Enhanced lepton flavor violation in the supersymmetric inverse seesaw model

Teixeira

Vicente

et al. 2014

113

107

Abstract:We address the impact of a modified W ℓν coupling on a wide range of observables, such as τ leptonic and mesonic decays, leptonic decays of pseudoscalar mesons, as well as semileptonic meson decays. In particular, we concentrate on deviations from lepton flavour universality, focusing on the ratios, and BR(B → τ ν). We further consider leptonic gauge boson decays, such as W → ℓν and Z → νν. For all the above observables, we provide the corresponding complete analytical expressions, derived for the case of massive neutrinos. Working in the framework of the Standard Model extended by additional sterile fermions, which mix with the active (left-handed) neutrinos, we numerically study the impact of active-sterile mixings on the above mentioned observables.

Section: Discussionmentioning

confidence: 99%

Section: Jhep02(2014)091mentioning

confidence: 99%

See 1 more Smart Citation

Sterile neutrinos in leptonic and semileptonic decays

Teixeira

Vicente

et al. 2014

113

107

“…In our analysis we compute the contribution of the sterile states to all these observables [24,29,[79][80][81][82][83][84], imposing compatibility with the bounds summarised in table 1, also considering the impact of the future experimental sensitivities.…”

Section: Jhep02(2016)083mentioning

confidence: 99%

Impact of sterile neutrinos on nuclear-assisted cLFV processes

Romeri

Teixeira

2016

We discuss charged lepton flavour violating processes occurring in the presence of muonic atoms, such as muon-electron conversion in nuclei CR(µ − e, N), the (Coulomb enhanced) decay of muonic atoms into a pair of electrons BR(µ − e − → e − e − , N), as well as Muonium conversion and decay, Mu − Mu and Mu → e + e − . Any experimental signal of these observables calls for scenarios of physics beyond the Standard Model. In this work, we consider minimal extensions of the Standard Model via the addition of sterile fermions, providing the corresponding complete analytical expressions for all the considered observables. We first consider an "ad hoc" extension with a single sterile fermion state, and investigate its impact on the above observables. Two well motivated mechanisms of neutrino mass generation are then considered: the Inverse Seesaw embedded into the Standard Model, and the νMSM. Our study reveals that, depending on their mass range and on the active-sterile mixing angles, sterile neutrinos can give significant contributions to the above mentioned observables, some of them even lying within present and future sensitivity of dedicated cLFV experiments. We complete the analysis by confronting our results to other (direct and indirect) searches for sterile fermions.

“…In the "standard" type I seesaw, the masses of the RH neutrinos are required to be very large for sizeable (natural) values of the Yukawa couplings, implying that any direct (collider observables) or indirect signals (low-energy or high-intensity observables) are likely impossible to be discovered. When the masses of the additional RH states are around or below the electroweak scale, these states can be directly produced in colliders and their contribution to low-energy observables can be important: this is why low-scale seesaw models [8][9][10][11][12][13][14] prove to be appealing. Among them, the Inverse Seesaw mechanism [8], the νMSM [11], the low-scale type-I seesaw [12,13] and the Linear Seesaw [15,16] are examples of models with a rich phenomenology.…”

Section: Introductionmentioning

confidence: 99%

Electron electric dipole moment in Inverse Seesaw models

Toma

2016

Abstract:We consider the contribution of sterile neutrinos to the electric dipole moment of charged leptons in the most minimal realisation of the Inverse Seesaw mechanism, in which the Standard Model is extended by two right-handed neutrinos and two sterile fermion states. Our study shows that the two pairs of (heavy) pseudo-Dirac mass eigenstates can give significant contributions to the electron electric dipole moment, lying close to future experimental sensitivity if their masses are above the electroweak scale. The major contribution comes from two-loop diagrams with pseudo-Dirac neutrino states running in the loops. In our analysis we further discuss the possibility of having a successful leptogenesis in this framework, compatible with a large electron electric dipole moment.