scholarly journals Relativistic Langevin dynamics: charm versus beauty

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Shuang Li ◽  
Wei Xiong ◽  
Renzhuo Wan

AbstractThe production of heavy quarks (charm and beauty) provides unique insights into the transport properties of the Quark–Gluon Plasma (QGP) in heavy-ion collisions. Experimentally, the nuclear modification factor $$R_{\mathrm{AA}}$$ R AA and the azimuthal anisotropy coefficient $$v_{\mathrm{2}}$$ v 2 of heavy-flavor mesons are powerful observables to study the medium-related effects, such as energy loss and collectivity, on the heavy quark propagation through the QGP evolution. The latest measurements of the prompt and non-prompt open heavy-flavor hadrons allow a systematic comparison of the transport behaviors probed by charm and beauty quarks. In this work we make such an attempt utilizing our recently developed framework. By performing a quantitative investigation of $$R_{\mathrm{AA}}$$ R AA and $$v_{\mathrm{2}}$$ v 2 , it is found that both charm and beauty quarks are efficient probes to capture the dynamical features of QGP, in particular the resulting mass hierarchy for the energy loss and azimuthal anisotropy, which are well inherited by the various D/B-meson species. Moreover, our calculations can describe simultaneously $$R_{\mathrm{AA}}$$ R AA and $$v_{\mathrm{2}}$$ v 2 data for the prompt and non-prompt $$D^{0}$$ D 0 mesons in central ($$0-10\%$$ 0 - 10 % ) and semi-central ($$30-50\%$$ 30 - 50 % ) Pb–Pb collisions at $$\sqrt{s_{\mathrm{NN}}}=5.02~{\mathrm{TeV}}$$ s NN = 5.02 TeV . The predictions for B-meson observables for upcoming experimental tests are also made down to the low momentum region.

2015 ◽  
Vol 37 ◽  
pp. 1560060
Author(s):  
Grigory Ovanesyan

We study the jet quenching effect in heavy ion collisions, based on medium-induced splitting functions calculated from Soft Collinear Effective Theory with Glauber Gluons. Our method is formulated in the language of DGLAP evolution equations with medium-induced splitting functions. In the small-x soft gluon approximation we analytically solve the evolution equations and find an intuitive connection to the energy loss approach. For central Pb+Pb collisions at the LHC we quantify the effect of finite-x corrections for the nuclear modification factor and compare to data.


2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
B. G. Zakharov

Abstract We perform an analysis of jet quenching in heavy and light ion collisions for scenarios without and with quark-gluon plasma formation in pp collisions. We find that the results for these scenarios are very similar, and both of them are in reasonable agreement with data for heavy ion collisions. However, their results become differ significantly for light nuclei. Using the parameters fitted to heavy ion data on the nuclear modification factor RAA, we make predictions for 0.2 and 7 TeV O+O collisions that can be verified by future experiments at RHIC and the LHC.


2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Adam Takacs ◽  
Konrad Tywoniuk

Abstract The steeply falling jet spectrum induces a bias on the medium modifications of jet observables in heavy-ion collisions. To explore this effect, we develop a novel analytic framework to study the quenched jet spectrum and its cumulative. We include many energy-loss-related effects, such as soft and hard medium induced emissions, broadening, elastic scattering, jet fragmentation, cone size dependence, and coherence effects. We show that different observables, based on the jet spectrum, are connected, e.g., the nuclear modification, spectrum shift, and the quantile procedure. We present the first predictions for the nuclear modification factor and the quantile procedure with cone size dependence. As a concrete example, we compare dijet and boson+jet events to unfold the spectrum bias effects, and improve quark-, and gluon-jet classification using arguments based on the cumulative. Besides pointing out its flexibility, finally, we apply our framework to other energy loss models such as the hybrid weak/strong-coupling approach.


2020 ◽  
Vol 1643 (1) ◽  
pp. 012011
Author(s):  
C Hills

Abstract The baryon-to-meson ratio Λ c + / D 0 and the nuclear modification factor RAA in the charm sector are important observables to gain an understanding of how charm quarks hadronise and lose energy in the Quark-Gluon Plasma produced in heavy-ion collisions. In this contribution, recent measurements performed with the ALICE detector in pp, p–Pb and Pb–Pb collisions at 5.02 TeV are presented and compared with previous measurements in pp collisions at 7 TeV, measurements by the LHCb Collaboration and theoretical model predictions.


2018 ◽  
Vol 171 ◽  
pp. 18009
Author(s):  
Javier Martín Blanco

Charmonium states, such as the J/ψ and ψ(2S) mesons, are excellent probes of the deconfined state of matter, the Quark-Gluon Plasma (QGP) created in heavy ion collisions. In addition, the measurements in pPb collisions allow to study the cold nuclear matter effects, being crucial to disentangle these from the QGP-related effects in PbPb collisions. In this talk the new nuclear modification factor RAA of prompt and nonprompt J/ψ in PbPb collisions at [see formula in PDF] = 5.02 TeV were presented over a wide kinematic range (3 < pT < 50 GeV/c, |y| < 2.4), and fine event-centrality intervals. The results were compared to those at 2.76 TeV over a similar kinematic range. In addition, new prompt ψ(2S) RAA results at 5.02 TeV were reported. Finally the final prompt and nonprompt J/ψ results, as well as preliminary ψ(2S) results, in pPb collisions at 5.02 TeV, were discussed.


2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Subhash Singha ◽  
Prashanth Shanmuganathan ◽  
Declan Keane

We review topics related to the first moment of azimuthal anisotropy (v1), commonly known as directed flow, focusing on both charged particles and identified particles from heavy-ion collisions. Beam energies from the highest available, at the CERN LHC, down to projectile kinetic energies per nucleon of a few GeV per nucleon, as studied in experiments at the Brookhaven AGS, fall within our scope. We focus on experimental measurements and on theoretical work where direct comparisons with experiment have been emphasized. The physics addressed or potentially addressed by this review topic includes the study of Quark Gluon Plasma and, more generally, investigation of the Quantum Chromodynamics phase diagram and the equation of state describing the accessible phases.


2018 ◽  
Vol 46 ◽  
pp. 1860019
Author(s):  
Renu Bala

The Large Hadron Collider at CERN allows us to study heavy-ion collisions at an un- precedented energy. ALICE, A Large Ion Collider Experiment, is the experiment ded- icated to the investigation of heavy-ion collisions. In this contribution, recent open heavy-flavour results from pp collisions at [Formula: see text]= 5.02, 7, 8 and 13 TeV and p–Pb collisions at [Formula: see text] = 5.02 TeV, collected with the ALICE detector during the LHC Run-1 and Run-2 are presented. The results include the production cross section, nuclear modification factor and multiplicity dependence studies of production of D mesons and electrons from heavy-flavour hadron decays at mid-rapidity and of muons from heavy-flavour hadron decays at forward rapidity. Charm production was measured down to [Formula: see text] = 0 GeV/[Formula: see text] in pp and p–Pb collisions. Recent measurements of the production cross section of heavy charmed baryons such as [Formula: see text] (in pp and p–Pb) and [Formula: see text] (in pp) are discussed. The results are compared with theoretical model predictions.


Universe ◽  
2019 ◽  
Vol 5 (5) ◽  
pp. 130 ◽  
Author(s):  
Róbert Vértesi

Heavy quarks (charm and beauty) are produced early in the nucleus–nucleus collisions, and heavy flavor survives throughout the later stages. Measurements of heavy-flavor quarks thus provide us with means to understand the properties of the Quark–Gluon Plasma, a hot and dense state of matter created in heavy-ion collisions. Production of heavy-flavor in small collision systems, on the other hand, can be used to test Quantum-chromodynamics models. After a successful completion of the Run-I data taking period, the increased luminosity from the LHC and an upgraded ALICE detector system in the Run-II data taking period allows for unprecedented precision in the study of heavy quarks. In this article we give an overview of selected recent results on heavy-flavor measurements with ALICE experiments at the LHC.


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