Studies on Conformal and Superconformal Extensions of the Standard Model with an Application to Gravity

Abstract

In this thesis we study some theoretical and phenomenological aspects of classical conformal symmetry in specific extensions of the SM. We consider both supersymmetric and non supersymmetric cases. We discuss the perturbative structure of the superconformal anomaly effective action. We show that the manifestation of the anomaly is in the presence of massless intermediate states in correlators involving the Ferrara-Zumino supercurrent with two vector supercurrents. This universal feature is typical both of chiral and conformal anomalies. These results are used in a study of a possible extension of the SM with a dilaton, deriving some bounds on a possible conformal scale. Then we turn to investigate a specific superconformal theory, the TNMSSM, which extends the MSSM with one extra triplet and a scalar singlet superfield. The manifestation of the classical conformal symmetry in this model is in the existence of a very light pseudoscalar in the physical spectrum. We study the main proprieties of this state and its potential discovery at the LHC. In the last part of this work we discuss an application of the graviton-photon-photon vertex to gravitational lensing for a Schwarzschild background. In particular, we introduce the notion of a semiclassical lens equation for the deflection of a photon nearing the horizon of a black hole.

185 pages, 84 figures, Ph.D. thesis

References in corpus (20)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Combined Measurement of the Higgs Boson Mass in $pp$ Collisions at $\sqrt{s}=7$ and 8 TeV with the ATLAS and CMS Experiments
• Precise determination of the mass of the Higgs boson and tests of compatibility of its couplings with the standard model predictions using proton collisions at 7 and 8 TeV
• SARAH 3.2: Dirac Gauginos, UFO output, and more
• Light scalar at LHC: the Higgs or the dilaton?
• Measurements of Higgs boson production and couplings in the four-lepton channel in $pp$ collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector
• Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions
• PYTHIA 6.3 Physics and Manual
• Search for charged Higgs bosons decaying via $H^{\pm }\to {\tau }^{\pm }\nu$ in fully hadronic final states using $pp$ collision data at $\sqrt{s}=8$ TeV with the ATLAS detector
• Minimal but non-minimal inflation and electroweak symmetry breaking
• Triplet Extended Supersymmetric Standard Model
• Triplet-Singlet Extension of the MSSM with a 125 Gev Higgs and Dark Matter
• Multi-Lepton Signatures of the Triplet Like Charged Higgs at the LHC
• Gravity and the Neutral Currents: Effective Interactions from the Trace Anomaly
• A Light Supersymmetric Axion in an Anomalous Abelian Extension of the Standard Model
• Axion and Neutralinos from Supersymmetric Extensions of the Standard Model with anomalous U(1)'s
• Charged Higgs boson phenomenology in Supersymmetric models with Higgs triplets
• Left-right supersymmetry after the Higgs boson discovery
• Dilaton cosmology and phenomenology
• Stability constraints in triplet extension of MSSM