Next to Last Update on  K Paul Bloom Alan Watson

Where Were We… Started with two rather different analyses One focused on event shape the other on PID Have converged on an analysis which after optimization uses the best of both Retain individual features of uncombined analyses for use as cross checks

Selection Criteria Selection criteria chosen by optimizing S 2 /(S+B) Assumes a visible signal, uncertainties dominated by statistics All “interesting” variables included in optimization procedure cos  T,  M , PID criteria (all permutations), cos  H, Fisher # tracks, E/p,  E, M ES not included Procedure cross checked with Poisson statistics

Background Estimation Two methods for estimating ratio A “Counting” in the off resonance data (PB) GSB fit in the on resonance data (AW) Signal = 6 MeV M ES + 60 MeV  E GSB = M ES MeV  E Each needs to perform the other method as a cross check and to provide an estimate of the systematic uncertainty

Background Estimation (2) Off resonance counting A=31/1132=0.0274±0.005 Stable for variation of GSB size On resonance fit Shape slightly sensitive to cuts Argus fn., Ebeam =   =  4.51  A =  (stat) Difference  systematic

Cut Optimization Results  Raw =.3575±.0062 = 2.7 = 7.7 (CLEO BF) S 2 /(S+B) =  sensitivity # GoodTracksVeryLoose > 4 |cos  T | < 0.9  M  < 13 MeV/c 2 |cos  H |>0.20 SMS notApion (all) E/p < 0.9 (all) Fisher < 0.0 |  E| < 60 MeV |M ES |<0.006 GeV/c 2 Optimization favored VL on bachelor Alan discovered “features” in his studies + almost no loss in sensitivity Why no fiducial cut? This cut is favored by tight PID strategies where the DIRC is a must

PID corrections Now using looser PID notApion + E/p<0.9 Measure efficiency using D* sample as before 3 decay tracks occupy different p/  bands, so measurements largely independent Correct MC PID efficiencies 3*notApion  corr =  *(notApion+E/p)  corr =  No Fiducial cuts notApion efficiency does not vary strongly with DIRC acceptance

Cut Performance CutSignal MCuds MC MC Off Res Data B Sel.6213± #trks.9683± cos  T.8758± MM.9686± K-ID.8881± E/p.9847± cos  H.9882± Fisher.7307± EE.9563± M ES.9683±.0029 Total.3575±.0062 Numbers based on PB’s samples AW samples give total signal MC  =  Most rejection from Fisher PID cos  T M 

Uncertainties and Corrections Track multiplicity2% Track finding 2.5%/trk  Br 1.4% Thrust cut1% Fisher7% PID 4.7%  mass2% Helicity1%  E3% M ES 3% Track finding6.6%/trk Total correction.815 MC/DATA PID 2-3.5%/trk Total correction Background subtraction 2 methods agree within 1  Assign difference (12%) as systematic uncertainty

Putting it Together Efficiency = *0.815*0.492*  S = 7.1 events (CLEO bf) B = 100 * = 2.74 S 2 /(S+B) = 5.12 If 10 events seen, prob of background fluctuation = 0.09%  3.1 sigma measurement Belle BF  ~21 events!

Outlook The analysis is basically complete Need to complete internal cross checks of background estimate And any sage advice from the AWG or review committee… BAD preparation in progress Draft by Tuesday (he says hopefully) Would like review committee to consider BAD draft + this talk Could we get a response by next Wednesday or Thursday? If so (and all is well) unblind the combined analysis + the two original analyses as cross checks Present result next at next Friday’s meeting