#include <TMath.h>
#include <iostream>

double powerGauss(double* xArray, double* par){
  double mu      = xArray[0];
  double alpha   = par[0];  
  double sigma   = par[1];      
  double y       = TMath::NormQuantile(1. - alpha);
  double power   = TMath::Freq(mu/sigma - y);
  return power;
}