Evidence for the Rare Decay B + → Λ ¯ p μ + μ −

Physical Review Letters, vol. 137, pp. 051801

Abstract

A search for the rare decay B^{+}→Λ[over ¯]pμ^{+}μ^{-} is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of sqrt[s]=13 TeV, corresponding to an integrated luminosity of 5.4 fb^{-1}. An excess of events is found with respect to the background-only expectation, with a signal significance of 3.5 standard deviations, in the low invariant-mass region of m(Λ[over ¯]p)<2.8 GeV/c^{2}. The branching fraction is measured to be B_{low}(B^{+}→Λ[over ¯]pμ^{+}μ^{-})=(1.70_{-0.56}^{+0.65}(stat)±0.17(syst)±0.14(ext))×10^{-8}, where the last uncertainty is due to external inputs on B(B^{+}→J/ψΛ[over ¯]p)×B(J/ψ→μ^{+}μ^{-}). With no significant signal observed in the high m(Λ[over ¯]p) region above 2.8 GeV/c^{2}, an upper limit is set to be B_{high}(B^{+}→Λ[over ¯]pμ^{+}μ^{-})<2.8(3.7)×10^{-9} at the 90% (95%) confidence level.

Authors 99

1. R. Aaij

   National Institute for Subatomic Physics

   Affiliation as printed

   Nikhef National Institute for Subatomic Physics

2. A. S. W. Abdelmotteleb

   University of Warwick

   Affiliation as printed

   University of Warwick

3. Carlos Abellán Beteta

   University of Zurich

   Affiliation as printed

   Universität Zürich

4. C. Abellán Beteta

   University of Warwick

   Affiliation as printed

   University of Warwick

5. T. Ackernley

   University of Liverpool

   Affiliation as printed

   University of Liverpool

6. A. A. Adefisoye

   Syracuse University

   Affiliation as printed

   Syracuse University

7. B. Adeva

   Universidade de Santiago de Compostela

   Affiliation as printed

   Universidade de Santiago de Compostela

8. M. Adinolfi

   University of Bristol

   Affiliation as printed

   University of Bristol

9. P. Adlarson

   Uppsala University · University of Glasgow

   Affiliation as printed

   University of Glasgow

   Uppsala University

10. C. Agapopoulou

    Université Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay

11. C. Aidala

    University of Michigan · Syracuse University

    Affiliation as printed

    Syracuse University

    University of Michigan

12. Z. Ajaltouni

    Université Clermont Auvergne

    Affiliation as printed

    Université Clermont Auvergne

13. S. Akar

    Université Clermont Auvergne

    Affiliation as printed

    Université Clermont Auvergne

14. K. Carvalho Akiba

    National Institute for Subatomic Physics

    Affiliation as printed

    Nikhef National Institute for Subatomic Physics

15. Muzammil Akthar

    AGH University of Krakow

    Affiliation as printed

    AGH - University of Krakow

16. P. Albicocco

    Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati

    Affiliation as printed

    INFN Laboratori Nazionali di Frascati

17. J. Albrecht

    TU Dortmund University

    Affiliation as printed

    Technische Universität Dortmund

18. R. Aleksiejūnas

    University of Freiburg · Vilnius University

    Affiliation as printed

    Albert-Ludwigs-Universität Freiburg

    Vilnius University

19. F. Alessio

    European Organization for Nuclear Research

    Affiliation as printed

    European Organization for Nuclear Research (CERN)

20. P. Álvarez Cartelle

    Universidade de Santiago de Compostela · University of Cambridge

    Affiliation as printed

    Universidade de Santiago de Compostela

    University of Cambridge

21. R. Amalric

    Sorbonne Université

    Affiliation as printed

    Sorbonne Université

22. S. Amato

    Universidade Federal do Rio de Janeiro

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    Universidade Federal do Rio de Janeiro (UFRJ)

23. Y. Amhis

    Université Paris-Saclay

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    Université Paris-Saclay

24. Liupan An

    Peking University

    Affiliation as printed

    Peking University

25. L. Anderlini

    Istituto Nazionale di Fisica Nucleare, Sezione di Firenze

    Affiliation as printed

    INFN Sezione di Firenze

26. M. Andersson

    University of Zurich

    Affiliation as printed

    Universität Zürich

27. P. Andreola

    University of Zurich

    Affiliation as printed

    Universität Zürich

28. M. Andreotti

    Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara

    Affiliation as printed

    INFN Sezione di Ferrara

29. Sergio Andres Estrada

    Universidade da Coruña

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    Universidade da Coruña

30. Alessia Anelli

    Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca

    Affiliation as printed

    INFN Sezione di Milano-Bicocca

31. D. Ao

    University of Chinese Academy of Sciences

    Affiliation as printed

    University of Chinese Academy of Sciences

32. C. Arata

    Université Paris-Saclay

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    Université Paris-Saclay

33. F. Archilli

    Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata

    Affiliation as printed

    INFN Sezione di Roma Tor Vergata

34. Zaratsyan Areg

    Syracuse University

    Affiliation as printed

    Syracuse University

35. Matteo Argenton

    Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara

    Affiliation as printed

    INFN Sezione di Ferrara

36. S. Arguedas Cuendis

    Consejo Nacional de Rectores · European Organization for Nuclear Research

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    Consejo Nacional de Rectores (CONARE)

    European Organization for Nuclear Research (CERN)

37. Lisa Arnone

    Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca

    Affiliation as printed

    INFN Sezione di Milano-Bicocca

38. A. Artamonov

    European Organization for Nuclear Research

    Affiliation as printed

    CERN

39. M. Artuso

    Syracuse University

    Affiliation as printed

    Syracuse University

40. E. Aslanides

    Aix-Marseille Université

    Affiliation as printed

    Aix Marseille Univ

41. R. Ataíde Da Silva

    École Polytechnique Fédérale de Lausanne

    Affiliation as printed

    Ecole Polytechnique Fédérale de Lausanne (EPFL)

42. M. Atzeni

    Massachusetts Institute of Technology

    Affiliation as printed

    Massachusetts Institute of Technology

43. B. Audurier

    Université Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay

44. Juliette Authier

    Laboratoire Leprince-Ringuet

    Affiliation as printed

    Laboratoire Leprince-Ringuet

45. D. Bacher

    University of Oxford

    Affiliation as printed

    University of Oxford

46. I. Bachiller

    École Polytechnique Fédérale de Lausanne

    Affiliation as printed

    Ecole Polytechnique Fédérale de Lausanne (EPFL)

47. S. Bachmann

    Heidelberg University

    Affiliation as printed

    Ruprecht-Karls-Universität Heidelberg

48. Marie Bachmayer

    École Polytechnique Fédérale de Lausanne

    Affiliation as printed

    Ecole Polytechnique Fédérale de Lausanne (EPFL)

49. John J Back

    University of Warwick

    Affiliation as printed

    University of Warwick

50. P. Baladrón Rodríguez

    Universidade de Santiago de Compostela

    Affiliation as printed

    Universidade de Santiago de Compostela

51. V. Balagura

    Laboratoire Leprince-Ringuet

    Affiliation as printed

    Laboratoire Leprince-Ringuet

52. A Balboni

    Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara

    Affiliation as printed

    INFN Sezione di Ferrara

53. W. Baldini

    Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara

    Affiliation as printed

    INFN Sezione di Ferrara

54. Zachary Baldwin

    TU Dortmund University · Ruhr University Bochum

    Affiliation as printed

    Ruhr Universitaet Bochum

    Technische Universität Dortmund

55. Luca Balzani

    TU Dortmund University

    Affiliation as printed

    Technische Universität Dortmund

56. H. Bao

    University of Chinese Academy of Sciences

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    University of Chinese Academy of Sciences

57. J. Baptista de Souza Leite

    Centro Brasileiro de Pesquisas Físicas

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    Centro Brasileiro de Pesquisas Físicas (CBPF)

58. C. Barbero Pretel

    Universidade de Santiago de Compostela · Université Paris-Saclay

    Affiliation as printed

    Universidade de Santiago de Compostela

    Université Paris-Saclay

59. M. Barbetti

    Istituto Nazionale di Fisica Nucleare, Sezione di Firenze

    Affiliation as printed

    INFN Sezione di Firenze

60. I. R. Barbosa

    Universidade Federal do Rio de Janeiro · Pontifícia Universidade Católica do Rio de Janeiro

    Affiliation as printed

    Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)

    Universidade Federal do Rio de Janeiro (UFRJ)

61. Roger John Barlow

    University of Manchester

    Affiliation as printed

    University of Manchester

62. Mikhail Barnyakov

    Istituto Nazionale di Fisica Nucleare, Sezione di Bologna

    Affiliation as printed

    INFN Sezione di Bologna

63. S. Barsuk

    Université Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay

64. W. Barter

    University of Edinburgh

    Affiliation as printed

    University of Edinburgh

65. W. Barter

    Syracuse University

    Affiliation as printed

    Syracuse University

66. B. Batsukh

    AGH University of Krakow

    Affiliation as printed

    AGH - University of Krakow

67. B. Batsukh

    Institute for High Energy Physics · Institute of High Energy Physics

    Affiliation as printed

    Institute Of High Energy Physics (IHEP)

68. Piera Battista

    Université Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay

69. Ali Bavarchee

    Eötvös Loránd University · European Organization for Nuclear Research

    Affiliation as printed

    Eotvos Lorand University

    European Organization for Nuclear Research (CERN)

70. A. Bay

    École Polytechnique Fédérale de Lausanne

    Affiliation as printed

    Ecole Polytechnique Fédérale de Lausanne (EPFL)

71. A. Beck

    Massachusetts Institute of Technology

    Affiliation as printed

    Massachusetts Institute of Technology

72. M. Becker

    TU Dortmund University

    Affiliation as printed

    Technische Universität Dortmund

73. F. Bedeschi

    Istituto Nazionale di Fisica Nucleare, Sezione di Pisa

    Affiliation as printed

    INFN Sezione di Pisa

74. I. Bediaga

    Centro Brasileiro de Pesquisas Físicas

    Affiliation as printed

    Centro Brasileiro de Pesquisas Físicas (CBPF)

75. Noah Albin Behling

    TU Dortmund University

    Affiliation as printed

    Technische Universität Dortmund

76. S. Belin

    Universidade de Santiago de Compostela

    Affiliation as printed

    Universidade de Santiago de Compostela

77. Alberto Bellavista

    Istituto Nazionale di Fisica Nucleare, Sezione di Bologna

    Affiliation as printed

    INFN Sezione di Bologna

78. K. Belous

    European Organization for Nuclear Research

    Affiliation as printed

    CERN

79. I. Belov

    Istituto Nazionale di Fisica Nucleare, Sezione di Genova

    Affiliation as printed

    INFN Sezione di Genova

80. I. Belyaev

    Istituto Nazionale di Fisica Nucleare, Sezione di Roma I

    Affiliation as printed

    INFN Sezione di Roma La Sapienza

81. G. Benane

    Aix-Marseille Université

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    Aix Marseille Univ

82. G. Bencivenni

    Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati

    Affiliation as printed

    INFN Laboratori Nazionali di Frascati

83. E. Ben-Haim

    Sorbonne Université

    Affiliation as printed

    Sorbonne Université

84. Alexander Berezhnoy

    European Organization for Nuclear Research

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    CERN

85. R. Bernet

    University of Zurich

    Affiliation as printed

    Universität Zürich

86. H. C. Bernstein

    Universitat Ramon Llull

    Affiliation as printed

    Universitat Ramon Llull

87. A. Bertolin

    Istituto Nazionale di Fisica Nucleare, Sezione di Padova

    Affiliation as printed

    INFN Sezione di Padova

88. F. Betti

    University of Edinburgh

    Affiliation as printed

    University of Edinburgh

89. J. Bex

    University of Cambridge

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    University of Cambridge

90. Oleg Bezshyyko

    Taras Shevchenko National University of Kyiv · Université Paris-Saclay

    Affiliation as printed

    Taras Schevchenko University of Kyiv

    Université Paris-Saclay

91. Senjuti Bhattacharya

    Eötvös Loránd University · European Organization for Nuclear Research

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    Eotvos Lorand University

    European Organization for Nuclear Research (CERN)

92. M. S. Bieker

    University of Bonn

    Affiliation as printed

    Universität Bonn - Helmholtz-Institut für Strahlen und Kernphysik

93. N. V. Biesuz

    Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara

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    INFN Sezione di Ferrara

94. Alice Biolchini

    National Institute for Subatomic Physics

    Affiliation as printed

    Nikhef National Institute for Subatomic Physics

95. M. Birch

    Imperial College London

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    Imperial College London

96. F. C. R. Bishop

    Université Savoie Mont Blanc

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    Université Savoie Mont Blanc

97. A. Bitadze

    University of Manchester

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    University of Manchester

98. A. Bizzeti

    Istituto Nazionale di Fisica Nucleare, Sezione di Firenze

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    INFN Sezione di Firenze

99. T. Blake

    University of Warwick

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    University of Warwick