $Q_0$
  16. ...and 5 more sections

Figures (8)

  • Figure 1: The probability distribution for the total medium-induced energy loss. Here, we show the numerical results of $\omega_c D(\epsilon)$ as a function of $\epsilon/\omega_c$ for $\alpha_s = 1/3$, along with the asymptotic solution in eq. \ref{['eq:Dasy']} from ref. Baier:2001yt.
  • Figure 2: Parton multiplicity distributions for quark (red) and gluon (blue) jets. Top: $Q_0 = 35~\rm{GeV}$ and $R = 1.0$. Middle: $Q_0 = 35~\rm{GeV}$ and $R = 0.4$. Bottom: $Q_0 = 20~\rm{GeV}$ and $R = 1.0$. The different curves in each plot correspond to different values of $p_T$, ranging from $100~\rm{GeV}$ to $1000~\rm{GeV}$.
  • Figure 3: Mean medium-induced energy loss for $\omega_c = 50~\rm{GeV}$. Left: the dependence on the jet radius for $R = 0.4$, $0.6$, and $1.0$ with a fixed $Q_0 = 35~\rm{GeV}$. Right: the dependence on the color decoherence for $Q_0 = 20$, $35$, and $100~\rm{GeV}$ with a fixed jet radius $R = 1.0$.
  • Figure 4: Nuclear modification factor $R_{AA}$ for $R=0.2$ jets and $R=1.0$ jets reclustered from $R=0.2$ jets in 0--10% PbPb collisions at $\sqrt{s_{NN}} = 5.02~\mathrm{TeV}$. Left: two-dimensional $\chi^2/\mathrm{d.o.f.}$ distribution obtained by scanning $Q_0$ and $\hat{q}_0$ using the experimental measurements of $R_{AA}$ reported in ref. ATLAS:2023hso. The red star denotes the minimum at $Q_0 = 35~\mathrm{GeV}$ and $\hat{q}_0 = 6.4~\mathrm{GeV}^2/\mathrm{fm}$. Right: theoretical results for $R_{AA}$ for these inclusive jets, compared with the ATLAS data ATLAS:2023hso.
  • Figure 5: Cone-size dependence of the jet suppression $R_{AA}$ with jet substructure in 0-10% PbPb collisions at $\sqrt{s_{NN}} = 5.02~\rm{TeV}$. Left: $R_{AA}$ for inclusive jets with radii $R = 0.4$, $0.6$, and $1.0$, reclustered from $R=0.2$ jets, in comparison with that for $R=0.2$. Right: the ratio of $R_{AA}$, shown in the left panel, normalized to the reference case $R = 0.2$. Here, $Q_0 = 35~\rm{GeV}$ and $\hat{q}_0 = 6.4~\rm{GeV^2/fm}$.
  • ...and 3 more figures