M martini s miscetti
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M. Martini, S. Miscetti. Status of K s  3  0 analysis. Summary of work in progress Data-MC calibration of c 2 2 p and c 2 3 p New fit procedure for bkg Systematics on bkg determination time-scale for the paper. Summary of work in progress.

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Status of K s  3  0 analysis

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M martini s miscetti

M. Martini, S. Miscetti

Status of Ks 3  0 analysis

  • Summary of work in progress

  • Data-MC calibration of c22p and c23p

  • New fit procedure for bkg

  • Systematics on bkg determination

  • time-scale for the paper


Status of k s 3 0 analysis

Summary of work in progress

  • Almost all the questions posed by Matt have been attached

  • The MC production 2004 have been successfully used after calibration of the

  • energy scale as shown in the past meeting.

  • We now refer as:

  • -- OLDMC the production AllPhys+NeuKaon 2003

  • -- NEWMC the poduction AllPhys+NeuKaon 2004

  • For a whole MC Luminosity of 450x2 pb-1.

  • Considering the ekcra (MC/data)= 50% vs 30% we gain another factor 5/3.

  • Whole MC eff.Lumi 1500 pb-1

  • We have modified/added some steps in our analysis to simplify

  • and improve the procedure for the bkg calibration.

  • We believe that the background studies is now COMPLETE

  • Tomorrow we will have a private meeting with the referees to show in further

  • details the analysis status and if we agree in all points we start immediately to

  • update the memo.


Status of k s 3 0 analysis

Calibration of c22p and c23p

DATA

MC

Mp

Mp

MC

DATA

DE

DE

In the construction of the c2 we have used, up to now, the values of

sE and sM observed in a

golden sample of

KS2p0 events.

We have now modified this in the analysis using a different sigma for each sample. DATA and MC

(OLDMC, NEWMC)

(2001 ,2002 ).


Status of k s 3 0 analysis

New calibration procedure for fakes

One of the criticized step of our analysis is the determination of the

quantity of fake KCRASH. Two questions were posed:

1) Quantify the statistical error connected to the calibration:

Instead of using our old standalone recipe we move to fitting

the 1D-plots with HMCMLL inserted in a standalone Minuit program.

Statistics of data and MC sample are now considered in the fitting procedure and an error is assigned to the resulting fake content.

2) Evaluate the systematic on fake determination due to the

range used for fit.

Instead of trying all possible cuts we decided to use a 2D-Fit.

We have translated a 2d-Histogram of 20x40 bins in 1D-Histogram

of 800 bins and used the standard HMCMLL procedure.


Status of k s 3 0 analysis

New fake-calibration procedure

c22p

c23p

In the new calibration we use 2D histogram with an almost entire scale

Old SBox definition:

14<c22p<40

c23p<3.5


Status of k s 3 0 analysis

New Fake-Acci-Split calibration procedure

  • To better calibrate DATA and MC, we have also questioned how well the MC reproduces the amount of double shower fragments and double accidental clusters. To understand and calibrate this we have divided the MC Kcrash events into 2 further classes:

  • 2A: events of Ks2p0 in overlap with 2 accidental (~ 60% )

  • 2S: events of Ks2p0 with 2 splitted clusters or 1 accidental + 1

    splitted cluster (~ 35%)

To do this, we perform a 3 components fit (2S, 2A and fake events)


Status of k s 3 0 analysis

New Fake-Acci-Split calibration procedure

c22p

c22p

ALL

2 S

c23p

c23p

c22p

c22p

Fake

2 A

c23p

c23p


Status of k s 3 0 analysis

New Fake-Acci-Split calibration procedure

ALL

2 S

Bin Number

Bin Number

Fake

2 A

Bin Number

Bin Number


Status of k s 3 0 analysis

New Fake-Acci-Split calibration procedure

Bin Number

Bin Number

Bin Number

Bin Number

  • Data

  • FIT

  • We remind that the calibration

  • is carried out separately

  • for the different samples:

  • NEW 2001

  • NEW 2002

  • OLD 2001

  • OLD 2002

  • For each sample we now have

  • 3 weights with a whole

  • correlation matrix


Status of k s 3 0 analysis

New Fake-Acci-Split calibration procedure

sample

Correlation matrix dij

Weights Wi with errors eWi

Events of each type Ni with errors eNi

Ndata with error

expected from MC

For a single sample this is a typical fit result


Status of k s 3 0 analysis

Result of Fake-Acci-Split calibration

 DATA

-- MC

ALL

c22p<14

c23p

c23p

14<c22p<40

c22p>40

c23p

c23p

A good agreement is observed in each scatter plot region


Status of k s 3 0 analysis

DATA-MC comparison at beginning of ana

Sbox

CSbox

UP

Cup

Down

CDown

Summing up 2001-2002 for each MC, we can compare DATA with the two different MC productions.

NEW

OLD

A reasonable data-MC comparison is found for both samples.


Status of k s 3 0 analysis

Result of Fake-Acci-Split calibration

CUP

UP

Sbox

CSbox

Cdown

Down


Status of k s 3 0 analysis

Review of the analysis chain

OLD

counting

Track Veto

DECUT

c2fit

Sbox

optimization

NEW

Track Veto

Optimiz

counting

DE/sE

c2fit

Sbox

DE

DE/sE

Since we have observed a little difference on sE between DATA and MC (and we have correct this effect into c2 definition), we have changed DE_CUT into DE_CUT/sE.


Status of k s 3 0 analysis

Events rejected by Track veto

 DATA

-- MC

DE/sE


Status of k s 3 0 analysis

Events retained afterTrack veto

 DATA

-- MC

DE/sE


Status of k s 3 0 analysis

Optimization

The optimization is done with the usual technique with a factor

two improvement on the MC statistics thus reducing the

Discretization problem.

In this case we obtain the best ratio between surviving background and signal efficiency with the following set of cuts:

c23p< 4.64

12.07 < c22p< 60

c2fit < 40.43

DE/sE > 1.69

In this way we have a signal efficiency esig = (24.8 ± 0.8stat )%

and we found2 eventswith3.1 ± 1.6statexpected by MC


Status of k s 3 0 analysis

Data-MC comparison after optimization

ALL

c22p<14

c23p

c23p

14<c22p<40

c22p<40

c23p

c23p

 DATA

-- MC


Status of k s 3 0 analysis

Data-MC comparison after optimization

Comparison between DATA and MC after the optimization procedure.


Status of k s 3 0 analysis

Evaluation of Systematic errors on bkg

To evaluate systematic error, we perform our analysis changing

the most relevant parameters

  • Increase sE and sM to sE+dsE and sM+dsM

  • Decrease sE and sM to sE-dsE and sM-dsM

  • We correct in the MC the little data-MC shift on the average

  • MC values found in the control sample Ks2p0.

  • 5) Use the fit parameters calculated including also the signal box

  • 6) Use the fit parameters calculated not distinguishing between 2S - 2A


Status of k s 3 0 analysis

Evaluation of Systematic errors on bkg c2fit

-- DATA

-- MC

c2fit

From optimization we obtain:

c2fit < 40.5

We search the value for MC cut which gives the some retain integral observed in DATA.

We obtain a variation of +5%.


Status of k s 3 0 analysis

Systematic error

11,63

9,57

0,00

24,86

12,28

6,98

We have evaluated the events shift in each box:


Status of k s 3 0 analysis

Time scale for paper …

  • From our side the evaluation of the bkg has been completed and

  • all suggestions/critiques of referees have been taken into

  • consideration. However, tomorrow we will have a long meeting

  • to go much further in detail on each item with the referees.

  • We have another week of work to do in addressing the questions

  • related to the systematics on the efficiency for the signal and the

  • normalization.

  • We expect to complete the revision of the analysis for first week

  • of December.

  • next week we start updating the memo for the background side.

  • and then we will give it back to the referees for final approval.

  • Plan is to have a complete memo for mid-Dicember and a first PLB

  • for x-mas


Status of k s 3 0 analysis

Conclusions

  • We have successfully calibrated and used the whole new and

  • old MC production so doubling the statistics for the BKG evaluation.

  • Most of the referees comments on the bkg determination pushed us

  • to improve and clean our technique which now seems to us to be

  • very stable showing satisfactory data-MC comparisons.

  • We have other two weeks of hard work to complete the syst. on

  • the evaluation of signal efficiency and normalization

  • Planning to have a paper as a x-mass gift.


Status of k s 3 0 analysis

OLD calibration procedure

Normalization 1

c22pwith

c23p<3.5

MC

KcraMC

Fake

Both calibration done excluding signal box.

We use the mean value of weights.

MC

KcraMC

Fake

Normalization 2

c22pwith

c23p<8.8


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