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. H. Afsharnia

    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. Aleksiejunas

    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. J. L. Amey

    University of Bristol

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    University of Bristol

24. Y. Amhis

    Université Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay

25. L. An

    Peking University

    Affiliation as printed

    Peking University

26. L. An

    Istituto Nazionale di Fisica Nucleare, Sezione di Firenze

    Affiliation as printed

    INFN Sezione di Firenze

27. M. Andersson

    University of Zurich

    Affiliation as printed

    Universität Zürich

28. P. Andreola

    University of Zurich

    Affiliation as printed

    Universität Zürich

29. M. Andreotti

    Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara

    Affiliation as printed

    INFN Sezione di Ferrara

30. S. Andres Estrada

    Universidade da Coruña

    Affiliation as printed

    Universidade da Coruña

31. A. Anelli

    Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca

    Affiliation as printed

    INFN Sezione di Milano-Bicocca

32. D. Ao

    University of Chinese Academy of Sciences

    Affiliation as printed

    University of Chinese Academy of Sciences

33. C. Arata

    Université Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay

34. F Archilli

    Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata

    Affiliation as printed

    INFN Sezione di Roma Tor Vergata

35. Z. Areg

    Syracuse University

    Affiliation as printed

    Syracuse University

36. M. Argenton

    Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara

    Affiliation as printed

    INFN Sezione di Ferrara

37. 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)

38. L. Arnone

    Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca

    Affiliation as printed

    INFN Sezione di Milano-Bicocca

39. A Artamonov

    European Organization for Nuclear Research

    Affiliation as printed

    CERN

40. M. Artuso

    Syracuse University

    Affiliation as printed

    Syracuse University

41. E. Aslanides

    Aix-Marseille Université

    Affiliation as printed

    Aix Marseille Univ

42. R. Ataíde Da Silva

    École Polytechnique Fédérale de Lausanne

    Affiliation as printed

    Ecole Polytechnique Fédérale de Lausanne (EPFL)

43. M. Atzeni

    Massachusetts Institute of Technology

    Affiliation as printed

    Massachusetts Institute of Technology

44. B. Audurier

    Université Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay

45. Juliette Authier

    Laboratoire Leprince-Ringuet

    Affiliation as printed

    Laboratoire Leprince-Ringuet

46. D. Bacher

    University of Oxford

    Affiliation as printed

    University of Oxford

47. I. Bachiller

    École Polytechnique Fédérale de Lausanne

    Affiliation as printed

    Ecole Polytechnique Fédérale de Lausanne (EPFL)

48. S. Bachmann

    Heidelberg University

    Affiliation as printed

    Ruprecht-Karls-Universität Heidelberg

49. M. Bachmayer

    École Polytechnique Fédérale de Lausanne

    Affiliation as printed

    Ecole Polytechnique Fédérale de Lausanne (EPFL)

50. John J Back

    University of Warwick

    Affiliation as printed

    University of Warwick

51. P. Baladron Rodriguez

    Universidade de Santiago de Compostela

    Affiliation as printed

    Universidade de Santiago de Compostela

52. V. Balagura

    Laboratoire Leprince-Ringuet

    Affiliation as printed

    Laboratoire Leprince-Ringuet

53. A Balboni

    Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara

    Affiliation as printed

    INFN Sezione di Ferrara

54. W. Baldini

    Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara

    Affiliation as printed

    INFN Sezione di Ferrara

55. Z. Baldwin

    TU Dortmund University · Ruhr University Bochum

    Affiliation as printed

    Ruhr Universitaet Bochum

    Technische Universität Dortmund

56. L. Balzani

    TU Dortmund University

    Affiliation as printed

    Technische Universität Dortmund

57. H Bao

    University of Chinese Academy of Sciences

    Affiliation as printed

    University of Chinese Academy of Sciences

58. J. Baptista de Souza Leite

    Centro Brasileiro de Pesquisas Físicas

    Affiliation as printed

    Centro Brasileiro de Pesquisas Físicas (CBPF)

59. C. Barbero Pretel

    Universidade de Santiago de Compostela · Université Paris-Saclay

    Affiliation as printed

    Universidade de Santiago de Compostela

    Université Paris-Saclay

60. M. Barbetti

    Istituto Nazionale di Fisica Nucleare, Sezione di Firenze

    Affiliation as printed

    INFN Sezione di Firenze

61. 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)

62. Roger John Barlow

    University of Manchester

    Affiliation as printed

    University of Manchester

63. Mikhail Barnyakov

    Istituto Nazionale di Fisica Nucleare, Sezione di Bologna

    Affiliation as printed

    INFN Sezione di Bologna

64. Sergey Barsuk

    Université Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay

65. W. Barter

    University of Edinburgh

    Affiliation as printed

    University of Edinburgh

66. J. Bartz

    Syracuse University

    Affiliation as printed

    Syracuse University

67. S. Bashir

    AGH University of Krakow

    Affiliation as printed

    AGH - University of Krakow

68. B. Batsukh

    Institute for High Energy Physics · Institute of High Energy Physics

    Affiliation as printed

    Institute Of High Energy Physics (IHEP)

69. Piera Battista

    Université Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay

70. A. Bavarchee

    Eötvös Loránd University · European Organization for Nuclear Research

    Affiliation as printed

    Eotvos Lorand University

    European Organization for Nuclear Research (CERN)

71. A. Bay

    École Polytechnique Fédérale de Lausanne

    Affiliation as printed

    Ecole Polytechnique Fédérale de Lausanne (EPFL)

72. M. Becker

    Massachusetts Institute of Technology

    Affiliation as printed

    Massachusetts Institute of Technology

73. F Bedeschi

    Istituto Nazionale di Fisica Nucleare, Sezione di Pisa

    Affiliation as printed

    INFN Sezione di Pisa

74. I. B. Bediaga

    Centro Brasileiro de Pesquisas Físicas

    Affiliation as printed

    Centro Brasileiro de Pesquisas Físicas (CBPF)

75. N. A. 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. A. 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

    Affiliation as printed

    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. A Berezhnoy

    European Organization for Nuclear Research

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    CERN

85. R. Bernet

    University of Zurich

    Affiliation as printed

    Universität Zürich

86. S. Bernet Andres

    Universitat Ramon Llull

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    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

    Affiliation as printed

    University of Cambridge

90. O. Bezshyyko

    Taras Shevchenko National University of Kyiv · Université Paris-Saclay

    Affiliation as printed

    Taras Schevchenko University of Kyiv

    Université Paris-Saclay

91. S. 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. A. Biolchini

    National Institute for Subatomic Physics

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    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