10 research outputs found
Inclusive Jet and Hadron Suppression in a Multi-Stage Approach
We present a new study of jet interactions in the Quark-Gluon Plasma created
in high-energy heavy-ion collisions, using a multi-stage event generator within
the JETSCAPE framework. We focus on medium-induced modifications in the rate of
inclusive jets and high transverse momentum (high-) hadrons.
Scattering-induced jet energy loss is calculated in two stages: A high
virtuality stage based on the MATTER model, in which scattering of highly
virtual partons modifies the vacuum radiation pattern, and a second stage at
lower jet virtuality based on the LBT model, in which leading partons gain and
lose virtuality by scattering and radiation. Coherence effects that reduce the
medium-induced emission rate in the MATTER phase are also included. The
\trento\ model is used for initial conditions, and the (2+1)D VISHNU model is
used for viscous hydrodynamic evolution. Jet interactions with the medium are
modeled via 2-to-2 scattering with Debye screened potentials, in which the
recoiling partons are tracked, hadronized, and included in the jet clustering.
Holes left in the medium are also tracked and subtracted to conserve transverse
momentum. Calculations of the nuclear modification factor ()
for inclusive jets and high- hadrons are compared to
experimental measurements at RHIC and the LHC. Within this framework, we find
that two parameters for energy-loss, the coupling in the medium and the
transition scale between the stages of jet modification, suffice to
successfully describe these data at all energies, for central and semi-central
collisions, without re-scaling the jet transport coefficient .Comment: 33 pages, 23 figure
Multi-scale evolution of charmed particles in a nuclear medium
Parton energy-momentum exchange with the quark gluon plasma (QGP) is a
multi-scale problem. In this work, we calculate the interaction of charm quarks
with the QGP within the higher twist formalism at high virtuality and high
energy using the MATTER model, while the low virtuality and high energy portion
is treated via a (linearized) Boltzmann Transport (LBT) formalism. Coherence
effect that reduces the medium-induced emission rate in the MATTER model is
also taken into account. The interplay between these two formalisms is studied
in detail and used to produce a good description of the D-meson and charged
hadron nuclear modification factor RAA across multiple centralities. All
calculations were carried out utilizing the JETSCAPE framework
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Phenomenological Constraints on the Transport Properties of QCD Matter with Data-Driven Model Averaging.
Using combined data from the Relativistic Heavy Ion and Large Hadron Colliders, we constrain the shear and bulk viscosities of quark-gluon plasma (QGP) at temperatures of ∼150-350  MeV. We use Bayesian inference to translate experimental and theoretical uncertainties into probabilistic constraints for the viscosities. With Bayesian model averaging we propagate an estimate of the model uncertainty generated by the transition from hydrodynamics to hadron transport in the plasma's final evolution stage, providing the most reliable phenomenological constraints to date on the QGP viscosities
Phenomenological Constraints on the Transport Properties of QCD Matter with Data-Driven Model Averaging
Using combined data from the Relativistic Heavy Ion and Large Hadron Colliders, we constrain the shear and bulk viscosities of quark-gluon plasma (QGP) at temperatures of ∼150–350  MeV. We use Bayesian inference to translate experimental and theoretical uncertainties into probabilistic constraints for the viscosities. With Bayesian model averaging we propagate an estimate of the model uncertainty generated by the transition from hydrodynamics to hadron transport in the plasma’s final evolution stage, providing the most reliable phenomenological constraints to date on the QGP viscosities
Determining the jet transport coefficient q̂ from inclusive hadron suppression measurements using Bayesian parameter estimation
We report a new determination of ˆq, the jet transport coefficient of the quark-gluon plasma. We use the JETSCAPE framework, which incorporates a novel multistage theoretical approach to in-medium jet evolution and Bayesian inference for parameter extraction. The calculations, based on the Matter and Lbt jet quenching models, are compared to experimental measurements of inclusive hadron suppression in Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and Pb+Pb collisions at the CERN Large Hadron Collider (LHC). The correlation of experimental systematic uncertainties is accounted for in the parameter extraction. The functional dependence of ˆq on jet energy or virtuality and medium temperature is based on a perturbative picture of in-medium scattering, with components reflecting the different regimes of applicability of Matter and Lbt. In the multistage approach, the switch between Matter and Lbt is governed by a virtuality scale Q0. Comparison of the posterior model predictions to the RHIC and LHC hadron suppression data shows reasonable agreement, with moderate tension in limited regions of phase space. The distribution of ˆq/T3 extracted from the posterior distributions exhibits weak dependence on jet momentum and medium temperature T, with 90% credible region (CR) depending on the specific choice of model configuration. The choice of Matter+Lbt, with switching at virtuality Q0, has 90% CR of 240 GeV/c. The value of Q0, determined here for the first time, is in the range 2.0–2.7 GeV