Search for B^+ to μ^+\, ν_μ and B^+ to μ^+\, N with inclusive tagging
read the original abstract
We report the result for a search for the leptonic decay of $B^+ \to \mu^+ \, \nu_{\mu}$ using the full Belle data set of 711 fb${}^{-1}$ of integrated luminosity at the $\Upsilon(4S)$ resonance. In the Standard Model leptonic $B$-meson decays are helicity and CKM suppressed. To maximize sensitivity an inclusive tagging approach is used to reconstruct the second $B$ meson produced in the collision. The directional information from this second $B$ meson is used to boost the observed $\mu$ into the signal $B$ meson rest-frame, in which the $\mu$ has a monochromatic momentum spectrum. Though its momentum is smeared by the experimental resolution, this technique improves the analysis sensitivity considerably. Analyzing the $\mu$ momentum spectrum in this frame we find $\mathcal{B}(B^+ \to \mu^+ \, \nu_\mu) = \left( 5.3 \pm 2.0 \pm 0.9 \right) \times 10^{-7}$ with a one-sided significance of 2.8 standard deviations over the background-only hypothesis. This translates to a frequentist upper limit of $\mathcal{B}(B^+ \to \mu^+ \, \nu_{\mu}) < 8.6 \times 10^{-7}$ at 90% CL. The experimental spectrum is then used to search for a massive sterile neutrino, $B^+ \to \mu^+ \, N$, but no evidence is observed for a sterile neutrino with a mass in a range of 0 - 1.5 GeV. The determined $B^+ \to \mu^+ \, \nu_{\mu}$ branching fraction limit is further used to constrain the mass and coupling space of the type II and type III two-Higgs-doublet models.
This paper has not been read by Pith yet.
Forward citations
Cited by 2 Pith papers
-
The $B^+ \to K^+ \nu \bar \nu$ decay as a search for the QCD axion
Model-independent reinterpretation of Belle II B+ → K+ νν̄ data using public kinematic mapping yields a factor-of-nine improvement on the limit for B+ → K+ a and constrains the axion's b-s flavor-changing coupling.
-
Impact of Hadronic Resonances on $B\to K^{(*)}\tau^+\tau^-$ decays
Including resonant contributions from LHCb muon data enhances standard model predictions for B to K(*) tau tau decays and makes short-distance new physics comparable to or larger than resonant effects over the full q2 range.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.