A new evaluation of the $HZZ$ coupling: direct bounds on anomalous contributions and $CP$ violating effects via a new assymetry

Abstract

We present an evaluation of the standard model one-loop contributions to the H * Z * Z * coupling, where all the three particles are taken off-shell. Our results are presented in terms of Passarino-Veltman scalar functions. We then use the most current CMS results to obtain bounds on the off-shell H * ZZ coupling, which at the one-loop level can be parametrized in terms of two CP conserving and one CP violating form factors. The limits are studied in three different context, which are usually used to analyze the HZZ coupling. In general, such limits are of the order of 10 −2 − 10 −4 for different energy intervals. The Standard Model (SM) one-loop contributions for the H * ZZ case are revisited, whereas the HZZ * case is calculated for the first time. The imaginary part of these couplings is also studied for the first time.