Anne Dabrowski Northwestern University NA48/2 Collaboration Meeting 30 November 2005

1

A. Dabrowski, November 30 2005Ratio(ke3/pipi0); Ratio(kmu3/pipi0)

Semileptonic Decays

Γ(Ke3) / Γ(pipi0) Γ(Kmu3) / Γ(pipi0) Γ(Kmu3) / Γ(ke3)

Emphasis … numbers in the first draft of Semleptonics Paper

Anne DabrowskiNorthwestern University

NA48/2 Collaboration Meeting30 November 2005

2 A. Dabrowski, November 30 2005Ratio(ke3/pipi0); Ratio(kmu3/pipi0)

• Introduction• Comments about numbers in the first draft of the paper

– Form factor used was KTeV Pole for Ke3 and Kmu3 (In the October 2005 talk, the linear form factor was the nominal form factor used)

– Acceptances– Table of Systematic errors– Results

• Additional Comments– Numerical Checks – can we trust PAW with weighted events?

• A preliminary comment the Σweights PAW v.s. FORTRAN– (important because systematic error due to form factor based on weighted events

in the draft paper)• For the final paper, MC events will be regenerated with the KTeV Pole MC …

so no need for weights– Update on KLOE vs. Ginsberg + PHOTOS MC

– Form factor normalisation – Acceptance comparison ke3

• Conclusion

Outline


Draft of the First paper released to Collaboration

• Mayda sent out the first draft of the Semileptonics paper on November 21st

• I will present the numbers on that paper today.

• Comment on the paper are encouraged, and

should be sent by Dec 5th to – Alan Norton [email protected]

– Heinrich Wahl <[email protected]>– Mayda Velasco <[email protected]>

Ratio(ke3/pipi0); Ratio(kmu3/pipi0)

4 A. Dabrowski, November 30 2005Ratio(ke3/pipi0); Ratio(kmu3/pipi0)Ratio(ke3/pipi0); Ratio(kmu3/pipi0)


Choice of which form factor to use

• In the October 2005 Analysis meeting it was agreed by the collaboration, that is it better to use the Pole Model for the form factor.

• Numbers in the draft paper were recalculated, weighting the MC (generated with the linear form factors) by the ratio of the square of the form factors dependence in the matrix element

GeVm

GeVm

s 040.0173.1

007.0882.0


For the pole

For the linear

Values of parameters chosen:They are the only published results for both ms and mν

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A. Dabrowski, November 30 2005Ratio(ke3/pipi0); Ratio(kmu3/pipi0)

Update

Comparison radiative corrections

Ginsberg + PHOTOS compared to KLOE


Input needed to extract the ratios


1. Acceptance2. Particle ID efficiency3. Trigger efficiency4. Number of events in Data5. Background substraction, done in both

signal and normalisation

8 A. Dabrowski, November 30 2005Ratio(ke3/pipi0); Ratio(kmu3/pipi0) A. Dabrowski, October 27 2005Ratio(ke3/pipi0); Ratio(kmu3/pipi0)

Summary Table of inputs for the ratios

9 A. Dabrowski, November 30 2005Ratio(ke3/pipi0); Ratio(kmu3/pipi0) A. Dabrowski, October 27 2005Ratio(ke3/pipi0); Ratio(kmu3/pipi0)

Main Contributions to the background


Contributions to the systematic of Contributions to the systematic of ke3/pipi0ke3/pipi0

We have used Pole Form factor model as the reference, as measured by KTeV

Form factor model Acceptance Change in

Quadratic (ISTRA 2004)

Linear (PDG 2004 based on π0 ) normalisation

Difference when varying the mν in the pole model by ±1 sigma of the measured values


Contributions to the systematic of Contributions to the systematic of kmu3/pipi0kmu3/pipi0

Form factor model Acceptance Change in

Quadratic (ISTRA 2004)

Linear (PDG 2004 based on π0 ) normalisation

Form factor model systematic also dominated by the quadratic.

Reference parameterisation is KTeV pole measurement


Summary of resultsSummary of results


Ratio kmu3/ke3Ratio kmu3/ke3


Summary of experimental ResultsSummary of experimental Results

Using the PDG 2004 value for the branching ratio of pipi0


To do before final paper goes out

• Re-generate the MC with the Chosen Form factor (Pole in this case)– Avoid using unnecessary weights and

relying on PAW


Report on KLOE vs Ginsberg+PHOTOs MC ke3

from Cambridge meeting, showed ridges in KLOE/Ginsberg MC

After checks with C. Gatti (From KLOE), numerical solution solved. Still a slope in the Dalitz plane. This slope will be investigated.

Cambridge

Now i.e. October 2005

Recall: October 2005

Meeting


Report on KLOE vs Ginsberg+PHOTOs MC ke3

KLOE code revisited

Form factor – linear

BUT

Mπ was put as the Mπ

+

Here plotted is the dalitz distribution for KLOE code with the two different pion masses in the denominator


Ratio KLOE code (charge/neutral pion mass) DIV Ginsberg + PHOTOS


Ratio KLOE code (charge/neutral pion mass) DIV Ginsberg + PHOTOS

Still a difference between the two distributions, as a function of electron energy. Our selection is not sensitive to the acceptance change.

Will pass this result onto the theorists


Conclusion

• First draft of the paper out on 21st November

• This draft had the pole model of KTeV for the form factor

• Suggestion are welcome• Before final paper goes out, MC will be re-

generated with chosen form factor to avoid weighting the MC, at the compact level.

Documents

Anne Dabrowski Northwestern University NA48/2 Collaboration Meeting 30 November 2005