Constraining the evaporation rate of primordial black holes using archival data from VERITAS

TL;DR

This study aims to improve constraints on the evaporation rate of primordial black holes by analyzing additional archival data from VERITAS, enhancing previous upper limits through increased data and lower energy thresholds.

Contribution

The paper introduces an improved method for constraining PBH evaporation rates by incorporating more recent VERITAS data and lower energy thresholds, refining previous upper limit estimates.

Findings

Expected to tighten the upper limit on PBH evaporation rate.

Utilizes additional VERITAS data from 2012-2017.

Enhances sensitivity to VHE gamma-ray bursts from PBHs.

Abstract

Primordial black holes (PBHs) are thought to have been formed as a result of density fluctuations in the very early Universe. It is suggested that PBHs of mass $\sim 5 \times 10^{14} \mathrm{\ g}$ or less have evaporated through the release of Hawking radiation by the present day. However, PBHs of initial mass $10^{15} \mathrm{\ g}$ should still be evaporating at the present epoch. Over the past few years, very high-energy (VHE; E $>$ 100 GeV) gamma-ray emission from PBHs in the form of a burst has been searched for using ground-based gamma-ray instruments. However, no observational evidence has been reported on the detection of VHE emission from PBHs yet. Previously, an upper limit on the rate density of PBHs was calculated using 750 hours of archival data taken between 2009 and 2012 by the VERITAS gamma-ray observatory. We will augment this study with additional data taken between 2012 and 2017. In addition to more data, the lower energy threshold on the newer data will help to produce an improved upper limit on the rate at which PBHs are evaporating in our local neighborhood. This work is still in progress, therefore we will only report an expected change to the upper limit on the rate density of PBH evaporation.