Abstract
This article presents new measurements of the fragmentation properties of jets in both proton–proton (pp) and heavy-ion collisions with the ALICE experiment at the Large Hadron Collider (LHC). We report distributions of the fraction zr of transverse momentum carried by subjets of radius r within jets of radius R. Charged-particle jets are reconstructed at midrapidity using the anti-k T algorithm with jet radius R = 0.4, and subjets are reconstructed by reclustering the jet constituents using the anti-k T algorithm with radii r = 0.1 and r = 0.2. In proton–proton collisions, we measure both the inclusive and leading subjet distributions. We compare these measurements to perturbative calculations at next-to-leading logarithmic accuracy, which suggest a large impact of threshold resummation and hadronization effects on the zr distribution. In heavy-ion collisions, we measure the leading subjet distributions, which allow access to a region of harder jet frag- mentation than has been probed by previous measurements of jet quenching via hadron fragmentation distributions. The zr distributions enable extraction of the parton-to-subjet fragmentation function and allow for tests of the universality of jet fragmentation functions in the quark–gluon plasma (QGP). We find no significant modification of zr distributions in Pb–Pb compared to pp collisions. However, the distributions are also consistent with a hardening trend for zr < 0.95, as predicted by several jet quenching models. As zr → 1 our results indicate that any such hardening effects cease, exposing qualitatively new possibilities to disentangle competing jet quenching mechanisms. By comparing our results to theoretical calculations based on an independent extraction of the parton-to-jet fragmentation function, we find consistency with the universality of jet fragmentation and no indication of factorization breaking in the QGP. [Figure not available: see fulltext.].
| Original language | English |
|---|---|
| Article number | 245 |
| Number of pages | 34 |
| Journal | Journal of High Energy Physics |
| Volume | 2023 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - Jun 2023 |
Bibliographical note
Funding Information:The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centres and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences, Austrian Science Fund (FWF): [M 2467-N36] and Nationalstiftung für Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (Finep), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Universidade Federal do Rio Grande do Sul (UFRGS), Brazil; Bulgarian Ministry of Education and Science, within the National Roadmap for Research Infrastructures 2020¿2027 (object CERN), Bulgaria; Ministry of Education of China (MOEC) , Ministry of Science & Technology of China (MSTC) and National Natural Science Foundation of China (NSFC), China; Ministry of Science and Education and Croatian Science Foundation, Croatia; Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Cubaenergía, Cuba; Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research | Natural Sciences, the VILLUM FONDEN and Danish National Research Foundation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat à l’Energie Atomique (CEA) and Institut National de Physique Nucléaire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS), France; Bundesministerium für Bildung und Forschung (BMBF) and GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany; General Secretariat for Research and Technology, Ministry of Education, Research and Religions, Greece; National Research, Development and Innovation Office, Hungary; Department of Atomic Energy Government of India (DAE), Department of Science and Technology, Government of India (DST), University Grants Commission, Government of India (UGC) and Council of Scientific and Industrial Research (CSIR), India; National Research and Innovation Agency — BRIN, Indonesia; Istituto Nazionale di Fisica Nucleare (INFN), Italy; Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Japan Society for the Promotion of Science (JSPS) KAKENHI, Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnología, through Fondo de Cooperación Internacional en Ciencia y Tecnología (FONCICYT) and Dirección General de Asuntos del Personal Academico (DGAPA), Mexico; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; The Research Council of Norway, Norway; Commission on Science and Technology for Sustainable Development in the South (COMSATS), Pakistan; Pontificia Universidad Católica del Perú, Peru; Ministry of Education and Science, National Science Centre and WUT ID-UB, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Korea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics, Ministry of Research and Innovation and Institute of Atomic Physics and University Politehnica of Bucharest, Romania; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foundation of South Africa, South Africa; Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; Suranaree University of Technology (SUT), National Science and Technology Development Agency (NSTDA), Thailand Science Research and Innovation (TSRI) and National Science, Research and Innovation Fund (NSRF), Thailand; Turkish Energy, Nuclear and Mineral Research Agency (TENMAK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America. In addition, individual groups or members have received support from: Marie Skłodowska Curie, Strong 2020 — Horizon 2020, European Research Council (grant nos. 824093, 896850, 950692), European Union; Academy of Finland (Center of Excellence in Quark Matter) (grant nos. 346327, 346328), Finland; Programa de Apoyos para la Superación del Personal Académico, UNAM, Mexico;
Publisher Copyright:
© 2023, The Author(s).
Funding
The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centres and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences, Austrian Science Fund (FWF): [M 2467-N36] and Nationalstiftung für Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (Finep), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Universidade Federal do Rio Grande do Sul (UFRGS), Brazil; Bulgarian Ministry of Education and Science, within the National Roadmap for Research Infrastructures 2020¿2027 (object CERN), Bulgaria; Ministry of Education of China (MOEC) , Ministry of Science & Technology of China (MSTC) and National Natural Science Foundation of China (NSFC), China; Ministry of Science and Education and Croatian Science Foundation, Croatia; Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Cubaenergía, Cuba; Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research | Natural Sciences, the VILLUM FONDEN and Danish National Research Foundation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat à l’Energie Atomique (CEA) and Institut National de Physique Nucléaire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS), France; Bundesministerium für Bildung und Forschung (BMBF) and GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany; General Secretariat for Research and Technology, Ministry of Education, Research and Religions, Greece; National Research, Development and Innovation Office, Hungary; Department of Atomic Energy Government of India (DAE), Department of Science and Technology, Government of India (DST), University Grants Commission, Government of India (UGC) and Council of Scientific and Industrial Research (CSIR), India; National Research and Innovation Agency — BRIN, Indonesia; Istituto Nazionale di Fisica Nucleare (INFN), Italy; Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Japan Society for the Promotion of Science (JSPS) KAKENHI, Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnología, through Fondo de Cooperación Internacional en Ciencia y Tecnología (FONCICYT) and Dirección General de Asuntos del Personal Academico (DGAPA), Mexico; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; The Research Council of Norway, Norway; Commission on Science and Technology for Sustainable Development in the South (COMSATS), Pakistan; Pontificia Universidad Católica del Perú, Peru; Ministry of Education and Science, National Science Centre and WUT ID-UB, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Korea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics, Ministry of Research and Innovation and Institute of Atomic Physics and University Politehnica of Bucharest, Romania; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foundation of South Africa, South Africa; Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; Suranaree University of Technology (SUT), National Science and Technology Development Agency (NSTDA), Thailand Science Research and Innovation (TSRI) and National Science, Research and Innovation Fund (NSRF), Thailand; Turkish Energy, Nuclear and Mineral Research Agency (TENMAK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America. In addition, individual groups or members have received support from: Marie Skłodowska Curie, Strong 2020 — Horizon 2020, European Research Council (grant nos. 824093, 896850, 950692), European Union; Academy of Finland (Center of Excellence in Quark Matter) (grant nos. 346327, 346328), Finland; Programa de Apoyos para la Superación del Personal Académico, UNAM, Mexico;
| Funders | Funder number |
|---|---|
| A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia | |
| Austrian Science Fund (FWF), Austria | |
| Nationalstiftung fur Forschung, Technologie und Entwicklung, Austria | |
| Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan | |
| Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brazil | |
| Financiadora de Estudos e Projetos (Finep), Brazil | |
| Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Brazil | |
| Universidade Federal do Rio Grande do Sul (UFRGS), Brazil | |
| Bulgarian Ministry of Education and Science, within the National Roadmap for Research Infrastructures 2020-2027 (object CERN), Bulgaria | |
| Ministry of Science & Technology of China (MSTC), China | |
| National Natural Science Foundation of China (NSFC), China | |
| Croatian Science Foundation, Croatia | |
| Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Cubaenergia, Cuba | |
| Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic | |
| Danish Council for Independent Research | Natural Sciences, Denmark | |
| VILLUM FONDEN, Denmark | |
| Danish National Research Foundation (DNRF), Denmark | |
| Helsinki Institute of Physics (HIP), Finland | |
| Commissariat a l'Energie Atomique (CEA), France | |
| Centre National de la Recherche Scientifique (CNRS), France | |
| Bundesministerium fur Bildung und Forschung (BMBF), Germany | |
| GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Germany | |
| Council of Scientific and Industrial Research (CSIR), India | |
| Istituto Nazionale di Fisica Nucleare (INFN), Italy | |
| Japan Society for the Promotion of Science (JSPS) KAKENHI, Japan | |
| Consejo Nacional de Ciencia (CONACYT) y Tecnologia, through Fondo de Cooperacion Internacional en Ciencia y Tecnologia (FONCICYT), Mexico | |
| Direccion General de Asuntos del Personal Academico (DGAPA), Mexico | |
| Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands | |
| Research Council of Norway, Norway | |
| Commission on Science and Technology for Sustainable Development in the South (COMSATS), Pakistan | |
| Pontificia Universidad Catolica del Peru, Peru | |
| Ministry of Education and Science, Poland | |
| National Science Centre, Poland | |
| WUT ID-UB, Poland | |
| Korea Institute of Science and Technology Information, Republic of Korea | |
| Austrian Academy of Sciences, Austria | |
| Ministry of Education and Scientific Research, Romania | |
| Institute of Atomic Physics, Romania | |
| Ministry of Research and Innovation, Romania | |
| University Politehnica of Bucharest, Romania | |
| Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia | |
| National Research Foundation of South Africa, South Africa | |
| Swedish Research Council (VR), Sweden | |
| Knut & Alice Wallenberg Foundation (KAW), Sweden | |
| European Organization for Nuclear Research, Switzerland | |
| Suranaree University of Technology (SUT), Thailand | |
| National Science and Technology Development Agency (NSTDA), Thailand | |
| National Research Foundation of Korea (NRF), Republic of Korea | |
| Thailand Science Research and Innovation (TSRI) , Thailand | |
| National Science, Research and Innovation Fund (NSRF), Thailand | |
| Turkish Energy, Nuclear and Mineral Research Agency (TENMAK), Turkey | |
| National Academy of Sciences of Ukraine, Ukraine | |
| Science and Technology Facilities Council (STFC), United Kingdom | |
| National Science Foundation of the United States of America (NSF) , United States of America | |
| United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America | |
| Marie Skodowska Curie, European Union | |
| Strong 2020 - Horizon 2020, European Union | |
| European Research Council , European Union | 824093, 896850, 950692 |
| Academy of Finland (Center of Excellence in Quark Matter), Finland | 346327, 346328 |
| Programa de Apoyos para la Superacion del Personal Academico, UNAM, Mexico | |
| Ministry of Education of China (MOEC) , China | |
| Ministry of Science and Education, Croatia | |
| Institut National de Physique Nucleaire et de Physique des Particules (IN2P3), France | |
| General Secretariat for Research and Technology, Ministry of Education, Research and Religions, Greece | |
| National Research, Development and Innovation Office, Hungary | |
| Department of Atomic Energy Government of India (DAE) | |
| Department of Science and Technology, Government of India (DST) | |
| University Grants Commission, Government of India (UGC) | |
| National Research and Innovation Agency - BRIN, Indonesia | |
| Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan | |
| European Research Council (ERC) | 950692 |
| Marie Curie Actions (MSCA) | 896850 |
Keywords
- Jets and Jet Substructure
- Quark-Gluon Plasma