1 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results ALEPH Results on  Branching Ratios and Spectral Functions Michel Davier Laboratoire de l’Accélérateur Linéaire, Orsay Tau Workshop 2004 September , 2004, Nara, Japan

2 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Final ALEPH Analysis only data published for  branching ratios, for spectral functions statistics  x selection efficiencies obtained from data for each topology improved photon ID  better separation between good and fake photons new method to correct the number of fake photons (hadron interactions in ECAL and splitting of EM showers) in MC simulation reduced feedthrough in low BR channels improved methods for the estimation of systematic uncertainties Final analysis of the complete LEP 1 data sample Detailed publication available shortly

3 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results  Event Selection and non-  Background  events selected by vetoing backgrounds total energy: Bhabhas,  -pairs p T balance, low visible energy:  -induced processes high multiplicity: Z  qq Break-mix method to determine efficiency on data for every selection cut tag one hemisphere to get sample unbiased/cut keep opposite hemisphere as unbiased  decay construct event sample with pairs of selected hemispheres apply cut and measure efficiency (small correlations taken from MC)  event selection efficiency 79% (92% in polar acceptance,  5% / modes) Non-  background measured on data sample for leptonic channels, from MC for hadronic channels (  -induced, 4-fermion, qq)  kept relatively high (1.2%) to retain large  efficiency

4 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Photon ID Collimated  decays  granularity - transverse:  75,000 ECAL cells - 3-fold longitudinal segmentation Large improvement compared to published results on data Likelihood method  probability to be a good photon, discriminating variables to distinguish good/fake photons data MC good  fake photons

5 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Decay Classification e e ID, not in ECAL cracks   ID, P  2 GeV hadronic channels -  0 reconstruction: 2 resolved photons + kimenatic fit merged photons (energy-weighted moments) single photons (single,radiative, collinear; fake) - track (1 - 2,3,4 – 5) and  0 (1 – 4 for 1-pr, 1 – 3 for 3-pr ) multiplicities - low BR channels: 3 tighter tracks required for 3h 2-3  0, only resolved  0 ’s for h 4  0 and 3h 3  0 ‘garbage can’ for rejected hemispheres (‘class 14’) 3.6% e in cracks: 21%  with P  2 GeV: 27% 1-pr hadronic (mostly P  2 GeV): 41% 3,5-pr hadronic: 11%

6 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results  Sample

7 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Global BR Analysis

8 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Systematic Uncertainties method: identify sources of systematics, for each one - link systematic source to relevant variables - study data/MC distributions of these variables - characterize and measure systematic bias  stat error  syst error - correct MC for measured bias and keep total error as quoted syst uncertainty main sources -  /  0 reconstruction - non-  backgrounds - event selection efficiency - particle ID efficiency matrix - secondary interactions - tracking - MC dynamics - MC statistics

9 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results  /  0 Systematic Sources - efficiency at low-energy (threshold) - efficiency at high energy (track overlap) - conversions rate h misID in multiprong environment p misID in secondary interactions - ID efficiency (good/fake probability) - fake photon rate correction - energy calibration -  0 efficiency - Dalitz decays - radiative photons

10 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Systematic Errors (  B in %)

11 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Particle Spectra (leptons) non-  background Data/MC comparison

12 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Particle Spectra (hadrons) Data/MC comparison

13 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Mass spectra Data/MC comparison All multihadrons h  0 non-   feedthrough

14 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Exclusive BR‘s topological BR’s defined by charged-track and  0 multiplicities class 14 (removed decays) consistent with 0 B 14 = (0.065   0.028) % consistent with  standard decays dedicated analysis found no ‘invisible’ decay (efficiency=0 in our selection) B invisible  0.11% (95% CL)  assume that all considered modes add to 100% and proceed to the determination of exclusive BR’s modes with kaons (K S, K L, K  ) have been measured separately (complete study with full LEP 1 ALEPH data up to 4 hadrons/mode), subtracted on a statistical basis correct for EM modes (all  decays,     ,  0  ) using measured channels with  and 

15 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Non-strange Branching Ratios

16 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Leptonic modes () )(

17 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Hadronic modes (1-prong)

18 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Hadronic modes (3,5-prong)

19 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Lepton Universality in the Charged Current B e uni = (  0.039) % B e and B  g  / g e =  B e, B  and   WA (290.6  1.1) fs g  / g  =    g  / g e =    (B e, B  ) (   ) (m  ) B  and   WA g  / g  =     (radiative corrections)

20 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results The Hadronic Sector CVC + isospin breaking e  e  ALEPH  B     0.33 (%) B  3     0.12 B 3     0.23 a 1 decays B 3  / B  2  0 =  to be compared to CLEO (PWA + isospin breaking /  masses) V,A separation R  = 1  Be – =  R ,S =   R ,V+A =  R ,V =   R ,A =   R ,V  A =   0.005

21 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Spectral Functions hadronic mass spectra corrected by kinematic factor and scaled by B i  B e unfolding from detector effects by regularized inversion of 140x140 detector response matrix (Höcker-Kartvelishvili) specific systematic studies using full analysis for every syst. source, constructing corresponding covariance matrices -  and  0 reconstruction - energy calibration and resolution (charged particles and  0 ‘s) - tracking and secondary interactions - unfolding procedure (test distributions) spectral functions obtained for the leading channels  0,  2  0,  3  0, 3 , 3  0

22 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Spectral Functions: Results

23 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Spectral Functions: V, A V A

24 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Spectral Functions: V  A V + A V  A

25 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Spectral Functions: QCD analysis changes since 1998 published analysis: full LEP1 statistics for BR re-analysis of spectral functions analysis now even more limited by theoretical uncertainties some progress in the calculation of the  S 4 term (Chetyrkin-Kühn et al) but not complete yet: favours Kataev-Starshenko estimate K4  30 use R ,V, R ,A, R ,V+A, and the mass-weighted moments (shapes) results soon available - very close to published ones with smaller experimental and slightly smaller theoretical errors - some evidence for OPE problems, except in the V+A case where it does not matter (non-perturbative contributions below 1%) recall published results  S (m  2 ) =  exp  th  S (M Z 2 ) =  exp  th  ext from Z width (EW fit)  S (M Z 2 ) = 

26 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results The Complete List of ALEPH Branching Ratios

27 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Backup Slides

28 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results  –   –  0  : Comparing ALEPH, CLEO, OPAL Good agreement observed between ALEPH and CLEO ALEPH more precise at low s CLEO better at high s Shape comparison only. SFs normalized to WA branching fraction (dominated by ALEPH).

29 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results Testing CVC Infer  branching fractions from e + e – data: Difference: BR[  ] – BR[e + e – (CVC) ]: Mode  (  – e + e – ) „Sigma“  –   –  0  ±  –   – 3  0  – 0.08 ±  –  2  –  +  0  ± leaving out CMD-2 : B  0 = (23.69  0.68) %  (7.4  2.9) % relative discrepancy!

30 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results New Precise e + e –  +  – Data from KLOE Using the „Radiative Return“... Overall: agreement with CMD-2 Some discrepancy on  peak and above...

31 Tau Workshop, Nara, Sept 14-17, 2004 M. Davier – ALEPH  Results The Problem (revisited) Relative difference between  and e + e – data: zoom No correction for  ± –  0 mass (~ 2.3 ± 0.8 MeV) and width (~ 3 MeV) splitting applied Jegerlehner, hep-ph/ Davier, hep-ex/