Neutrino Masses in Extended Higgs Models
IDPASC Portugal - PHD Programme 2016
2016 / 2017
Theoretical Particle Physics
J W F Valle
Instituto Superior Técnico
Centro de Física Teórica de Partículas
The spontaneous breaking of the standard SU(3)_c x SU(2)_L x U(1)_Y electroweak gauge symmetry initially proposed in 1964 by Peter Higgs and others leads to the existence of an elementary scalar particle. After CERN announced the monumental discovery of a particle with Higgs-like properties, Higgs and Englert received the 2013 Physics Nobel Prize. This particle corresponds to a spin-zero field, necessary to give mass to the remaining particles in the Standard Model of electroweak interactions, playing a central role in the formulation of the standard model and its extensions. As there is no fundamental argument determining the number of scalar particles, one should settle this question experimentally looking for the differences which will exist in case there are more than one scalar. This has become more important after both ATLAS and CMS reported signs of a possible second scalar occurring at 750 GeV. Moreover, in some models, extensions of the minimal Higgs model are needed in order to explain the smallness of neutrino masses. In this project, we wish to explore the consequences of the presence of more than one Higgs field, specially in seesaw models which give mass to neutrinos, a fact that was at the origin of 2015 Physics Nobel Prize. The project will be co-supervised by Jorge C. Romão and José W.F. Valle and can be more theoretical or phenomenological, depending on the interests of the student. We have a large publication record and impact in this field; the last student working with us on similar topics had two published articles in about one year.