This series consists of talks in the areas of Particle Physics, High Energy Physics & Quantum Field Theory.
Observing lepton-number violating processes is a decisive step toward establishing the Majorana nature of the neutrino mass. We explore the prospects searching for Delta L = 2 processes and propose the tests for the three types of the Seesaw mechanisms. Potential signals at the LHC
are studied and correlations to the neutrino oscillation parameters are investigated.
Two uncertainties define the prevailing attitude toward the LHC: uncertainty about what new physics it may find (if any); together with dissatisfaction with the "technical naturalness" arguments which (when applied to the hierarchy problem) help suggest what it should be looking for. The dissatisfaction arises because of a wide-spread despair about finding a technically natural solution to the cosmological constant problem, despite much effort spent seeking it.
I will discuss cosmological, astrophysical and collider constraints on thermal dark matter with mass in the range 1 MeV to 10 GeV. CMB observations can be evaded if the DM relic density is sufficiently asymmetric, while collider constraints generally require sufficiently light mediators. These light mediators can give rise to significant DM self-interactions, and I will describe bounds on such interactions from dark matter halo shapes.
We propose that the fermionic superpartner of a weak-scale Goldstone boson can be a nat- ural WIMP candidate. The p-wave annihilation of this `Goldstone fermion' into pairs of Gold- stone bosons automatically generates the correct relic abundance, whereas the XENON100 direct detection bounds are evaded due to suppressed couplings to the Standard Model. Further, it is able to avoid indirect detection constraints because the relevant s-wave annihi- lations are small.
We show that a baryon asymmetry can be generated by dissipative effects during warm inflation via a supersymmetric two-stage mechanism, where the inflaton is coupled to heavy mediator fields that then decay into light species through B- and CP-violating interactions. In contrast with thermal GUT baryogenesis models, the temperature during inflation is always below the heavy mass threshold, simultaneously suppressing thermal and quantum corrections to the inflaton potential and the production of dangerous GUT relics.