Observation of the decay 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇−

LHCb Collaboration; W. Barter; F. Betti; A. Bohare; E. Buchanan; P. E. L. Clarke; R. Currie; S. Eisenhardt; K. Farmer; D. Foulds-Holt; S. Gambetta; M. Kane; Y. Liu; F. Muheim; M. Needham; F. Oliva; K. Prasanth; L. Soares Lavra; A.R. Thomson-Strong; B. Urbach; C. Vrahas; M. R. J. Williams

doi:10.1103/jqvq-sbp7

Observation of the decay 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇−

LHCb Collaboration, W. Barter, F. Betti, A. Bohare, E. Buchanan, P. E. L. Clarke, R. Currie, S. Eisenhardt, K. Farmer, D. Foulds-Holt, S. Gambetta, M. Kane, Y. Liu, F. Muheim, M. Needham, F. Oliva, K. Prasanth, L. Soares Lavra, A.R. Thomson-Strong, B. UrbachC. Vrahas, M. R. J. Williams

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

Abstract

The first observation of the 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇− decay is reported using proton-proton collision data recorded with the LHCb detector corresponding to an integrated luminosity of 9 fb−1. The decay mode is observed for the first time, with a significance of 6.5⁢𝜎. Its branching fraction is measured relative to the 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜋+⁢𝜋−
decay mode ℬ⁡(𝜒𝑐⁢1⁡(3872)→𝐽/𝜓⁢𝜇+⁢𝜇−)ℬ⁡(𝜒𝑐⁢1⁡(3872)→𝐽/𝜓⁢𝜋+⁢𝜋−)=(1.68±0.32±0.05)×10−3, where the first uncertainty includes both statistical contributions and systematic contributions which are uncorrelated between data-taking periods, and the second represents the systematic contributions that are correlated between data-taking periods.

Original language	English
Article number	072019
Pages (from-to)	1-14
Number of pages	14
Journal	Physical Review D
Volume	113
Issue number	7
Early online date	1 Apr 2026
DOIs	https://doi.org/10.1103/jqvq-sbp7
Publication status	Published - 30 Apr 2026

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10.1103/jqvq-sbp7Licence: Creative Commons: Attribution (CC-BY)

3 Active
4 Finished

Experimental Particle Physics at the University of Edinburgh
Leonidopoulos, C. (Principal Investigator)
Science and Technology Facilities Council
1/04/23 → 30/09/26
Project: Research
Experimental Particle Physics at the University of Edinburgh
Leonidopoulos, C. (Principal Investigator)
Science and Technology Facilities Council
1/10/22 → 30/09/26
Project: Research
Beautiful Flavours: Discovering New Physics with B-hadrons and Tau-leptons
Barter, W. (Principal Investigator)
UKRI (formerly RCUK)
1/07/22 → 11/08/27
Project: Research

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LHCb Collaboration, Barter, W., Betti, F., Bohare, A., Buchanan, E., Clarke, P. E. L., Currie, R., Eisenhardt, S., Farmer, K., Foulds-Holt, D., Gambetta, S., Kane, M., Liu, Y., Muheim, F., Needham, M., Oliva, F., Prasanth, K., Soares Lavra, L., Thomson-Strong, A. R., ... Williams, M. R. J. (2026). Observation of the decay 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇−. Physical Review D, 113(7), 1-14. Article 072019. https://doi.org/10.1103/jqvq-sbp7

@article{02f957c1e01d4796b54de142e97552d3,

title = "Observation of the decay 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇−",

abstract = "The first observation of the 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇− decay is reported using proton-proton collision data recorded with the LHCb detector corresponding to an integrated luminosity of 9 fb−1. The decay mode is observed for the first time, with a significance of 6.5⁢𝜎. Its branching fraction is measured relative to the 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜋+⁢𝜋− decay mode ℬ⁡(𝜒𝑐⁢1⁡(3872)→𝐽/𝜓⁢𝜇+⁢𝜇−)ℬ⁡(𝜒𝑐⁢1⁡(3872)→𝐽/𝜓⁢𝜋+⁢𝜋−)=(1.68±0.32±0.05)×10−3, where the first uncertainty includes both statistical contributions and systematic contributions which are uncorrelated between data-taking periods, and the second represents the systematic contributions that are correlated between data-taking periods.",

author = "\{LHCb Collaboration\} and W. Barter and F. Betti and A. Bohare and E. Buchanan and Clarke, \{P. E. L.\} and R. Currie and S. Eisenhardt and K. Farmer and D. Foulds-Holt and S. Gambetta and M. Kane and Y. Liu and F. Muheim and M. Needham and F. Oliva and K. Prasanth and \{Soares Lavra\}, L. and A.R. Thomson-Strong and B. Urbach and C. Vrahas and Williams, \{M. R. J.\}",

year = "2026",

month = apr,

day = "30",

doi = "10.1103/jqvq-sbp7",

language = "English",

volume = "113",

pages = "1--14",

journal = "Physical Review D",

issn = "2470-0010",

publisher = "American Physical Society",

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LHCb Collaboration, Barter, W, Betti, F, Bohare, A, Buchanan, E , Clarke, PEL , Currie, R , Eisenhardt, S, Farmer, K, Foulds-Holt, D , Gambetta, S , Kane, M, Liu, Y, Muheim, F , Needham, M , Oliva, F , Prasanth, K , Soares Lavra, L, Thomson-Strong, AR, Urbach, B, Vrahas, C & Williams, MRJ 2026, 'Observation of the decay 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇−', Physical Review D, vol. 113, no. 7, 072019, pp. 1-14. https://doi.org/10.1103/jqvq-sbp7

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T1 - Observation of the decay 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇−

AU - LHCb Collaboration

AU - Barter, W.

AU - Betti, F.

AU - Bohare, A.

AU - Buchanan, E.

AU - Clarke, P. E. L.

AU - Currie, R.

AU - Eisenhardt, S.

AU - Farmer, K.

AU - Foulds-Holt, D.

AU - Gambetta, S.

AU - Kane, M.

AU - Liu, Y.

AU - Muheim, F.

AU - Needham, M.

AU - Oliva, F.

AU - Prasanth, K.

AU - Soares Lavra, L.

AU - Thomson-Strong, A.R.

AU - Urbach, B.

AU - Vrahas, C.

AU - Williams, M. R. J.

PY - 2026/4/30

Y1 - 2026/4/30

N2 - The first observation of the 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇− decay is reported using proton-proton collision data recorded with the LHCb detector corresponding to an integrated luminosity of 9 fb−1. The decay mode is observed for the first time, with a significance of 6.5⁢𝜎. Its branching fraction is measured relative to the 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜋+⁢𝜋− decay mode ℬ⁡(𝜒𝑐⁢1⁡(3872)→𝐽/𝜓⁢𝜇+⁢𝜇−)ℬ⁡(𝜒𝑐⁢1⁡(3872)→𝐽/𝜓⁢𝜋+⁢𝜋−)=(1.68±0.32±0.05)×10−3, where the first uncertainty includes both statistical contributions and systematic contributions which are uncorrelated between data-taking periods, and the second represents the systematic contributions that are correlated between data-taking periods.

AB - The first observation of the 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇− decay is reported using proton-proton collision data recorded with the LHCb detector corresponding to an integrated luminosity of 9 fb−1. The decay mode is observed for the first time, with a significance of 6.5⁢𝜎. Its branching fraction is measured relative to the 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜋+⁢𝜋− decay mode ℬ⁡(𝜒𝑐⁢1⁡(3872)→𝐽/𝜓⁢𝜇+⁢𝜇−)ℬ⁡(𝜒𝑐⁢1⁡(3872)→𝐽/𝜓⁢𝜋+⁢𝜋−)=(1.68±0.32±0.05)×10−3, where the first uncertainty includes both statistical contributions and systematic contributions which are uncorrelated between data-taking periods, and the second represents the systematic contributions that are correlated between data-taking periods.

U2 - 10.1103/jqvq-sbp7

DO - 10.1103/jqvq-sbp7

M3 - Article

SN - 2470-0010

VL - 113

SP - 1

EP - 14

JO - Physical Review D

JF - Physical Review D

IS - 7

M1 - 072019

ER -

Observation of the decay 𝜒𝑐⁢1⁡(3872) →𝐽/𝜓⁢𝜇+⁢𝜇−

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Experimental Particle Physics at the University of Edinburgh

Experimental Particle Physics at the University of Edinburgh

Beautiful Flavours: Discovering New Physics with B-hadrons and Tau-leptons

Cite this