Angular analysis of the B+→ π+μ+μ− decay

The LHCb collaboration

doi:10.1007/JHEP08(2026)004

Angular analysis of the B⁺→ π⁺μ⁺μ⁻ decay

The LHCb collaboration

Science Park 105
Syracuse University
University of Warwick
Physik-Institut der Universität Zürich
University of Edinburgh
University of Liverpool
Universidade de Santiago de Compostela
University of Bristol
National Centre for Nuclear Research (NCBJ)
Department of Physics and Astronomy
Uppsala University
Université Paris-Saclay
University of Michigan, Ann Arbor
Clermont-Auvergne University
LNF-INFN
Fakultät Physik
University of Dortmund
Vilnius University
European Organization for Nuclear Research
Instituto de Biofisica da UFRJ
State Key Laboratory of Nuclear Physics and Technology
Istituto Nazionale di Fisica Nucleare, Sezione di Firenze
Sezione INFN di Ferrara
Universidade da Coruña
INFN Sezione di Milano-Bicocca
University of Chinese Academy of Sciences
INFN Roma Tor Vergata
Consejo Nacional de Rectores (CONARE)
Aix-Marseille Université
Institute of Physics
ENAC-IIC-GEL
Massachusetts Institute of Technology
Ip Paris
University of Oxford
University of Heidelberg

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

Abstract

This paper presents the first measurement of the forward-backward asymmetry, A_FB, and the flat term, F_H, that parameterise the angular distribution of the B⁺ → π⁺μ⁺μ⁻ decay. The proton-proton collision dataset used in the analysis corresponds to an integrated luminosity of 9 fb⁻¹, collected with the LHCb experiment between 2011 and 2018. The analysis is performed in two intervals of dimuon mass squared, one above and one below the region containing the J/ψ and ψ(2S) narrow charmonium resonances. The Standard Model predictions lie within the obtained 68% confidence level interval in the high-mass and within the 99% interval in the low-mass region.

Original language	English
Article number	4
Journal	Journal of High Energy Physics
Volume	2026
Issue number	8
DOIs	https://doi.org/10.1007/JHEP08(2026)004
Publication status	Published - 1 Aug 2026

Keywords

B Physics
Flavour Physics
Hadron-Hadron Scattering
Rare Decay

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10.1007/JHEP08(2026)004

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@article{4bd89edc5cc54ec4a3af7c82620cdf96,

title = "Angular analysis of the B+→ π+μ+μ− decay",

abstract = "This paper presents the first measurement of the forward-backward asymmetry, AFB, and the flat term, FH, that parameterise the angular distribution of the B+ → π+μ+μ− decay. The proton-proton collision dataset used in the analysis corresponds to an integrated luminosity of 9 fb−1, collected with the LHCb experiment between 2011 and 2018. The analysis is performed in two intervals of dimuon mass squared, one above and one below the region containing the J/ψ and ψ(2S) narrow charmonium resonances. The Standard Model predictions lie within the obtained 68\% confidence level interval in the high-mass and within the 99\% interval in the low-mass region.",

keywords = "B Physics, Flavour Physics, Hadron-Hadron Scattering, Rare Decay",

author = "\{The LHCb collaboration\} and R. Aaij and M. Abdelfatah 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 S. Akar and K. Akiba and P. Albicocco and J. Albrecht and R. Aleksiejunas and F. Alessio and \{Alvarez Cartelle\}, P. 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 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 V. Balagura and F. Fleuret and E. Maurice and Niel, \{E. M.\}",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2026.",

year = "2026",

month = aug,

day = "1",

doi = "10.1007/JHEP08(2026)004",

language = "English",

volume = "2026",

journal = "Journal of High Energy Physics",

issn = "1126-6708",

publisher = "Springer Verlag",

number = "8",

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TY - JOUR

T1 - Angular analysis of the B+→ π+μ+μ− decay

AU - The LHCb collaboration

AU - Aaij, R.

AU - Abdelfatah, M.

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 - Akar, S.

AU - Akiba, K.

AU - Albicocco, P.

AU - Albrecht, J.

AU - Aleksiejunas, R.

AU - Alessio, F.

AU - Alvarez Cartelle, P.

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 - 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 - Balagura, V.

AU - Fleuret, F.

AU - Maurice, E.

AU - Niel, E. M.

PY - 2026/8/1

Y1 - 2026/8/1

N2 - This paper presents the first measurement of the forward-backward asymmetry, AFB, and the flat term, FH, that parameterise the angular distribution of the B+ → π+μ+μ− decay. The proton-proton collision dataset used in the analysis corresponds to an integrated luminosity of 9 fb−1, collected with the LHCb experiment between 2011 and 2018. The analysis is performed in two intervals of dimuon mass squared, one above and one below the region containing the J/ψ and ψ(2S) narrow charmonium resonances. The Standard Model predictions lie within the obtained 68% confidence level interval in the high-mass and within the 99% interval in the low-mass region.

AB - This paper presents the first measurement of the forward-backward asymmetry, AFB, and the flat term, FH, that parameterise the angular distribution of the B+ → π+μ+μ− decay. The proton-proton collision dataset used in the analysis corresponds to an integrated luminosity of 9 fb−1, collected with the LHCb experiment between 2011 and 2018. The analysis is performed in two intervals of dimuon mass squared, one above and one below the region containing the J/ψ and ψ(2S) narrow charmonium resonances. The Standard Model predictions lie within the obtained 68% confidence level interval in the high-mass and within the 99% interval in the low-mass region.

KW - B Physics

KW - Flavour Physics

KW - Hadron-Hadron Scattering

KW - Rare Decay

UR - https://www.scopus.com/pages/publications/105047852284

U2 - 10.1007/JHEP08(2026)004

DO - 10.1007/JHEP08(2026)004

M3 - Article

AN - SCOPUS:105047852284

SN - 1126-6708

VL - 2026

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 8

M1 - 4

ER -

Angular analysis of the B⁺→ π⁺μ⁺μ⁻ decay

Abstract

Keywords

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