Scalar dark matter explanation of the excess in the Belle II B+ → K++ invisible measurement-Reference-Cited by-同舟云学术

Scalar dark matter explanation of the excess in the Belle II B+ → K++ invisible measurement

Published:2024-07-18 Issue:7 Volume:2024 Page:
ISSN:1029-8479
Container-title:Journal of High Energy Physics
language:en
Short-container-title:J. High Energ. Phys.

Author:

He Xiao-Gang,Ma Xiao-Dong^ORCID,Schmidt Michael A.^ORCID,Valencia German^ORCID,Volkas Raymond R.^ORCID

Abstract

Abstract Recently Belle II reported the first measurement of B+ → K+ + invisible(inv), which is 2.7σ above the standard model (SM) prediction. If confirmed, this calls for new physics beyond SM. In the SM, the invisible particles are neutrino-anti-neutrino pairs. There are more possibilities when going beyond the SM. In this work, we focus on decays to dark matter (DM) and show that the B → K + inv excess from Belle II and DM relic density can be simultaneously explained in a simple extension of the SM. The model introduces a real scalar singlet ϕ acting as a DM candidate, and two heavy vector-like quarks Q, D with the same quantum numbers as the SM left-handed quark doublet and right-handed down-type quark singlet, respectively. All these new particles are odd under a ℤ2 symmetry while the SM particles are even. The model can successfully explain the Belle II anomaly and DM relic density for TeV-scale heavy quarks with hierarchical Yukawa couplings involving b and s quarks. At the same time, it can easily satisfy other flavour physics constraints. Direct detection searches utilizing the Migdal effect constrain some of the parameter space.

Publisher

Springer Science and Business Media LLC

Link

https://link.springer.com/content/pdf/10.1007/JHEP07(2024)168.pdf

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