CPsuperH2.0: An improved computational tool for Higgs phenomenology in the MSSM with explicit CP violation

We describe the Fortran code CPsuperH2.0, which contains several improvements and extensions of its predecessor CPsuperH. It implements improved calculations of the Higgs-boson pole masses, notably a full treatment of the 4 x 4 neutral Higgs propagator matrix including the Goldstone boson and a more complete treatment of threshold effects in self-energies and Yukawa couplings, improved treatments of two-body Higgs decays, some important three-body decays, and two-loop Higgs-mediated contributions to electric dipole moments. CPsuperH2.0 also implements an integrated treatment of several B-meson observables, including the branching ratios of B-s -> mu(+)mu(-), B-d -> tau(+)tau(-), B-u -> tau(v), B -> X-s gamma and the latter's CP-violating asymmetry Acp. and the supersymmetric contributions to the B-s.d(0) - (B) over bar (0)(s.d) mass differences. These additions make CPsuperH2.0 an attractive integrated tool for analyzing supersymmetric CP and flavour physics as well as searches for new physics at high-energy colliders such as the Tevatron, LHC and linear colliders.