Scalar triplet leptogenesis in the presence of right-handed neutrinos with S3 symmetry

Leptogenesis appears to be a viable alternative to account for the baryon asymmetry of the universe through baryogenesis. In this context, we consider a scenario in which the standard model is extended with $S_3$ and $Z_2$ symmetry in addition to the two scalar triplets, two scalar doublets and three right handed neutrinos. Presence of scalar triplets and right-handed neutrinos in the scenarios of both type-I and type-II seesaw framework provide a different leptogenesis option and can help us to understand the matter-antimatter asymmetry with simple $S_3$ symmetry. We discuss the neutrino phenomenology and leptogenesis in both high ($O(10^{10})$ GeV) and low energy scale ($O$(2)TeV) by constraining the Yukawa couplings. Moreover, we also consider the constraints on model parameters from neutrino oscillation data and leptogenesis to explain the rare lepton flavor violating decay and muon g-2 anomaly.Comment: 32 pages, 10 figure

Scalar dark matter, Neutrino mass and Leptogenesis in a U(1)B−L\rm U(1)_{B-L} model

We investigate the phenomenology of singlet scalar dark matter in a simple $\rm U(1)_{B-L}$ gauge extension of standard model, made anomaly free with four exotic fermions. The enriched scalar sector and the new gauge boson $Z^\prime$, associated with $\rm U(1)$ gauge extension, connect the dark sector to the visible sector. We compute relic density, consistent with Planck limit and $Z^\prime$ mediated dark matter-nucleon cross section, compatible with PandaX bound. The mass of $Z^\prime$ and the corresponding gauge coupling are constrained from LEP-II and LHC dilepton searches. We also briefly scrutinize the tree level neutrino mass with dimension five operator. Furthermore, resonant leptogenesis phenomena is discussed with TeV scale exotic fermions to produce the observed baryon asymmetry of the Universe. Further, we briefly explain the impact of flavor in leptogenesis and we also project the combined constraints on Yukawa, consistent with oscillation data and observed baryon asymmetry. Additionally, we restrict the new gauge parameters by using the existing data on branching ratios of rare $B(\tau)$ decay modes. We see that the constraints from dark sector are much more stringent from flavor sector.Comment: 31 pages, 14 figures, version to appear in Journal of Physics

Scalar triplet leptogenesis with S 3 symmetry

Extension of standard model with simplest discrete symmetry S 3 is conisidered to explain the neutrino masses and mixing consistent with the current observations. The particle content is extended by addition of right handed neutrinos and scalar triplets and explain the observed data in the neutrino sector. We mostly focus here on baryogenesis from the decay of a heavy triplets in the presence of right-handed neutrinos. The scenario also provides us the viability of TeV scale particles in the framework in the context of future collider searches of lepton flavor violation

Neutrino Phenomenology and Dark matter in an A4A_4 flavour extended B-L model

We present an $A_4$ flavor extended $\rm B-L$ model for realization of eV scale sterile neutrinos, motivated by the recent experimental hints from both particle physics and cosmology. The framework considered here is a gauged $\rm B-L$ extension of standard model without the introduction of right-handed neutrinos, where the gauge triangle anomalies are canceled with the inclusion of three exotic neutral fermions $N_{i}$ ($i=1,2,3$) with $\rm B-L$ charges $-4,-4$ and $5$. The usual Dirac Yukawa couplings between the SM neutrinos and the exotic fermions are absent and thus, the model allows natural realization of eV scale sterile-like neutrino and its mixing with standard model neutrinos by invoking $\rm A_4$ flavor symmetry. We demonstrate how the exact tri-bimaximal mixing pattern is perturbed due to active-sterile mixing by analyzing $1+3$ case in detail. We also show the implication of eV scale sterile-like neutrino on various observables in neutrino oscillation experiments and the effective mass in neutrinoless double beta decay. Another interesting feature of the model is that one of three exotic fermions is required to explain eV scale phenomena, while other two fermions form stable dark matter candidates and their total relic density satisfy the observed $3\sigma$ limit of Planck data. We constrain the gauge parameters associated with $U(1)$ gauge extension, using relic density and collider bounds.Comment: 29 pages, 13 figures, version to appear in EPJ

Majorana dark matter and neutrino mass with S3 symmetry

This model includes a minimal extension of the standard model with S3 and Z2 symmetries to explain neutrino masses and mixing along with the dark matter phenomenology. Neutrino phenomenology is explored, consistent with the 3 σ observation of oscillation parameters, and a nonzero reactor mixing angle (θ13) is obtained. The S3 singlet Majorana neutrino couples to the third generation of leptons, which gives a correct relic density compatible with the Planck data. This model does not allow tree-level direct detection; therefore, we discuss the loop-level effective interaction with the nucleus mediated by gauge boson, which is allowed by the experimental limit of LUX and PICO-60. Also the constraints from the lepton flavor violating rare decay mode are commented. However, this model has some limitations to address the exact quark mixing and is consistent with the block diagonal structure of quark mixing matrix and nearly massless first-generation quarks. This can be resolved by the extension of the quark or Higgs sector of the present model, which is not explored in the current analysis. © 2020, Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature

Majorana dark matter and neutrino mass with S3 symmetry

This model includes a minimal extension of the standard model with S3 and Z2 symmetries to explain neutrino masses and mixing along with the dark matter phenomenology. Neutrino phenomenology is explored, consistent with the 3σ observation of oscillation parameters and a nonzero reactor mixing angle (θ13) is obtained. The S3 singlet Majorana neutrino couples to the third generation of leptons, gives a correct relic density compatible with the Planck data. This model does not allow tree level direct detection, therefore we discuss the loop level effective interaction with the nucleus mediated by gauge boson. Also the constraints from the lepton flavor violating rare decay mode is commented