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arXiv · hep-ph/9707517

Gauge-Independent Analysis of K_L --> e μin Left-Right Models

Zoltan Gagyi-Palffy·Apostolos Pilaftsis·Karl Schilcher
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Abstract

The lepton-flavour-violating decay K_L --> e μis studied in detail within the context of SU(2)_R x SU(2)_L x U(1)_(B-L) models, which include heavy Majorana neutrinos. Particular attention is paid to the gauge independence of this decay process to one loop. In analogy with earlier studies on the K^0\bar{K}^0 mixing, it is explicitly shown how restoration of gauge invariance occurs in the decay amplitude containing the box diagrams, when the relevant Higgs-dependent self-energy and vertex graphs are taken into account in the on-shell skeleton renormalization scheme. Based on the analytic expressions so derived, we find that the branching ratio B(K_L --> e μ) can be considerably enhanced due to the presence of left- and right-handed currents in the loop, and can reach values close to or even larger than the present experimental limit 3.3 x 10^{-11} in the manifest left-right symmetric model. Constraints on the parameter space of typical left-right models are derived from the possible decay K_L --> e μand a global analysis of other low-energy data.

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Zoltan Gagyi-Palffy, Apostolos Pilaftsis, Karl Schilcher. 1997-07-30. Gauge-Independent Analysis of K_L --> e μin Left-Right Models. https://doi.org/10.1016/s0550-3213(97)00764-5

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