Ernesto Arganda

Imprints of massive inverse seesaw model neutrinos in lepton flavor violating Higgs boson decays

In this paper we consider a Higgs boson with mass and other properties compatible with those of the recently discovered Higgs particle at the LHC, and explore the possibility of new Higgs leptonic decays, beyond the standard model, with the singular feature of being lepton flavor violating (LFV). We study these LFV Higgs decays, H → l k l ¯ m , within the context of the inverse seesaw model (ISS) and consider the most generic case where three additional pairs of massive right-handed singlet neutrinos are added to the standard model particle content. We require in addition that the input parameters of this ISS model are compatible with the present neutrino data and other constraints, like perturbativity of the neutrino Yukawa couplings. We present a full one-loop computation of the BR ( H → l k l ¯ m ) rates for the three possible channels, l k l ¯ m = μ τ ¯ , e τ ¯ , e μ ¯ , and analyze in full detail the predictions as functions of the various relevant ISS parameters. We study in parallel the correlated one-loop predictions for the radiative decays, l m → l k γ , within this same ISS context, and require full compatibility of our predictions with the present experimental bounds for the three radiative decays, μ → e γ , τ → μ γ , and τ → e γ . After exploring the ISS parameter space we conclude on the maximum allowed LFV Higgs decay rates within the ISS.

Impact of θ13 on lepton flavour violating processes within SUSY seesaw

We study the impact of neutrino masses and mixings on LFV processes within the context of the supersymmetric seesaw scenario, where the CMSSM is extended by three right-handed (s)neutrinos. A hierarchical spectrum is considered for both heavy and light neutrinos. We systematically analyse the interesting relation between the leptonic mixing angle �13 and LFV muon and tau decays, namely lj → li and lj → 3li, and discuss the interplay with the other relevant parameters. We require compatibility with low energy neutrino data, bounds on both LFV decays and charged lepton electric dipole moments, and impose a successful baryogenesis via thermal leptogenesis. Particular emphasis is given to the implications that a future �13 measurement can have on our knowledge of the heavy neutrino sector.

mu-e conversion in nuclei within the CMSSM seesaw: Universality versus non-universality

In this paper we study ??e conversion in nuclei within the context of the Constrained Minimal Supersymmetric Standard Model, enlarged by three right handed neutrinos and their supersymmetric partners, and where the neutrino masses are generated via a seesaw mechanism. Two different scenarios with either universal or non-universal soft supersymmetry breaking Higgs masses at the gauge coupling unification scale are considered. In the first part we present a complete one-loop computation of the conversion rate for this process that includes the photon-, Z-boson, and Higgs-boson penguins, as well as box diagrams, and compare their size in the two considered scenarios. Then, in these two scenarios we analyse the relevance of the various parameters on the conversion rates, particularly emphasising the role played by the heavy neutrino masses, tan ?, and especially ?13. In the case of hierachical heavy neutrinos, an extremely high sensitivity of the rates to ?13 is indeed found. The last part of this work is devoted to the study of the interesting loss of correlation between the ??e conversion and ??e? rates that occurs in the non-universal scenario. In the case of large tan ? and light H0 Higgs boson, an enhanced ratio of the ??e to ??e? rates, with respect to the universal case is found, and this could be tested with the future experimental sensitivities.

Enhancement of the lepton flavor violating Higgs boson decay rates from SUSY loops in the inverse seesaw model.

This work is supported by the European Union Grant No. FP7 ITN INVISIBLES (Marie Curie Actions, Grant No. PITN-GA-2011-289442), by the CICYT through Grant No. FPA2012-31880, by the Spanish Consolider-Ingenio 2010 Programme CPAN (Grant No. CSD2007-00042), and by the Spanish MINECO’s “Centro de Excelencia Severo Ochoa” Programme under Grant No. SEV-2012-0249. E. A. is financially supported by the Spanish DGIIDDGA Grant No. 2013-E24/2 and the Spanish MICINN Grants No. FPA2012-35453 and No. CPAN-CSD2007- 00042. X. M. is supported through the FPU Grant No. AP- 2012-6708. C. W. received financial support as an International Research Fellow of the Japan Society for the Promotion of Science and from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant NuMass Agreement No. 617143 during different stages of this work.

Effective lepton flavor violating Hℓiℓj vertex from right-handed neutrinos within the mass insertion approximation

In this work we present a new computation of the lepton flavor violating Higgs boson decays that are generated radiatively to one-loop from heavy right-handed neutrinos. We work within the context of the inverse seesaw model with three

LFV in tau and muon decays within SUSY seesaw

\nu_R

Higgs effective

and three extra singlets

\boldsymbol{H\ell_i\ell_j}

X

vertex from heavy

, but the results could be generalized to other low scale seesaw models. The novelty of our computation is that it uses a completely different method by means of the mass insertion approximation which works with the electroweak interaction states instead of the usual 9 physical neutrino mass eigenstates of the inverse seesaw model. This method also allows us to write the analytical results explicitly in terms of the most relevant model parameters, that are the neutrino Yukawa coupling matrix

\boldsymbol{\nu_R}

Y_\nu