Speaker
Description
A light CP-even scalar singlet $S$ mixing with the Standard Model (SM) Higgs boson can be produced abundantly in hot and dense astrophysical environments such as the supernova core via nucleon bremsstrahlung process $NN \to NNS$. We reevaluate the production rate of $S$ and its subsequent decay and reabsorption in the supernova core. We then consider secondary photons from the scalar decay $S \to e^+ e^-$, which could give rise to an observable gamma-ray signal. We subsequently use the gamma-ray limits from SN 1987A based on the Solar Maximum Mission data to place new constraints on the mixing of the scalar $S$ with the SM Higgs boson. These gamma-ray constraints cover substantially new parameter space in the scalar mass-mixing plane, compared to the existing limits.
