arXiv subjects

Yichao Dang

Publications and source records attributed to Yichao Dang.

4 recordsLinked to original sources

arXiv2026

Geometric Bias and Centrality Dependence of Jet Quenching in High-Energy Nuclear Collisions

Jet quenching provides a valuable measure of the opacity of the quark-gluon plasma (QGP) produced in high-energy heavy-ion collisions. However, substantial suppression of charged hadron spectra is observed in highly peripheral collisions, despite the expectation of negligible jet-QGP interactions in this regime. To address this, we develop a HIJING-based initial condition model that accounts for the impact parameter dependence of both inelastic nucleon-nucleon (NN) collisions and the number of hard partonic scatterings per inelastic NN collision. This dependence introduces a geometric bias effect on the jet yield within a given centrality class of nucleus-nucleus (AA) collisions, suppressing the high-transverse-momentum hadron spectrum in peripheral collisions due to dilute nucleon overlap at large AA impact parameters. By combining this improved initial condition model with a linear Boltzmann transport model for jet-QGP interactions, we obtain a satisfactory description of the centrality dependence of charged hadron suppression in Pb+Pb collisions at $\sqrt{s_\mathrm{NN}}=5.02$ TeV.

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arXiv2026

An improved linear Boltzmann transport model for hadron and jet suppression in ultrarelativistic heavy-ion collisions

Jets serve as powerful tomographic probes of the quark-gluon plasma (QGP) created in relativistic heavy-ion collisions. While the expanding landscape of jet observables reveals multi-faceted aspects of jet-medium interactions, a precise and simultaneous description of the nuclear modification factors of hadrons and full jets remains a challenge for theoretical models. In this work, we present two essential improvements to the linear Boltzmann transport (LBT) model to bridge this gap. First, instead of implementing in-medium parton transport after vacuum parton showers complete, we introduce a medium scale at which in-medium parton transport is inserted into the vacuum parton showers, providing a more physical picture of parton-QGP interactions. Second, we incorporate color flow information into the LBT model, enabling string connections between partons whose configurations are correlated with the medium-modified parton showers before hadronization. We demonstrate that both improvements alter the predicted ratio of hadron to jet quenching, leading to a satisfactory unified description of the nuclear modification factors of hadrons and jets with different flavors.

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arXiv2025

Emergence of thermal recoil jets in high-energy heavy-ion collisions

In the established paradigm of jet quenching in relativistic heavy-ion collisions, jets from initial hard parton scatterings are suppressed due to their interaction with the quark-gluon plasma (QGP), serving as crucial tomographic probes of QGP properties. Within the linear Boltzmann transport model, we find that the QGP is also capable of absorbing and reprocessing energy deposited by the hard jets into emergent jet-like objects, providing an alternative production mechanism of thermal recoil jets. These emergent thermal recoil jets exhibit distinct transverse momentum ($p_\mathrm{T}$) and jet-cone size ($R$) dependencies different from the hard jets, and interpret the puzzling observation of the enhanced yields of hadron triggered jets at large azimuthal angle relative to the away side and solely at small $p_\mathrm{T}$ and large $R$. These thermal recoil jets are predicted to have unique substructures, such as a jet shape that increases with radius and a thermal-like distribution of their constituents, which await verification in future experimental analyses.

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arXiv2024

Reexamining charm versus bottom quark energy loss inside a color-deconfined medium

The general intuition that heavier partons suffer weaker energy loss inside a quark-gluon plasma (QGP) medium is critically re-examined. Within a linear Boltzmann transport model that includes both Yukawa and string types of interactions between heavy quarks and the QGP, we find that while the radiative energy loss is suppressed by the parton mass, heavier partons can experience stronger string potential scatterings with the medium. Their competition may result in less energy loss of bottom quarks than charm quarks at low transverse momentum ($p_\mathrm{T}$) but an inverse order at high $p_\mathrm{T}$. Our model calculation shows a weaker nuclear modification on bottom particles than charm particles at low $p_\mathrm{T}$, as observed by both RHIC and LHC experiments, but predicts an opposite hierarchy at high $p_\mathrm{T}$. A larger momentum space transport coefficient ($\hat{q}$) and a smaller spatial diffusion coefficient ($D_\mathrm{s}$) are found for bottom quarks than for charm quarks.

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