Constraining primordial black hole abundance with Insight-HXMT

Primordial black holes (PBHs), a major candidate for dark matter, have been extensively constrained across most mass ranges. However, PBHs in the mass range 10 17 –10 21 g remain a viable explanation for all dark matter. In this study, we use observational data from the Hard X-ray Modulation Telescope (Insight-HXMT) to refine constraints on PBHs within the mass range 2 × 10 16 –5 × 10 17 g. Our analysis explores three scenarios: directly using observational data, incorporating the astrophysical background model, and employing the power-law spectrum with an exponential cutoff. Our research results indicate that although Insight-HXMT does not have an advantage in the first two scenarios, when considering the power-law model, its exceptional sensitivity in the hard X-ray regime and sufficiently high upper energy limit significantly strengthen the constraints on PBHs with masses greater than 10 17 g compared to previous limits. Furthermore, the exclusion limit for PBHs as dark matter has reached 4 × 10 17 g, which is comparable to the current threshold.