Angular analysis of charged and neutral B + μ decays

Abstract

The angular distributions of the rare decays B +K + μ + μ and \( {B^0}\to K_{\mathrm{S}}^0{\mu^{+}}{\mu^{-}} \) are studied with data corresponding to 3fb−1 of integrated luminosity, collected in proton-proton collisions at 7 and 8 TeV centre-of-mass energies with the LHCb detector. The angular distribution is described by two parameters, F H and the forward-backward asymmetry of the dimuon system A FB, which are determined in bins of the dimuon mass squared. The parameter F H is a measure of the contribution from (pseudo)scalar and tensor amplitudes to the decay width. The measurements of A FB and F H reported here are the most precise to date and are compatible with predictions from the Standard Model.

A preprint version of the article is available at ArXiv.

References

  1. [1]

    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 

  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]

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

    ADS  Google Scholar 

  4. [4]

    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].

    Article  Google Scholar 

  5. [5]

    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 

  6. [6]

    LHCb collaboration, Differential branching fraction and angular analysis of the B +K + μ + μ decay, JHEP 02 (2013) 105 [arXiv:1209.4284] [INSPIRE].

    Google Scholar 

  7. [7]

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

    ADS  Google Scholar 

  8. [8]

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

  9. [9]

    R. Arink et al., Performance of the LHCb Outer Tracker, 2014 JINST 9 P01002 [arXiv:1311.3893] [INSPIRE].

  10. [10]

    LHCb RICH collaboration, Performance of the LHCb RICH detector at the LHC, Eur. Phys. J. C 73 (2013) 2431 [arXiv:1211.6759] [INSPIRE].

    Google Scholar 

  11. [11]

    A.A. Alves Jr. et al., Performance of the LHCb muon system, 2013 JINST 8 P02022 [arXiv:1211.1346] [INSPIRE].

  12. [12]

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

    ADS  Article  MATH  Google Scholar 

  13. [13]

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

    Google Scholar 

  14. [14]

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

    ADS  Article  Google Scholar 

  15. [15]

    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 

  16. [16]

    GEANT4 collaboration, J. Allison et al., Geant4 developments and applications, IEEE Trans. Nucl. Sci. 53 (2006) 270.

    Article  Google Scholar 

  17. [17]

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

    ADS  Google Scholar 

  18. [18]

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

    Article  Google Scholar 

  19. [19]

    R. Aaij et al., The LHCb Trigger and its Performance in 2011, 2013 JINST 8 P04022 [arXiv:1211.3055] [INSPIRE].

  20. [20]

    LHCb collaboration, Observation of a resonance in B +K + μ + μ decays at low recoil, Phys. Rev. Lett. 111 (2013) 112003 [arXiv:1307.7595] [INSPIRE].

    Article  Google Scholar 

  21. [21]

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

    MATH  Google Scholar 

  22. [22]

    R.E. Schapire and Y. Freund, 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 

  23. [23]

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

    ADS  Google Scholar 

  24. [24]

    B. Sen, M. Walker and M. Woodroofe, On the unified method with nuisance parameters, Statistica Sinica 19 (2009) 301.

    MathSciNet  MATH  Google Scholar 

  25. [25]

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

    ADS  Article  MATH  Google Scholar 

  26. [26]

    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 

  27. [27]

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

    ADS  Article  MATH  Google Scholar 

  28. [28]

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

    ADS  Article  MATH  Google Scholar 

  29. [29]

    LHCb collaboration, Measurement of the \( \overline{B}_s^0\to {\mu^{+}}{\mu^{-}} \) branching fraction and search for B 0μ + μ decays at the LHCb experiment, Phys. Rev. Lett. 111 (2013) 101805 [arXiv:1307.5024] [INSPIRE].

    Article  Google Scholar 

  30. [30]

    CMS collaboration, Measurement of the \( \overline{B}_s^0\to {\mu^{+}}{\mu^{-}} \) branching fraction and search for B 0μ + μ with the CMS Experiment, Phys. Rev. Lett. 111 (2013) 101804 [arXiv:1307.5025] [INSPIRE].

    ADS  Article  Google Scholar 

Download references

Open Access

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.

Author information

Affiliations

Authors