## grc4f

 {\tt grc4f}} is a Monte-Carlo package
for generating $e^+e^-\to 4\hbox{-fermion}$ processes in
the standard model. All of the 76 LEP-2
allowed fermionic final state
processes evaluated at tree level are included in version 1.0.
{\tt grc4f} addresses event simulation requirements at $e^+e^-$
colliders such as LEP and up-coming linear colliders.
Most of the attractive aspects of {\tt grc4f} come from its link
to the {\tt GRACE} system: a Feynman diagram automatic computation
system.The {\tt GRACE} system has
been used to produce the computational code for all final states, giving
a
higher level of confidence in the calculation correctness.
Based on the helicity amplitude calculation technique,
all fermion masses can be kept finite
and helicity information can be propagated down to the final state
particles.
The phase space integration of the matrix element
gives the total and differential cross sections, then unweighted events
are Generated. Initial state
radiation (ISR) corrections are implemented in two ways, one is based on
the
electron structure function
formalism and the second uses the parton shower algorithm called {\tt
QEDPS}.
The latter can also
be applied for final state radiation (FSR) though the interference with
the
ISR is not yet taken into account. Parton shower and hadronization of
the final quarks are performed through an interface to
{\tt JETSET}. Coulomb correction between two intermediate $W$'s,
anomalous coupling as well as gluon contributions
in the hadronic processes are also included.

E-mail:grace@suchi.kek.jp