Missing in Action: New Physics and the Black Hole Mass Gap

Understand

We demonstrate the power of the black hole mass gap as a novel probe of fundamental physics.

• New light particles that couple to the Standard Model can act as an additional source of energy loss in the cores of population-III stars, dramatically altering their evolution.
• We investigate the effects of two paradigmatic weakly coupled, low-mass particles, axions and hidden photons, and find that the pulsational pair instability, which causes a substantial amount of mass loss, is suppressed.
• As a result, it is possible to form black holes of $72\msun$ or heavier, deep inside the black hole mass gap predicted by the Standard Model.