Differential branching fraction and angular analysis of the B +K + μ + μ decay

Abstract

The angular distribution and differential branching fraction of the decay B +K + μ + μ are studied with a dataset corresponding to 1.0fb−1 of integrated luminosity, collected by the LHCb experiment. The angular distribution is measured in bins of dimuon invariant mass squared and found to be consistent with Standard Model expectations. Integrating the differential branching fraction over the full dimuon invariant mass range yields a total branching fraction of \( \mathcal{B} \) (B +K + μ + μ ) = (4.36 ± 0.15 ± 0.18) × 10−7. These measurements are the most precise to date of the B +K + μ + μ decay.

References

  1. [1]

    A. Ali, P. Ball, L. Handoko and G. Hiller, A comparative study of the decays B(K, K )ℓ+ in standard model and supersymmetric theories, Phys. Rev. D 61 (2000) 074024 [hep-ph/9910221] [INSPIRE].

    ADS  Google Scholar 

  2. [2]

    C. Bobeth, G. Hiller and G. Piranishvili, Angular distributions of \( \overline{B}\to K\overline{l}l \) decays,JHEP 12 (2007) 040 [arXiv:0709.4174] [INSPIRE].

    ADS  Article  Google Scholar 

  3. [3]

    LHCb collaboration, Differential branching fraction and angular analysis of the decay B 0K ∗0 μ + μ , Phys. Rev. Lett. 108 (2012) 181806 [arXiv:1112.3515] [INSPIRE].

    Article  Google Scholar 

  4. [4]

    LHCb collaboration, Differential branching fraction and angular analysis of the B 0K ∗0 μ + μ decay, LHCb-CONF-2012-008 (2012).

  5. [5]

    A.K. Alok, A. Dighe and S.U. Sankar, Large forward-backward asymmetry in B + μ from new physics tensor operators, Phys. Rev. D 78 (2008) 114025 [arXiv:0810.3779] [INSPIRE].

    ADS  Google Scholar 

  6. [6]

    A. Khodjamirian, T. Mannel, A. Pivovarov and Y.-M. Wang, Charm-loop effect in BK (∗)+ and BK γ,JHEP 09 (2010) 089[arXiv:1006.4945] [INSPIRE].

    ADS  Article  Google Scholar 

  7. [7]

    C. Bobeth, G. Hiller, D. van Dyk and C. Wacker, The decay BKl + l at low hadronic recoil and model-independent ΔB = 1 constraints, JHEP 01 (2012) 107 [arXiv:1111.2558] [INSPIRE].

    ADS  Article  Google Scholar 

  8. [8]

    LHCb collaboration, Strong constraints on the rare decays B sμ + μ and B 0μ + μ , Phys. Rev. Lett. 108 (2012) 231801 [arXiv:1203.4493] [INSPIRE].

    Article  Google Scholar 

  9. [9]

    CMS collaboration, Search for \( B_s^0\to {\mu^{+}}{\mu^{-}} \) and B 0μ + μ decays, JHEP 04 (2012) 033 [arXiv:1203.3976] [INSPIRE].

    ADS  Google Scholar 

  10. [10]

    F. Beaujean, C. Bobeth, D. van Dyk and C. Wacker, Bayesian fit of exclusive \( b\to s\overline{\ell}\ell \) decays: the standard model operator basis, JHEP 08 (2012) 030 [arXiv:1205.1838] [INSPIRE].

    ADS  Article  Google Scholar 

  11. [11]

    W. Altmannshofer and D.M. Straub, Cornering new physics in bs transitions, JHEP 08 (2012) 121 [arXiv:1206.0273] [INSPIRE].

    ADS  Article  Google Scholar 

  12. [12]

    LHCb collaboration, Measurement of the isospin asymmetry in BK (∗) μ + μ decays, JHEP 07 (2012) 133 [arXiv:1205.3422] [INSPIRE].

    Google Scholar 

  13. [13]

    LHCb collaboration, The LHCb detector at the LHC, 2008 JINST 3 S08005 [INSPIRE].

  14. [14]

    T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 physics and manual, JHEP 05 (2006) 026 [hep-ph/0603175] [INSPIRE].

    ADS  Article  Google Scholar 

  15. [15]

    I. Belyaev et al., Handling of the generation of primary events in Gauss, the LHCb simulation framework, IEEE Nucl. Sci. Symp. Conf. Rec. (2010) 1155.

  16. [16]

    D. Lange, The EvtGen particle decay simulation package, Nucl. Instrum. Meth. A 462 (2001) 152 [INSPIRE].

    ADS  Article  Google Scholar 

  17. [17]

    P. Golonka and Z. Was, PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays, Eur. Phys. J. C 45 (2006) 97 [hep-ph/0506026] [INSPIRE].

    ADS  Article  Google Scholar 

  18. [18]

    GEANT4 collaboration, J. Allison et al., GEANT4 developments and applications, IEEE Trans. Nucl. Sci. 53 (2006) 270.

    ADS  Article  Google Scholar 

  19. [19]

    GEANT4 collaboration, S. Agostinelli et al., GEANT4: a simulation toolkit, Nucl. Instrum. Meth. A 506 (2003) 250 [INSPIRE].

    ADS  Article  Google Scholar 

  20. [20]

    M. Clemencic et al., The LHCb simulation application, Gauss: design, evolution and experience, J. Phys Conf. Ser. 331 (2011) 032023.

    ADS  Article  Google Scholar 

  21. [21]

    V.V. Gligorov, A single track HLT1 trigger, LHCb-PUB-2011-003 (2011).

  22. [22]

    V.V. Gligorov, C. Thomas, and M. Williams, The HLT inclusive B triggers, LHCb-PUB-2011-016 (2011).

  23. [23]

    L. Breiman, J.H. Friedman, R.A. Olshen and C.J. Stone, Classification and regression trees, Wadsworth international group, Belmont, California U.S.A. (1984).

  24. [24]

    Y. Freund and R.E. Schapire, A decision-theoretic generalization of on-line learning and an application to boosting, J. Comp. Syst. Sci. 55 (1997) 119.

    MathSciNet  Article  MATH  Google Scholar 

  25. [25]

    LHCb collaboration, RICH pattern recognition for LHCb, Nucl. Instrum. Meth. A 433 (1999) 257 [INSPIRE].

    ADS  Google Scholar 

  26. [26]

    BABAR collaboration, B. Aubert et al., Evidence for direct CP-violation from Dalitz-plot analysis of B ±K ±ππ±, Phys. Rev. D 78 (2008) 012004 [arXiv:0803.4451] [INSPIRE].

    ADS  Google Scholar 

  27. [27]

    LHCb collaboration, First observation of the decay B + → π+ μ + μ , LHCb-PAPER-2012-020 (2012).

  28. [28]

    LHCb collaboration, First observation of B + → π+ μ + μ , LHCb-CONF-2012-006 (2012).

  29. [29]

    T. Skwarnicki, A study of the radiative cascade transitions between the \( {\varUpsilon^{\prime }} \) and \( \varUpsilon \) resonances, Ph.D. thesis, Institute of Nuclear Physics, Krakow, Poland (1986) [INSPIRE].

  30. [30]

    Particle Data Group collaboration, J. Beringer et al., Review of particle physics, Phys. Rev. D 86 (2012) 010001 [INSPIRE].

    ADS  Google Scholar 

  31. [31]

    C. Bobeth, G. Hiller and D. van Dyk, More benefits of semileptonic rare B decays at low recoil: CP-violation, JHEP 07 (2011) 067 [arXiv:1105.0376] [INSPIRE].

    ADS  Article  Google Scholar 

  32. [32]

    M. Beneke, T. Feldmann and D. Seidel, Systematic approach to exclusive BV+ , V γ decays, Nucl. Phys. B 612 (2001) 25 [hep-ph/0106067] [INSPIRE].

    ADS  Article  Google Scholar 

  33. [33]

    B. Grinstein and D. Pirjol, Exclusive rare BK + decays at low recoil: controlling the long-distance effects, Phys. Rev. D 70 (2004) 114005 [hep-ph/0404250] [INSPIRE].

    ADS  Google Scholar 

  34. [34]

    M. Beylich, G. Buchalla and T. Feldmann, Theory of BK (∗)+ decays at high q 2 : OPE and quark-hadron duality, Eur. Phys. J. C 71 (2011) 1635 [arXiv:1101.5118] [INSPIRE].

    ADS  Article  Google Scholar 

  35. [35]

    U. Egede, T. Hurth, J. Matias, M. Ramon and W. Reece, New observables in the decay mode \( {{\overline{B}}_d}\to {{\overline{K}}^{*0 }}{\ell^{+}}{\ell^{-}} \), JHEP 11 (2008) 032[arXiv:0807.2589] [INSPIRE].

    ADS  Article  Google Scholar 

  36. [36]

    A. Ali, E. Lunghi, C. Greub and G. Hiller, Improved model independent analysis of semileptonic and radiative rare B decays, Phys. Rev. D 66 (2002) 034002 [hep-ph/0112300] [INSPIRE].

    ADS  Google Scholar 

  37. [37]

    P. Ball and R. Zwicky, New results on B → π, K, η decay formfactors from light-cone sum rules, Phys. Rev. D 71 (2005) 014015 [hep-ph/0406232] [INSPIRE].

    ADS  Google Scholar 

  38. [38]

    G.J. Feldman and R.D. Cousins, A unified approach to the classical statistical analysis of small signals, Phys. Rev. D 57 (1998) 3873 [physics/9711021] [INSPIRE].

    ADS  Google Scholar 

  39. [39]

    BABAR collaboration, B. Aubert et al., Measurements of branching fractions, rate asymmetries and angular distributions in the rare decays BK+ and BK +, Phys. Rev. D 73 (2006) 092001 [hep-ex/0604007] [INSPIRE].

    ADS  Google Scholar 

  40. [40]

    BABAR collaboration, J. Lees et al., Measurement of branching fractions and rate asymmetries in the rare decays BK (∗) l + l , Phys. Rev. D 86 (2012) 032012 [arXiv:1204.3933] [INSPIRE].

    ADS  Google Scholar 

  41. [41]

    BELLE collaboration, J.-T. Wei et al., Measurement of the differential branching fraction and forward-backword asymmetry for BK (∗)+, Phys. Rev. Lett. 103 (2009) 171801 [arXiv:0904.0770] [INSPIRE].

    ADS  Article  Google Scholar 

  42. [42]

    CDF collaboration, T. Aaltonen et al., Measurements of the angular distributions in the decays BK (∗) μ + μ at CDF, Phys. Rev. Lett. 108 (2012) 081807 [arXiv:1108.0695] [INSPIRE].

    ADS  Article  Google Scholar 

Download references

Author information

Affiliations

Authors