Beam-beam effects simulation for VEPP-2M with flat and round beams

Increasing of the luminosity is one of the main reasons of VEPP-2M optics modernization and transition from flat to round beams, which can be realized by a few optical schemes, including so-called Mobius lattice. The beam-beam simulations have been performed for the different schemes of VEPP-2M optics, such as Mobius, conventional round (equal betatron tunes), and flat beams. The main source of nonlinearities on the ring, sextupoles, have been accounted as well as nonlinear beam-beam kick. The simulations show an essential advantage of the round beams over the flat ones, but the Mobius scheme turns out to be more difficult for realization and in general worse than the conventional round beams