DSTUtil::RICH Namespace Reference

Functions
bool	GoodSeed (const MIPPRICHSummary *rich, float ptot)
	Returns true if RICH summary object is likely to come from a valid ring.
float	CorrectedRad (const MIPPRICHSummary *rich)
	Returns ring radius corrected for position and radius dependent ripples from geometric effect of missing columns in the RICH.
int	SimpleRadPID (const MIPPEventSummary *evt, const MIPPTrackSummary *trk)

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Function Documentation

bool DSTUtil::RICH::GoodSeed	(	const MIPPRICHSummary *	rich,
		float	ptot
	)

Returns true if RICH summary object is likely to come from a valid ring.

Definition at line 1031 of file DSTUtil.cxx.

References MIPPRICHSummary::rad, MIPPRICHSummary::xr, MIPPRICHSummary::xseed, MIPPRICHSummary::yr, and MIPPRICHSummary::yseed.

Referenced by NuMIPID::Fill().

{
  if (rich->rad < 8 || rich->rad > 34) return false;
  if (ptot < 0.5) return false;

  float dx = rich->xseed - rich->xr;
  float dy = rich->yseed - rich->yr;

  const float coeffX = 360;
  const float coeffY = 400;

  if (ptot > 120) ptot = 120;

  float maxDX = coeffX / ptot;
  if (maxDX > 10) maxDX = 10;
  float maxDY = coeffY / ptot;
  if (maxDY > 10) maxDY = 10;

  // Stay within half the window
  dx /= 0.5 * maxDX;
  dy /= 0.5 * maxDY;

  return dx*dx + dy*dy <= 1;
}

float DSTUtil::RICH::CorrectedRad

(

const MIPPRICHSummary *

rich

)

Returns ring radius corrected for position and radius dependent ripples from geometric effect of missing columns in the RICH.

Definition at line 1060 of file DSTUtil.cxx.

References MIPPRICHSummary::rad, MIPPRICHSummary::xr, and MIPPRICHSummary::yr.

Referenced by NuMIPID::Fill(), main(), and SimpleRadPID().

{
  const double kOmegaX = 0.5 * 3.141592 / 1.396746;

  // Compute radius-dependent amplitudes
  double Ax = -0.1331;
  double r = rich->rad;
  if (r > 29.5) r = 29.5;
  double Ax4 = 7.44922e-02 - 
    pow((3.01123e+01 - r) * 2.26274e+01, -7.05946e-01);
  double Ay = -4.82457e-02 -
    pow((3.99752e+01 - r) * 1.08708e-01, -2.13366e+01);
  double omegaY = 0.22;
  double phaseY = 0.5;
  
  // Compute corrections in x and y
  double corrX = Ax * sin(kOmegaX * rich->rad) * cos(kOmegaX * rich->xr) +
    Ax4 * cos(kOmegaX * rich->xr * 0.25);
  double corrY = Ay * cos(omegaY * rich->yr + phaseY);

  return rich->rad - corrX - corrY;
}

int DSTUtil::RICH::SimpleRadPID	(	const MIPPEventSummary *	evt,
		const MIPPTrackSummary *	trk
	)

Definition at line 1085 of file DSTUtil.cxx.

References CorrectedRad(), MIPPEventSummary::GetRICH(), MIPPTrackSummary::irich, PIDDef::kMuon, PIDDef::kProton, PIDDef::kRBmass, PIDDef::kUndef, RICH::L, p, and MIPPTrackSummary::ptot.

Referenced by main().

                                                             {
  MIPPRICHSummary* rich = evt->GetRICH(trk->irich);
  if (!rich) return PIDDef::kUndef;
  
  double p = trk->ptot;
  double r = DSTUtil::RICH::CorrectedRad(rich);
  //const double dr = 1;
  //const double dp = 5;

  double L = 990.0;  // Length of RICH radiator volume in cm
  double n = 1.00045;// Index of Refraction for this run
  double Theta;      // Cerenkov angle
  double Beta;       // p/E for particle
  double masssqr;    // Particle mass^2
  Theta = asin(r/L);
  Beta = 1. / n / (1. - 0.5*pow(Theta, 2));
  
  masssqr = (pow(p/Beta, 2) - pow(p, 2));

  int id=PIDDef::kUndef;
  for (int i=PIDDef::kProton; i!=PIDDef::kMuon; --i) {
    double msq = PIDDef::kRBmass[i] * PIDDef::kRBmass[i];
    if (fabs(1-masssqr/msq) < 0.05) {
      id = i;
      break;
    }
  }

  return id;
}

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