17 research outputs found
Inflationary Cosmological Perturbations of Quantum-Mechanical Origin
This review article aims at presenting the theory of inflation. We first
describe the background spacetime behavior during the slow-roll phase and
analyze how inflation ends and the Universe reheats. Then, we present the
theory of cosmological perturbations with special emphasis on their behavior
during inflation. In particular, we discuss the quantum-mechanical nature of
the fluctuations and show how the uncertainty principle fixes the amplitude of
the perturbations. In a next step, we calculate the inflationary power spectra
in the slow-roll approximation and compare these theoretical predictions to the
recent high accuracy measurements of the Cosmic Microwave Background radiation
(CMBR) anisotropy. We show how these data already constrain the underlying
inflationary high energy physics. Finally, we conclude with some speculations
about the trans-Planckian problem, arguing that this issue could allow us to
open a window on physical phenomena which have never been probed so far.Comment: Review Article, 47 pages, 3 figures. Lectures given at the 40th
Karpacz Winter School on Theoretical Physics (Poland, Feb. 2004), submitted
to Lecture Notes in Physic
Resonant conversions of extremely high energy neutrinos in dark matter halos
We study the effect of adiabatically resonant conversion in galactic halos of
neutrinos at the highest energies ( - eV), when the
source is in the center of a galaxy. Using the standard neutrino
properties and the standard cosmological scenario for the hot dark part of
matter, we find that interesting conversions may take place just for neutrino
parameters relevant to the solar and atmospheric neutrino problem. The effect
is due to the large enhancement in the density in galactic halos and to
the form of the effective matter potential both below and above the pole of the
resonance.Comment: 8 pages, revtex, some comments and references added, to appear in
Phys. Rev.
New Constraints on Neutralino Dark Matter in the Supersymmetric Standard Model
We investigate the prospects for neutralino dark matter within the
Supersymmetric Standard Model (SSM) including the constraints from universal
soft supersymmetry breaking and radiative breaking of the electroweak symmetry.
The latter is enforced by using the one-loop Higgs effective potential which
automatically gives the one-loop corrected Higgs boson masses. We perform an
exhaustive search of the allowed five-dimensional parameter space and find that
the neutralino relic abundance depends most strongly on the
ratio . For the relic abundance is almost
always much too large, whereas for the opposite occurs. For
there are wide ranges of the remaining parameters for which
. We also determine that m_{\tilde q}\gsim250\GeV and
m_{\tilde l}\gsim100\GeV are necessary in order to possibly achieve
. These lower bounds are much weaker than the corresponding
ones derived previously when radiative breaking was {\it not} enforced.Comment: 12 pages plus 6 figures (not included), CERN-TH.6584/92,
CTP-TAMU-56/92, UAHEP921