Flavor changing neutral decay effects in models with two Higgs boson doublets: Applications to LHC Physics

TL;DR

This thesis investigates flavor changing neutral current effects in top quark and Higgs boson decays within Two Higgs Doublet Models and the MSSM, emphasizing potential signals at the LHC to explore physics beyond the Standard Model.

Contribution

It provides detailed calculations of FCNC decay branching ratios and event rates in 2HDM and MSSM, applying experimental constraints to identify observable signatures at the LHC.

Findings

FCNC effects can be significant in 2HDM and MSSM

LHC can potentially detect FCNC signals beyond the Standard Model

Experimental constraints like b -> sγ restrict FCNC process rates

Abstract

In this Thesis we have investigated some effects appearing in top quark and Higgs boson decays with flavor changing neutral currents (FCNC) in the framework of generic Two Higgs Doblet Models (2HDM) and the Minimal Supersymmetric Standard Model (MSSM). We have applied these two extensions to the SM to see whether they can produce new FCNC effects. Introductory chapters deal with the 2HDM and the MSSM. In the next chapters we have computed the following FCNC decays: (1) the branching ratios (B) of the top quark to Higgs bosons and charm quark in the 2HDM; (2) B and number of events at the Large Hadron Collider (LHC) of the Higgs bosons to top and charm quarks in the 2HDM; (3) B of the Higgs bosons to bottom and strange quarks in the MSSM; (4) cross section and number of events at the LHC of the Higgs bosons to FCNC final states involving the heavy quarks like the top and bottom quark in the MSSM (Higgs bosons = h^0, H^0, A^0). We also studied the experimental signatures that would allow discover of the nature of these Higgs bosons in the LHC. In this study we have applied the severe restrictions from observed low-energy FCNC processes like b -> s\gamma. Our general conclusion is that the physics of the processes with flavor changing neutral currents can be very important in seeing the physics beyond the Standard Model and to disentangle the nature of the most adequate model. Experiments at the LHC can be crucial to unravel signs of FCNC physics beyond the SM.