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arXiv · 2509.23210

Scrutinizing dark-matter scenarios with $B\to(K,K^*)\bar\nu\nu$ decays

Alexander Berezhnoy·Wolfgang Lucha·Dmitri Melikhov
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Abstract

Conceivable explanations of Belle-II measurements of a (surprising) excess of missing-energy decays of the $B$ meson to the $K$ meson not covered by standard-model neutrino-antineutrino pairs might be offered by additional contributions of dark-matter fermion-antifermion pairs. Assuming the excessive missing-energy events to be mediated by a (generic) scalar or vector boson, a simultaneous inspection of both of the missing-energy $B$ decays into a pseudoscalar $K$ meson or a vector $K^*$ meson allows to gain information on the nature of bosons relating standard-model and dark-matter sectors, irrespective of any (unknown) dark-sector details. Upon availability of indispensable experimental data, most prominent among such insights might be the identification of the mediator spin from the differential $B$-meson decay widths.

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Alexander Berezhnoy, Wolfgang Lucha, Dmitri Melikhov. 2025-09-27. Scrutinizing dark-matter scenarios with $B\to(K,K^*)\bar\nu\nu$ decays. https://doi.org/10.3390/universe11120385

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