Year: 2013
Type: article
Abstract: Recent evidence from observation of the flavor-changing neutral current decay ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ by the LHCb Collaboration $\mathcal{B}({B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})=({3.2}_{\ensuremath{-}1.2}^{+1.5})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$ is consistent with the latest standard model prediction ${\mathcal{B}}_{\mathcal{S}\mathcal{M}}({B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})=(3.23\ifmmode\pm\else\textpm\fi{}0.27)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$. While new physics can still affect this decay amplitude, its contribution is certainly not the dominant one. We analyze branching ratios of the decays ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}X$, with $X=\ensuremath{\gamma}$ or $\ensuremath{\nu}\overline{\ensuremath{\nu}}$, which can mimic ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ on portions of the parameter space where $X$ is soft. Since detection efficiency of $\ensuremath{\gamma}$ or $\ensuremath{\nu}\overline{\ensuremath{\nu}}$ in modern charm-physics experiments is quite low in that region, those processes could be misidentified as ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. We perform a model-independent standard model calculation of those processes incorporating heavy quark and chiral symmetries of QCD concentrating on the soft-$X$ region. We show that misidentification of the considered processes can only boost the ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ rate by less than a percent.
Authors: Y. G. Aditya, K. J. Healey, Alexey A. Petrov
Institutions: Wayne State University, University of Michigan
Language: Latvian
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: U.S. Department of Energy
OpenAlex ID: W1785939634