לוח שנה משולב

We consider a simple supersymmetric hidden sector: pure SU(N) gauge theory. Dark matter is made up of hidden glueballinos and hidden glueballs with mass near the confinement scale. For glueballino mass ~TeV and glueball mass ~100 MeV, the glueballinos freeze out with the correct relic density and self-interact through glueball exchange to resolve small-scale structure puzzles. An immediate consequence is that the glueballino spectrum has a hyperfine splitting. We show that the radiative decays of the excited state can explain the observed 3.5 keV X-ray line signal from clusters of galaxies, Andromeda, and the Milky Way.

The LAO/STO interface hosts a two-dimensional electron system that is unusually sensitive to the application of an in-plane magnetic field. Low-temperature experiments have revealed a giant negative magnetoresistance (dropping by 70\%), attributed to a magnetic-field induced transition between interacting phases of conduction electrons with Kondo-screened magnetic impurities. Here we report on experiments over a broad temperature range, showing the persistence of the magnetoresistance up to the 20~K range --- indicative of a single-particle mechanism. Motivated by a striking correspondence between the temperature and carrier density dependence of our magnetoresistance measurements we propose an alternative explanation. Working in the framework of semiclassical Boltzmann transport theory we demonstrate that the combination of spin-orbit coupling and scattering from finite-range impurities can explain the observed magnitude of the negative magnetoresistance, as well as the temperature and electron density dependence. I will present both experimental results and our theoretical transport model.

The observations of neutrino oscillations have shown that the neutrinos have mass and have determined their mass splittings. The existence of zero-neutrino double beta decay will show that the neutrino is its own anti-particle, and the half-life will determine the absolute mass scale. The rate for this decay is proportional to the square of a nuclear matrix element that must be calculated. I will how this matrix element together with the one involved in two-neutrino beta decay, can be understood in terms of the nuclear shell model. There are a variety of two-body operators involved that probe the particle-hole and particle-particle (pairing) correlations in the nuclear wave functions. The absolute matrix elements depend on accurate configurations mixing for the valence orbitals together with renormalizations from all of the other orbitals. The results can related to other nuclear properties including isospin symmetry, Gamow-Teller beta decay, the odd-even oscillations in the binding energies, and to nucleon transfer experiments.

Impact crater are useful tools to study planetary surfaces. First, they are natural drills into planetary crusts. I will present a combination of studies of the martian crust by the analyses of the composition of central peaks of martian impact craters. These results are part of an ERC project eMars dedicated to the geological evolution of Mars. As part of this project too, a martian data processing application has been built allowing the teleprocessing of imagery data, topographic data and hypespectral data from the 4 last martian orbiters dedicated to the surface of Mars. Secondly, impact crater statistics have recorded both bombardment and the complex geological evolution of a planetary surfaces. I will present how martian crater statistics allow to decipher the climatic evolution of the planet