Théorie

Radiative decay of keV-mass sterile neutrinos in a strongly magnetized plasma

The radiative decay of sterile neutrinos with typical masses of 10 keV 

is investigated in the presence of a strong magnetic field and degenerate

electron plasma. The modification of the photon dispersion relation by 

the active external medium is taken into account. The limiting cases 

of relativistic and non-relativistic plasma are analyzed. The decay rate 

in a strongly magnetized plasma as a function of the plasma electron number 

density is compared with the unmagnetized case. It Was found that the strong 

Solving the flatness problem with an anisotropic instanton in Horava-Lifshitz gravity

The first half of this talk reviews the basic construction and some
known cosmological implications of a renormalizable theory of
gravitation called Horava-Lishitz gravity. In particular, I will
explain that (i) the anisotropic scaling with the dynamical critical
exponent z=3 renders a field theory of gravity renormalizable, that
(ii) the same anisotropic scaling solves the horizon problem and leads
to scale-invariant cosmological perturbations even without inflation
and that (iii) the infrared instability of the so-called projectable

Infrared QCD: perturbative or non perturbative?

A model suited for calculating correlation functions in QCD from the ultraviolet to the infrared is reviewed. The model consist in standard Faddeev-Popov Lagrangian for Landau gauge with an extra mass term for gluons. It is shown that once this mass term is included, two and three point correlation functions can be calculated with good precision at one-loop order even at very low momenta in the quenched approximation. After that, the inclusion of quarks is analyzed.

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