Hardi Veermäe

Primordial black hole constraints for extended mass functions

We revisit the cosmological and astrophysical constraints on the fraction of the dark matter in primordial black holes (PBHs) with an extended mass function. We consider a variety of mass functions, all of which are described by three parameters: a characteristic mass and width and a dark matter fraction. Various observations then impose constraints on the dark matter fraction as a function of the first two parameters. We show how these constraints relate to those for a monochromatic mass function, demonstrating that they usually become more stringent in the extended case than the monochromatic one. Considering only the well-established bounds, and neglecting the ones that depend on additional astrophysical assumptions, we find that there are three mass windows, around

Non-minimal CW inflation, electroweak symmetry breaking and the 750 GeV anomaly

4\times 10^{-17}M_\odot,

Bigravitational origin of dark matter

2\times 10^{-14}M_\odot

Frame-Independent Classification of Single-Field Inflationary Models

and

Heavy spin-2 Dark Matter

25-100M_\odot

Gravitational waves from primordial black hole mergers

, where PBHs can constitute all dark matter. However, if one includes all the bounds, PBHs can only constitute of order

On the Quantisation of Complex Higher Derivative Theories and Avoiding the Ostrogradsky Ghost

10\%

The evolving Planck mass in classically scale-invariant theories

of the dark matter.

Simulations of Galaxy Cluster Collisions with a Dark Plasma Component

A bstractWe study whether the hinted 750 GeV resonance at the LHC can be a Coleman-Weinberg inflaton which is non-minimally coupled to gravity. Since the inflaton must couple to new charged and coloured states to reproduce the LHC diphoton signature, the same interaction can generate its effective potential and trigger the electroweak symmetry breaking via the portal coupling to the Higgs boson. This inflationary scenario predicts a lower bound on the tensor-to-scalar ratio of r ≳ 0.006, where the minimal value corresponds to the measured spectral index ns ≃ 0.97. However, we find that the compatibility with the LHC diphoton signal requires exotic new physics at energy scales accessible at the LHC. We study and quantify the properties of the predicted exotic particles.