Invisible $K_L$ decays in the SM extensions

Abstract

In the Standard Model (SM) the branching ratio for the decay $K_L\to \nu \bar{\nu }$ into two neutrinos is helicity suppressed and predicted to be very small $\le O(10^{-17})$. We consider two natural extensions of the SM, such as two-Higgs-doublet model (2HDM) and the $\nu$MSM with additional singlet scalar, those main features is that they can lead to an enhanced $Br(K_L\to invisible)$. In the 2HDM the smallness of the neutrino mass is explained due to the smallness of the second Higgs doublet vacuum expectation value. Moreover, the $\nu$MSM extension with additional singlet field can explain the $(g-2)$ muon anomaly. The considered models demonstrate that the $K_L\to invisible$ decay is a clean probe of new physics scales well above 100 TeV, that is complementary to rare $K\to \pi +invisible$ decay, and provide a strong motivation for its sensitive search in a near future low-energy experiment.

11 pages, no figures

References in corpus (5)

• Big-Bang Nucleosynthesis
• Muon g-2 and searches for a new leptophobic sub-GeV dark boson in a missing-energy experiment at CERN
• Search for invisible decays of ${\pi }^0,\eta ,{\eta }^{\prime },K_S$ and $K_L$: A probe of new physics and tests using the Bell-Steinberger relation
• Invisible $K_L$ decays as a probe of new physics
• Report of the Quark Flavor Physics Working Group

Cited by in corpus (3)

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