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Looking in gamma_ana.txt, I found the exact cuts that Eric was using. Namely, the prefilters that were being applied before the cut efficiencies were evaluated. I've listed them here for completeness.

nSig

nBkg

~9 x 10^5

~4 x 10^6

Name

Purpose

Gamma Efficiency

Bkg Efficiency

Cut

!( IrrFilter )

Remove irreducible bkg events

0%

87% 13% (cut)

Code Block
((McZDir < -.2 && McId < 20) | (McZDir < .1 & McId > 20))
&& McAcdZEnter > 100 && McCharge !=0 && McTHPosHitOthers < 6

TkrCalCore

Take only "good" events

  6.2%

2.2%

Code Block
TkrNumTracks>0 && CalEnergyRaw > 5 && CalCsIRLn>4 && CTBCORE>0.1

!( AcdEngFilter )

Only events with moderate signal in the ACD

  0%

53% 47%

Code Block
(AcdTotalEnergy+AcdRibbonEnergy<0.05) && McZDir > 0

Prefilter

Only select relevant events

  6.2%

1.2%

Code Block
(TkrCalCore && !(IrrFilter) && !(AcdEngFilter)

nSig

nBkg

55015

48614

Name

Purpose

Gamma Efficiency
(5783)

Bkg Efficiency
(3784)

Cut

BasicTileCut

  

95.2%

7.85%

Code Block
(Tkr1SSDVeto == 0 && AcdTkr1ActiveDist > -16 && 
AcdTkr1ActDistTileEnergy > .4)

RibbonCut

  

94.9%

7.43%

Code Block
(AcdRibbonActDist > -(2 +350/sqrt(max(20,CTBBestEnergy))) && 
Tkr1SSDVeto < 3 && AcdRibbonEnergy > .05 )

TotalTileEnergyCut

  

89.3%

1.17%

Code Block
(AcdTotalTileEventEnergyRatio > .8 || (AcdTkr1ActiveDistENorm > -300 && 
AcdTotalTileEventEnergyRatio > max(.005, .1 - .0001*AcdTkr1ActiveDistENorm)))

CornerCut

  

88.4%

1.15%

Code Block
((Tkr1LATEdge/1.5) ^ 2 + (AcdCornerDocaENorm - 10)^ 2 < 3800 || 
(Tkr1LATEdge < 80 && abs(AcdCornerDocaENorm-2) < 4)) && Tkr1SSDVeto < 3

TileEdgeCut

  

88.3%

1.15%

Code Block
(abs(AcdTkr1ActiveDistENorm) < 15 && AcdTotalTileEventEnergyRatio > .005)

These numbers seem to agree well with Eric's results. However, it naively seems like there are still some photons sneaking into the bkg sample. This is because selecting !(IrrFilter) will return True if McCharge == 0 (leaving about ~50 gamma events out of ~550). Putting a cut on McCharge, we now get a background rejection of 1.03%.