Supernova Cooling in a Dark Matter Smog

Understand

A light hidden gauge boson with kinetic mixing with the usual photon is a popular setup in theories of dark matter.

• The supernova cooling via radiating the hidden boson is known to put an important constraint on the mixing.
• I consider the possible role dark matter, which under reasonable assumptions naturally exists inside supernova, can play in the cooling picture.
• Because the interaction between the hidden gauge boson and DM is likely unsuppressed, even a small number of dark matter compared to protons inside the supernova could dramatically shorten the free streaming length of the hidden boson.