Programme

O.4 -- Oral, IWTCP-2

Date: Tuesday, 29-07-2014

Time: 17h10 - 17h30

Higgs boson mass, neutrino masses and mixing and 7 keV sterile neutrino dark matter in a $U(1)_R$ lepton number model

Sabyasachi Chakraborty, Sourov Roy.

Indian Association for the Cultivation of Science, India.

We discuss neutrino masses and mixing in the framework of a supersymmetric model with a $U(1)_{R}$ symmetry, consisting of a single right handed neutrino superfield with an appropriate R charge. The lepton number ($L$) of the standard model fermions are identified with the negative of their R-charges. As a result, a subset of leptonic R-parity violating operators can be present and are consistent with the $U(1)_R$ symmetry. This model can produce one light Dirac neutrino mass at the tree level without the need of introducing a very small neutrino Yukawa coupling. We analyze the scalar sector of this model in detail, where one of the sneutrinos might acquire a substantial vacuum expectation value and plays the role of a down type Higgs field. A new tree level correction to the Higgs boson mass is obtained, which is proportional to the square of the neutrino Yukawa coupling $f$. This allows for a 125 GeV Higgs boson at the tree level for $f \sim {\cal O} (1)$ and still having a small tree level mass for the active neutrino. In order to fit the experimental results involving neutrino masses and mixing angles we introduce a small breaking of $U(1)_R$ symmetry, in the context of anomaly mediated supersymmetry breaking. In the presence of this small R-symmetry breaking, light neutrino masses receive contributions at the one-loop level involving the R-parity violating interactions. We also identify the right handed neutrino as a warm dark matter candidate in our model, which can also explain the 3.5 keV X-ray line, as observed in the spectra of Andromeda galaxy and various other galaxy clusters by space telescopes.

Presenter: Chakraborty Sabyasachi