Some implications of lepton flavor violating processes in a supersymmetric Type II seesaw model at TeV scale

We have conceived a supersymmetric Type II seesaw model at TeV scale, which has some additional particles consisting of scalar and fermionic triplet Higgs states, whose masses being around few hundred GeV. In this particular model, we have studied constraints on the masses of triplet states arising from the lepton flavor violating (LFV) processes, such as $\mu\to 3e$ and $\mu\to e\gamma$. We have analyzed the implications of these constraints on other observable quantities such as the muon anomalous magnetic moment and the decay patterns of scalar triplet Higgses. Scalar triplet Higgs states can decay into leptons and into supersymmetric fields. We have found that the constraints from LFV can effect these various decay modes.Comment: 32 pages, 13 figures, 3 tables, a new section on detection prospects of the model and references are added, sharpened the content of the paper but conclusions are unchanged; accepted by Eur. Phys. J.

Muon (g-2) from the bulk neutrino field in a warped extra dimensional model

In the Randall-Sundrum model, a bulk neutrino field in the 5-dimensional space-time can give rise to tiny Dirac masses to neutrinos. In such a scenario, we have computed the contribution of the bulk neutrino field to the anomalous magnetic moment $(g-2)_\mu$ of muon. We have computed this contribution in the 't Hooft-Feynman gauge and have found that the contribution has the right sign to fit the current discrepancy between the experiment and the standard model value of $(g-2)_\mu$. We have also studied possible constraints on the model parameters by including contributions to $(g-2)_\mu$ from other sources such as bulk gravitons.Comment: 18 pages, 3 figures, 2 tables, minor changes, this version has been published in Physical Review

Implications of Higgs to diphoton decay rate in the bilinear R-parity violating supersymmetric model

The Large Hadron Collider has recently discovered a Higgs-like particle having a mass around 125 GeV and also indicated that there is an enhancement in the Higgs to diphoton decay rate as compared to that in the standard model. We have studied implications of these discoveries in the bilinear R-parity violating supersymmetric model, whose main motivation is to explain the non-zero masses for neutrinos. The R-parity violating parameters in this model are $\epsilon$ and $b_\epsilon$, and these parameters determine the scale of neutrino masses. If the enhancement in the Higgs to diphoton decay rate is true, then we have found \epsilon\gapprox 0.01 GeV and $b_\epsilon\sim$ 1 GeV$^2$ in order to be compatible with the neutrino oscillation data. Also, in the above mentioned analysis, we can determine the soft masses of sleptons ($m_L$) and CP-odd Higgs boson mass ($m_A$). We have estimated that m_L\gapprox 300 GeV and m_A\gapprox 700 GeV. We have also commented on the allowed values of $\epsilon$ and $b_\epsilon$, in case there is no enhancement in the Higgs to diphoton decay rate. Finally, we present a model to explain the smallness of $\epsilon$ and $b_\epsilon$.Comment: 23 pages, 10 eps figures, minor changes, new references added, accepted by Physical Review

Bulk Higgs and Gauge fields in a multiply warped braneworld model

We readdress the problems associated with bulk Higgs and the gauge fields in a 5-dimensional Randall-Sundrum model by extending the model to six dimensions with double warping along the two extra spatial dimensions. In this 6-dimensional model we have a freedom of two moduli scales as against one modulus in the 5-dimensional model. With a little hierarchy between these moduli we can obtain the right magnitude for $W$ and $Z$ boson masses from the Kaluza-Klein modes of massive bulk gauge fields where the spontaneous symmetry breaking is triggered by bulk Higgs . We also have determined the gauge couplings of the standard model fermions with Kaluza-Klein modes of the gauge fields. Unlike the case of 5-dimensional model with a massless bulk gauge field, here we have shown that the gauge couplings and the masses of the Kaluza-Klein gauge fields satisfy the precision electroweak constraints and also obey the Tevatron bounds.Comment: 15 Pages, Late

Addressing \mu-b_\mu and proton lifetime problems and active neutrino masses in a U(1)^\prime-extended supergravity model

We present a locally supersymmetric extension of the minimal supersymmetric Standard Model (MSSM) based on the gauge group $SU(3)_C\times SU(2)_L\times U(1)_Y\times U(1)^\prime$ where, except for the supersymmetry breaking scale which is fixed to be $\sim 10^{11}$ GeV, we require that all non-Standard-Model parameters allowed by the {\it local} spacetime and gauge symmetries assume their natural values. The $U(1)^\prime$ symmetry, which is spontaneously broken at the intermediate scale, serves to ({\it i}) explain the weak scale magnitudes of $\mu$ and $b_\mu$ terms, ({\it ii}) ensure that dimension-3 and dimension-4 baryon-number-violating superpotential operators are forbidden, solving the proton-lifetime problem, ({\it iii}) predict {\it bilinear lepton number violation} in the superpotential at just the right level to accommodate the observed mass and mixing pattern of active neutrinos (leading to a novel connection between the SUSY breaking scale and neutrino masses), while corresponding trilinear operators are strongly supppressed. The phenomenology is like that of the MSSM with bilinear R-parity violation, were the would-be lightest supersymmetric particle decays leptonically with a lifetime of $\sim 10^{-12}-10^{-8}$ s. Theoretical consistency of our model requires the existence of multi-TeV, stable, colour-triplet, weak-isosinglet scalars or fermions, with either conventional or exotic electric charge which should be readily detectable if they are within the kinematic reach of a hadron collider. Null results of searches for heavy exotic isotopes implies that the re-heating temperature of our Universe must have been below their mass scale which, in turn, suggests that sphalerons play a key role for baryogensis. Finally, the dark matter cannot be the weakly interacting neutralino.Comment: 33 pages, 2 figures, Discussion on proton decay and radiative neutrino masses augmented, and references adde

Neutrino masses along with fermion mass hierarchy

Recently a new mechanism has been proposed to cure the problem of fermion mass hierarchy in the Standard Model (SM) model. In this scenario, all SM charged fermions other than top quark arise from higher dimensional operators involving the SM Higgs field. This model also predicted some interesting phenomenology of the Higgs boson. We generalize this model to accommodate neutrino masses (Dirac & Majorana) and also obtain the mixing pattern in the leptonic sector. To generate neutrino masses, we add extra three right handed neutrinos $(N_{iR})$ in this model.Comment: 20 pages, the content on results and phenomenology have been expanded, a new section on UV completion of the model has been added and also some new references, this version has been accepted by Physical Review