## July 2, 2002

Efficiency at 20 GeV -- PiMinus, KMinus and Pbar

See
eff.html for details on procedure followed.

The present efficiencies were obtained from the series 901-905, for a
total
of 3149 events, after centrality (10% most central) and vertex (vtxZ<30)
cuts. Total number of events in MC before cuts = 96517.

In the Mc, it was used a hijing distribution in Pt, not a flat
distribution in Pt. Hence the stats for high Pt in Pions is poor. See
the distribution in
eff.html . Also, binomial errors were used for the efficiencies.

Note: in the figures, the fits were done to the function

m1*exp(-1*(m2/Pt)^m3) (i.e., M0 stands for Pt)

A) y=0

1)
efficiency PiMinus, fit to all points

efficiency PiMinus, fit excluding low Pt

2)
efficiency KMinus, fit to all points

efficiency KMinus, fit excluding low Pt

3)
efficiency Pbar, fit to all points

efficiency Pbar, fit excluding low Pt

B) y=.2

efficiency PiMinus, fit excluding low Pt

efficiency KMinus, fit excluding low Pt

efficiency Pbar, fit excluding low Pt

C) y=.4

efficiency PiMinus, fit excluding low Pt

efficiency KMinus, fit excluding low Pt

efficiency Pbar, fit excluding low Pt

The next show the fits used to correct the spectra.

efficiencies at y=0

efficiencies at y=.2

efficiencies at y=.4

cuts Mc:

centCut= mNUncorrectedPrimaries>=237 (10% most central)

vtxCut= abs(mVertexZ)<30&&((mVertexX+0.246)^2+(mVertexY-0.378)^2)<1

eventCut = centCut+vtxCut

ycuts (example for y=0)

yCut=(asinh((mMcTracks.mPtMc/(1/sinh(mMcTracks.mEtaMc)))/sqrt(0.13956995^2+mMcTracks.mPtMc^2))>-.1)&&(asinh((mMcTracks.mPtMc/(1/sinh(mMcTracks.mEtaMc)))/sqrt(0.13956995^2+mMcTracks.mPtMc^2))<.1)

pCut= eventCut + yCut

cuts Matched tracks:

centCut= mNUncorrectedPrimaries>=237 (10% most central)

vtxCut= abs(mVertexZ)<30&&((mVertexX+0.246)^2+(mVertexY-0.378)^2)<1

eventCut = centCut+vtxCut

ycuts (example for y=0)

yCut=(asinh((mMatchedPairs.mPtMc/(1/sinh(mMatchedPairs.mEtaMc)))/sqrt(0.13956995^2+mMatchedPairs.mPtMc^2))>-.1)&&(asinh((mMatchedPairs.mPtMc/(1/sinh(mMatchedPairs.mEtaMc)))/sqrt(0.13956995^2+mMatchedPairs.mPtMc^2))<.1)

hitsCut= mMatchedPairs.mFitPtst>=25&&mMatchedPairs.mNCommonHit>=10

dcaCut= mMatchedPairs.mDcaGl<=3

pCut= eventCut + yCut + hitsCut + dcaCut