BR(KS

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

•• DATA-- MC all Signal Background

Fit Data with the complete MC sample

•• DATA-- MC all Signal Background

Data 2004-2005 fit results

Fit Data with the complete MC sample

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

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

Combined 2.58 ± 0.17

Total 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

Old MC sample

BR obtained compatible with previous results but…

We still need more MC statistics to decrease uncertainty

Data-MC energy scale MC01-02

2BKG

4KS

•• Data-- MC

MC 2001-2002

Before scale calibration

Data-MC energy scale MC01-02

2BKG

4KS

•• Data-- MC

MC 2001-2002

After scale calibration

Data-MC energy scale MC04

2BKG

4KS

•• Data-- MC

MC 2004

Before scale calibration

Data-MC energy scale MC04

2BKG

4KS

•• Data-- MC

MC 2004

After scale calibration

Data-MC energy scale

Before

After

We have a not significant effect on M for KS signal events from MC

Data-MC energy scale

•• DATA-- MC all Signal Background

Fit Data with the adjusted MC sample

DATA-MC energy scale

sample Nsig Nbkg BR x 10-6

2001/2002 166.0 ± 20.3 323.0 ± 24.9 2.96 ± 0.36

2004/2005 502.5 ± 34.7 716.5 ± 40.6 2.81 ± 0.20

Combined -- -- 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 = 72.32 = 1.64

DATA-MC energy scale

Data 2004-2005

Calibrated

FCN = 80.32 = 1.82

QCAL simulation

TQCAL:

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 T

QCAL simulation

Final comparison:

DataMC QCAL simulation

QCAL simulation – Statistical variation

2001 2002ev ev real fraction ev ev real fraction

2 47389 47389 56483 56483 ALL 3 9099 3639600 0,252505 10742 4296800 0,24836994

4 25115 10046000 0,696961 30519 12207600 0,70564162 5 1821 728400 0,050534 1989 795600 0,04598844

2 16178 16178 0,341387 19212 19212 0,34013774

QCAL 3 4959 1983600 0,545005 5991 2396400 0,557717374 22633 9053200 0,901175 28536 11414400 0,935024085 1416 566400 0,777595 1693 677200 0,8511815

2001 2002 2004ev ev real fraction ev ev real fraction ev ev real fraction

2 95598 95598 0,00734 140400 140400 0,00734448 31366 31366 0,006428 ALL 3 16607 3321400 0,256915 24410 4882000 0,25727234 5922 1184400 0,244297

4 44661 8932200 0,690919 65670 13134000 0,69213744 17215 3443000 0,71016 5 3372 674400 0,052166 4800 960000 0,05059022 1104 220800 0,045543

2 45928 45928 0,480428 67710 67710 0,48226496 13596 13596 0,433463

QCAL 3 10852 2170400 0,653459 15950 3190000 0,65342073 3712 742400 0,6268154 43340 8668000 0,970422 63724 12744800 0,97036699 16697 3339400 0,969915 3060 612000 0,907473 4374 874800 0,91125 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!

DATA

MC

M after QCAL veto

Old simul.

New simul.

QCAL simulation

As example:

Data 01-02MC 01-02

•• DATA-- MC all Signal Background

Fit Data with the adjusted QCAL MC sample

QCAL simulation

No QCAL sim QCAL sim

Comparison between adjusted and not adjusted MC sample for the BKG shape

QCAL simulation

Sample Original QCAL sim.

Nbkg 345.126.2 346.029.1

Nsig 143.920.1 143.0 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 01- 02 .. 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