Research seminar from HEP Theory Antonio Delgado 3 faculty members: Profs. Bigi, Kolda and myself 1 postdoc – David Diego 5 graduate students: Bryan Dudley, Joel Griffith, Pokie Olson, Ayan Paul & Dipajan Ray I am actively looking for one student, Prof. Kolda may and Prof. Bigi is not

The goal of theoretical particle physics is to understand the ultimate building blocks of nature The standard model of particle physics consists of: uct dsb quarks eμτ νeνe νμνμ ντντ leptons vector bosons γ g W Z higgs bosonh Not yet discovered!!!

For that purpose we use the language of Quantum Field Theory the theory that results when Quantum Mechanics and Special Relativity are merged:

Although very successful from the experimental point of view some predictions have been tested to great accuracy, it is far from being a complete theory: the higgs is still to be discovered the rôle of the higgs itself introduces certain problems into the theory Therefore theorist go beyond the SM in order to address questions of physics at TeV scales

Let me summarize the research interests of the other two senior members of the group: ✴ Professor Bigi is interested in flavour physics, i.e., the physics that deals with the interaction between the different families of quarks and leptons. These processes are rare in the SM and evidence for new physics can come in an excess of some of this effects. He is also a susy fan. ✴ Professor Kolda is interested in supersymmetry as a direction for physics BSM. Supersymmetry predicts the existence of new particles to be discovered at the LHC and provides us with a nice explanation for the EW scale.

In my case I am interested in the EW sector and studying models that may provide us with an explanation of what the higgs is and why it is much lighter than the Planck mass There are models where the higgs is a fundamental particle and the scale is protected by a symmetry: susy, little higgs There are even models without a higgs

My work is on the study of different models, their viability both on the theoretical side, i.e. no inconsistencies, and on the experimental side, i.e. they do not contradict any measurement we have already done. It is a great opportunity that LHC will start to collect data next years and to probe the TeV scale so it will be a challenging time for particle physics. Because of that we have to take advantage of our experimental colleagues that have a major rôle in CMS

As a last word I should say that the group is also interested on any interplay of particle physics and cosmology taking into account that there is a very good astro group here in ND.