Improving the Search for Primordial Black Holes with HAWC

Primordial Black Holes (PBHs) are black holes that may have been created by density fluctuations in the early Universe and could be as massive 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 via Hawking Radiation. PBHs with initial masses of ~5e14 g should be expiring today, producing bursts of high-energy gamma radiation in the GeV--TeV energy range. The High-Altitude Water Cherenkov (HAWC) Observatory is sensitive to particles with energies of ~300 GeV to above 100 TeV, which corresponds to the high end of the PBH burst spectrum. With its large instantaneous field of view of ~2 sr and a duty cycle above 95%, the HAWC Observatory is ideally suited to perform searches for PBH bursts. We advanced HAWC's already world-leading data-driven limit on the burst rate density of PBHs to incorporate extended durations to search and combined limits, as well as to take advantage of recent structural and algorithmic upgrades to the Observatory.