HFEGammaSLCorrector.cc

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#include "HFEGammaSLCorrector.h"
#include "CLHEP/Vector/LorentzVector.h"

namespace hf_egamma {

    double eSeLCorrected(double es, double el, double pc, double px, double py){
        double x  = log(el/100) ;
        double y  = es / el ;
        return pc + px*x + py*y ;
    }

    double eSeLCorrected(double es, double el, int era){
        double pc=0.0,px=0.0,py=0.0;

        switch (era) {  
            case (0): //Data 41
                pc = -1.02388e-1 ;
                px = -1.51130e-1 ;
                py =  9.88514e-1 ;
                break;
            case (1): //Fall 10 MC
                pc = -4.06012e-2 ;
                px = -1.34769e-1 ;
                py =  9.90877e-1 ;
                break;
            case (2): //Spring 11 MC
                pc =   5.98732e-3 ;
                px =  -1.74767e-1 ;
                py =   9.84610e-1 ;
                break;
            case (3): //Summer 11 MC
                pc =  -0.036416 ;
                px =  -0.195854 ;
                py =  0.980633 ;
                break;
                    case (4): //July 5 Data
                            pc = -0.008077 ;
                                px = -0.216002 ;
                        py = 0.976393 ;
                break;
        }

        //After fitting the 2D histogram, we find a y-intercept b, a slope m, 
        //and a point x0 around which we choose to rotate the data points. We 
        //will map (x,y) --> (x,y') where y' = pc + px*x + py*y, with 
        //pc = sin(atan(m))*x0 - cos(atan(m))*(m*x0+b), px = -sin(atan(m)), 
        //and py = cos(atan(m)). This transformation preserves the x-value of the 
        //data point and takes y' to be the y-value of the original point after it 
        //is rotated through angle atan(m) (to flatten the line of best fit) and 
        //transposed vertically downward by b (to make the line of best fit coincide with the x-axis).

        return eSeLCorrected(es, el, pc, px, py) ;
    }
}