Flavor structure of the three site Higgsless model

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-changing neutral current (FCNC) in the light sector at the tree level. Owing to the flavor mixing between the light and heavy partner fields, new effects on FCNCs appear at the one-loop level. As an example of such FCNC processes, we calculate the contribution to the b → sγ amplitude in the three site Higgsless model. Interestingly, heavy particles that exist in the three site Higgsless model do not completely decouple in the heavy-mass limit. The one-loop level b → sγ amplitude is calculated by considering all possible combinations of particles in the loop; then, it is compared with the experiment. The result shows that the central value of the B → Xsγ branching ratio in the three site Higgsless model is closer to its experimental central value as one takes the larger value of a free parameter, εtR, within a range allowed by the precision electroweak measurement. (author)