Flavor Structure of the Three Site Higgsless Model

TL;DR

This paper investigates the flavor structure and FCNC effects in the three site Higgsless model, highlighting how heavy particles influence rare B meson decays and comparing theoretical predictions with experimental data.

Contribution

It introduces a detailed analysis of flavor mixing and FCNC processes in the three site Higgsless model, including the calculation of the b -> s gamma amplitude at one-loop level.

Findings

Heavy particles do not fully decouple at high masses.

The model's predictions for B -> X_s gamma align better with experiments for larger _{tR}.

One-loop FCNC effects are significant in constraining the model.

Abstract

We study the flavor structure in the three site Higgsless model. In this model, the gauge bosons and fermions have heavy partners, coming from the Kaluza-Klein excitation in the dimensional deconstruction picture. The yukawa couplings are introduced in a way to minimize the flavor chaning neutral current in the light sector at the tree level. Due to the flavor mixing between the light and the heavy partner fields, new effects on FCNC's appear at one-loop level. As an example of such FCNC processes, we calculate the contribution to the b -> s gamma amplitude in the three site Higgsless model. Interestingly, heavy particles which exist in the three site Higgsless model do not completely decouple in the heavy-mass limit. One-loop level b -> s gamma amplitude is calculated by considering all possible combinations of particles in the loop, then it is compared to the experiment. The result shows that the central value of the B -> X_s gamma branching ratio in the three site Higgsless model takes closer value to its experimental central value as one takes the larger value of a free parameter, \varepsilon_{tR}, within a range allowed by the precision electroweak measurement.