Date and time: October 14th 2014 @ 15:00 (CET)
Title: The 3.5 keV X-ray line saga
Presenter: Stefano Profumo (UC Santa Cruz)
Abstract: An X-ray line at an energy of 3.5 keV has been reported from several observations of galaxies and clusters of galaxies. The origin of the line might be related to the decay of dark matter, or to more complicated processes, possibly related to new physics, or more mundanely to atomic transitions. I will review the status of observations and of theoretical models, and outline future possible steps.
Presenter: Alberto Salvio (IFT-UAM)
Abstract: We will explore the possibility that the fundamental theory of nature does not contain any scale. This implies a renormalizable quantum gravity, which can be reinterpreted as a graviton minus an anti-graviton (agravity). We will show the super-Planckian renormalization group equations of gravity coupled to a generic matter sector. The Planck scale and a flat space can arise dynamically at quantum level provided that the quartic coupling of a scalar, which we call the Higgs of gravity, and its β function vanish at the Planck scale; for example, this is how the Higgs boson behaves for a Higgs mass Mh ≃ 125GeV and a top mass Mt ≃ 171GeV. We will also discuss the implementation of this general idea in specific models and discuss possible dark matter candidates. Within agravity, inflation is a generic phenomenon: the slow-roll parameters are given by the β-functions of the theory, and are small if couplings are perturbative. If the inflaton is identified with the Higgs of gravity the predictions for the scalar spectral index ns ≃0.967 and the tensor-to-scalar ratio r ≃ 0.13 arise. Furthermore, a small weak scale can be natural and is generated by agravity quantum corrections.
Title: Thermal baryogenesis at low energies
Presenter: Juan Racker (U. Valencia)
Abstract: We will explain the problems and some solutions for having thermal baryogensis at low temperatures (T<100 TeV).