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A New Parametrization of the Seesaw Mechanism and Applications in Supersymmetric Models

John Ellis·Junji Hisano·Martti Raidal·Yasuhiro Shimizu
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Abstract

We present a new parametrization of the minimal seesaw model, expressing the heavy-singlet neutrino Dirac Yukawa couplings $(Y_ν)_{ij}$ and Majorana masses $M_{N_i}$ in terms of effective light-neutrino observables and an auxiliary Hermitian matrix $H.$ In the minimal supersymmetric version of the seesaw model, the latter can be related directly to other low-energy observables, including processes that violate charged lepton flavour and CP. This parametrization enables one to respect the stringent constraints on muon-number violation while studying the possible ranges for other observables by scanning over the allowed parameter space of the model. Conversely, if any of the lepton-flavour-violating process is observed, this measurement can be used directly to constrain $(Y_ν)_{ij}$ and $M_{N_i}.$ As applications, we study flavour-violating $τ$ decays and the electric dipole moments of leptons in the minimal supersymmetric seesaw model.

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John Ellis, Junji Hisano, Martti Raidal, Yasuhiro Shimizu. 2002-06-19. A New Parametrization of the Seesaw Mechanism and Applications in Supersymmetric Models. https://doi.org/10.1103/physrevd.66.115013

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