Processes 302 and 307 represent the production of a Z boson (or virtual photon) in association with a real photon and at least one jet. The Z∕γ* subsequently decays into either an e+e- pair (nproc=302) or neutrinos (nproc=307). Since these processes include a real photon and a jet, the cross section diverges when the photon or jet is very soft or in the direction of the beam. Thus in order to produce sensible results, the input file must supply values for both gammptmin and gammrapmax, and ptjetmin and etajetmax. Moreover, when the parameters zerowidth and removebr are set to .false., the decay Z → e-e+ (nproc=302) will include photon radiation from both leptons, so that a non-zero R(γ,ℓ)min (Rgalmin) should also be supplied. This will ensure that the cross section is well-defined. The calculation of processes 302 and 307 may be performed at NLO using the Frixione algorithm [1] or standard isolation. Anomalous couplings are not currently implemented for these processes.
nplotter_zgamjet.f is the default plotting routine.
[1] S. Frixione, Isolated photons in perturbative QCD, Phys. Lett. B429 (1998) 369 [hep-ph/9801442].