public void doCorrection(Track trkcand, Geometry geo) {
double B = bstSwim.Bfield(Points[0][0] / 10, Points[0][0] / 10, Points[0][0] / 10).z();
double ELossMax = 600; // 600Mev
double stepSize = 0.001; // 1 MeV
int nbins = (int) ELossMax;
double pt0 = trkcand.get_Pt() + ELossMax * stepSize; // Assumes the max ELoss is 600 MeV
double pt = pt0;
double curv =
(Constants.LIGHTVEL * Math.abs(B)) * Math.signum(this.OrigTrack.get_curvature()) / pt;
for (int j = 0; j < nbins; j++) {
if (Math.abs(this.OrigTrack.get_curvature()) < Math.abs(curv)) {
double correctedCurv =
(Constants.LIGHTVEL * Math.abs(B))
* Math.signum(this.OrigTrack.get_curvature())
/ (pt + stepSize);
trkcand.get_Helix().set_curvature(correctedCurv);
trkcand.set_HelicalTrack(trkcand.get_Helix());
return;
}
pt = pt0 - j * stepSize;
double aveCurv = 0;
for (int k = 0; k < trkcand.size(); k++) {
aveCurv += doEnergyLossCorrection(k, pt);
}
aveCurv /= trkcand.size();
curv = aveCurv;
}
}
private double doEnergyLossCorrection(int m, double pt) {
double B =
bstSwim
.Bfield(Points[m][0] / 10, Points[m][0] / 10, Points[m][0] / 10)
.z(); // Bfield takes units of cm
double tanL = this.OrigTrack.get_tandip();
// pz = pt*tanL
double pz = pt * tanL;
double p = Math.sqrt(pt * pt + pz * pz);
double mass = MassHypothesis(massHypo); // assume given mass hypothesis
double beta = p / Math.sqrt(p * p + mass * mass); // use particle momentum
double gamma = 1. / Math.sqrt(1 - beta * beta);
double cosEntranceAngle = cosEntAnglesPlanes[m];
double s = eMass / mass;
// double Wmax = 2.*mass*beta*beta*gamma*gamma/(1.+2.*s*Math.sqrt(1+beta*gamma*beta*gamma)+s*s);
double Wmax = 2. * mass * beta * beta * gamma * gamma / (1. + 2. * s * gamma + s * s);
double I = 0.000000172;
double logterm = 2. * mass * beta * beta * gamma * gamma * Wmax / (I * I);
double delta = 0.;
// double dEdx =
// 0.0001535*(Constants.detMatZ/Constants.detMatA)*(Math.log(logterm)-2*beta*beta-delta)/(beta*beta);
double dEdx =
0.00001535
* Constants.detMatZ_ov_A_timesThickn
* (Math.log(logterm) - 2 * beta * beta - delta)
/ (beta * beta);
double tmpPtot = p;
double tmpEtot =
Math.sqrt(MassHypothesis(massHypo) * MassHypothesis(massHypo) + tmpPtot * tmpPtot);
// double tmpEtotCorrected = tmpEtot-dEdx*Constants.LAYRGAP/cosEntranceAngle;
double tmpEtotCorrected = tmpEtot - dEdx / cosEntranceAngle;
double tmpPtotCorrSq =
tmpEtotCorrected * tmpEtotCorrected - MassHypothesis(massHypo) * MassHypothesis(massHypo);
double newPt = Math.sqrt(tmpPtotCorrSq / (1 + tanL * tanL));
double newCurv =
(Constants.LIGHTVEL * Math.abs(B)) * Math.signum(this.OrigTrack.get_curvature()) / newPt;
return newCurv;
}