2012

Revisiting the $\Gamma(K \to e \nu)/\Gamma(K \to \mu \nu)$ ratio in supersymmetric unified models

Fonseca, R. M., Romao, J. C., Teixeira, A. M.

Understand

It has been pointed out that supersymmetric extensions of the Standard Model can induce significant changes to the theoretical prediction of the ratio $\Gamma(K\rightarrow e\nu)/\Gamma (K\rightarrow\mu\nu)\equiv R_{K}$, through lepton flavour violating couplings.

  • In this work we carry out a full computation of all one-loop corrections to the relevant $\nu\ell H^{+}$ vertex, and discuss the new contributions to $R_{K}$ arising in the context of different constrained (minimal supergravity inspired) models which succeed in accounting for neutrino data, further considering the possibility of accommodating a near future observation of a $\mu\to e\gamma$ transition.
  • We also re-evaluate the prospects for $R_{K}$ in the framework of unconstrained supersymmetric models.
  • In all cases, we address the question of whether it is possible to saturate the current experimental sensitivity on $R_{K}$ while in agreement with the recent limits on $B$-meson decay observables (in particular BR($B_{s}\to\mu^+\mu^-$) and R($B_{u}\to\tau\nu$)), as well as BR($\tau\to e \gamma$) and available collider constraints.

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