Jet substructure modification in a QGP from a multi-scale description of jet evolution with JETSCAPE
Y. Tachibana, A. Angerami, S. A. Bass, S. Cao, J. Coleman, L. Cunqueiro, T. Dai, L. Du, H. Elfner, D. Everett, W. Fan, R. Fries, C. Gale, Y. He, U. Heinz, B. V.… 展开作者
Y. Tachibana, A. Angerami, S. A. Bass, S. Cao, J. Coleman, L. Cunqueiro, T. Dai, L. Du, H. Elfner, D. Everett, W. Fan, R. Fries, C. Gale, Y. He, U. Heinz, B. V. Jacak, P. M. Jacobs, S. Jeon, K. Kauder, W. Ke, E. Khalaj, M. Kordell, A. Kumar, T. Luo, A. Majumder, M. McNelis, C. Nattrass, D. Oliinychenko, D. Pablos, L. G. Pang, C. Park, J. -F. Paquet, J. H. Putschke, G. Roland, B. Schenke, L. Schwiebert, C. Shen, C. Sirimanna, R. A. Soltz, G. Vujanovic, X. -N. Wang, R. L. Wolpert, Y. Xu, Z. Yang
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4 pages, 3 figures, Proceedings of Hard Probes 2018, 30 September-5 October, Aix-Les-Bains, France
The modification of jet substructure in relativistic heavy-ion collisions is studied using JETSCAPE, a publicly available software package containing a framework for Monte Carlo event generators. Multi-stage jet evolution in JETSCAPE provides an integrated description of jet quenching by combining multiple models, with each becoming active at a different stage of the parton shower evolution. Jet substructure modification due to different aspects of jet quenching is studied using jet shape and jet fragmentation observables. Various combinations of jet energy loss models are exploed, with medium background provided by (2 + 1)-D VISHNU with TRENTo+freestreaming initial conditions. Results reported here are from simulations performed within JETSCAPE framework.
The JETSCAPE Collaboration has recently announced the first release of the JETSCAPE package that provides a modular, flexible, and extensible Monte Carlo event generator. This innovative framework makes it possible to perform a comprehensive study of multi-stage high-energy jet evolution in the Quark-Gluon Plasma. In this work, we illustrate the performance of the event generator for different algorithmic approaches to jet energy loss, and reproduce the measurements of several jet and hadron observables as well as correlations between the hard and soft sector. We also carry out direct comparis…
The dynamics of shower development for a jet traveling through the QGP involves a variety of scales, one of them being the heavy quark mass. Even though the mass of the heavy quarks plays a subdominant role during the high virtuality portion of the jet evolution, it does affect longitudinal drag and diffusion, stimulating additional radiation from heavy quarks. These emissions partially compensate the reduction in radiation from the dead cone effect. In the lower virtuality part of the shower, when the mass is comparable to the transverse momenta of the partons, scattering and radiation proces…
The JETSCAPE Collaboration reports a new determination of jet transport coefficients in the Quark-Gluon Plasma, using both reconstructed jet and hadron data measured at RHIC and the LHC. The JETSCAPE framework incorporates detailed modeling of the dynamical evolution of the QGP; a multi-stage theoretical approach to in-medium jet evolution and medium response; and Bayesian inference for quantitative comparison of model calculations and data. The multi-stage framework incorporates multiple models to cover a broad range in scale of the in-medium parton shower evolution, with dynamical choice of …
Bayesian Inference analysis of jet quenching using inclusive jet and hadron suppression measurements
University of California, Berkeley（加州大学伯克利分校）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Massachusetts Institute of Technology（麻省理工学院）；Vanderbilt University（范德堡大学）；Duke University（杜克大学）；University of Regina（里贾纳大学）；McGill University（麦吉尔大学）；Wayne State University（韦恩州立大学）；Lawrence Livermore National Laboratory（劳伦斯利弗莫尔国家实验室）
Jets produced by the initial hard scattering in heavy ion collision events lose energy due to interactions with the color-deconfined medium formed around them: the quark-gluon plasma (QGP). Jet-medium interactions constitute an important theoretical and experimental field for studies of QGP, and various models with different assumptions have been proposed to describe them. A fair and direct comparison of these models requires that all other aspects of the simulation be fixed, which is achieved in this work by relying on the JETSCAPE framework. We employ JETSCAPE to directly and comprehensively…
The interaction of heavy flavor with the quark-gluon plasma (QGP) in relativistic heavy-ion collisions is studied using JETSCAPE, a publicly available software package containing a framework for Monte Carlo event generators. Multi-stage (and multi-model) evolution of heavy quarks within JETSCAPE provides a cohesive description of heavy flavor quenching inside the QGP. As the parton shower develops, a model becomes active as soon as its kinematic region of validity is reached. Two combinations of heavy-flavor energy-loss models are explored within a realistic QGP medium, using parameters which …
It is now well established that jet modification is a multistage effect; hence a single model alone cannot describe all facets of jet modification. The JETSCAPE framework is a multistage framework that uses several modules to simulate different stages of jet propagation through the QGP medium. These simulations require a set of parameters to ensure a smooth transition between stages. We fine tune these parameters to successfully describe a variety of observables, such as the nuclear modification factors of leading hadrons and jets, jet shape, and jet fragmentation function. Photons can be prod…
We apply a well tested hybrid transport model, which couples viscous hydrodynamics to a hadronic afterburner, to describe bulk observables in proton-lead and lead-lead collisions at $\sqrt{s_{NN}}=5.02$ TeV. The quark-gluon plasma (QGP) initial conditions are modeled using the parametric TRENTO model with additional nucleon substructure parameters to vary the number and size of hot spots inside each nucleon, followed by a pre-equilibrium free streaming stage to match the full energy-momentum tensor of the initial state onto viscous hydrodynamics. Initial condition and QGP medium parameters, su…
We posit a unified hydrodynamic and microscopic description of the quark-gluon plasma (QGP) produced in ultrarelativistic $p$-Pb and Pb-Pb collisions at $\sqrt{s_\mathrm{NN}}=5.02$ TeV and evaluate our assertion using Bayesian inference. Specifically, we model the dynamics of both collision systems using initial conditions with parametric nucleon substructure, a pre-equilibrium free-streaming stage, event-by-event viscous hydrodynamics, and a microscopic hadronic afterburner. Free parameters of the model which describe the initial state and QGP medium are then simultaneously calibrated to fit …
The jet quenching phenomenon in heavy ion collisions provides a strong evidence of the modification of parton shower in the quark-gluon plasma (QGP). Jet substructure observables can probe various aspects of the jet formation mechanism. They contain useful information about the QGP and allow us to study the medium properties in great details. Here we present theoretical calculations of jet shapes and cross sections in proton-proton and lead-lead collisions at the LHC using soft-collinear effective theory, with Glauber gluon interactions in the medium. We find that resumming large logarithms in…
A Breath of Fresh Air for Molière: Detecting Molière Scattering using Jet Substructure Observables in Oxygen Collisions
Center for Theoretical Physics — a Leinweber Institute, Massachusetts Institute of Technology（麻省理工学院理论物理中心（莱因韦伯研究所））；Massachusetts Institute of Technology（麻省理工学院）；Departamento de Física, Universidad de Oviedo（奥维耶多大学物理系）；Instituto Universitario de Ciencias y Tecnologías Espaciales de Asturias (ICTEA)（阿斯图里亚斯空间科学与技术大学研究所）
In these proceedings, we report on recent results related to vector boson-tagged jet production in heavy ion collisions and the related modification of jet substructure, such as jet shapes and jet momentum sharing distributions. $Z^0$-tagging and $γ$-tagging of jets provides new opportunities to study parton shower formation and propagation in the quark-gluon plasma and has been argued to provide tight constrains on the energy loss of reconstructed jets. We present theoretical predictions for isolated photon-tagged and electroweak boson-tagged jet production in Pb+Pb collisions at $\sqrt{s_{NN…
The quark gluon plasma (QGP) is one of the most interesting forms of matter providing us with insight on quantum chromodynamics (QCD) and the early universe. It is believed that the heavy-ion collision experiments at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) have created the QGP medium by colliding two heavy nuclei at nearly the speed of light. Since the collision happens really fast, we can not observe the QGP directly. Instead, we look at the hundreds or even thousands of final hadrons coming out of the collision. In particular, jet and heavy flavor obser…
Mapping jet substructure in heavy-ion collisions with track functions
CERN（欧洲核子研究中心）；Brookhaven National Laboratory（布鲁海文国家实验室）；Universidad de Oviedo（奥维耶多大学）；Instituto Universitario de Ciencias y Tecnologías Espaciales de Asturias (ICTEA)（阿斯图里亚斯宇宙科学与技术大学研究所）
PHENIX has performed an extensive study on the evolution of medium effects from small to large systems. PHENIX has continued searching for Quark-Gluon Plasma (QGP) in small systems by measuring collectivity, modification of light hadron and quarkonia production, and jet substructure. In large systems, detailed studies on the property of the QGP have been done using direct photon, $π^{0}$-hadron correlation, heavy-flavor electron, and $J/ψ$ flow with a large statistics of data collected in 2014. This report covers new results from the PHENIX experiment in various collision systems.
QCD jets, produced copiously in heavy-ion collisions at LHC and also at RHIC, serve as probes of the dynamics of the quark-gluon plasma (QGP). Jet fragmentation in the medium is interesting in its own right and, in order to extract pertinent information about the QGP, it has to be well understood. We present a brief overview of the physics involved and argue that jet substructure observables provide new opportunities for understanding the nature of the modifications.
Emergence of thermal recoil jets in high-energy heavy-ion collisions
Institute of Frontier and Interdisciplinary Science, Shandong University（山东大学前沿交叉科学研究院）；Department of Modern Physics, University of Science and Technology of China（中国科学技术大学近代物理系）；School of Physics, Southeast University（东南大学物理学院）；Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University（华中师范大学粒子物理与夸克轻子物理教育部重点实验室）
I develop an Effective Field Theory (EFT) framework to compute jet substructure observables for heavy ion collision experiments. As an illustration, I consider dijet events that accompany the formation of a weakly coupled Quark Gluon Plasma(QGP) medium in a heavy ion collision and look at an observable insensitive to jet selection bias: the simultaneous measurement of jet mass along with the transverse momentum imbalance between the jets that are groomed to remove soft radiation. Treating the jet as an open quantum system, I write down a factorization formula within the SCET(Soft Collinear Eff…
High-$p_T$ jets are an important tool for characterizing the quark-gluon plasma (QGP) created in heavy-ion collisions. However, a precise understanding of the jet-medium interaction is still lacking, and the development of more sophisticated observables is needed. This work presents a tool that allows for the exploration of alternative high-$p_T$ observables in a variety of collision systems. The tool builds on the publicly available JEWEL Monte Carlo code, and allows for the evolution of a jet on any given (2+1)-dimensional background. Proof-of-concept observables are also presented, studied …
Understanding the detailed structure of energy flow within jets, a field known as jet substructure, plays a central role in searches for new physics, and precision studies of QCD. Many applications of jet substructure require an understanding of jets initiated by heavy quarks, whose description has lagged behind remarkable recent progress for massless jets. In this Letter, we initiate a study of correlation functions of energy flow operators on beauty and charm jets to illuminate the effects of the intrinsic mass of the elementary particles of QCD. We present a factorization theorem incorporat…
The jet quenching phenomenon in heavy ion collisions provides a strong evidence of the modification of parton shower in the quark-gluon plasma. This contribution focuses on the hard probes of QGP using jets and summarizes the new theoretical progress of jet substructure modification studies using effective field theory techniques. We emphasize the important role of jet substructure observables as they probe various aspects of the jet formation mechanism and allow us to study the medium properties in great details. The precise calculations require the systematic resummation and consistently inc…
I look at propagation of jets that act as a probe of the medium in the phenomenologically relevant case of a short lived dilute Quark Gluon Plasma(QGP) created during heavy ion collisions. Working in the regime where the lifetime of the medium is of the order or smaller than the formation time of the energetic jet, I derive a factorization formula with a manifest separation of scales for an illustrative jet substructure observable using the Open Quantum system Effective Field Theory(EFT) approach developed in \cite{Vaidya:2020lih}, in terms of a medium structure function and a medium induced j…
Reconstructed jets initiated from heavy quarks provide a powerful tool to probe the properties of the quark-gluon plasma (QGP) and to explore the mass hierarchy of jet quenching. In this article, we review the recent theoretical progresses on heavy-flavour jets in high-energy nuclear collisions at the RHIC and LHC. We focus on the yields and substructures of charm and bottom quark jets with jet quenching effect, such as the nuclear modification factors, transverse momentum imbalance, angular correlation, radial profiles, fragmentation functions, the "dead-cone" effect, etc.
