The axion, motivated as a solution to the strong $CP$ problem, is also viable dark matter candidate. axion field takes random values in causally disconnected regions if symmetry breaking that establishes particle occurs after inflation, leading white-noise density fluctuations at low wave numbers and forming dense minihalos with sub-planetary masses subsequently. There have been two recent proposals appear capable of testing this scenario, namely using pulsar timing arrays studying...

Abstract Many theories of dark matter beyond the weakly interacting massive particles paradigm feature an enhanced power spectrum on subparsec scales, leading to formation dense minihalos. Future local observations are promising search for and constrain such substructures. The survival probability these minihalos in Milky Way environment is crucial interpreting observations. In this work, we investigate two environmental effects: stellar disruption (smooth) tidal disruption. These mechanisms...

The LHAASO Collaboration has recently reported a measurement of the diffuse gamma-ray emission from Galactic Plane at energies between 10 TeV and 1 PeV. While this is brighter than that expected cosmic-ray interactions in interstellar medium alone, we show intensity, spectrum, morphology excess are good agreement with predicted ``TeV halos'' which surround Milky Way's pulsar population. These results support conclusion halos dominate ultrahigh-energy sky, these objects convert...

The authors propose a novel method to probe potential Dark Matter substructures by means of Fast Radio Burst (FRB) observations. They discuss two observational scenarios, as well experimental setups and challenges.

Wave or fuzzy dark matter that is produced with relativistic wave numbers exhibits free-streaming effects analogous to warm hot particle momenta. Axions after inflation provide such a mildly candidate, where the enhanced suppression and observational bounds are only moderately stronger than from propagation of initially cold axions. More generally, damping also impacts isocurvature fluctuations generation in causally disconnected patches. As coherent spatial free stream away they leave...

The default assumption of early Universe cosmology is that the postinflationary was radiation dominated until it about 47,000 years old. Direct evidence for radiation-dominated epoch extends back nucleosynthesis, which began during first second. However there are theoretical reasons to prefer a period earlier matter domination, prior e.g., due late decaying massive particles needed explain baryogenesis. Axion quantitatively affected by an with different axion mass range preferred and greater...

Axionlike dark matter whose symmetry breaking occurs after the end of inflation predicts enhanced primordial density fluctuations at small scales. This leads to dense axion minihalos (or miniclusters) forming early in history Universe. Condensation axions formation and subsequent growth stars cores these halos. If, like QCD axion, axionlike particle has attractive self-interactions there is a maximal mass for stars, above which star rapidly shrinks converts an $\mathcal{O}(1)$ fraction its...

The axion, as a leading dark matter candidate, is the target of many ongoing and proposed experimental searches based on its coupling to photons. Ultralight axions that couple photons can also cause polarization rotation light which be probed by cosmic microwave background. In this work, we show large axion field inevitably developed around black holes due Bose-Einstein condensation axions, enhancing induced birefringence effects. Therefore, measuring modulation supermassive hole imaging...

Many works have concentrated on the observable signatures of dark matter being an ultralight axion-like particle (ALP). We concentrate a particularly dramatic signature in late-time cosmological power spectrum that occurs if symmetry breaking establishes ALP happens after inflation -- white-noise density fluctuations dominate at small scales over adiabatic from inflation. These alter early history nonlinear structure formation. find for $f_A \sim 10^{13}-10^{15}$GeV, which requires high...

Abstract The QCD axion and axion-like particles, as leading dark matter candidates, can also have interesting implications for substructures if the Peccei-Quinn symmetry is broken after inflation. In such a scenario, perturbations on small scales will lead to formation of miniclusters at matter-radiation equality, subsequently stars. Such compact objects open new windows indirect searches axions. We compute star mass function based recent minicluster studies Bose simulations. Applying this...

We point out a unique mechanism to produce the relic abundance for glueball dark matter from gauged $\mathrm{SU}(N{)}_{d}$ hidden sector which is bridged standard model through heavy vectorlike quarks colored under gauge interactions both sides. A necessary ingredient of our assumption that quarks, produced either thermally or nonthermally, are abundant enough dominate universe some time in early universe. They later undergo color confinement and form unstable vectorlike-quarkonium states...

A bstract Low-scale baryogenesis and dark matter generation can occur via the production of neutral B mesons at MeV temperatures in early Universe, which undergo CP-violating oscillations subsequently decay into a sector. In this work, we discuss consequences realizing mechanism supersymmetric model with an unbroken U(1) R symmetry is identified baryon number. sector through number conserving operator mediated by TeV scale squarks GeV Dirac bino. The particles be sterile neutrinos their...

Axion-like dark matter whose symmetry breaking occurs after the end of inflation predicts enhanced primordial density fluctuations at small scales. This leads to dense axion minihalos (or miniclusters) forming early in history Universe. Condensation axions formation and subsequent growth stars cores these halos. If, like QCD axion, axion-like particle has attractive self-interactions there is a maximal mass for stars, above which star rapidly shrinks converts an $\mathcal{O}(1)$ fraction its...

We show how $CP$ violating $B$ meson oscillations in conjunction with baryon number decays can generate the cosmological asymmetry between matter and antimatter, explore parameter space of a simple, self-contained model, which be tested via exotic decays, charge semileptonic neutral mesons.

Abstract The existence of supermassive black holes (SMBHs) with masses greater than ∼ 10 9 M ☉ at high redshift ( z ≳ 7) is difficult to accommodate in standard astrophysical scenarios. We study the possibility that (nearly) totally dissipative self-interacting dark matter (tdSIDM)–in rare, density fluctuations early Universe — produces SMBH seeds through catastrophic collapse. use a semi-analytic model, tested and calibrated by series N-body simulations isolated halos, compute collapse...

Correlated red noise recently reported from pulsar timing observations may be an indication of stochastic gravitational waves emitted by cosmic strings that formed during a primordial phase transition near the grand unification energy scale. Unfortunately, known probes strings, namely microwave background anisotropies and string lensing extragalactic galaxies, are not sensitive enough for low dimensionless tensions...

We propose Fast Radio Burst (FRB) timing, which uses the precision measurements of arrival time differences repeated FRB signals along multiple sightlines, as a new probe gravitational waves (GWs) around nHz to $\mu$Hz frequencies, with highest frequency limited by repeating period. The anticipated experiment requires sightline separation tens AU, achieved sending radio telescopes space. find signal difference induced GWs depends only on local in solar system and we can correlate from...

Many theories of dark matter beyond the Weakly Interacting Massive Particles (WIMP) paradigm feature an enhanced power spectrum on sub-parsec scales, leading to formation dense minihaloes. Future local observations are promising search for and constrain such substructures. The survival probability these minihaloes in Milky Way environment is crucial interpreting observations. In this work, we investigate two environmental effects: stellar disruption (smooth) tidal disruption. These...

The axion, as a leading dark matter candidate, is the target of many on-going and proposed experimental searches based on its coupling to photons. Ultralight axions that couple photons can also cause polarization rotation light which be probed by cosmic microwave background. In this work, we show large axion field inevitably developed around black holes due Bose-Einstein condensation axions, enhancing induced birefringence effects. Therefore, propose measuring modulation supermassive hole...

We propose measuring the arrival time difference of Fast Radio Bursts (FRBs) along two adjacent sightlines as a new probe to dark matter substructures on scales down $\sim 1\,$AU. discuss observational scenarios in which it may be possible place interesting constraints such models through monitoring repeating FRB sources: 1) By sending radio receivers space form baseline tens AU or more and temporal variation between receivers. 2) lensed images one strongly repeater. In both scenarios,...

The QCD axion and axion-like particles, as leading dark matter candidates, can also have interesting implications for substructures if the Peccei-Quinn symmetry is broken after inflation. In such a scenario, perturbations on small scales will lead to formation of miniclusters at matter-radiation equality, subsequently stars. Such compact objects open new windows indirect searches axions. We compute star mass function based recent minicluster studies Bose simulations. Applying this function,...

If primordial black holes (PBH) are present in the early universe, their contribution to energy budget grows relative that of radiation and generically becomes dominant unless initial abundance is exponentially small. This hole domination scenario largely unconstrained for PBHs with masses $\lesssim 10^9\,\mathrm{g}$, which evaporate prior Big Bang nucleosynthesis. However, if era PBH sufficiently long, form clusters can merge appreciably within these objects. We calculate population...