skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Observation of the rare $$B^0_s\to\mu^+\mu^-$$ decay from the combined analysis of CMS and LHCb data

Abstract

The standard model of particle physics describes the fundamental particles and their interactions via the strong, electromagnetic and weak forces. It provides precise predictions for measurable quantities that can be tested experimentally. We foudn that the probabilities, or branching fractions, of the strange B meson (B 0 2 ) and the B 0 meson decaying into two oppositely charged muons (μ + and μ -) are especially interesting because of their sensitivity to theories that extend the standard model. The standard model predicts that the B 0 2 → μ + and μ - and (B 0 → μ + and μ - decays are very rare, with about four of the former occurring for every billion mesons produced, and one of the latter occurring for every ten billion B 0 mesons1. A difference in the observed branching fractions with respect to the predictions of the standard model would provide a direction in which the standard model should be extended. Before the Large Hadron Collider (LHC) at CERN2 started operating, no evidence for either decay mode had been found. Upper limits on the branching fractions were an order of magnitude above the standard model predictions. The CMS (Compact Muon Solenoid)more » and LHCb (Large Hadron Collider beauty) collaborations have performed a joint analysis of the data from proton–proton collisions that they collected in 2011 at a centre-of-mass energy of seven teraelectronvolts and in 2012 at eight teraelectronvolts. Here we report the first observation of the μ + and μ -decay, with a statistical significance exceeding six standard deviations, and the best measurement so far of its branching fraction. We then obtained evidence for the B 0 → μ + and μ - decay with a statistical significance of three standard deviations. Both measurements are statistically compatible with standard model predictions and allow stringent constraints to be placed on theories beyond the standard model. The LHC experiments will resume taking data in 2015, recording proton–proton collisions at a centre-of-mass energy of 13 teraelectronvolts, which will approximately double the production rates of B 0 2 and B 0 mesons and lead to further improvements in the precision of these crucial tests of the standard model.« less

Authors:
 [1]
  1. Yerevan Physics Inst. (YerPhI) (Armenia). et al.
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Org.:
CMS Collaboration
OSTI Identifier:
1234865
Report Number(s):
FERMILAB-PUB-14-489-CMS; CERN-PH-EP-2014-220; CMS-BPH-13-007
Journal ID: ISSN 0028-0836; arXiv eprint number arXiv:1411.4413; TRN: US1600714
Grant/Contract Number:  
AC02-07CH11359
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nature (London)
Additional Journal Information:
Journal Volume: 522; Journal Issue: 7554; Journal ID: ISSN 0028-0836
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; experimental particle physics

Citation Formats

Khachatryan, Vardan. Observation of the rare $B^0_s\to\mu^+\mu^-$ decay from the combined analysis of CMS and LHCb data. United States: N. p., 2015. Web. doi:10.1038/nature14474.
Khachatryan, Vardan. Observation of the rare $B^0_s\to\mu^+\mu^-$ decay from the combined analysis of CMS and LHCb data. United States. doi:10.1038/nature14474.
Khachatryan, Vardan. Wed . "Observation of the rare $B^0_s\to\mu^+\mu^-$ decay from the combined analysis of CMS and LHCb data". United States. doi:10.1038/nature14474. https://www.osti.gov/servlets/purl/1234865.
@article{osti_1234865,
title = {Observation of the rare $B^0_s\to\mu^+\mu^-$ decay from the combined analysis of CMS and LHCb data},
author = {Khachatryan, Vardan},
abstractNote = {The standard model of particle physics describes the fundamental particles and their interactions via the strong, electromagnetic and weak forces. It provides precise predictions for measurable quantities that can be tested experimentally. We foudn that the probabilities, or branching fractions, of the strange B meson (B 02 ) and the B0 meson decaying into two oppositely charged muons (μ+ and μ-) are especially interesting because of their sensitivity to theories that extend the standard model. The standard model predicts that the B 02 → μ+ and μ- and (B 0 → μ+ and μ- decays are very rare, with about four of the former occurring for every billion mesons produced, and one of the latter occurring for every ten billion B0 mesons1. A difference in the observed branching fractions with respect to the predictions of the standard model would provide a direction in which the standard model should be extended. Before the Large Hadron Collider (LHC) at CERN2 started operating, no evidence for either decay mode had been found. Upper limits on the branching fractions were an order of magnitude above the standard model predictions. The CMS (Compact Muon Solenoid) and LHCb (Large Hadron Collider beauty) collaborations have performed a joint analysis of the data from proton–proton collisions that they collected in 2011 at a centre-of-mass energy of seven teraelectronvolts and in 2012 at eight teraelectronvolts. Here we report the first observation of the μ+ and μ-decay, with a statistical significance exceeding six standard deviations, and the best measurement so far of its branching fraction. We then obtained evidence for the B 0 → μ+ and μ- decay with a statistical significance of three standard deviations. Both measurements are statistically compatible with standard model predictions and allow stringent constraints to be placed on theories beyond the standard model. The LHC experiments will resume taking data in 2015, recording proton–proton collisions at a centre-of-mass energy of 13 teraelectronvolts, which will approximately double the production rates of B 02 and B0 mesons and lead to further improvements in the precision of these crucial tests of the standard model.},
doi = {10.1038/nature14474},
journal = {Nature (London)},
issn = {0028-0836},
number = 7554,
volume = 522,
place = {United States},
year = {2015},
month = {5}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 174 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

B s , d + in the Standard Model with Reduced Theoretical Uncertainty
journal, March 2014


LHC Machine
journal, August 2008


Planck 2013 results. XVI. Cosmological parameters
journal, October 2014


Standard model CP-violation and baryon asymmetry (I). Zero temperature
journal, November 1994


B and B s meson decay constants from lattice QCD
journal, August 2012


B - and D -meson decay constants from three-flavor lattice QCD
journal, June 2012


Promising process to distinguish supersymmetric models with large tan β from the standard model: B X s μ + μ
journal, November 1998


Dileptonic decay of Bs meson in SUSY models with large tanβ
journal, April 1999


Higgs-Mediated B 0 μ + μ in Minimal Supersymmetry
journal, January 2000


Analysis of neutral Higgs-boson contributions to the decays B s l + l and B ¯ Kl + l
journal, September 2001


Relations between ΔMs,d and Bs,d→μμ̄ in models with minimal flavour violation
journal, July 2003


Review of lattice results concerning low-energy particle physics
journal, September 2014


Minimal flavour violation: an effective field theory approach
journal, November 2002


First Evidence for the Decay B s 0 μ + μ
journal, January 2013


Measurement of the B s 0 μ + μ Branching Fraction and Search for B 0 μ + μ with the CMS Experiment
journal, September 2013


Measurement of the B s 0 μ + μ Branching Fraction and Search for B 0 μ + μ Decays at the LHCb Experiment
journal, September 2013


Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
journal, September 2012


Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
journal, September 2012


A Decision-Theoretic Generalization of On-Line Learning and an Application to Boosting
journal, August 1997

  • Freund, Yoav; Schapire, Robert E.
  • Journal of Computer and System Sciences, Vol. 55, Issue 1
  • DOI: 10.1006/jcss.1997.1504

Measurement of b hadron production fractions in 7 TeV p p collisions
journal, February 2012


The Large-Sample Distribution of the Likelihood Ratio for Testing Composite Hypotheses
journal, March 1938


Unified approach to the classical statistical analysis of small signals
journal, April 1998


Limits on rare exclusive decays of B mesons
journal, January 1987


A search for exclusive penguin decays of B mesons
journal, June 1989


Search for B 0 decays to two charged leptons
journal, June 1994


Search for decays of B 0 mesons into pairs of leptons: B 0 e + e , B 0 μ + μ , and B 0 e ± μ
journal, October 2000


B meson decays into charmonium states
journal, December 1987


Low mass Dimuon production at the CERN proton-antiproton collider
journal, August 1988


A search for rare B meson decays at the CERN Spp̄S collider
journal, June 1991


Search for Flavor-Changing Neutral Current B Meson Decays in p p ¯ Collisions at s = 1.8 TeV
journal, June 1996


Anharmonic contribution to the temperature dependence of photoemission core-level spectroscopy of adsorbates on surfaces: Oxygen on Rh(110)
journal, February 1998

  • Baraldi, Alessandro; Lizzit, Silvano; Cocco, Daniele
  • Physical Review B, Vol. 57, Issue 7
  • DOI: 10.1103/PhysRevB.57.3811

Search for B s 0 μ + μ and B d 0 μ + μ Decays in p p ¯ Collisions at s = 1.96 T e V
journal, July 2004


Search for B s 0 μ + μ and B d 0 μ + μ Decays in p p ¯ Collisions with CDF II
journal, November 2005


Search for B s 0 μ + μ and B 0 μ + μ Decays with CDF II
journal, November 2011


Search for B s 0 μ + μ and B 0 μ + μ decays with the full CDF Run II data set
journal, April 2013


Search for neutral B meson decays to two charged leptons
journal, January 1997


Search for the decay b→Xsμ+μ−
journal, March 1998


Search for B s 0 μ + μ decays at D0
journal, November 2007


Search for the rare decay <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo>→</mml:mo><mml:msup><mml:mi>μ</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>μ</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math>
journal, October 2010


Search for the rare decay B s 0 μ + μ
journal, April 2013


Search for B 0 l + l at the Belle detector
journal, December 2003


Search for Decays of B 0 e + e , B 0 μ + μ , B 0 e ± μ
journal, June 2005


Search for decays of B 0 mesons into e + e , μ + μ and e ± μ final states
journal, February 2008


Search for the rare decays <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo>→</mml:mo><mml:msup><mml:mi>μ</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>μ</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math> and <mml:math altimg="si2.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msup><mml:mi>B</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mo>→</mml:mo><mml:msup><mml:mi>μ</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>μ</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math>
journal, May 2011


Strong Constraints on the Rare Decays B s 0 μ + μ and B 0 μ + μ
journal, June 2012


Search for the rare decays <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msubsup><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msubsup><mml:mo>→</mml:mo><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:math> and <mml:math altimg="si2.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msup><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup><mml:mo>→</mml:mo><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:math>
journal, February 2012


Search for B s 0 μ + μ and B 0 μ + μ Decays in p p Collisions at s = 7 TeV
journal, November 2011


Search for the decay <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd"><mml:msubsup><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msubsup><mml:mo>→</mml:mo><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:math> with the ATLAS detector
journal, July 2012


Probing New Physics via the B s 0 μ + μ Effective Lifetime
journal, July 2012


Form factors and strong couplings of heavy baryons from QCD light-cone sum rules
journal, September 2011

  • Khodjamirian, A.; Klein, Ch.; Mannel, Th.
  • Journal of High Energy Physics, Vol. 2011, Issue 9
  • DOI: 10.1007/JHEP09(2011)106

Precision measurement of the ratio of the <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd" xmlns:sa="http://www.elsevier.com/xml/common/struct-aff/dtd"><mml:msubsup><mml:mrow><mml:mi>Λ</mml:mi></mml:mrow><mml:mrow><mml:mi>b</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msubsup></mml:math> to <mml:math altimg="si2.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd" xmlns:sa="http://www.elsevier.com/xml/common/struct-aff/dtd"><mml:msup><mml:mrow><mml:mover accent="true"><mml:mi>B</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup></mml:math> lifetimes
journal, June 2014


    Works referencing / citing this record:

    Averages of b-hadron, c-hadron, and $$\tau $$ τ -lepton properties as of summer 2016
    journal, December 2017


    Invisible decay of the Higgs boson in the context of a thermal and nonthermal relic in MSSM
    journal, May 2017

    • Barman, Rahool Kumar; Bélanger, Genevieve; Bhattacherjee, Biplob
    • Physical Review D, Vol. 95, Issue 9
    • DOI: 10.1103/physrevd.95.095018

    Update of the global electroweak fit and constraints on two-Higgs-doublet models
    journal, August 2018


    FlavBit: a GAMBIT module for computing flavour observables and likelihoods
    journal, November 2017


    Machine learning at the energy and intensity frontiers of particle physics
    journal, August 2018


    Global fits of GUT-scale SUSY models with GAMBIT
    journal, December 2017


    Search for Supersymmetry at the LHC
    journal, January 2017