How well can new particles interacting with neutrinos be constrained after a galactic supernova?

Understand

A supernova event in our own galaxy will result in a large number of neutrinos detected on Earth within the time-frame of a few seconds.

• These neutrinos will have been produced thermally with, in principle, three distinct temperatures for the electron, anti-electron and remaining heavy flavours respectively.
• We revisit the possibility that new MeV-mass particles $\chi$ are also produced thermally during the event, which scatter with the neutrinos and alter their temperatures.
• Our main emphasis is on the detectability of this effect using the neutrino spectrum, given the large uncertainty on the temperature and density profiles of the stellar matter.