Comparison of the p + p - g signal selection with past results
description
Transcript of Comparison of the p + p - g signal selection with past results
Comparison of the signal selection with past results
C. Di Donato, M. Jacewicz
Signal/BackgroundReaction: 0
ee0
ee0
X-section [b]:2.04 10-3
9.87 10-3
0.30 10-3
0. 460.14 10-3
• Most frequent charged decays:BR() = (22.73±0.28) 10-2
BR(0) = (4.60±0.16) 10-2
BR(ee) = (6.8±0. 8) 10-3
New VS Old• RAD Stream• 2 pnc• 1 charged vertex
rxy<4cm & |z|<8cm• 2 tracks balanced charge• Kinematic fit:
quadrimomentum conservation with 2 clusters compatible with photon hypothesys
• Cut on M(recoil) to reject +-0
• RAD + RPI + KPM• At least 2pnc one of them
with E>250MeV• Two tracks with balanced
charge and closest to IP using info at pca
• 2 neutral cluster in time, with most energetic assumed to originate from
• E(recoil) calculated from 2 body kinematics
• Using eta decay kinematic we correct E()
• Cut on E() to reject background
Analysis versus EVCL
• Stream correlation for MC charged RAD investigated: run RAD, RPI & RAD, KPM & RAD & RPI
ALLRADRPIKPM
Using new approach
MC 2005: All Phys, runs 34410-34499 (12.7pb-1) Only RAD stream
Total
(1194777)Event Signature |Et-Pt|<10MeV OpAn<0.2
(22131)
10904(49%) 9771(44%) 9271(42%)
0
(105791)59489 (56%) 1429 (1.3%) 75
0
(651153)238261(36%) 47723(7%) 10814(2%)
TrackTrack Selection VS VertexVertex Selection• Best Results from track selection using
PCA at IP parametersTotal:22131 Preselection Event Signature |Et-Pt|<10MeV OpAn<0.2
ALL 17619 (80%) 12553(57%) 10321(47%) 9629(43%)
RAD 10916 (49%) 9430(43%) 8284(37%) 7877(36%)
KPM 1210(5.5%) 595(2.7%) 255(1.1%) 186(0.8%)
RPI 1665(7.5%) 1524(6.8%) 1415(6.4%) 1336(6.0%)
Total:22131 Preselection Event Signature |Et-Pt|<10MeV OpAn<0.2
ALL 17619 (80%) 15335(69%) 12499(56%) 11550(52%)
RAD 10916 (49%) 10904(49%) 9771(44%) 9271(42%)
KPM 1210(5.5%) 998(4.5%) 475(2.1%) 359(1.6%)
RPI 1665(7.5%) 1665(7.5%) 1575(7.1%) 1493(6.7%)
Tra
ckT
rack
Ver
tex
Ver
tex
Event Signature in RADPreselection and Event Signature
M(MeV)M(MeV)
MOLD: 2 PNC + VTX
=46%
Lint(2001) =95.7pb-1
NEW: 2 PNC + 2 TRK
=49%
Lint(MC2005) =12.7pb-1
Signal/background
cos2
22
PE
mmE recoilrecoil MassInvcalc .
recoilcalc
Signal/background
MeVPE ttcalc 10
recoilcalc
Signal/background
Opening angle between calculated and selected neutralcluster from pnc, rejects background
calc
recoil
calc
recoil
Signal Selection
ALL0
0
ALL0
0
ALL0
0
ALL0
0
Two photons invariant massMeasured Corrected
Measured Corrected
Before cuts
After cuts
Two photons invariant mass corrected variables
ALL0
0
100 MeV < M< 170 MeV
Bg=1%
()=39%
Control Sample 0
recoilcalc 0. MMassInvcalc
MeVMMcalc 15|().| 0
Control Sample 0
0. MMassInvcalc
MeVMMcalc 15|().| 0
ALL0
0
BG
recoilcalc
95.0
clu
i
recoil
Frac
E
EEE
cal
Outlooks
• Analysis in RAD stream:– Ilaria’s cuts to reject BG– Evaluate efficiency– Control sample
• Analysis in KPM+RPI stream:– Evaluate efficiency