Decaying Dark Matter in the Supersymmetric Standard Model with Freeze-in and Seesaw mechanims

TL;DR

This paper proposes a supersymmetric model with decaying dark matter at the TeV scale, explaining cosmic ray anomalies, neutrino masses, and baryon asymmetry through a combination of seesaw, freeze-in, and R-parity mechanisms.

Contribution

It introduces a novel TeV-scale dark matter sector with specific symmetries and interactions, linking dark matter decay, neutrino masses, and baryogenesis within a supersymmetric framework.

Findings

Dark matter lifetime around 10^{26} seconds consistent with cosmic ray data.

Correct relic density achieved via freeze-in mechanism.

Small-scale structure problems addressed through decays of metastable states.

Abstract

Inspired by the decaying dark matter (DM) which can explain cosmic ray anomalies naturally, we consider the supersymmetric Standard Model with three right-handed neutrinos (RHNs) and R-parity, and introduce a TeV-scale DM sector with two fields \phi_{1,2} and a $Z_3$ discrete symmetry. The DM sector only interacts with the RHNs via a very heavy field exchange and then we can explain the cosmic ray anomalies. With the second right-handed neutrino N_2 dominant seesaw mechanism at the low scale around 10^4 GeV, we show that \phi_{1,2} can obtain the vacuum expectation values around the TeV scale, and then the lightest state from \phi_{1,2} is the decay DM with lifetime around \sim 10^{26}s. In particular, the DM very long lifetime is related to the tiny neutrino masses, and the dominant DM decay channels to \mu and \tau are related to the approximate \mu-\tau symmetry. Furthermore, the correct DM relic density can be obtained via the freeze-in mechanism, the small-scale problem for power spectrum can be solved due to the decays of the R-parity odd meta-stable states in the DM sector, and the baryon asymmetry can be generated via the soft leptogensis.