scholarly journals Jet Quenching Beyond the Energy Loss Approach

2015 ◽  
Vol 37 ◽  
pp. 1560060
Author(s):  
Grigory Ovanesyan
Keyword(s):  
Energy Loss ◽  
Evolution Equations ◽  
Heavy Ion ◽  
Jet Quenching ◽  
Effective Theory ◽  
Dglap Evolution ◽  
Quenching Effect ◽  
Nuclear Modification Factor ◽  
Ion Collisions ◽  
Modification Factor

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.

scholarly journals Jet quenching from heavy to light ion collisions

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
B. G. Zakharov
Keyword(s):  
Quark Gluon Plasma ◽  
Reasonable Agreement ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Jet Quenching ◽  
Light Nuclei ◽  
Nuclear Modification Factor ◽  
Nuclear Modification ◽  
Ion Collisions ◽  
Modification Factor

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.

scholarly journals Relativistic Langevin dynamics: charm versus beauty

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Shuang Li ◽  
Wei Xiong ◽  
Renzhuo Wan
Keyword(s):  
Energy Loss ◽  
Experimental Tests ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Azimuthal Anisotropy ◽  
Mass Hierarchy ◽  
Heavy Flavor ◽  
Nuclear Modification Factor ◽  
Ion Collisions ◽  
Modification Factor

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.

scholarly journals Quenching effects in the cumulative jet spectrum

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Adam Takacs ◽  
Konrad Tywoniuk
Keyword(s):  
Energy Loss ◽  
Size Dependence ◽  
Heavy Ion ◽  
Nuclear Modification Factor ◽  
Nuclear Modification ◽  
Ion Collisions ◽  
Modification Factor ◽  
Coupling Approach ◽  
Jet Fragmentation ◽  
Jet Observables

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.

scholarly journals Probing jet medium interactions via Z(H) + jet momentum imbalances

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Lin Chen ◽  
Shu-Yi Wei ◽  
Han-Zhong Zhang
Keyword(s):  
Transport Coefficient ◽  
Good Description ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
Quenching Effect ◽  
Nuclear Collisions ◽  
Ion Collisions ◽  
Pqcd Approach

AbstractDifferent types of high energy hard probes are used to extract the jet transport properties of the Quark-Gluon Plasma created in heavy-ion collisions, of which the heavy boson tagged jets are undoubtedly the most sophisticated due to its clean decay signature and production mechanism. In this study, we used the resummation improved pQCD approach with high order correction in the hard factor to calculate the momentum ratio $$x_J$$ x J distributions of Z and Higgs (H) tagged jets. We found that the formalism can provide a good description of the 5.02 TeV pp data. Using the BDMPS energy loss formalism, along with the OSU 2 + 1D hydro to simulate the effect of the medium, we extracted the value of the jet transport coefficient to be around $${\hat{q}}_0=4\sim 8~\text {GeV}^2/\text {fm}$$ q ^ 0 = 4 ∼ 8 GeV 2 / fm by comparing with the Z + jet PbPb experimental data. The H + jet $$x_J$$ x J distribution were calculated in a similar manner in contrast and found to have a stronger Sudakov effect as compared with the Z + jet distribution. This study uses a clean color-neutral boson as trigger to study the jet quenching effect and serves as a complimentary method in the extraction of the QGP’s transport coefficient in high energy nuclear collisions.

scholarly journals The global geometrical property of jet events in high-energy nuclear collisions

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Shi-Yong Chen ◽  
Wei Dai ◽  
Shan-Liang Zhang ◽  
Qing Zhang ◽  
Ben-Wei Zhang
Keyword(s):  
Energy Loss ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
High Energy ◽  
Jet Quenching ◽  
Relativistic Heavy Ion Collisions ◽  
Parton Energy Loss ◽  
Boltzmann Transport ◽  
Ion Collisions ◽  
Medium Modifications

AbstractWe present the first theoretical study of medium modifications of the global geometrical pattern, i.e., transverse sphericity ($$S_{\perp }$$ S ⊥ ) distribution of jet events with parton energy loss in relativistic heavy-ion collisions. In our investigation, POWHEG + PYTHIA is employed to make an accurate description of transverse sphericity in the p + p baseline, which combines the next-to-leading order (NLO) pQCD calculations with the matched parton shower (PS). The Linear Boltzmann Transport (LBT) model of the parton energy loss is implemented to simulate the in-medium evolution of jets. We calculate the event normalized transverse sphericity distribution in central Pb + Pb collisions at the LHC, and give its medium modifications. An enhancement of transverse sphericity distribution at small $$S_{\perp }$$ S ⊥ region but a suppression at large $$S_{\perp }$$ S ⊥ region are observed in A + A collisions as compared to their p + p references, which indicates that in overall the geometry of jet events in Pb + Pb becomes more pencil-like. We demonstrate that for events with 2 jets in the final-state of heavy-ion collisions, the jet quenching makes the geometry more sphere-like with medium-induced gluon radiation. However, for events with $$\ge 3$$ ≥ 3 jets, parton energy loss in the QCD medium leads to the events more pencil-like due to jet number reduction, where less energetic jets may lose their energies and then fall off the jet selection kinematic cut. These two effects offset each other and in the end result in more jetty events in heavy-ion collisions relative to that in p + p.

scholarly journals Jet tomography in high-energy nuclear collisions

2019 ◽  
Vol 206 ◽  
pp. 04004 ◽  
Author(s):  
Ben-Wei Zhang ◽  
Guo-Yang Ma ◽  
Wei Dai ◽  
Sa Wang ◽  
Shan-Liang Zhang
Keyword(s):  
Energy Loss ◽  
Heavy Ion ◽  
High Energy ◽  
Jet Quenching ◽  
Parton Energy Loss ◽  
Matrix Elements ◽  
Leading Order ◽  
Nuclear Collisions ◽  
Ion Collisions ◽  
Jet Observables

When an energetic parton traversing the QCD medium, it may suffer multiple scatterings and lose energy. This jet quenching phenomenon may lead to the suppression of leading hadron productions as well as medium modifications of full jet observables in heavy-ion collisions. In this talk we discuss the nuclear modificationfactors and yield ratios of identified meson such as η, ρ0, φ, ω, and $ K_{\rm{S}}^0 $ as well as π meson at large pT in A+A collisions at the next to-leading order (NLO) with high-twist approach of parton energy loss. Then we discuss a newly developed formalism of combing NLO matrix elements and parton shower (PS) for initial hard production with parton energy loss in the QGP, and its application in investigating massivegauge boson(Z0/W±)tagged jet productions and b $ \bar {b} $ dijet correlations in Pb+Pb at the LHC.

scholarly journals Measurement of Open Heavy-Flavour Production in pp and p–Pb Collisions with ALICE at the LHC

2018 ◽  
Vol 46 ◽  
pp. 1860019
Author(s):  
Renu Bala
Keyword(s):  
Cross Section ◽  
Production Cross Section ◽  
Heavy Ion Collisions ◽  
D Mesons ◽  
Production Cross ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Nuclear Modification Factor ◽  
Ion Collisions ◽  
Modification Factor

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.

scholarly journals Measurements of jets in heavy ion collisions

2018 ◽  
Vol 172 ◽  
pp. 05010 ◽  
Author(s):  
Christine Nattrass
Keyword(s):  
Energy Loss ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
Relativistic Heavy Ion Collider ◽  
Ion Collisions

The Quark Gluon Plasma (QGP) is created in high energy heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). This medium is transparent to electromagnetic probes but nearly opaque to colored probes. Hard partons produced early in the collision fragment and hadronize into a collimated spray of particles called a jet. The partons lose energy as they traverse the medium, a process called jet quenching. Most of the lost energy is still correlated with the parent parton, contributing to particle production at larger angles and lower momenta relative to the parent parton than in proton-proton collisions. This partonic energy loss can be measured through several observables, each of which give different insights into the degree and mechanism of energy loss. The measurements to date are summarized and the path forward is discussed.

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