CARLOMAT_3.0, an automatic tool for the electron-positron annihilation into hadrons at low energies

A new version of CARLOMAT that allows to generate automatically the Monte Carlo programs dedicated to the description of the processes e+e- -> hadrons at low center-of-mass energies is presented. The program has been substantially modified in order to incorporate the photon-vector meson mixing terms and to make possible computation of the helicity amplitudes nvolving the Feynman interaction vertices of new tensor structures, like those predicted by the Resonance Chiral Theory or Hidden Local Symmetry model, and the effective Lagrangian of the electromagnetic interaction of the nucleons. Moreover, a number of new options have been introduced in the program in order to enable a better control over the effective models implemented. In particular, they offer a possibility to determine the dominant production mechanisms of the final state chosen by the user.Comment: 15 pages, 5 figures, matches version to be published in Computer Physics Communication