Speaker
Dr
Shreyashi Chakdar
(University of Virginia)
Description
In this work, we show that a neutral scalar field, $\sigma$, of two Higgs doublet extensions of the Standard Model incorporating the
seesaw mechanism for neutrino masses can be identified as a consistent `warm' dark matter candidate with a mass of order keV. The relic density of $\sigma$ is correctly reproduced by virtue of the late decay of a right-handed neutrino $N$ participating in the seesaw mechanism. Constraints from cosmology determine the mass and lifetime of $N$ to be $M_N \approx 25 ~{\rm GeV} - 20 ~{\rm TeV}$ and $\tau_N \approx (10^{-4} - 1)$ sec. These models can also explain the 3.5 keV $X$-ray anomaly in the extra-galactic spectrum that has been recently reported in terms of the decay $\sigma \rightarrow \gamma \gamma$. Future tests of these models at colliders and in astrophysical settings are also discussed.
Primary author
Dr
Shreyashi Chakdar
(University of Virginia)
Co-authors
Kaladi Babu
(Oklahoma State University)
Rabindra Mohapatra
(University of Maryland)
