Neutrino Helioseismology

The observed deficit of $\rm ^8B$ solar neutrinos may call for an improved standard model of the sun or an expanded standard model of particle physics ({\it e.g.,} with neutrino masses and mixing). In the former case, contemporary fluid motions and thermal fluctuations in the sun's core may modify nuclear reaction rates and restore agreement. To test this notion, we propose a search for short--term variations of the solar neutrino flux.Comment: 4 pages, HUTP-92/A03

The Frobenius group T13 and the canonical see-saw mechanism applied to neutrino mixing

The compatibility of the Frobenius group T13 with the canonical see-saw mechanism of neutrino mixing is examined. The Standard Model is extended in a minimalist way, by introducing a family symmetry and three right-handed neutrinos. To fit experiments and place constraints on the possibilities, tribimaximal mixing is used as a guideline. The application of both a family symmetry group and the canonical see-saw mechanism naturally generates small neutrino masses. The various possibilities from combining these two models are listed. Enough constraints are produced to narrow down the parameters of the neutrino mass matrix to two. This is therefore a predictive model where neutrino mass eigenvalues and allowed regions for neutrinoless double beta decay are suggested.Comment: Accepted for publication in Physical Review D. 13 page

Quark-lepton symmetry and complementarity

We argue that the difference between the observed approximate quark-lepton complementarity and the theoretical prediction based on realistic quark-lepton symmetry within the seesaw mechanism may be adjusted by means of a triplet contribution in the seesaw formula.Comment: 7 pages, RevTex

Tri-N-ification

We consider a natural generalization of trinification to theories with 3N SU(3) gauge groups. These theories have a simple moose representation and a gauge boson spectrum that can be interpreted via the deconstruction of a 5D theory with unified symmetry broken on a boundary. Although the matter and Higgs sectors of the theory have no simple extra-dimensional analog, gauge unification retains features characteristic of the 5D theory. We determine possible assignments of the matter and Higgs fields to unified multiplets and present theories that are viable alternatives to minimal trinified GUTs.Comment: 21 pages LaTeX, 6 eps figure

Muonium-Antimuonium Oscillations in an extended Minimal Supersymmetric Standard Model with right-handed neutrinos

The electron and muon number violating muonium-antimuonium oscillation process in an extended Minimal Supersymmetric Standard Model is investigated. The Minimal Supersymmetric Standard Model is modified by the inclusion of three right-handed neutrino superfields. While the model allows the neutrino mass terms to mix among the different generations, the sneutrino and slepton mass terms have only intra-generation lepton number violation but not inter-generation lepton number mixing. So doing, the muonium-antimuonium conversion can then be used to constrain those model parameters which avoid further constraint from the $\mu\to e\gamma$ decay bounds. For a wide range of parameter values, the contributions to the muonium-antimuonium oscillation time scale are at least two orders of magnitude below the sensivity of current experiments. However, if the ratio of the two Higgs field VEVs, $\tan\beta$, is very small, there is a limited possibility that the contributions are large enough for the present experimental limit to provide an inequality relating $\tan\beta$ with the light neutrino mass scale $m_\nu$ which is generated by see-saw mechanism. The resultant lower bound on $\tan\beta$ as a function of $m_\nu$ is more stringent than the analogous bounds arising from the muon and electron anomalous magnetic moments as computed using this model.Comment: 29 pages, 7 figures, 3 tables, Late

The mass of the Higgs boson in the trinification subgroup of E6

The extension of the standard model to SU(3)_L x SU(3)_R x SU(3)_C is considered. Spontaneous symmetry breaking requires two Higgs field multiplets with a strong hierarchical structure of vacuum expectation values. These vacuum expectation values, some of them known from experiment, are used to construct invariant potentials in form of a sum of individual potentials relevant at the weak scale. As in a previous suggestion one may normalize the most important individual potentials such that their mass eigenvalues agree with their very large vacuum expectation values. In this case (for a wide class of parameters) the scalar field corresponding to the standard model Higgs turns out to have the precise mass value m_Higgs = v/sqrt(2) = 123 GeV at the weak scale. The physical mass (pole mass) is larger and found to be 125 +/- 1.4 GeV.Comment: 5 pages, version appearing in Phys. Rev.

The effect of supersymmetry breaking in the Mass Varying Neutrinos

We discuss the effect of the supersymmetry breaking on the Mass Varying Neutrinos(MaVaNs) scenario. Especially, the effect mediated by the gravitational interaction between the hidden sector and the dark energy sector is studied. A model including a chiral superfield in the dark sector and the right handed neutrino superfield is proposed. Evolutions of the neutrino mass and the equation of state parameter are presented in the model. It is remarked that only the mass of a sterile neutrino is variable in the case of the vanishing mixing between the left-handed and a sterile neutrino on cosmological time scale. The finite mixing makes the mass of the left-handed neutrino variable.Comment: 6 pages, 7 figures, RevTeX4, references added, discussions and figures revise

Observing Signals of the Bulk Matter RS Model through Rare Decays of SUSY Particles

The bulk matter Randall-Sundrum (RS) model is a setup where Standard Model (SM) matter and gauge fields reside in the bulk of 5D warped spacetime while the Higgs field is confined on the IR brane. The wavefunctions of the 1st and 2nd generation matter particles are localized towards the UV brane and those of the 3rd generation towards the IR brane, so that the hierarchical structure of the Yukawa couplings arises geometrically without hierarchy in fundamental parameters. This paper discusses an experimental test of this model in the case where the Kaluza-Klein scale is far above the collider scale, but the model is combined with 5D Minimal SUSY Standard Model (MSSM) and SUSY particles are in the reach of collider experiments. A general SUSY breaking mass spectrum consistent with the bulk matter RS model is considered: SUSY breaking sector locates on the IR brane and its effects are mediated to 5D MSSM through a hybrid of gravity mediation, gaugino mediation and gauge mediation. This paper argues that it is possible to observe the signals of the bulk matter RS model through rare decays of "almost SU(2) singlet mass eigenstates" that are induced by flavor-violating gravity mediation contributions to matter soft SUSY breaking terms

GeV Majorana Neutrinos in Top-quark Decay at the LHC

We explore the \Delta L=2 same-sign dilepton signal from top-quark decay via a Majorana neutrino at the LHC in the top anti-top pair production samples. The signature is same-sign dilepton plus multi-jets with no significant missing energy. The most optimistic region lies where the Majorana neutrino mass is between 15-65 GeV. For 300 fb^-1 integrated luminosity, it is possible to probe S_{ij}, the effective mixing parameter, to order of 10^-5.Comment: 15 pages, 8 figure