R-Parity Breaking via Type II Seesaw, Decaying Gravitino Dark Matter and PAMELA Positron Excess

TL;DR

This paper introduces a new R-parity violating MSSM extension with type II seesaw that explains the PAMELA positron excess through decaying gravitino dark matter, while also accounting for neutrino masses without high-scale physics.

Contribution

It presents a novel model linking R-parity violation, type II seesaw, and gravitino decay to explain cosmic ray positron excess and neutrino masses.

Findings

Gravitino decays produce positron excess consistent with PAMELA data.

The model naturally explains neutrino masses without high-scale physics.

It preserves the baryon asymmetry of the universe.

Abstract

We propose a new class of R-parity violating extension of MSSM with type II seesaw mechanism for neutrino masses where an unstable gravitino is the dark matter of the Universe. It decays predominantly into three leptons final states, thereby providing a natural explanation of the positron excess but no antiproton excess in the PAMELA experiment. The model can explain neutrino masses without invoking any high scale physics while keeping the pre-existing baryon asymmetry of the universe in tact.