119187487
Neutrino mass from a d=7 effective operator in a SUSY-GUT framework
A bstractModels, where neutrino mass originates from physics at the TeV scale and which are potentially testable at the LHC, need additional suppression mechanisms to describe the smallness of neutrino masses. We consider models in which neutrino mass is generated from the d = 7 operator LLHuHuHdHu in the context of SUSY-GUTs containing an SU(5) subgroup, where the d = 5 Weinberg operator can be forbidden by a discrete symmetry. That is, we identify the embeddings in GUT multiplets and their consequences for phenomenology and renormalization group evolution. We use a specific example to exemplify the challenges. In this case, additional heavy d-quarks are predicted, which are constrained by cosmology, in particular, by big bang nucleosynthesis and direct searches for heavy nuclei. We show that in the NMSSM extension of the model, the discrete symmetry needs to be broken, which can be the origin of deviations from tri-bimaximal mixings. Finally we demonstrate that our example is the only tree level decomposition which is consistent with perturbativity up to the GUT scale and neutrino mass generation by a leading d = 7 contribution.
53529353
Higher dimensional effective operators for direct dark matter detection
A bstractWe discuss higher dimensional effective operators describing interactions between fermionic dark matter and Standard Model particles. They are typically suppressed compared to the leading order effective operators, which can explain why no conclusive direct dark matter detection has been made so far. The ultraviolet completions of the effective operators, which we systematically study, require new particles. These particles can potentially have masses at the TeV scale and can therefore be phenomenologically interesting for LHC physics. We demonstrate that the lowest order options require Higgsportal interactions generated by dimension six operators. We list all possible tree-level completions with extra fermions and scalars, and we discuss the LHC phenomenology of a specific example with extra heavy fermion doublets.
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.
118011302
Big bang nucleosynthesis : the morning after