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Manuscript Title: GRAPE-Dilepton (version 1.1) a generator for dilepton production in ep collisions.
Authors: T. Abe
Program title: GRAPE-Dilepton (v1.1)
Catalogue identifier: ADNR_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 136(2001)126
Programming language: Fortran.
Operating system: UNIX.
RAM: 9M words
Keywords: Elementary particle physics, QCD, Dilepton, Lepton-pair, ep collision, Bethe-Heitler, Z boson, Dipole form factor, Hadron tensor, Lepton tensor, Structure function, Parton density, GRACE.
Classification: 11.5.

Nature of problem:
A precise estimation of the cross-section of the electroweak dilepton production in ep collisions is required in various physics analyses, where 8~48 Feynman diagrams can contribute.

Solution method:
The automatic calculation system GRACE is used to obtain all of the relevant helicity amplitudes. The phase space is divided into the 3 regions according to the kinematics at the proton vertex, and the 3 different calculation methods are applied. The radiative corrections are included using the structure function and the parton shower methods.

Restrictions:
Higgs, the proton-Z0 coupling and lepton-pair production through photon radiation from the proton are not included. The contribution from the resolved photon, i.e. Drell-Yan process in ep collisions is not included.

Running time:
1 hour for a cross-section integration and 1 msec per 1 event for an event generation.