Seminarium "Teoria cząstek elementarnych i kosmologia"

The associated production of a Higgs boson with a vector boson, W or Z, provides the third-largest cross section for Higgs boson production at the LHC. Furthermore, it is an important process for the measurement of the Higgs coupling to bottom quarks, which is difficult in other Higgs production processes due to large backgrounds. The process of ZH production receives contributions from a gluon-initiated subprocess, which formally enters at higher orders in QCD, but is enhanced due to the large gluon luminosity at a hadron collider.  In this talk, I will present recent calculations for the 2-loop virtual amplitudes for this process valid in general kinematics, as well as the calculation of the associated 3-loop virtual amplitudes in the large top mass expansion. Afterwards, I present the public C++ library ggxy, where these corrections are implemented and which allows to freely modify all input parameters, such as the top-quark mass and its renormalization scheme and the masses of the external Z and Higgs bosons.  In addition, ggxy has been interfaced to Powheg and Herwig, which allows the matching to parton showers.