Paper detail

Parameterization of General Z-gamma-Z' Mixings in an Electroweak Chiral Theory

A new general parameterization with eight mixing parameters among Z, gamma and an extra neutral gauge boson Z' is proposed and subjected to phenomenological analysis. We show that in addition to the conventional Weinberg angle theta_W, there are seven other phenomenological parameters G', xi, eta, theta_l, theta_r, r, l for the most general Z-gamma-Z' mixings, in which parameter G' arises due to the presence of an extra Stueckelberg-type mass coupling. Combined with the conventional Z-Z' mass mixing angle theta', the remaining six parameters xi, eta, theta_l-theta', theta_r-theta', r, l are caused by general kinetic mixings. In all the eight phenomenological parameters theta_W, G', xi, eta, theta_l, theta_r, r, l, we can determine the Z-Z' mass mixing angle theta' and the mass ratio M_Z/M_Z'. The Z-gamma-Z' mixings we discuss are based on the model-independent description of the extended electroweak chiral Lagrangian (EWCL) previous proposed by us. In addition, we show that there are eight corresponding independent theoretical coefficients in our EWCL which are fully fixed by our eight phenomenological mixing parameters. We further find that the experimental measurability of these eight parameters does not rely on the extended neutral current for Z', but depends on the Z-Z' mass ratio.