Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userAbsorption from Primordial Black Holes as source of baryon asymmetry
104
0
0.0
(
0
)
Added by
Damiano Francesco Giuseppe Fiorillo
Publication date
2021
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
We propose a new mechanism for baryogenesis, in which baryon asymmetry is generated by absorption of a new particle $X$ carrying baryon number onto Primordial Black Holes (PBHs). Due to CP violation of $X$ and $overline{X}$ scattering with the plasma surrounding PBHs, the two conjugate particles are differently absorbed by PBHs, leading to the production of an asymmetry in the $X$ sector. The production is halted by PBH evaporation, after which the asymmetry is transferred into the baryonic sector via $X$ decay. We show that this mechanism can produce the correct amount of asymmetry without violating the known constraints on PBHs concentration. Furthermore, we provide a systematic study of the parameter space, identifying the regions leading to the production of the correct baryon asymmetry.
rate research
Read More
We have refined our previously suggested scenario of generation of the cosmological baryon asymmetry through an asymmetric capture of baryons and antibaryons by primordial block hole arXiv:2009.04361. It is found that in the limit of weak interactions of hypothetical heavy baryons with the primeval plasma the effect can be strongly enhanced and the observed magnitude of the asymmetry can be obtained for a wide range of the model parameters.
Primordial black holes (PBHs) have been proposed to explain at least a portion of dark matter. Observations have put strong constraints on PBHs in terms of the fraction of dark matter which they can represent, $f_{rm PBH}$, across a wide mass range -- apart from the stellar-mass range of $20M_odotlesssim M_{rm PBH}lesssim 100M_odot$. In this paper, we explore the possibility that such PBHs could serve as point-mass lenses capable of altering the gravitational-wave (GW) signals observed from binary black hole (BBH) mergers along their line-of-sight. We find that careful GW data analysis could verify the existence of such PBHs based on the $fitting~factor$ and odds ratio analyses. When such a lensed GW signal is detected, we expect to be able to measure the redshifted mass of the lens with a relative error $Delta M_{rm PBH}/M_{rm PBH}lesssim0.3$. If no such lensed GW events were detected despite the operation of sensitive GW detectors accumulating large numbers of BBH mergers, it would translate into a stringent constraint of $f_{rm PBH}lesssim 10^{-2}-10^{-5}$ for PBHs with a mass larger than $sim10M_odot$ by the Einstein Telescope after one year of running, and $f_{rm PBH}lesssim 0.2$ for PBHs with mass greater than $sim 50M_odot$ for advanced LIGO after ten years of running.
We investigate the effects of producing dark matter by Hawking evaporation of primordial black holes (PBHs) in scenarios that may have a second well-motivated dark matter production mechanism, such as freeze-out, freeze-in, or gravitational production. We show that the interplay between PBHs and the alternative sources of dark matter can give rise to model-independent modifications to the required dark matter abundance from each production mechanism, which in turn affect the prospects for dark matter detection. In particular, we demonstrate that for the freeze-out mechanism, accounting for evaporation of PBHs after freeze-out demands a larger annihilation cross section of dark matter particles than its canonical value for a thermal dark matter. For mechanisms lacking thermalization due to a feeble coupling to the thermal bath, we show that the PBH contribution to the dark matter abundance leads to the requirement of an even feebler coupling. Moreover, we show that when a large initial abundance of PBHs causes an early matter-dominated epoch, PBH evaporation alone cannot explain the whole abundance of dark matter today. In this case, an additional production mechanism is required, in contrast to the case when PBHs are formed and evaporate during a radiation-dominated epoch.
We show that accreting black hole systems could be sources for keV light dark matter flux through several different mechanisms. We discuss two types of systems: coronal thermal plasmas around supermassive black holes in active galactic nuclei (AGNs), and accretion disks of stellar-mass X-ray black hole binaries (BHBs). We explore how these black hole systems may produce keV light dark matter fluxes and find that in order to account for the XENON1T excess, the dark fluxes from the observed AGNs and BHBs sources have to exceed the Eddington limit. We also extend the black hole mass region to primordial black holes (PBHs) and discuss the possibility of contributing to keV light dark flux via superradiance or Hawking radiation of PBHs. Besides, black holes can be good accelerators to accrete and boost heavy dark matter particles. If considering collisions or dark electromagnetism, those particles could then escape and reach the benchmark speed of 0.1c at the XENON1T detector.
We set a new upper limit on the abundance of primordial black holes (PBH) based on existing X-ray data. PBH interactions with interstellar medium should result in significant fluxes of X-ray photons, which would contribute to the observed number density of compact X-ray objects in galaxies. The data constrain PBH number density in the mass range from a few $M_odot$ to $2times 10^7 M_odot$. PBH density needed to account for the origin of black holes detected by LIGO is marginally allowed.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
