  The calculation of rare loop decays in the Standard Model of Particle Physics
and its extensions is an extremely tedious work. The Mathematica package
MasterTwo facilitates this task. It automatically calculates all loop integrals
reducible to scalar integrals depending on up to two different masses
independent of external momenta. MasterTwo consists of two sub packages,
Fermions and Integrals. Whereas Fermions covers the standard Dirac Algebra,
Integrals performs the Taylor expansion, partial fraction, tensor reduction and
the integration of the thus achieved scalar integrals. The package works
completely inside Mathematica and can be easily customised for both educational
and research purposes.
