Eur. Phys. J. C (2024) 84: 1079
https://doi.org/10.1140/epjc/s10052-024-13228-0

Regular Article

Multiplicity dependence of charged-particle intra-jet properties in pp collisions at $\sqrt{\mathit{s}}$ = 13 TeV

¹ A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation, Yerevan, Armenia
² AGH University of Krakow, Cracow, Poland
³ Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, Kiev, Ukraine
⁴ Department of Physics and Centre for Astroparticle Physics and Space Science (CAPSS), Bose Institute, Kolkata, India
⁵ California Polytechnic State University, San Luis Obispo, CA, USA
⁶ Central China Normal University, Wuhan, China
⁷ Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Havana, Cuba
⁸ Centro de Investigación y de Estudios Avanzados (CINVESTAV), Mexico City and Mérida, Mexico
⁹ Chicago State University, Chicago, IL, USA
¹⁰ China Institute of Atomic Energy, Beijing, China
¹¹ China University of Geosciences, Wuhan, China
¹² Chungbuk National University, Cheongju, Republic of Korea
¹³ Comenius University Bratislava, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovak Republic
¹⁴ COMSATS University Islamabad, Islamabad, Pakistan
¹⁵ Creighton University, Omaha, NE, USA
¹⁶ Department of Physics, Aligarh Muslim University, Aligarh, India
¹⁷ Department of Physics, Pusan National University, Pusan, Republic of Korea
¹⁸ Department of Physics, Sejong University, Seoul, Republic of Korea
¹⁹ Department of Physics, University of California, Berkeley, CA, USA
²⁰ Department of Physics, University of Oslo, Oslo, Norway
²¹ Department of Physics and Technology, University of Bergen, Bergen, Norway
²² Dipartimento di Fisica, Università di Pavia, Pavia, Italy
²³ Dipartimento di Fisica dell’Università and Sezione INFN, Cagliari, Italy
²⁴ Dipartimento di Fisica dell’Università and Sezione INFN, Trieste, Italy
²⁵ Dipartimento di Fisica dell’Università and Sezione INFN, Turin, Italy
²⁶ Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Bologna, Italy
²⁷ Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Catania, Italy
²⁸ Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Padua, Italy
²⁹ Dipartimento di Fisica ‘E.R. Caianiello’ dell’Università and Gruppo Collegato INFN, Salerno, Italy
³⁰ Dipartimento DISAT del Politecnico and Sezione INFN, Turin, Italy
³¹ Dipartimento di Scienze MIFT, Università di Messina, Messina, Italy
³² Dipartimento Interateneo di Fisica ‘M. Merlin’ and Sezione INFN, Bari, Italy
³³ European Organization for Nuclear Research (CERN), Geneva, Switzerland
³⁴ Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Split, Split, Croatia
³⁵ Faculty of Engineering and Science, Western Norway University of Applied Sciences, Bergen, Norway
³⁶ Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic
³⁷ Faculty of Physics, Sofia University, Sofia, Bulgaria
³⁸ Faculty of Science, P.J. Šafárik University, Košice, Slovak Republic
³⁹ Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
⁴⁰ Fudan University, Shanghai, China
⁴¹ Gangneung-Wonju National University, Gangneung, Republic of Korea
⁴² Gauhati University, Department of Physics, Guwahati, India
⁴³ Helmholtz-Institut für Strahlen- und Kernphysik, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
⁴⁴ Helsinki Institute of Physics (HIP), Helsinki, Finland
⁴⁵ High Energy Physics Group, Universidad Autónoma de Puebla, Puebla, Mexico
⁴⁶ Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, Romania
⁴⁷ HUN-REN Wigner Research Centre for Physics, Budapest, Hungary
⁴⁸ Indian Institute of Technology Bombay (IIT), Mumbai, India
⁴⁹ Indian Institute of Technology Indore, Indore, India
⁵⁰ INFN, Laboratori Nazionali di Frascati, Frascati, Italy
⁵¹ INFN, Sezione di Bari, Bari, Italy
⁵² INFN, Sezione di Bologna, Bologna, Italy
⁵³ INFN, Sezione di Cagliari, Cagliari, Italy
⁵⁴ INFN, Sezione di Catania, Catania, Italy
⁵⁵ INFN, Sezione di Padova, Padua, Italy
⁵⁶ INFN, Sezione di Pavia, Pavia, Italy
⁵⁷ INFN, Sezione di Torino, Turin, Italy
⁵⁸ INFN, Sezione di Trieste, Trieste, Italy
⁵⁹ Inha University, Incheon, Republic of Korea
⁶⁰ Institute for Gravitational and Subatomic Physics (GRASP), Utrecht University/Nikhef, Utrecht, The Netherlands
⁶¹ Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic
⁶² Institute of Physics, Homi Bhabha National Institute, Bhubaneswar, India
⁶³ Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic
⁶⁴ Institute of Space Science (ISS), Bucharest, Romania
⁶⁵ Institut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
⁶⁶ Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico
⁶⁷ Instituto de Física, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
⁶⁸ Instituto de Física, Universidad Nacional Autónoma de México, Mexico City, Mexico
⁶⁹ iThemba LABS, National Research Foundation, Somerset West, South Africa
⁷⁰ Jeonbuk National University, Jeonju, Republic of Korea
⁷¹ Johann-Wolfgang-Goethe Universität Frankfurt Institut für Informatik, Fachbereich Informatik und Mathematik, Frankfurt, Germany
⁷² Korea Institute of Science and Technology Information, Daejeon, Republic of Korea
⁷³ KTO Karatay University, Konya, Turkey
⁷⁴ Laboratoire de Physique Subatomique et de Cosmologie, Université Grenoble-Alpes, CNRS-IN2P3, Grenoble, France
⁷⁵ Lawrence Berkeley National Laboratory, Berkeley, CA, USA
⁷⁶ Division of Particle Physics, Department of Physics, Lund University, Lund, Sweden
⁷⁷ Nagasaki Institute of Applied Science, Nagasaki, Japan
⁷⁸ Nara Women’s University (NWU), Nara, Japan
⁷⁹ Department of Physics, School of Science, National and Kapodistrian University of Athens, Athens, Greece
⁸⁰ National Centre for Nuclear Research, Warsaw, Poland
⁸¹ National Institute of Science Education and Research, Homi Bhabha National Institute, Jatni, India
⁸² National Nuclear Research Center, Baku, Azerbaijan
⁸³ National Research and Innovation Agency-BRIN, Jakarta, Indonesia
⁸⁴ Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
⁸⁵ Nikhef, National institute for subatomic physics, Amsterdam, The Netherlands
⁸⁶ Nuclear Physics Group, STFC Daresbury Laboratory, Daresbury, UK
⁸⁷ Nuclear Physics Institute of the Czech Academy of Sciences, Husinec-Řež, Czech Republic
⁸⁸ Oak Ridge National Laboratory, Oak Ridge, TN, USA
⁸⁹ Ohio State University, Columbus, Ohio, USA
⁹⁰ Physics Department, Faculty of Science, University of Zagreb, Zagreb, Croatia
⁹¹ Physics Department, Panjab University, Chandigarh, India
⁹² Physics Department, University of Jammu, Jammu, India
⁹³ Physics Program and International Institute for Sustainability with Knotted Chiral Meta Matter (SKCM2), Hiroshima University, Hiroshima, Japan
⁹⁴ Physikalisches Institut, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
⁹⁵ Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
⁹⁶ Physik Department, Technische Universität München, Munich, Germany
⁹⁷ Politecnico di Bari and Sezione INFN, Bari, Italy
⁹⁸ Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
⁹⁹ Saga University, Saga, Japan
¹⁰⁰ Saha Institute of Nuclear Physics, Homi Bhabha National Institute, Kolkata, India
¹⁰¹ School of Physics and Astronomy, University of Birmingham, Birmingham, UK
¹⁰² Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Lima, Peru
¹⁰³ Stefan Meyer Institut für Subatomare Physik (SMI), Vienna, Austria
¹⁰⁴ SUBATECH, IMT Atlantique, Nantes Université, CNRS-IN2P3, Nantes, France
¹⁰⁵ Sungkyunkwan University, Suwon City, Republic of Korea
¹⁰⁶ Suranaree University of Technology, Nakhon Ratchasima, Thailand
¹⁰⁷ Technical University of Košice, Košice, Slovak Republic
¹⁰⁸ The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
¹⁰⁹ The University of Texas at Austin, Austin, TX, USA
¹¹⁰ Universidad Autónoma de Sinaloa, Culiacán, Mexico
¹¹¹ Universidade de São Paulo (USP), São Paulo, Brazil
¹¹² Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
¹¹³ Universidade Federal do ABC, Santo Andre, Brazil
¹¹⁴ Universitatea Nationala de Stiinta si Tehnologie Politehnica Bucuresti, Bucharest, Romania
¹¹⁵ University of Cape Town, Cape Town, South Africa
¹¹⁶ University of Derby, Derby, UK
¹¹⁷ University of Houston, Houston, TX, USA
¹¹⁸ University of Jyväskylä, Jyväskylä, Finland
¹¹⁹ University of Kansas, Lawrence, KS, USA
¹²⁰ University of Liverpool, Liverpool, UK
¹²¹ University of Science and Technology of China, Hefei, China
¹²² University of South-Eastern Norway, Kongsberg, Norway
¹²³ University of Tennessee, Knoxville, TN, USA
¹²⁴ University of the Witwatersrand, Johannesburg, South Africa
¹²⁵ University of Tokyo, Tokyo, Japan
¹²⁶ University of Tsukuba, Tsukuba, Japan
¹²⁷ Universität Münster, Institut für Kernphysik, Münster, Germany
¹²⁸ Université Clermont Auvergne, CNRS/IN2P3, LPC, Clermont-Ferrand, France
¹²⁹ Université de Lyon, CNRS/IN2P3, Institut de Physique des 2 Infinis de Lyon, Lyon, France
¹³⁰ Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
¹³¹ Départment de Physique Nucléaire (DPhN), Université Paris-Saclay, Centre d’Etudes de Saclay (CEA), IRFU, Saclay, France
¹³² Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
¹³³ Università degli Studi di Foggia, Foggia, Italy
¹³⁴ Università del Piemonte Orientale, Vercelli, Italy
¹³⁵ Università di Brescia, Brescia, Italy
¹³⁶ Variable Energy Cyclotron Centre, Homi Bhabha National Institute, Kolkata, India
¹³⁷ Warsaw University of Technology, Warsaw, Poland
¹³⁸ Wayne State University, Detroit, MI, USA
¹³⁹ Yale University, New Haven, CT, USA
¹⁴⁰ Yonsei University, Seoul, Republic of Korea
¹⁴¹ Zentrum für Technologie und Transfer (ZTT), Worms, Germany
¹⁴² Affiliated with an Institute Covered by a Cooperation Agreement with CERN, Geneva, Switzerland
¹⁴³ Affiliated with an International Laboratory Covered by a Cooperation Agreement with CERN, Switzerland, Switzerland
¹⁴⁴ Max-Planck-Institut fur Physik, Munich, Germany
¹⁴⁵ Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Bologna, Italy
¹⁴⁶ Dipartimento DET del Politecnico di Torino, Turin, Italy
¹⁴⁷ Yildiz Technical University, Istanbul, Turkey
¹⁴⁸ Department of Applied Physics, Aligarh Muslim University, Aligarh, India
¹⁴⁹ Institute of Theoretical Physics, University of Wroclaw, Wroclaw, Poland
¹⁵⁰ An Institution Covered by a Cooperation Agreement with CERN, Geneva, Switzerland
¹⁵¹ CERN, 1211, Geneva 23, Switzerland

^a alice-publications@cern.ch

Received: 11 December 2023
Accepted: 11 August 2024
Published online: 17 October 2024

Abstract

The first measurement of the multiplicity dependence of intra-jet properties of leading charged-particle jets in proton–proton (pp) collisions is reported. The mean charged-particle multiplicity and jet fragmentation distributions are measured in minimum-bias and high-multiplicity pp collisions at center-of-mass energy $\sqrt{s}$ = 13 TeV using the ALICE detector. Jets are reconstructed from charged particles produced in the midrapidity region ($|\eta |<0.9$) using the sequential recombination anti-$k_{\text{T}}$ algorithm with jet resolution parameters R = 0.2, 0.3, and 0.4 for the transverse momentum ($p_{\text{T}}$) interval 5–110 GeV/c. The high-multiplicity events are selected by the forward V0 scintillator detectors. The mean charged-particle multiplicity inside the leading jet cone rises monotonically with increasing jet $p_{\text{T}}$ in qualitative agreement with previous measurements at lower energies. The distributions of jet fragmentation function variables $z^{\text{ch}}$ and ${\xi }^{\text{ch}}$ are measured for different jet-$p_{\text{T}}$ intervals. Jet-$p_{\text{T}}$ independent fragmentation of leading jets is observed for wider jets except at high- and low-$z^{\text{ch}}$ values. The observed “hump-backed plateau” structure in the ${\xi }^{\text{ch}}$ distribution indicates suppression of low-$p_{\text{T}}$ particles. In high-multiplicity events, an enhancement of the fragmentation probability of low-$z^{\text{ch}}$ particles accompanied by a suppression of high-$z^{\text{ch}}$ particles is observed compared to minimum-bias events. This behavior becomes more prominent for low-$p_{\text{T}}$ jets with larger jet radius. The results are compared with predictions of QCD-inspired event generators, PYTHIA 8 with Monash 2013 tune and EPOS LHC. It is found that PYTHIA 8 qualitatively reproduces the jet modification in high-multiplicity events except at high jet $p_{\text{T}}$. These measurements provide important constraints to models of jet fragmentation.