Towards a Minimal Particle-Cosmology Supersymmetric Standard Model

por Apostolos Pilaftsis (University of Manchester)

viernes 4 abr. 2008 12:00 → 13:00 Europe/Madrid

Sala Seminarios (Dpto. de Física Teórica (UVEG))

I will present a novel and minimal supersymmetric framework of hybrid inflation, which has been called $F_D$-term hybrid inflation. The $F_D$-term hybrid model utilizes a subdominant Fayet--Iliopoulos $D$-term whose presence explicitly breaks a $D$-parity in the inflaton-waterfall sector. This scenario of inflation can naturally predict lepton number violation at the electroweak scale, by tying the $\mu$-parameter of the MSSM to an SO(3)-symmetric Majorana mass $m_N$, via the vacuum expectation value of the inflaton field. In my talk, I will show how a negative Hubble-induced mass term in a next-to-minimal extension of supergravity helps to accommodate the present CMB data and considerably weaken the strict constraints on the theoretical parameters, resulting from cosmic string effects on the power spectrum. The usual gravitino overabundance constraint may be significantly relaxed in this model, once the enormous entropy release from the late decays of the ultraheavy waterfall gauge particles is properly considered. As the Universe enters a second thermalization phase involving a very low reheat temperature, which might be as low as about 0.3 TeV, thermal electroweak-scale resonant leptogenesis provides a viable mechanism for successful baryogenesis, while thermal right-handed sneutrinos emerge as new possible candidates for solving the cold dark matter problem. The $F_D$-term hybrid model offers rich particle-physics phenomenology, which could be probed at high-energy colliders, as well as in low-energy experiments of lepton flavour or number violation.