{"title":"Transverse momentum balance of dijets in Xe+Xe collisions at the LHC","authors":"Yao Li, Shu-Wan Shen, Sa Wang, Ben-Wei Zhang","doi":"10.1007/s41365-024-01482-6","DOIUrl":null,"url":null,"abstract":"<p>We present a theoretical study of the medium modifications of the <span>\\(p_\\textrm{T}\\)</span> balance (<span>\\(x_\\textrm{J}\\)</span>) of dijets in Xe+Xe collisions at <span>\\(\\sqrt{s_\\textrm{NN}}=5.44\\)</span> TeV. The initial production of dijets was carried out using the POWHEG+PYTHIA8 prescription, which matches the next-to-leading-order (NLO) QCD matrix elements with the parton shower (PS) effect. The SHELL model described the in-medium evolution of nucleus–nucleus collisions using a transport approach. The theoretical results of the dijet <span>\\(x_\\textrm{J}\\)</span> in the Xe+Xe collisions exhibit more imbalanced distributions than those in the p+p collisions, consistent with recently reported ATLAS data. By utilizing the Interleaved Flavor Neutralisation, an infrared-and-collinear-safe jet flavor algorithm, to identify the flavor of the reconstructed jets, we classify dijets processes into three categories: gluon–gluon (<i>gg</i>), quark–gluon (<i>qg</i>), and quark–quark (<i>qq</i>), and investigated the respective medium modification patterns and fraction changes of the <i>gg</i>, <i>qg</i>, and <i>qq</i> components of the dijet sample in Xe+Xe collisions. It is shown that the increased fraction of <i>qg</i> component at a small <span>\\(x_\\textrm{J}\\)</span> contributes to the imbalance of the dijet; in particular, the <span>\\(q_1g_2\\)</span> (quark-jet-leading) dijets experience more significant asymmetric energy loss than the <span>\\(g_1q_2\\)</span> (gluon-jet-leading) dijets traversing the QGP. By comparing the <span>\\(\\Delta \\langle x_\\textrm{J}\\rangle = \\langle x_\\textrm{J} \\rangle _\\textrm{pp} - \\langle x_\\textrm{J} \\rangle _\\textrm{AA}\\)</span> of inclusive, <span>\\(c\\bar{c}\\)</span> and <span>\\(b\\bar{b}\\)</span> dijets in Xe+Xe collisions, we observe <span>\\(\\Delta \\langle x_\\textrm{J} \\rangle _\\mathrm{incl.}>\\Delta \\langle x_\\textrm{J} \\rangle _\\mathrm{c\\bar{c}}>\\Delta \\langle x_\\textrm{J} \\rangle _\\mathrm{b\\bar{b}}\\)</span>. Moreover, <span>\\(\\rho _\\textrm{Xe, Pb}\\)</span>, the ratios of the nuclear modification factors of dijets in Xe+Xe to those in Pb+Pb, were calculated, which indicates that the yield suppression of dijets in Pb+Pb is more pronounced than that in Xe+Xe owing to the larger radius of the lead nucleus.</p>","PeriodicalId":19177,"journal":{"name":"Nuclear Science and Techniques","volume":"14 1","pages":""},"PeriodicalIF":3.6000,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nuclear Science and Techniques","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1007/s41365-024-01482-6","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"NUCLEAR SCIENCE & TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
We present a theoretical study of the medium modifications of the \(p_\textrm{T}\) balance (\(x_\textrm{J}\)) of dijets in Xe+Xe collisions at \(\sqrt{s_\textrm{NN}}=5.44\) TeV. The initial production of dijets was carried out using the POWHEG+PYTHIA8 prescription, which matches the next-to-leading-order (NLO) QCD matrix elements with the parton shower (PS) effect. The SHELL model described the in-medium evolution of nucleus–nucleus collisions using a transport approach. The theoretical results of the dijet \(x_\textrm{J}\) in the Xe+Xe collisions exhibit more imbalanced distributions than those in the p+p collisions, consistent with recently reported ATLAS data. By utilizing the Interleaved Flavor Neutralisation, an infrared-and-collinear-safe jet flavor algorithm, to identify the flavor of the reconstructed jets, we classify dijets processes into three categories: gluon–gluon (gg), quark–gluon (qg), and quark–quark (qq), and investigated the respective medium modification patterns and fraction changes of the gg, qg, and qq components of the dijet sample in Xe+Xe collisions. It is shown that the increased fraction of qg component at a small \(x_\textrm{J}\) contributes to the imbalance of the dijet; in particular, the \(q_1g_2\) (quark-jet-leading) dijets experience more significant asymmetric energy loss than the \(g_1q_2\) (gluon-jet-leading) dijets traversing the QGP. By comparing the \(\Delta \langle x_\textrm{J}\rangle = \langle x_\textrm{J} \rangle _\textrm{pp} - \langle x_\textrm{J} \rangle _\textrm{AA}\) of inclusive, \(c\bar{c}\) and \(b\bar{b}\) dijets in Xe+Xe collisions, we observe \(\Delta \langle x_\textrm{J} \rangle _\mathrm{incl.}>\Delta \langle x_\textrm{J} \rangle _\mathrm{c\bar{c}}>\Delta \langle x_\textrm{J} \rangle _\mathrm{b\bar{b}}\). Moreover, \(\rho _\textrm{Xe, Pb}\), the ratios of the nuclear modification factors of dijets in Xe+Xe to those in Pb+Pb, were calculated, which indicates that the yield suppression of dijets in Pb+Pb is more pronounced than that in Xe+Xe owing to the larger radius of the lead nucleus.
期刊介绍:
Nuclear Science and Techniques (NST) reports scientific findings, technical advances and important results in the fields of nuclear science and techniques. The aim of this periodical is to stimulate cross-fertilization of knowledge among scientists and engineers working in the fields of nuclear research.
Scope covers the following subjects:
• Synchrotron radiation applications, beamline technology;
• Accelerator, ray technology and applications;
• Nuclear chemistry, radiochemistry, radiopharmaceuticals, nuclear medicine;
• Nuclear electronics and instrumentation;
• Nuclear physics and interdisciplinary research;
• Nuclear energy science and engineering.