Measurements of and production within fully reconstructed jets

doi:10.1140/epjc/s10052-025-13852-4

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2025) 85: 562
https://doi.org/10.1140/epjc/s10052-025-13852-4

Regular Article - Experimental Physics

Measurements of $ψ (2 S)$ $\psi (2S)$ and $χ_{c 1} (3872)$ $\chi _{c1}(3872)$ production within fully reconstructed jets

LHCb Collaboration¹¹⁰^a

¹ School of Physics and Astronomy, Monash University, Melbourne, Australia
² Centro Brasileiro de Pesquisas Físicas (CBPF), Rio de Janeiro, Brazil
³ Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
⁴ Department of Engineering Physics, Tsinghua University, Beijing, China
⁵ Institute of High Energy Physics (IHEP), Beijing, China
⁶ School of Physics State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China
⁷ University of Chinese Academy of Sciences, Beijing, China
⁸ Institute of Particle Physics, Central China Normal University, Wuhan, Hubei, China
⁹ Consejo Nacional de Rectores (CONARE), San Jose, Costa Rica
¹⁰ CNRS, IN2P3-LAPP, Université Savoie Mont Blanc, Annecy, France
¹¹ CNRS/IN2P3, LPC, Université Clermont Auvergne, Clermont-Ferrand, France
¹² CNRS/IN2P3, CPPM, Aix Marseille Univ, Marseille, France
¹³ CNRS/IN2P3, IJCLab, Université Paris-Saclay, Orsay, France
¹⁴ Laboratoire Leprince-Ringuet, CNRS/IN2P3, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
¹⁵ LPNHE, CNRS/IN2P3, Sorbonne Université, Paris Diderot Sorbonne Paris Cité, Paris, France
¹⁶ I. Physikalisches Institut, RWTH Aachen University, Aachen, Germany
¹⁷ Universität Bonn-Helmholtz-Institut für Strahlen und Kernphysik, Bonn, Germany
¹⁸ Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
¹⁹ Max-Planck-Institut für Kernphysik (MPIK), Heidelberg, Germany
²⁰ Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
²¹ School of Physics, University College Dublin, Dublin, Ireland
²² INFN Sezione di Bari, Bari, Italy
²³ INFN Sezione di Bologna, Bologna, Italy
²⁴ INFN Sezione di Ferrara, Ferrara, Italy
²⁵ INFN Sezione di Firenze, Firenze, Italy
²⁶ INFN Laboratori Nazionali di Frascati, Frascati, Italy
²⁷ INFN Sezione di Genova, Genoa, Italy
²⁸ INFN Sezione di Milano, Milan, Italy
²⁹ INFN Sezione di Milano-Bicocca, Milan, Italy
³⁰ INFN Sezione di Cagliari, Monserrato, Italy
³¹ INFN Sezione di Padova, Padua, Italy
³² INFN Sezione di Perugia, Perugia, Italy
³³ INFN Sezione di Pisa, Pisa, Italy
³⁴ INFN Sezione di Roma La Sapienza, Rome, Italy
³⁵ INFN Sezione di Roma Tor Vergata, Rome, Italy
³⁶ Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands
³⁷ Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam, Netherlands
³⁸ Faculty of Physics and Applied Computer Science, AGH-University of Krakow, Kraków, Poland
³⁹ Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland
⁴⁰ National Center for Nuclear Research (NCBJ), Warsaw, Poland
⁴¹ Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania
⁴² Affiliated with an Institute Covered by a Cooperation Agreement with CERN, Geneva, Switzerland
⁴³ DS4DS, La Salle, Universitat Ramon Llull, Barcelona, Spain
⁴⁴ ICCUB, Universitat de Barcelona, Barcelona, Spain
⁴⁵ Instituto Galego de Física de Altas Enerxías (IGFAE), Universidade de Santiago de Compostela, Santiago de Compostela, Spain
⁴⁶ Instituto de Fisica Corpuscular, Centro Mixto Universidad de Valencia-CSIC, Valencia, Spain
⁴⁷ European Organization for Nuclear Research (CERN), Geneva, Switzerland
⁴⁸ Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
⁴⁹ Physik-Institut, Universität Zürich, Zurich, Switzerland
⁵⁰ NSC Kharkiv Institute of Physics and Technology (NSC KIPT), Kharkiv, Ukraine
⁵¹ Institute for Nuclear Research of the National Academy of Sciences (KINR), Kyiv, Ukraine
⁵² School of Physics and Astronomy, University of Birmingham, Birmingham, UK
⁵³ H.H. Wills Physics Laboratory, University of Bristol, Bristol, UK
⁵⁴ Cavendish Laboratory, University of Cambridge, Cambridge, UK
⁵⁵ Department of Physics, University of Warwick, Coventry, UK
⁵⁶ STFC Rutherford Appleton Laboratory, Didcot, UK
⁵⁷ School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
⁵⁸ School of Physics and Astronomy, University of Glasgow, Glasgow, UK
⁵⁹ Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK
⁶⁰ Imperial College London, London, UK
⁶¹ Department of Physics and Astronomy, University of Manchester, Manchester, UK
⁶² Department of Physics, University of Oxford, Oxford, UK
⁶³ Massachusetts Institute of Technology, Cambridge, MA, USA
⁶⁴ University of Cincinnati, Cincinnati, OH, USA
⁶⁵ University of Maryland, College Park, MD, USA
⁶⁶ Los Alamos National Laboratory (LANL), Los Alamos, NM, USA
⁶⁷ Syracuse University, Syracuse, NY, USA
⁶⁸ Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil
⁶⁹ School of Physics and Electronics, Hunan University, Changsha City, China
⁷⁰ Guangdong Provincial Key Laboratory of Nuclear Science, Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Institute of Quantum Matter, South China Normal University, Guangzhou, China
⁷¹ Lanzhou University, Lanzhou, China
⁷² School of Physics and Technology, Wuhan University, Wuhan, China
⁷³ Departamento de Fisica, Universidad Nacional de Colombia, Bogotá, Colombia
⁷⁴ Ruhr Universitaet Bochum, Fakultaet f. Physik und Astronomie, Bochum, Germany
⁷⁵ Eotvos Lorand University, Budapest, Hungary
⁷⁶ Van Swinderen Institute, University of Groningen, Groningen, Netherlands
⁷⁷ Universiteit Maastricht, Maastricht, Netherlands
⁷⁸ Tadeusz Kosciuszko Cracow University of Technology, Cracow, Poland
⁷⁹ Universidade da Coruña, A Coruña, Spain
⁸⁰ Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
⁸¹ University of Michigan, Ann Arbor, MI, USA
⁸² Université Paris-Saclay, Centre d’Etudes de Saclay (CEA), IRFU, Saclay, France, Gif-Sur-Yvette, France
⁸³ Universidade de Brasília, Brasília, Brazil
⁸⁴ Centro Federal de Educacão Tecnológica Celso Suckow da Fonseca, Rio de Janeiro, Brazil
⁸⁵ Center for High Energy Physics, Tsinghua University, Beijing, China
⁸⁶ Hangzhou Institute for Advanced Study, UCAS, Hangzhou, China
⁸⁷ School of Physics and Electronics, Henan University, Kaifeng, China
⁸⁸ LIP6, Sorbonne Université, Paris, France
⁸⁹ Lamarr Institute for Machine Learning and Artificial Intelligence, Dortmund, Germany
⁹⁰ Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
⁹¹ Università di Bari, Bari, Italy
⁹² Università di Bergamo, Bergamo, Italy
⁹³ Università di Bologna, Bologna, Italy
⁹⁴ Università di Cagliari, Cagliari, Italy
⁹⁵ Università di Ferrara, Ferrara, Italy
⁹⁶ Università di Genova, Genoa, Italy
⁹⁷ Università degli Studi di Milano, Milan, Italy
⁹⁸ Università degli Studi di Milano-Bicocca, Milan, Italy
⁹⁹ Università di Padova, Padua, Italy
¹⁰⁰ Università di Perugia, Perugia, Italy
¹⁰¹ Scuola Normale Superiore, Pisa, Italy
¹⁰² Università di Pisa, Pisa, Italy
¹⁰³ Università della Basilicata, Potenza, Italy
¹⁰⁴ Università di Roma Tor Vergata, Rome, Italy
¹⁰⁵ Università di Siena, Siena, Italy
¹⁰⁶ Università di Urbino, Urbino, Italy
¹⁰⁷ Universidad de Alcalá, Alcalá de Henares, Spain
¹⁰⁸ Facultad de Ciencias Fisicas, Madrid, Spain
¹⁰⁹ Department of Physics/Division of Particle Physics, Lund, Sweden
¹¹⁰ CERN, 1211, Geneva 23, Switzerland

^a naomi.cooke@cern.ch

Received: 25 October 2024
Accepted: 23 January 2025
Published online: 22 May 2025

Abstract

This paper presents the first measurement of $ψ (2 S)$ $\psi {(2S)}$ and $χ_{c 1} (3872)$ $\chi _{c1}(3872)$ meson production within fully reconstructed jets. Each quarkonium state (tag) is reconstructed via its decay to the $J / ψ$ ${{J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }}$ ( $\to$ $\rightarrow$ $μ^{+} μ^{-}$ $\mu ^+\mu ^-$ ) $π^{+} π^{-}$ $\pi ^+\pi ^-$ final state in the forward region using proton-proton collision data collected by the LHCb experiment at the center-of-mass-energy of $13 TeV$ $13\text {TeV}$ in 2016, corresponding to an integrated luminosity of $1.64 {\,fb}^{- 1}$ $1.64\,\text {\,fb} ^{-1}$ . The fragmentation function, presented as the ratio of the quarkonium-tag transverse momentum to the full jet transverse momentum ( $p_{T} (tag) / p_{T} (jet)$ $p_{\textrm{T}} (\text {tag})/p_{\textrm{T}} (\text {jet})$ ), is measured differentially in $p_{T} (jet)$ $p_{\textrm{T}} (\text {jet})$ and $p_{T} (tag)$ $p_{\textrm{T}} (\text {tag})$ bins. The distributions are separated into promptly produced quarkonia from proton-proton collisions and quarkonia produced from displaced b-hadron decays. While the displaced quarkonia fragmentation functions are in general well described by parton-shower predictions, the prompt quarkonium distributions differ significantly from fixed-order non-relativistic QCD (NRQCD) predictions followed by a QCD parton shower.

A. Brossa Gonzalo, A. Gomes: Deceased.

© The Author(s) 2025

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.