,rad.in.top.dk
This process is calculable at leading LO and next-to-leading order NLO. These processes describe the hadronic production of a pair of top quarks, with one quark decaying hadronically and one quark decaying semi-leptonically. For processes 146--148, the top quark decays semi-leptonically whereas the anti-top quark decays hadronically. For processes 149--151, the top quark decays hadronically whereas the anti-top quark decays semi-leptonically. The base processes for physics are process 146 and 149 which include radiative corrections in both production and decay. Switching zerowidth from .true. to .false. only affects the W bosons from the top quark decay, because our method of including spin correlations requires the top quark to be on shell. When one wishes to calculate observables related to the decay of the top quark, removebr should be false in processes 146 and 149. The LO calculation proceeds as normal. At NLO, there are two options:
part=virt, real or tota : final state radiation is included in the production stage only
part = todk : radiation is included in the decay of the top quark also and the final result corresponds to the sum of real and virtual diagrams. Note that these runs automatically perform an extra integration, so will take a little longer.
Processes 147 and 150 include only the radiative corrections in the decay of the top quark without including the radiative corrections in the hadronic decay of the W-boson. Because of the method that we have used to include the radiation in the decays, the inclusion of the corrections in this stage of the decay does not change the total cross section. Process 148 (151) includes only the radiative corrections in the hadronic decay of the W-boson coming from the anti-top (top). The inclusion of the corrections in this stage of the decay increases the partial width by the normal αs∕π factor.
nplotter_ttbar.f is the default plotting routine.