Bilarge neutrino mixing from supersymmetry with high scale nonrenormalizable interactions

Abstract

We suggest a supersymmetric (SUSY) explanation of neutrino masses and mixing, where nonrenormalizable interactions in the hidden sector generate lepton number violating Majorana mass terms for both right-chiral sneutrinos and neutrinos. It is found necessary to start with a superpotential including an array of gauge singlet chiral superfields. This leads to nondiagonal ∆L = 2 mass terms and almost diagonal SUSY breaking A-terms. As a result, the observed pattern of bilarge mixing can be naturally explained by the simultaneous existence of the seesaw mechanism and radiatively induced masses. Allowed ranges of parameters in the gauge singlet sector are delineated, corresponding to each of the cases of normal hierarchy, inverted hierarchy and degenerate neutrinos.

Analysis of the parameter space and spectrum of the μνSSM

“…Besides, they contribute to generate effective Majorana masses for neutrinos at the electroweak scale. Terms of the typeν cĤ dĤu andν cνcνc have also been analysed as sources of the observed baryon asymmetry in the Universe [27] and of neutrino masses and bilarge mixing [28], respectively.…”

Bilarge neutrino mixing inR-parity violating supersymmetry: The role of right-chiral neutrino superfields

“…In the earlier study we used a global symmetry (called R-symmetry), whose purpose was to solve the µ-problem [10,26] and make the right-handed neutrino mass to be of order 1 TeV. However, since such R-charge is not an observed quantum number in low-energy physics, one can assign it to fields differently compared to the choices in [14]. By thus identifying an appropriate set of R-charges for both visible and hidden sector chiral superfields, we have found terms which violate lepton number by three units.…”

“…The additional feature in this approach is the inclusion of a right-chiral neutrino superfield for every family, something that is inevitably required for a scheme like the seesaw mechanism. Such a postulate has been been utilized earlier, where nonrenormalizable interactions involving the right-chiral neutrinos and hidden sector fields are included [10,11,12,13,14]. As can be seen in reference [10], it is possible to explain the value of the Higgsino mass parameter µ, obtaining it as an artifact of the breakdown of a global symmetry (R-symmetry) at a scale of about 10 11 GeV.…”

“…It was argued in reference [14], using such a scenario, that the special nature of neutrino mixing is due to some terms in the high-scale SUSY breaking scheme, including the right-chiral neutrino superfield, for which there is no analogue in the quark sector. While the viability of reproducing neutrino masses in the correct range, using the intermediate scale of SUSY breaking in the hidden sector, was successfully employed in earlier works [10], later studies took a more comprehensive approach [11], including radiative as well as seesaw masses, and pointing out consistent regions in the parameter space of the model answering to the bilarge mixing pattern [14]. The relative likelihood of the different neutrino mass scenarios, namely, normal hierarchy, inverted hierarchy and degenerate neutrinos, could also be studied in this approach [14].…”

Supergravity can reconcile dark matter with lepton number violating neutrino masses

“…This assumption forbids the usual N c N c term in the superpotential, but a nonrenormalizable term XX M P N c N c is allowed. If X acquires a vacuum expectation value (vev) L 2 terms can be generated for neutrinos, and to have right-handed neutrino mass at the TeV scale the vev of X should be at the intermediate scale (10)(11).…”