Status of K l 3 analysis Charged Kaon

Improvements wrt 10/03 presentation • Data sample: 2001+2002, with data quality ( 410 pb-1).

TCA efficiency for muons - Old The track-to-cluster association (TCA) efficiency is evaluated using

TCA efficiency for muons - New The TCA efficiency is evaluated using 2 sample:

Fiducial volume efficiency • Two private MC samples K m 2, K all with

Quality of fit of the m 2 distribution - Old Fit of the sample:

Quality of fit of the m 2 distribution - New Correct MC shapes for:

Conclusions • Possible correction of the “separation-of-charge” in the BR(Km 3) measurement. • t.

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Status of K l 3 analysis Charged Kaon Meeting 20 April 2005 - LNF 1 Barbara Sciascia – 20 Apr 05 - LNF

Improvements wrt 10/03 presentation • Data sample: 2001+2002, with data quality ( 410 pb-1). • BR(Km 3): difference between charges check TCA correction for m. • Fiducial volume efficiency: check wrt t. K variations. • Fit procedure: bad c 2, bad residual distribution. • Conclusions 2 Barbara Sciascia – 20 Apr 05 - LNF

TCA efficiency for muons - Old The track-to-cluster association (TCA) efficiency is evaluated using KL charged decays, specifically KLe 3 and KLm 3, identified by kinematical selection. Data/MC ratio The efficiency is evaluated in bin of impinging angle. 3 • Not a pure msample (p ) • Different contamination from positive and negative p Barbara Sciascia – 20 Apr 05 - LNF

TCA efficiency for muons - New The TCA efficiency is evaluated using 2 sample: • kinematical selection of m from K m 2 decays • K m 2: high statistics, purity 99. 94(1)% Data/MC ratio • m from p m kink, in K p 2 decays • K p 2: low statistics, purity 98. 0(8)% 4 • The Km 2 sample is used to correct e. KINE • No more difference between charges. Barbara Sciascia – 20 Apr 05 - LNF

Fiducial volume efficiency • Two private MC samples K m 2, K all with t. KPDG(12. 37 ns) f f = 0. 98, f = 1. 02 • Variation of e. FV as a function of f. • A second order correction in the ratio e. SELE_MC e. DATA e. MC. • Final check: direct calculation of e. SELE_MC e. DATA e. MC using two more MC samples (f=0. 98, 1. 02) K m 2, K l 3 (in progress, few days). 5 Barbara Sciascia – 20 Apr 05 - LNF

Quality of fit of the m 2 distribution - Old Fit of the sample: • Tag K+p 2, Sig K-l 3 • Data 2001+2002 • MC kpm 04 + all_phys The residuals for all the Tag samples show the same trend. Tag K+m 2 Tag K-m 2 The residuals of the fit signal different Data-MC resolution and possibly a Data-MC shift. 6 Barbara Sciascia – 20 Apr 05 - LNF Tag K-p 2

Quality of fit of the m 2 distribution - New Correct MC shapes for: • Measured D(dt) (p 0 photons from kaon decay vertex) difference between Data and MC (14 18 ps shift). • To. F in Emc (“Pezzetto” correction) in me hypothesis, correct Km 3 for the difference m. DATA–m. MC (20 24 ps shift). • Ok for positive tags and negative signal; not enough for the CC. P(c 2> c. M 2) c 2/Do. F P(c 2> c. M 2) K+m 2 499/222 0. 236/222 24. 75% K+p 2 329/220 0. 208/220 70. 91% K-m 2 532/222 0. 343/222 0. K-p 2 339/220 0. 239/222 20. 65% Tag 7 c 2/Do. F Barbara Sciascia – 20 Apr 05 - LNF Tag K+m 2 • Residual different Data. MC resolution. • Tag Kp 2: lesser stat. • More investigation on positive signal.

Conclusions • Possible correction of the “separation-of-charge” in the BR(Km 3) measurement. • t. K-variation-effect on e. FV and on involved MC efficiencies has been measured in special MC samples. • Fine corrections to charged-cluster time give good c 2 for the fit of negative signals; some investigation needed for the fit of positive signals. • Work in progress for the systematics related to efficiency determination. • “Put all together” 8 Barbara Sciascia – 20 Apr 05 - LNF