Sensitivity of HAWC to Primordial Black Hole Bursts

Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of ∼ 5.0× 1014 g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV/TeV energy range. The HAWC (High Altitude Water Cherenkov) high energy observatory is sensitive to the high end of the PBH evaporation gammaray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the HAWC observatory is well suited to perform a search for PBH bursts. In this work, we show that if the PBH explodes within 0.074 parsec from Earth and within 26 degrees of zenith, HAWC will have a 95% probability of detecting the PBH burst at 5 sigma level. Conversely a null detection from HAWC for a >2 year search will set PBH upper limits which are significantly better than any other upper limits set by previous PBH searches.