119117884
Proceedings of the 2nd Workshop on Flavor Symmetries and Consequences in Accelerators and Cosmology (FLASY12)
Although existing theoretical models generally prefer extremely heavy right-handed neutrinos to generate light neutrino masses via the seesaw mechanism, there are several observed phenomena that point to the existence of both keVand eV-scale sterile neutrinos. We present two A4 flavor symmetry models that can accommodate light sterile neutrinos and remain compatible with neutrino data. Higher order seesaw terms and higher-dimensional operators are studied, and the phenomenological implications of light sterile neutrinos on neutrinoless double beta decay are discussed. 1.
120538467
Neutrino mass from higher than d=5 effective operators with discrete symmetries
In beyond Standard Model physics scenarios one often has to extend the Higgs sector and introduce additional (discrete) symmetries. In such models it is possible that the Weinberg operator is forbidden and the leading contribution to neutrino mass is generated by operators with mass dimension d > 5. These higher-dimensional operators are stronger suppressed and therefore the new physics scale can be as low as the TeV scale. With this approach it is possible to test neutrino mass models at colliders, such as the LHC. We will demonstrate how these operators can be systematically studied and present an exemplary implementation of such a model and its phenomenological consequences. We also show how it can be embedded into an SU(5) GUT framework. Finally we present a specific realization of this model where we can have tri-bimaximal mixing with large deviations due to a softly broken symmetry.
118587432
SO(10) inspired gauge-mediated supersymmetry breaking
We consider a supersymmetric model motivated by a SO(10) grand unified theory: the gauge sector near the supersymmetry scale consists of SU(3)_c x SU(2)_L x U(1)_R x U(1)_{B-L}. We embed this model in minimal gauge mediation and incorporate neutrino data via an inverse seesaw mechanism. Also in this restricted model, the additional D terms can rise the light Higgs mass in a sizable way. Therefore, it is much easier to obtain m_h \simeq 125 GeV without the need to push the supersymmetry spectrum to extremely large values as it happens in models with minimal supersymmetric standard model particle content only. We show that this model predicts a diphoton rate of the Higgs equal to or smaller than the standard model expectation. We discuss briefly the collider phenomenology with a particular focus on the next to lightest supersymmetric particle in which this model offers the sneutrino as an additional possiblity. Moreover, we point out that, also in this model variant, supersymmetry can be discovered in Z' decays even in scenarios in which the strongly interacting particles are too heavy to be produced at a sizable rate at the LHC with 14 TeV. In addition, we show that lepton flavor violating observables constrain the size of the neutrino Yukawa couplings for which, in particular, muon decays and \mu-e conversion in heavy atoms are of particular importance. Once these constraints are fulfilled the rates for \tau decays are predicted to be below the reach of near-future experiments.