Sensitivity of HAWC to Primordial Black Hole Bursts

TL;DR

This paper evaluates HAWC's capability to detect gamma-ray bursts from evaporating primordial black holes within 0.25 light years, highlighting its sensitivity and potential to improve existing upper limits on PBH abundance.

Contribution

It demonstrates HAWC's high sensitivity to PBH bursts and quantifies detection probabilities, establishing new upper limits if no detections occur.

Findings

HAWC can detect PBH bursts within 0.25 light years with 95% probability.

Null results from 2-year searches will improve existing PBH upper limits.

HAWC's large field of view and high energy sensitivity make it ideal for PBH burst searches.

Abstract

Primordial Black Holes (PBHs) are black holes that may have been created in the early Universe and could be as large as supermassive black holes or as small as the Planck scale. It is believed that a black hole has a temperature inversely proportional to its mass and will thermally emit all species of fundamental particles. PBHs with initial masses of 5.0 x 10^14 g should be expiring today with bursts of high-energy gamma radiation in the GeV/TeV energy range. The High Altitude Water Cherenkov (HAWC) observatory is sensitive to the high end of the PBH gamma-ray burst spectrum. Due to its large field of view, duty cycle above 90% and sensitivity up to 100 TeV, the HAWC observatory is well suited to perform a search for PBH bursts. We report that if the PBH explodes within 0.25 light years from Earth and within 26 degrees of zenith, HAWC will have a 95% probability of detecting the PBH burst at the 5 sigma level. Conversely, a null detection from a 2 year or longer HAWC search will set PBH upper limits which are significantly better than the upper limits set by any previous PBH search.