Study of transverse momentum and nuclear modification factors distribution of charged particles produced in pp and Pb–Pb collisions at s NN = 2.76TeV and 5.02TeV

We have studied transverse momentum distributions of charged particles produced in pp and Pb–Pb collisions at [Formula: see text] TeV and 5.02 TeV in the pseudorapidity interval [Formula: see text] and transverse momentum range [Formula: see text][Formula: see text]GeV/[Formula: see text]. We simulated data using EPOS-LHC, EPOS-1.99 and QGSJETII-04 models. The simulation data is compared with the ALICE experimental data values at [Formula: see text] TeV and 5.02 TeV for pp and most central Pb–Pb collisions. It has been observed that, EPOS-LHC and QGSJETII-04 models explain the experimental results for pp collision at [Formula: see text] TeV and 5.02 TeV. The behavior of nuclear modification factors has been studied. The simulation codes of all three models EPOS-LHC, EPOS-1.99 and QGSJETII-04 overestimate the experimental results at low transverse momentum interval: [Formula: see text] GeV/[Formula: see text], for Pb–Pb collisions at [Formula: see text] TeV and 5.02 TeV. However, only EPOS-LHC model can explain the experimental data at high transverse momentum in the range: [Formula: see text] GeV/[Formula: see text]. EPOS-1.99 and QGSJETII-04 underestimate in the region of Cronin effect and cannot give satisfactory estimates for the [Formula: see text] values for which [Formula: see text] demonstrates stronger suppression because of the collective parton effect. It can be inferred that these effects are not taken into account in EPOS-1.99 and QGSJETII-04 models. These models, however, satisfactorily explain the ALICE experimental data in the ranges of [Formula: see text] for which nuclear modification factor [Formula: see text] shows rising trend.

QGP modification to single inclusive jets in a calibrated transport model

We study inclusive jet suppression and modifications in the quark-gluon plasma (QGP) with a transport-based model. The model includes vacuum-like parton shower evolution at high-virtuality, a linearized transport for jet-medium interactions, and a simple ansatz for the jet-induced hydrodynamic response of the medium. Model parameters are calibrated to nuclear modification factors for inclusive hadron $$ {R}_{AA}^h $$ R AA h and single inclusive jets $$ {R}_{AA}^j $$ R AA j with cone size R = 0.4 in 0–10% central Au-Au and Pb-Pb collisions measured at the RHIC and LHC. The calibrated model consistently describes the cone-size dependent $$ {R}_{AA}^j $$ R AA j (R), modifications to inclusive jet fragmentation functions and jet shape. We discuss the origin of these modifications by analyzing the medium-induced jet energy flow in this model and elucidate the interplay of hard parton evolution and jet-induced medium response. In particular, we demonstrate that the excess of soft hadrons at pT∼ 2 GeV/c in jet fragmentation function and jet shape at large $$ r=\sqrt{\Delta {\eta}^2+\Delta {\phi}^2} $$ r = Δ η 2 + Δ ϕ 2 are consequences of both soft medium-induced gluon radiation and jet-induced medium excitation.

Nuclear modification factors for jet fragmentation

Using a recently-developed perturbative-QCD approach for jet evolution in a dense quark-gluon plasma, we study the nuclear modification factor for the jet fragmentation function. The qualitative behaviour that we find is in agreement with the respective experimental observations in Pb+Pb collisions at the LHC: a pronounced nuclear enhancement at both ends of the spectrum. Our Monte Carlo simulations are supplemented with analytic estimates which clarify the physical interpretation of the results. The main source of theoretical uncertainty is the sensitivity of our calculations to a low-momentum cutoff which mimics confinement. To reduce this sensitivity, we propose a new observable, which describes the jet fragmentation into subjets and is infrared-and-collinear safe by construction. We present Monte Carlo predictions for the associated nuclear modification factor together with their physical interpretation.

Open Bottom Production in Au Au Collisions at √sNN = 200 GeV with the STAR Experiment

In these proceedings, we present measurements of open bottom hadron production through multiple decay channels in Au + Au collisions at s NN = 200 GeV by the STAR experiment. Specifically, measurements of nuclear modification factors for electrons, J / ψ , and D 0 from open bottom hadron decays, enabled by the Heavy Flavor Tracker, are shown. A large suppression for non-prompt J / ψ and non-prompt D 0 are observed at high transverse momenta. On the other hand, there seems to be less suppression for electrons from bottom hadron decays than for those from charm hadron decays at ∼ 2 σ significance level.

Light flavour hadron and inclusive charged particle pT-spectra measured with the ALICE experiment at CERN

Light flavor hadron and inclusive charged particle spectra provide an interesting probe of the particle production mechanisms and the transport properties of QCD matter. Charged particle and neutral meson inclusive pT-differential cross sections in pp, p-Pb, Pb-Pb and Xe-Xe collisions have been measured by ALICE. Charged particles are studied in different multiplicity (for pp and p-Pb where available) and centrality classes (for A-A). The comparison of spectra at similar〈dNch/dη〉, the nuclear modification factors, the mean pTand particle ratios will also be presented considering those are observables important to get information on the properties of the medium formed in the collisions. Comparisons with model calculations will also be discussed.