ShowerDepth.cc

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#include "RecoEgamma/EgammaTools/interface/ShowerDepth.h"
#include <cmath>

using namespace hgcal;

float ShowerDepth::getClusterDepthCompatibility(float measuredDepth, float emEnergy, float& expectedDepth, float& expectedSigma) const {
    float lny = (emEnergy > criticalEnergy_) ? std::log(emEnergy/criticalEnergy_) : 0.;

    // inject here parametrization results
    float meantmax = meant0_ + meant1_*lny;
    float meanalpha = meanalpha0_ + meanalpha1_*lny;
    if ( meanalpha < 1. ) meanalpha = 1.1; // no poles
    float sigmalntmax = 1. / (sigmalnt0_+sigmalnt1_*lny);
    float sigmalnalpha = 1. / (sigmalnalpha0_+sigmalnalpha1_*lny);
    float corrlnalphalntmax = corrlnalphalnt0_+corrlnalphalnt1_*lny;

    float invbeta = meantmax/(meanalpha-1.);
    float predictedDepth = meanalpha*invbeta;
    predictedDepth *= radiationLength_;

    float predictedSigma = sigmalnalpha*sigmalnalpha/((meanalpha-1.)*(meanalpha-1.));
    predictedSigma += sigmalntmax*sigmalntmax;
    predictedSigma -= 2*sigmalnalpha*sigmalntmax*corrlnalphalntmax/(meanalpha-1.);
    if ( predictedSigma < 0. ) predictedSigma = 1.e10; // say we can't predict anything
    predictedSigma = predictedDepth*std::sqrt(predictedSigma);

    expectedDepth = predictedDepth;
    expectedSigma = predictedSigma;
    return (measuredDepth-predictedDepth)/predictedSigma;
}