LIGO Signals from the Mirror World

Speaker: Prof. Merab Gogberashvili (Tbilisi State University)
Date/Time: Thursday, 28 August 2025, 14:00
Room: A.1.01/03 - Alps (MPP, Garching)

Title: LIGO Signals from the Mirror World

Abstract:
We suggest that a significant fraction of binary black hole and neutron star mergers - potential sources of gravitational wave signals detectable by LIGO/VIRGO - may originate from the hidden mirror sector. Mirror particles do not interact with ordinary matter except gravitationally, which is why no electromagnetic signals are expected to accompany gravitational waves from mergers involving mirror matter.

Mirror matter is a candidate for dark matter, and its density may exceed that of ordinary matter by a factor of five. Since the mirror world is expected to be colder, star formation there likely began earlier, allowing mirror black holes more time to accumulate mass and form binary systems within the LIGO detection range. Overall, we estimate a tenfold amplification of black hole merger rates in the mirror world compared to our own, which aligns with LIGO observations.

If dark matter is primarily composed of mirror particles, we predict that only about one in ten binary neutron star (or neutron star-black hole) mergers detectable by LIGO/VIRGO would be accompanied by a gamma-ray burst. Interestingly, the candidate events recorded by LIGO/VIRGO during the third observational run appear to support this prediction.

We also consider the possibility that LIGO events GW190521, GW190425, and GW190814 may have originated from mirror world binaries. Conventional stellar evolution theories predict so-called upper and lower mass gaps, and the merger component masses of these events fall within those gaps. Explaining these challenging events within standard models requires highly specific assumptions, whereas such scenarios are orders of magnitude more probable in the mirror world.