Test of Lepton Flavor Universality with B0 →k∗0ℓ+ℓ- Decays at Large Dilepton Invariant Mass

(LHCb Collaboration)

doi:10.1103/vzv9-hcks

Test of Lepton Flavor Universality with B0 →k∗0ℓ+ℓ- Decays at Large Dilepton Invariant Mass

(LHCb Collaboration)

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

Abstract

Muon-electron universality is tested in B0→K∗0ℓ+ℓ- decays, in the dilepton-invariant-mass region above the ψ(2S) resonance. The analysis uses beauty mesons produced in proton-proton collisions recorded by the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The ratio of branching fractions between the muon and electron channels RK∗0 is measured to be 1.08-0.12+0.14(stat)±0.07(syst) for a dilepton-invariant-mass squared above 14.0 GeV2/c4, consistent with the standard model prediction. This result represents the most precise measurement of RK∗0 in this region and the first such measurement performed at a hadron collider.

Original language	English
Article number	051803
Journal	Physical Review Letters
Volume	137
Issue number	5
DOIs	https://doi.org/10.1103/vzv9-hcks
State	Published - 31 Jul 2026

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@article{ee8fd0e1ca4c49b6938cfba03dd9e6ba,

title = "Test of Lepton Flavor Universality with B0 →k∗0ℓ+ℓ- Decays at Large Dilepton Invariant Mass",

abstract = "Muon-electron universality is tested in B0→K∗0ℓ+ℓ- decays, in the dilepton-invariant-mass region above the ψ(2S) resonance. The analysis uses beauty mesons produced in proton-proton collisions recorded by the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The ratio of branching fractions between the muon and electron channels RK∗0 is measured to be 1.08-0.12+0.14(stat)±0.07(syst) for a dilepton-invariant-mass squared above 14.0 GeV2/c4, consistent with the standard model prediction. This result represents the most precise measurement of RK∗0 in this region and the first such measurement performed at a hadron collider.",

author = "\{(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 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 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 Milanes, \{D. A.\} and E. Shmanin",

note = "Publisher Copyright: {\textcopyright} 2026 CERN. ",

year = "2026",

month = jul,

day = "31",

doi = "10.1103/vzv9-hcks",

language = "English",

volume = "137",

journal = "Physical Review Letters",

issn = "0031-9007",

number = "5",

}

TY - JOUR

T1 - Test of Lepton Flavor Universality with B0 →k∗0ℓ+ℓ- Decays at Large Dilepton Invariant Mass

AU - (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 - 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 - 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 - Milanes, D. A.

AU - Shmanin, E.

PY - 2026/7/31

Y1 - 2026/7/31

N2 - Muon-electron universality is tested in B0→K∗0ℓ+ℓ- decays, in the dilepton-invariant-mass region above the ψ(2S) resonance. The analysis uses beauty mesons produced in proton-proton collisions recorded by the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The ratio of branching fractions between the muon and electron channels RK∗0 is measured to be 1.08-0.12+0.14(stat)±0.07(syst) for a dilepton-invariant-mass squared above 14.0 GeV2/c4, consistent with the standard model prediction. This result represents the most precise measurement of RK∗0 in this region and the first such measurement performed at a hadron collider.

AB - Muon-electron universality is tested in B0→K∗0ℓ+ℓ- decays, in the dilepton-invariant-mass region above the ψ(2S) resonance. The analysis uses beauty mesons produced in proton-proton collisions recorded by the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The ratio of branching fractions between the muon and electron channels RK∗0 is measured to be 1.08-0.12+0.14(stat)±0.07(syst) for a dilepton-invariant-mass squared above 14.0 GeV2/c4, consistent with the standard model prediction. This result represents the most precise measurement of RK∗0 in this region and the first such measurement performed at a hadron collider.

UR - https://www.scopus.com/pages/publications/105047158261

U2 - 10.1103/vzv9-hcks

DO - 10.1103/vzv9-hcks

M3 - Article

AN - SCOPUS:105047158261

SN - 0031-9007

VL - 137

JO - Physical Review Letters

JF - Physical Review Letters

IS - 5

M1 - 051803

ER -

Test of Lepton Flavor Universality with B0 →k∗0ℓ+ℓ- Decays at Large Dilepton Invariant Mass

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