Elementary particle physics at the TeV scale

Abstract

The research group Fundamental Interactions at the TeV Scale (FITS or GIFT in Portuguese), is formed by professors and graduate students at the Instituto de Fisica Teorica-UNESP, has worked since several years ago in the physics beyond the standard model (SM). The main motivation of the group is the fact that, whatever the physics beyond the standard model is, it may be discovery at the next leptonic or hadron colliders. Their consequences in astrophysics and cosmological processes should be studied too. In particular the group study the following issues: Colliders Physics: we study, in particular, in context of the next colliders, LHC and ILC, many observables that will be measured. For instance, in models with extra Z' vector bosons, several asymmetries can be studies at the pole or far away from it. These models also have right-handed neutrinos and extra Higgs scalars and their phenomenology must be studied; Scalar Higgs phenomenology: most of the extensions of the standard model imply a large Higgs sector that can be elementary or composite particles. In either case, their effects may be discovery indirectly by the low energy physics, directly in the next generations of colliders. They may also have cosmological consequences; Mass generation, leptonic and hadronic mixing matrices: whatever the new physics beyond the standard model is, we hope that it will give, at least, some insight concerning the origin of the masses and mixing matrices. Thus, we are considering this issue in several models that we have proposed in the past and other we are working on at present; Raditive correction effects: in the context of the standard model the Coleman-Weinberg mechanism has been excluded at the 1-loop level not only for cosmological troubles but also by the large mass of the quark top. We are interested in the possibility that it may be implemented in other models like the 3-3-1 ones. This may have consequences on the hierarchy problem and maybe it may be the mechanism for stabilizing the electroweak scale; Axions and neutrino masses mechanism: the group is studying the possible relation between axions and the generation of neutrino masses. The axion must be invisible and at the same time the PQ symmetry must be an automatic symmetry of the classical lagrangian involving the degrees of freedom of the SM. The axion parameters must also be stabilized i.e., keep the axion as a solution to the strong CP problem, against possible effects of semiclassical gravity. An inter-esting issue that we will particularly concerned are axion models in which the axion parameters are related to the neutrino masses; Grand unification models: we are also considering grand unification theories (GUT) without super symmetry at the TeV scale. For example, this symmetry may be realized at higher scale, say, the PQ scale. In particular we are studying a super gravity SU(5) model in which the standard model degrees of freedom are not in complete multiplets of SU(5). Other models based on different symmetries will also be considered. Summarizing, the main goal of the present research project is to study, from the phe¬nomenological and quantum field theory points of view, gauge models that may describe the fundamental interactions at the TeV scale. In fact, the discovery of new physics at this energy scale is the main subject of the experimental physics in the present decade. We will consider multi-Higgs extensions of the SM, left-right and Pati-Salam models, models with SU(3)w symmetry, with extra dimensions, with and without super symmetry, and some GUTs models like SU(5), SU(5) x U(1), E6’, SU(6), and SU(6) x U(1). In fact, to discover the physics at work at the TeV scale is the main concern of the elementary particle physics in the next decade. (AU)