The radial distribution of
D
0
mesons in jets probes the diffusion of charm quark relative to the jet axis and provides a new perspective to study the interaction mechanisms between heavy quarks and ...the medium in the nucleus-nucleus collisions. The in-medium parton propagations are described by a Monte Carlo transport model which uses the next-to-leading order (NLO) plus parton shower (PS) event generator SHERPA as input and includes elastic (collisional) and inelastic (radiative) interaction for heavy quarks as well as light partons. At low
D
0
meson
p
T
, the radial distribution significantly shifts to larger radius indicating a strong diffusion effect which is consistent with the recent experimental data. We demonstrate that the angular deviation of charm quarks declines with
p
T
and is very sensitive to the collisional more than radiative interaction at
p
T
<
5
GeV. As predictions, we present the
D
0
meson radial distribution in jets in p + p and
0
-
10
%
Au + Au collisions at
s
NN
=
200
GeV at the RHIC, and also estimate the nuclear modification factor of charm jet in central Au + Au collisions at 200 GeV at the RHIC and central Pb + Pb collisions at 5.02 TeV at the LHC.
We study the incoherent multiple scattering effects on heavy meson production in the backward rapidity region of p+A collisions within the generalized high-twist factorization formalism. We calculate ...explicitly the double scattering contributions to the heavy meson differential cross sections by taking into account both initial-state and final-state interactions, and find that these corrections are positive. We further evaluate the nuclear modification factor for muons that come form the semi-leptonic decays of heavy flavor mesons. Phenomenological applications in d+Au collisions at a center-of-mass energy s=200 GeV at RHIC and in p+Pb collisions at s=5.02 TeV at the LHC are presented. We find that incoherent multiple scattering can describe rather well the observed nuclear enhancement in the intermediate pT region for such reactions.
We investigate the flavor dependence of jet quenching, by performing a systematic analysis of medium modifications on the inclusive jet, γ+jet, and b-jet in Pb+Pb collisions at the LHC. Our results ...from MadGraph+PYTHIA exhibit excellent agreement with experimental measurements of the inclusive jet, γ+jet and b-jet simultaneously in p+p collisions. We then utilize a Bayesian data-driven method to extract systematically the flavor-dependent jet energy loss distributions from experimental data, where the gluon, light quark and b-quark initiated energy loss distributions are well constrained and satisfy the predicted flavor hierarchy of jet quenching, i.e. 〈ΔEg〉>〈ΔEq〉>〈ΔEb〉. It is shown that the quark-initiated jet energy loss distribution shows weaker centrality and pT dependence than the gluon-initiated one. We demonstrate the impacts of the slope of initial spectra, color-charge as well as parton mass dependent jet energy attenuation on the γ/b-jet suppression observed in heavy-ion collisions.
The transverse momentum spectrum of η meson in relativistic heavy-ion collisions is studied at the Next-to-Leading Order (NLO) within the perturbative QCD, where the jet quenching effect in the QGP ...is incorporated with the effectively medium-modified η fragmentation functions using the higher-twist approach. We show that the theoretical simulations could give nice descriptions of PHENIX data on η meson in both p+p and central Au + Au collisions at the RHIC, and also provide numerical predictions of η spectra in central Pb + Pb collisions with sNN=2.76 TeV at the LHC. The ratios of η/π0 in p+p and in central Au + Au collisions at 200 GeV are found to overlap in a wide pT region, which matches well the measured ratio η/π0 by PHENIX. We demonstrate that, at the asymptotic region when pT→∞ the ratios of η/π0 in both Au + Au and p+p are almost determined only by quark jets fragmentation and thus approach to the one in e+e− scattering; in addition, the almost identical gluon (quark) contribution fractions to η and to π result in a rather moderate variation of η/π0 distribution at intermediate and high pT region in A+A relative to that in p+p; while a slightly higher η/π0 at small pT in Au + Au can be observed due to larger suppression of gluon contribution fraction to π0 as compared to the one to η. The theoretical prediction for η/π0 at the LHC has also been presented.
We establish a statistical two-body fractal (STF) model to study the spectrum of J/ψ. J/ψ serves as a reliable probe in heavy-ion collisions. The distribution of J/ψ in hadron gas is influenced by ...flow, quantum and strong interaction effects. Previous models have predominantly focused on one or two of these effects while neglecting the others, resulting in the inclusion of unconsidered effects in the fitted parameters. Here, we study the issue from a new point of view by analyzing the fact that all three effects induce a self-similarity structure, involving a J/ψ-π two-meson state and a J/ψ, π two-quark state, respectively. We introduce modification factor qTBS and q2 into the probability and entropy of charmonium. qTBS denotes the modification of self-similarity on J/ψ, q2 denotes that of self-similarity and strong interaction between c and c¯ on quarks. By solving the probability and entropy equations, we derive the values of qTBS and q2 at various collision energies and centralities. Substituting the value of qTBS into distribution function, we successfully obtain the transverse momentum spectrum of low-pT J/ψ, which demonstrates good agreement with experimental data. The STF model can be employed to investigate other mesons and resonance states.
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