Improved measurement of η/η′ mixing in Bs0→J/ψη′ decays

The LHCb collaboration

doi:10.1007/JHEP10(2025)113

Improved measurement of η/η′ mixing in Bs0→J/ψη^′ decays

The LHCb collaboration

National Institute for Subatomic Physics
University of Warwick
University of Zurich
University of Liverpool
Syracuse University
Instituto Galego de Física de Altas Enerxías (IGFAE)
University of Bristol
Uppsala University
Université Paris-Saclay
University of Michigan, Ann Arbor
Université Clermont Auvergne
National Institute for Nuclear Physics
TU Dortmund University
Lamarr Institute for Machine Learning and Artificial Intelligence
Vilnius University
CERN
University of Cambridge
Sorbonne Université
Universidade Federal do Rio de Janeiro
Peking University
University of A Coruna
University of Milan - Bicocca
University of Chinese Academy of Sciences
University of Rome Tor Vergata
Consejo Nacional de Rectores (CONARE)
CPPM
Swiss Federal Institute of Technology Lausanne
Massachusetts Institute of Technology
Laboratoire Leprince-Ringuet
University of Oxford
Heidelberg University
Ruhr University Bochum
Pontifícia Universidade Católica do Rio de Janeiro
University of Manchester
University of Edinburgh
AGH University of Krakow
CAS - Institute of High Energy Physics
Centro Brasileiro de Pesquisas Físicas
Ramon Llull University
Kyiv National Taras Shevchenko University
Henryk Niewodniczanski Institute of Nuclear Physics of the Polish Academy of Sciences
University of Bonn
Imperial College London
Université Savoie Mont Blanc
University of Modena and Reggio Emilia
University of Victoria BC
Los Alamos National Laboratory
Maastricht University
University of Ferrara
Monash University
Cracow University of Technology
Ohio State University
Wuhan University
University of Barcelona
Facultad de Ciencias Fisicas
University of Bologna
University of Genoa
Scuola Normale Superiore di Pisa
University of Milan
Tsinghua University
Eötvös Loránd University
NASU - Institute of Nuclear Research
Horia Hulubei National Institute of Physics and Nuclear Engineering
University of Glasgow
University of Cincinnati
National Autonomous University of Honduras
Hunan University
University of Cagliari
University of Groningen
Centro Federal de Educação Tecnológica Celso Suckow da Fonseca
University of Bari
Central China Normal University
University College Dublin
South China Normal University
Rutherford Appleton Laboratory
University of Perugia
University of Valencia
University of Maryland, College Park
NASU - Kharkov Institute of Physics and Technology
University of Freiburg
University of Padua
National Centre for Nuclear Research
University of Pisa
RWTH Aachen University
Universidad Nacional de Colombia
University of Birmingham
Vrije Universiteit Amsterdam
Henan Normal University
Lanzhou University
University of Bergamo
Universidad de Ingeniería y Tecnología
University of Siena
University of Basilicata
Max Planck Institute for Nuclear Physics
University of Alcalá
University of Urbino
Universidad Andrés Bello

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

Abstract

Branching fraction ratios between the decays Bs0→J/ψη′ are measured using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb⁻¹. The measured ratios of these branching fractions are (Formula presented.) where the uncertainties are statistical, systematic and related to the precision of the η^(′) branching fractions, respectively. They are used to constrain the η/η′ mixing angle, ϕ_P, and to probe the presence of a possible glueball component in the η′ meson, described by the gluonic mixing angle ϕ_G. The obtained results are (Formula presented.) where the uncertainties are statistically dominated. While the value of ϕ_P is compatible with existing experimental determinations and theoretical calculations, the angle ϕ_G differs from zero by more than four standard deviations, which points to a substantial glueball component in the η′ meson and/or unexpectedly large contributions from gluon-mediated processes in these decays. The absolute branching fractions are also measured relative to that of the well-established Bs0→J/ψϕ decay, which serves as the normalisation channel. These results supersede the previous LHCb measurements and are the most precise to date.

Original language	English
Article number	113
Journal	Journal of High Energy Physics
Volume	2025
Issue number	10
DOIs	https://doi.org/10.1007/JHEP10(2025)113
State	Published - Oct 2025
Externally published	Yes

Keywords

B Physics
Branching fraction
Hadron-Hadron Scattering

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10.1007/JHEP10(2025)113

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@article{f112996fa8504d34b6139f8c0eb282fa,

title = "Improved measurement of η/η′ mixing in Bs0→J/ψη′ decays",

abstract = "Branching fraction ratios between the decays Bs0→J/ψη′ are measured using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The measured ratios of these branching fractions are (Formula presented.) where the uncertainties are statistical, systematic and related to the precision of the η(′) branching fractions, respectively. They are used to constrain the η/η′ mixing angle, ϕP, and to probe the presence of a possible glueball component in the η′ meson, described by the gluonic mixing angle ϕG. The obtained results are (Formula presented.) where the uncertainties are statistically dominated. While the value of ϕP is compatible with existing experimental determinations and theoretical calculations, the angle ϕG differs from zero by more than four standard deviations, which points to a substantial glueball component in the η′ meson and/or unexpectedly large contributions from gluon-mediated processes in these decays. The absolute branching fractions are also measured relative to that of the well-established Bs0→J/ψϕ decay, which serves as the normalisation channel. These results supersede the previous LHCb measurements and are the most precise to date.",

keywords = "B Physics, Branching fraction, Hadron-Hadron Scattering",

author = "\{The LHCb collaboration\} and R. Aaij and Abdelmotteleb, \{A. S.W.\} and \{Abellan Beteta\}, C. and F. Abudin{\'e}n and T. Ackernley and Adefisoye, \{A. A.\} and B. Adeva and M. Adinolfi and P. Adlarson and C. Agapopoulou and Aidala, \{C. A.\} and Z. Ajaltouni and S. Akar and K. Akiba and P. Albicocco and J. Albrecht and R. Aleksiejunas and F. Alessio and \{Alvarez Cartelle\}, P. and R. Amalric and S. Amato and Amey, \{J. L.\} and Y. Amhis and L. An and L. Anderlini and M. Andersson and P. Andreola and M. Andreotti and \{Andres Estrada\}, S. and A. Anelli and D. Ao and C. Arata and F. Archilli and Z. Areg and M. Argenton and \{Arguedas Cuendis\}, S. and L. Arnone and A. Artamonov and M. Artuso and E. Aslanides and \{Ata{\'i}de Da Silva\}, R. and M. Atzeni and B. Audurier and Authier, \{J. A.\} and D. Bacher and \{Bachiller Perea\}, I. and S. Bachmann and M. Bachmayer and Back, \{J. J.\} and \{Calderon Ramirez\}, S.",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2025.",

year = "2025",

month = oct,

doi = "10.1007/JHEP10(2025)113",

language = "Ingl{\'e}s",

volume = "2025",

journal = "Journal of High Energy Physics",

issn = "1029-8479",

number = "10",

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TY - JOUR

T1 - Improved measurement of η/η′ mixing in Bs0→J/ψη′ decays

AU - The LHCb collaboration

AU - Aaij, R.

AU - Abdelmotteleb, A. S.W.

AU - Abellan Beteta, C.

AU - Abudinén, F.

AU - Ackernley, T.

AU - Adefisoye, A. A.

AU - Adeva, B.

AU - Adinolfi, M.

AU - Adlarson, P.

AU - Agapopoulou, C.

AU - Aidala, C. A.

AU - Ajaltouni, Z.

AU - Akar, S.

AU - Akiba, K.

AU - Albicocco, P.

AU - Albrecht, J.

AU - Aleksiejunas, R.

AU - Alessio, F.

AU - Alvarez Cartelle, P.

AU - Amalric, R.

AU - Amato, S.

AU - Amey, J. L.

AU - Amhis, Y.

AU - An, L.

AU - Anderlini, L.

AU - Andersson, M.

AU - Andreola, P.

AU - Andreotti, M.

AU - Andres Estrada, S.

AU - Anelli, A.

AU - Ao, D.

AU - Arata, C.

AU - Archilli, F.

AU - Areg, Z.

AU - Argenton, M.

AU - Arguedas Cuendis, S.

AU - Arnone, L.

AU - Artamonov, A.

AU - Artuso, M.

AU - Aslanides, E.

AU - Ataíde Da Silva, R.

AU - Atzeni, M.

AU - Audurier, B.

AU - Authier, J. A.

AU - Bacher, D.

AU - Bachiller Perea, I.

AU - Bachmann, S.

AU - Bachmayer, M.

AU - Back, J. J.

AU - Calderon Ramirez, S.

PY - 2025/10

Y1 - 2025/10

N2 - Branching fraction ratios between the decays Bs0→J/ψη′ are measured using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The measured ratios of these branching fractions are (Formula presented.) where the uncertainties are statistical, systematic and related to the precision of the η(′) branching fractions, respectively. They are used to constrain the η/η′ mixing angle, ϕP, and to probe the presence of a possible glueball component in the η′ meson, described by the gluonic mixing angle ϕG. The obtained results are (Formula presented.) where the uncertainties are statistically dominated. While the value of ϕP is compatible with existing experimental determinations and theoretical calculations, the angle ϕG differs from zero by more than four standard deviations, which points to a substantial glueball component in the η′ meson and/or unexpectedly large contributions from gluon-mediated processes in these decays. The absolute branching fractions are also measured relative to that of the well-established Bs0→J/ψϕ decay, which serves as the normalisation channel. These results supersede the previous LHCb measurements and are the most precise to date.

AB - Branching fraction ratios between the decays Bs0→J/ψη′ are measured using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The measured ratios of these branching fractions are (Formula presented.) where the uncertainties are statistical, systematic and related to the precision of the η(′) branching fractions, respectively. They are used to constrain the η/η′ mixing angle, ϕP, and to probe the presence of a possible glueball component in the η′ meson, described by the gluonic mixing angle ϕG. The obtained results are (Formula presented.) where the uncertainties are statistically dominated. While the value of ϕP is compatible with existing experimental determinations and theoretical calculations, the angle ϕG differs from zero by more than four standard deviations, which points to a substantial glueball component in the η′ meson and/or unexpectedly large contributions from gluon-mediated processes in these decays. The absolute branching fractions are also measured relative to that of the well-established Bs0→J/ψϕ decay, which serves as the normalisation channel. These results supersede the previous LHCb measurements and are the most precise to date.

KW - B Physics

KW - Branching fraction

KW - Hadron-Hadron Scattering

UR - https://www.scopus.com/pages/publications/105021009704

U2 - 10.1007/JHEP10(2025)113

DO - 10.1007/JHEP10(2025)113

M3 - Artículo

AN - SCOPUS:105021009704

SN - 1029-8479

VL - 2025

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 10

M1 - 113

ER -

Improved measurement of η/η′ mixing in Bs0→J/ψη^′ decays

Abstract

Keywords

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