5 research outputs found
Supersymmetry Phenomenology in the Context of Neutrino Physics and the Large Hadron Collider LHC
Experimentally, it is well established that the Standard Model of particle physics requires an extension to accommodate the neutrino oscillation data, which indicates that at least two neutrinos are massive and that two of the neutrino mixing angles are large. Massive neutrinos are naturally present in a supersymmetric extension of the Standard Model which includes lepton-number violating terms (the B3 MSSM). Furthermore, supersymmetry stabilizes the hierarchy between the electroweak scale and the scale of unified theories or the Planck scale. In this thesis, we study in detail how neutrino masses are generated in the B3 MSSM. We present a mechanism how the experimental neutrino oscillation data can be realized in this framework. Then we discuss how recently published data from the Large Hadron Collider (LHC) can be used to constrain the parameter space of this model. Furthermore, we present work on supersymmetric models where R-parity is conserved, considering scenarios with light stops in the light of collider physics and scenarios with near-massless neutralinos in connection with cosmological restrictions
What is the discrete gauge symmetry of the R-parity violating MSSM?
The lack of experimental evidence for supersymmetry motivates R-parity
violating realizations of the MSSM. Dropping R-parity, alternative symmetries
have to be imposed in order to stabilize the proton. We determine the possible
discrete R and non-R symmetries, which allow for renormalizable R-parity
violating terms in the superpotential and which, at the effective level, are
consistent with the constraints from nucleon decay. Assuming a gauge origin, we
require the symmetry to be discrete gauge anomaly-free, allowing also for
cancellation via the Green Schwarz mechanism. Furthermore, we demand lepton
number violating neutrino mass terms either at the renormalizable or
non-renormalizable level. In order to solve the mu problem, the discrete Z_N or
Z_N^R symmetries have to forbid any bilinear superpotential operator at tree
level. In the case of renormalizable baryon number violation the smallest
possible symmetry satisfying all conditions is a unique hexality Z_6^R. In the
case of renormalizable lepton number violation the smallest symmetries are two
hexalities, one Z_6 and one Z_6^R.Comment: 25 pages, version to appear in PR
Neutrino masses and mixings in the baryon triality constrained minimal supersymmetric standard model
We discuss how the experimental neutrino oscillation data can be realized in
the framework of the baryon triality () constrained supersymmetric
Standard Model (cSSM). We show how to obtain phenomenologically viable
solutions, which are compatible with the recent WMAP observations. We present
results for the hierarchical, inverted and degenerate cases which illustrate
the possible size and structure of the lepton number violating couplings. We
work with a new, as yet unpublished version of SOFTSUSY, where we implemented
full one--loop neutrino masses. Finally, we shortly discuss some
phenomenological implications at the LHC.Comment: 25 pages, 17 figure
Gravitino cosmology with a very light neutralino
It has been shown that very light or even massless neutralinos are consistent with all current experiments, given nonuniversal gaugino masses. Furthermore, a very light neutralino is consistent with astrophysical bounds from supernovae and cosmological bounds on dark matter. Here we study the cosmological constraints on this scenario from big bang nucleosynthesis (taking gravitinos into account) and find that a very light neutralino is even favored by current observations.Herbi K. Dreiner, Marja Hanussek, Jong Soo Kim, and Subir Sarka