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Calculating the mass fraction of primordial black holes
journal contribution
posted on 2023-06-08, 20:33 authored by Sam Young, Christian ByrnesChristian Byrnes, Misao SasakiWe reinspect the calculation for the mass fraction of primordial black holes (PBHs) which are formed from primordial perturbations, finding that performing the calculation using the comoving curvature perturbation ?c in the standard way vastly overestimates the number of PBHs, by many orders of magnitude. This is because PBHs form shortly after horizon entry, meaning modes significantly larger than the PBH are unobservable and should not affect whether a PBH forms or not - this important effect is not taken into account by smoothing the distribution in the standard fashion. We discuss alternative methods and argue that the density contrast, ?, should be used instead as super-horizon modes are damped by a factor k2. We make a comparison between using a Press-Schechter approach and peaks theory, finding that the two are in close agreement in the region of interest. We also investigate the effect of varying the spectral index, and the running of the spectral index, on the abundance of primordial black holes.
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- Published
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- Accepted version
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JCAPISSN
1475-7516Publisher
IOP PublishingExternal DOI
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2014Department affiliated with
- Physics and Astronomy Publications
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- Yes
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- Yes
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2016-02-08First Open Access (FOA) Date
2016-02-08First Compliant Deposit (FCD) Date
2016-02-08Usage metrics
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