2 research outputs found
Primordial Black Holes: sirens of the early Universe
Primordial Black Holes (PBHs) are, typically light, black holes which can
form in the early Universe. There are a number of formation mechanisms,
including the collapse of large density perturbations, cosmic string loops and
bubble collisions. The number of PBHs formed is tightly constrained by the
consequences of their evaporation and their lensing and dynamical effects.
Therefore PBHs are a powerful probe of the physics of the early Universe, in
particular models of inflation. They are also a potential cold dark matter
candidate.Comment: 21 pages. To be published in "Quantum Aspects of Black Holes", ed. X.
Calmet (Springer, 2014
Anomaly Mediation and Cosmology
We consider an extension of the MSSM wherein anomaly mediation is the source
of supersymmetry breaking, and the tachyonic slepton problem is solved by a
gauged U(1) symmetry, which is broken at high energies in a manner preserving
supersymmetry, thereby also facilitating the see-saw mechanism for neutrino
masses and a natural source for the Higgs mu-term. We show that these
favourable outcomes can occur both in the presence and the absence of a large
Fayet-Iliopoulos (FI) D-term associated with the new U(1). We explore the
cosmological consequences of the model, showing that it naturally produces a
period of hybrid inflation, terminating in the production of cosmic strings. In
spite of the presence of a U(1) (even with an FI term), inflation is effected
by the F-term, with a D-flat tree potential (the FI term, if present, being
cancelled by non-zero squark and slepton fields). Calculating the 1-loop
corrections to the inflaton potential, we estimate the constraints on the
parameters of the model from Cosmic Microwave Background data. We will see that
a consequence of these constraints is that the Higgs mu-term necessarily small.
We briefly discuss the mechanisms for baryogenesis via conventional
leptogenesis, the out-of-equilibrium production of neutrinos from the cosmic
strings, or the Affleck-Dine mechanism. Cosmic string decays also boost the
relic density of dark matter above the low value normally obtained in AMSB
scenarios.Comment: 34 pages. Revised to incorporate discussion of the case when the
Fayet-Ilipoulos term is absen