Anatomy of kaon decays and prospects for lepton flavour universality violation

Abstract

The kaon sector is characterised by several processes which are under active investigation across different experiments. In this work, we present the global picture that emerges from a study of the different decay modes. We begin by revisiting the theoretical component of these decays and providing up-to-date predictions of the Standard Model as well as the corresponding uncertainties. Several new features emerge, in particular for $K_{S,L}\to \mu \bar{\mu }$, and are presented in considerable detail. This offers an ideal platform for extracting the parameter space supported by the existing data. Motivated by possible lepton flavour universality violation in $B$ decays, we investigate such Beyond the Standard Model effects also in rare kaon decays. Without loss of generality, our primary analyses correspond to the paradigm where the Wilson coefficients for operators involving tau leptons are chosen to be equal to that involving the muon, i.e. $\delta C^{\tau }=\delta C^{\mu }$. We conclude by presenting the possible picture that can be achieved towards the end of the run of data accumulation in the planned experiments. This includes assumptions on possible sensitivity goals that the experiments can aim to achieve, in order to extract the kind of physics highlighted in this paper.

32 pages, 14 figures. v2: references added

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Cited by in corpus (13)

• Probing flavor constrained SMEFT operators through $tc$ production at the Muon collider
• Search for the $K_L\to {\pi }^0\nu \bar{\nu }$ Decay at the J-PARC KOTO Experiment
• A measurement of the $K^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$ decay
• Beyond the Standard Model prospects for kaon physics at future experiments
• Observation of the $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ decay and measurement of its branching ratio
• Improved Standard-Model prediction for $K_L\to {\ell }^{+}{\ell }^{-}$
• A comprehensive study of vector leptoquark with $U(1{)}_{B_3-L_2}$ on the $B$-meson and Muon g-2 anomalies
• Workshop summary -- Kaons@CERN 2023
• ${\Sigma }^{+}\to p{\ell }^{+}{\ell }^{-}$ decays within the standard model and beyond
• Gauge $SU(2{)}_f$ flavour transfers
• A framework for missing-energy searches with anomalous light vectors
• $K\to {\mu }^{+}{\mu }^{-}$ as a third kaon golden mode
• Dark Matter emission at Belle II and NA62 in Minimal Flavor Violation framework