Analysis of $B\to K{M}_X$ and $B\to K^{\ast }{M}_X$ decays in scalar- and vector-mediator dark-matter scenarios

Abstract

The surprising excess of missing-energy events far beyond all standard-model expectations in the weak decays of the charged ground-state $B^{+}$ meson into some charged strange meson, rather recently observed by the Belle-II experiment, may (easily) be explained by the decay of the $B$ meson into the strange meson and a pair of dark-matter fermion and antifermion, mediated by an (intermediate) scalar or vector boson. Thorough inspections of both the total and the differential widths of these decays provide, among others, a simple means for the (straightforward) discrimination of such mediator boson's scalar or vector nature.

12 pages, 6 figures, contributed to "QFTHEP'270 - XXV International Workshop-School on High Energy Physics and Quantum Field Theory" (30 June - 5 July 2025, Moscow, Russia)

References in corpus (8)

• Evidence for $B^{+}\to K^{+}\nu \bar{\nu }$ decays
• Revisiting $B\to K^{(\ast )}\nu \bar{\nu }$ decays in the Standard Model and beyond
• Standard Model predictions for $B\to K{\ell }^{+}{\ell }^{-}$, $B\to K{\ell }_1^{-}{\ell }_2^{+}$ and $B\to K\nu \bar{\nu }$ using form factors from $N_f=2+1+1$ lattice QCD
• Understanding the first measurement of $\mathcal{B}(B\to K\nu \bar{\nu })$
• Decoding the $B\to K\nu \nu$ excess at Belle II: kinematics, operators, and masses
• $B\to K^{\ast }{M}_X$ vs $B\to K{M}_X$ as a probe of a scalar-mediator dark matter scenario
• Analysis of $q_{\mathrm{rec}}^2$-distribution for $B\to K{M}_X$ and $B\to K^{\ast }{M}_X$ decays in a scalar-mediator dark-matter scenario
• Probing vector- vs scalar-mediator dark-matter scenarios in $B\to (K,K^{\ast })M_X$ decays