PJC: Giacomo Ferrante "Accidentally Light Scalars from Large Representation"

Tuesday 2 Apr 2024, 13:00 → 14:00 Europe/Rome

INFN Sala direzione

 arxiv: 2307.10092

 

Elementary light scalar fields are notoriously difficult to obtain: as soon as we embed our theory in any sort of UV completion, their masses get corrections proportional to the scale of new physics. In models with spontaneous symmetry breaking by scalar fields in large group representations, we observe that some of the scalar masses can be loop-suppressed with respect to the naive expectation from symmetry selection rules. I will present the most minimal model — the SU(2) five-plet — with such accidentally light scalars, featuring compact tree-level flat directions lifted by radiative corrections. I will sketch some applications, from stable relics and slow roll in cosmology, to hierarchy and fine-tuning problems in particle physics. A particular focus will be devoted to constructing a successful model of hybrid inflation where slow roll dynamics takes place along an accidentally flat direction, leading to potentially interesting phenomenology.