Studying the physics beyond the Standard Model in rare semileptonic B-decay B--> K* mu+ mu- with ATLAS detector

The different analytical expressions for matrix element for B^0_d --> K^*0 mu+ mu- were implemented into PYTHIA and compared with results obtained with standard PYTHIA matrix element. It is shown that the matrix element do not change an inclusive parameters of muons and K^*0-meson, but strongly influence on the spectra of dimuon mass and forward-backward charge asymmetry. The signal-to-background ratio for the worse case is expected to be 1. It will allow us to measure the characteristics of B^0_d --> K^*0 mu+ mu- decay with sufficient accuracy to make choice between SM ans some variants of MSSM after 3 years LHC run at low luminosity.