Ascertain the value of the memory burden suppression parameter k

Ascertain the physical value of the parameter k that quantifies the suppression of the evaporation rate due to the memory burden effect in primordial black holes, where the emission rate beyond half-decay is reduced by a factor proportional to S(qM0)^{-k} relative to the semiclassical rate; determine k from first-principles theory or observational inference to enable definitive constraints on the primordial black hole dark matter fraction.

Background

The analysis introduces a suppression exponent k controlling the strength of the memory burden effect, implemented as a power of the black hole entropy. Constraints throughout the paper are presented as functions of k because its value is not established.

Pinning down k is pivotal for assessing whether light primordial black holes can constitute dark matter and for specifying the size of the newly opened mass window under the memory burden hypothesis.

References

Here, we compute the bounds on the dark matter fraction of PBHs as a function of the currently unknown parameter k that quantifies the strength of the memory burden effect.

Breakdown of Hawking Evaporation opens new Mass Window for Primordial Black Holes as Dark Matter Candidate (2402.17823 - Thoss et al., 27 Feb 2024) in Section 4 (Summary and Conclusions)