Double_t tPhi0 = GetPsi() + GetCharge() * 0.5 * pi / fabs(GetCharge()) ;
Double_t x0 = GetR0() * cos(GetPhi0()) ;
Double_t y0 = GetR0() * sin(GetPhi0()) ;
Double_t tPhi0 = GetPsi() + GetCharge() * 0.5 * pi / fabs(GetCharge()) ;
Double_t x0 = GetR0() * cos(GetPhi0()) ;
Double_t y0 = GetR0() * sin(GetPhi0()) ;