Constraints on new physics from K→ πνν¯

Xiao Gang He, German Valencia, Keith Wong

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17 Citations (Scopus)


We study generic effects of new physics on the rare decay modes KL→ π0νν¯ and K+→ π+νν¯. We discuss several cases: left-handed neutrino couplings; right handed neutrino couplings; neutrino lepton flavour violating (LFV) interactions; and Δ I= 3 / 2 interactions. The first of these cases has been studied before as it covers many new physics extensions of the standard model; the second one requires the existence of a new light (sterile) right-handed neutrino and its contribution to both branching ratios is always additive to the SM. The case of neutrino LFV couplings introduces a CP conserving contribution to KL→ π0νν¯ which affects the rates in a similar manner as a right handed neutrino as neither one of these interferes with the standard model amplitudes. Finally, we consider new physics with Δ I= 3 / 2 interactions to go beyond the Grossman-Nir bound. We find that the rare kaon rates are only sensitive to new physics scales up to a few GeV for this scenario.

Original languageEnglish
Article number472
Number of pages9
JournalEuropean Physical Journal C
Issue number6
Publication statusPublished - 9 Jun 2018

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