BR(KSgg)
Analysis update
M. Martini and S. Miscetti
14/12/2006
Talk Layout
- First sample of MC 2004 analyzed
• MC 2004 integrated luminosity, 214 pb-1
• Production stopped since some AFS problems +
token expiration (slowest queues for users), we will
restart the production asap
- Improved MC simulation of QCAL following
DATA (adding accidental, first fix to efficiency…)
- MC-DATA EMC energy scale adjusted
Monte Carlo sample
- Total integrated luminosity:
Sample
Int. Luminosity (pb-1)
2001
128
2002
246
2004
214
Total
588
To extract the BR, we use this MC sample
summing 2001-2002 and 2004-2005 production
Data 2001-2002 fit results
Fit Data with
the complete
MC sample
•• DATA
-- MC all
Signal
Background
Data 2004-2005 fit results
Fit Data with
the complete
MC sample
•• DATA
-- MC all
Signal
Background
BKG shapes resulting from 04-05 fit
MC old
MC all sample
Comparison
between old and
new MC sample
for the BKG
shape
Fit results
Total MC sample
Sample
Nsig
BR x 10-6
2001/2002
148.3 ± 19.9
2.64 ± 0.36
2004/2005
458.4 ± 34.4
2.57 ± 0.20
2.58 ± 0.17
Combined
Old MC sample
Sample
Nsig
BR x 10-6
2001/2002
143.9 ± 20.1
2.57 ± 0.36
2004/2005
462.8 ± 34.7
2.59 ± 0.20
Combined
2.58 ± 0.17
BR obtained compatible with previous results but…
We still need more MC statistics to decrease uncertainty
Data-MC energy scale MC01-02
MC 2001-2002
2g, BKG
•• Data
-- MC
4g, KS2p0
Before scale
calibration
Data-MC energy scale MC01-02
MC 2001-2002
2g, BKG
•• Data
-- MC
4g, KS2p0
After scale
calibration
Data-MC energy scale MC04
MC 2004
2g, BKG
•• Data
-- MC
4g, KS2p0
Before scale
calibration
Data-MC energy scale MC04
MC 2004
2g, BKG
•• Data
-- MC
4g, KS2p0
After scale
calibration
Data-MC energy scale
Before
We have a not
significant effect on
Mgg for KSgg
signal events from
MC
After
Data-MC energy scale
Fit Data with
the adjusted
MC sample
•• DATA
-- MC all
Signal
Background
DATA-MC energy scale
sample
Nsig
Nbkg
BR x 10-6
2001/2002
166.0 ± 20.3 323.0 ± 24.9
2004/2005
502.5 ± 34.7 716.5 ± 40.6 2.81 ± 0.20
Combined
--
--
2.96 ± 0.36
2.84 ± 0.17
We obtain an higher BR using the calibrated sample
(~10% more) but we have a slightly worst fit….
DATA-MC energy scale
Data 2004-2005
Not Calibrated
FCN = 72.3
c2 = 1.64
DATA-MC energy scale
Data 2004-2005
Calibrated
FCN = 80.3
c2 = 1.82
QCAL simulation
DTQCAL:
Comparison between
Data and the
standard MC
simulation of QCAL
We improve the
simulation
considering 3
different
contributions in MC
QCAL simulation
1 component:
Standard simulation +
Gaussian smearing +
Offset to center T-R/c
QCAL simulation
2 component:
Accidental hit
rephased with RF
QCAL simulation
3 component:
When there are
MC photons
hitting QCAL but
there are not
reconstructed hits,
we had the % of
losses found in
data by using a
gaussian
distribution of DT
QCAL simulation
Final comparison:
Data
MC QCAL simulation
QCAL simulation – Statistical variation
DATA
ALL
QCAL
MC
ALL
QCAL
2
3
4
5
2
3
4
5
2001
ev
ev real
fraction
47389
47389
9099 3639600 0,252505
25115 10046000 0,696961
1821
728400 0,050534
16178
4959
22633
1416
16178
1983600
9053200
566400
0,341387
0,545005
0,901175
0,777595
2002
ev
ev real
fraction
56483
56483
10742 4296800 0,24836994
30519 12207600 0,70564162
1989
795600 0,04598844
Mgg after QCAL
veto
19212
19212 0,34013774
5991 2396400 0,55771737
28536 11414400 0,93502408
1693
677200 0,8511815
2001
ev
ev real fraction
2 95598 95598 0,00734
3 16607 3321400 0,256915
4 44661 8932200 0,690919
5 3372 674400 0,052166
2002
ev
ev real fraction
140400 140400 0,00734448
24410 4882000 0,25727234
65670 13134000 0,69213744
4800 960000 0,05059022
2004
ev
ev real fraction
31366 31366 0,006428
5922 1184400 0,244297
17215 3443000 0,71016
1104 220800 0,045543
2 45928 45928 0,480428
3 10852 2170400 0,653459
4 43340 8668000 0,970422
5 3060 612000 0,907473
67710 67710 0,48226496
15950 3190000 0,65342073
63724 12744800 0,97036699
4374 874800 0,91125
13596 13596 0,433463
3712 742400 0,626815
16697 3339400 0,96991
1003 200600 0,908514
After QCAL veto, we now have the Adjusted Qcal
simulation which follows much better the vetoed
fraction in data
R = 0.34/0.48 = 71% vs 69.5% from plot!
Old simul.
New simul.
QCAL simulation
Fit Data with the
adjusted QCAL
MC sample
As example:
Data 01-02
MC 01-02
•• DATA
-- MC all
Signal
Background
QCAL simulation
Comparison
between
adjusted and not
adjusted MC
sample for the
BKG shape
No QCAL sim
QCAL sim
QCAL simulation
Sample
Original
QCAL sim.
Nbkg
345.126.2
346.029.1
Nsig
143.920.1
143.0 22.2
The larger error is due to the reduced statistics after QCAL veto.
The value of the BR is not modified using the simulation above.
Data 01-02
Original
Qcal sim.
BR x 10-6
2.57 ± 0.36
2.55 ± 0.40
Conclusions
- Using the new + old MC production we obtain a compatible result
for the BR.
- We started using the MC scale calibration for EMC .. OK for 0102 .. In progress for 04-05. Final BR will be estimated after fixing
the scale. Systematics will follow.
- The improved QCAL simulation on MC gives compatible results
and will be used as systematic
To be done:
- Prepare a significant MC 2004 sample to decrease BR uncertainty
- Process the few missing pb-1 of data (200-300)
- Meeting with referees to decide paper strategies
- Start writing the memo