6533b86cfe1ef96bd12c88a4

RESEARCH PRODUCT

Extra dimensions at the one loop level: Z -> b(b)over-bar and B-(B)over-bar mixing

subject

description

We study, at the one loop level, the dominant new physics contributions from extra dimensions to Z -> b(b)over-bar, as well as B-(B)over-bar and K-(K)over-bar mixing. We use a model with one extra dimension containing fermions which live in four dimensions, and gauge bosons and one scalar doublet propagating in five dimensions. We find that the effect of the infinite tower of Kaluza-Klein modes in Z -> b(b)over-bar is finite and gives a negative correction to Rb = Γb/Γh, which is used to set a lower bound of 1 TeV on the compactification scale Mc. On the other hand, we show that the box diagrams contributing to B-(B)over-bar and K-(K)over-bar mixing are divergent and, after proper regularization, we find that they increase the value of the function S(xt) which governs this mixing. The obtained value is perfectly compatible with available data.