Double_t SGaussPol2(Double_t *x, Double_t *par)
{
 Double_t arg = 0, arg2 = 0, arg3 = 0, arg4 = 0, arg5 = 0;
 if (par[3]) {
   arg = (x[0]-par[2])/par[3];
   arg2 = 1/(TMath::Sqrt(2*TMath::Pi())*par[3]);
   arg3 = par[4]/(2*par[3]);
 }
 if (par[5]) {
   arg4 = par[4]/(4*par[5]);
 }

 Double_t sig2 =
   par[0]*(
            par[1] * arg2 * TMath::Exp(-arg*arg/2)
         +  (1-par[1]) * arg3 * TMath::Exp(par[4]*par[5]*(par[6]-arg4)) * 
             TMath::Exp(-par[4]*arg) *(1+TMath::Erf(par[5]*arg-par[6]))
           )
 + par[7] + par[8]*x[0] + par[9]*TMath::Power(x[0],2);
 return sig2;

}