1. A.De Santis Radiative Meeting 30/05/07 Cross section e e Antonio De Santis Simona Giovannella

2. A.De Santis - Radiative Meeting 30/05/072 of 18 Amplitude contribution in cross section (b) could be represented as interference with continuum process (a) Interference is parametrized by term (Z) at -resonace peak.

3. A.De Santis - Radiative Meeting 30/05/073 of 18 Data sample Integrated luminosity onpeak 450 pb -1 Integrated luminosity offpeak 150 pb -1 Data: drc ( DBV-13/14 ) 01/02 drc ( DBV-24/25 ) 06 MC sample: Signal ( DBV-26 LSF=1 ) 01/02 (?)(?) mrc ( DBV-18 all_phys LSF=0.2 ) 01/02 mrc ( DVB-26 all_phys LSF=1(2) ) 06 Total Luminosity: 600 pb -1 Scan 01/02 Scan 06

4. A.De Santis - Radiative Meeting 30/05/074 of 18 Analisys strategy Acceptance –One vertex at Interaction Point (IP) –Two tracks connected at vertex –Four neutral cluster with: E clu grater than 10 MeV ToF compatible with prompt |cos( )| < 0.93 Kinematic Fit (33 input parameters, 8 constraints) (?)(?) Fine selection: – 2 < 50 – m /m Slice dataset in function of E CM (100 Kev Bin) Signal events counting (fit via HMCMLL) Cross section fit

5. A.De Santis - Radiative Meeting 30/05/075 of 18 Data vs MC: cos( ) 2 <50 2 >50 MC fit MC sig Data Same scale factors are used to normalize MC distributions in both selections

6. A.De Santis - Radiative Meeting 30/05/076 of 18 Data vs MC 2 <50 2 >50 MC fit MC sig Data Same scale factors are used to normalize MC distributions in both selections

7. A.De Santis - Radiative Meeting 30/05/077 of 18 Data vs MC 2 <50 2 >50 MC fit MC sig Data Same scale factors are used to normalize MC distributions in both selections

8. A.De Santis - Radiative Meeting 30/05/078 of 18 Data vs MC 2 <50 2 >50 MC fit MC sig Data Same scale factors are used to normalize MC distributions in both selections

9. A.De Santis - Radiative Meeting 30/05/079 of 18 Data vs MC 2 <50 2 >50 MC fit MC sig Data Same scale factors are used to normalize MC distributions in both selections

10. A.De Santis - Radiative Meeting 30/05/0710 of 18 Data vs MC E CoM =1000 MeV E CoM =1010 MeV E CoM =1030 MeV MC fit MC sig Data

11. A.De Santis - Radiative Meeting 30/05/0711 of 18 Efficiency Conditional efficiency: tot = 40.07 ± 0.03

12. A.De Santis - Radiative Meeting 30/05/0712 of 18 Systematic errors I Different source of systematic errors are taken into account. All of them are summed in quadrature with statistic error of the counting fit to get the final error on the visible cross section

13. A.De Santis - Radiative Meeting 30/05/0713 of 18 Cross section fit

14. A.De Santis - Radiative Meeting 30/05/0714 of 18 Fit result

15. A.De Santis - Radiative Meeting 30/05/0715 of 18 Systematic errors II Systematic errors on the fit parameters are evaluated as r.m.s. of the distributions obtained varying cuts and fitted distribution (counting). Cross section stability as been checked for each CoM energy.

16. A.De Santis - Radiative Meeting 30/05/0716 of 18 Final results KLOE results: SND results:

17. A.De Santis - Radiative Meeting 30/05/0717 of 18 GoodNews Referees at work

18. A.De Santis - Radiative Meeting 30/05/0718 of 18 Conclusions Cross section parameters accuracy better than SND results. Agreement between results due to large errors in SND measurements. Yesterday was my birthday and Today is exactly one months after my wedding and this work is completed… …Life is Beautiful

19. A.De Santis - Radiative Meeting 30/05/0719 of 18 Spare

20. A.De Santis - Radiative Meeting 30/05/0720 of 18 Amplitude: MC generator All term which differs for exchange between two 0 s or different charge must be summed. Resulting matrix element (M) could be expressed as modulus squared of current composed by two term( 0 s permutation) each composed by tree terms ( charge) Reference: hep-ex/9904024 v2

21. A.De Santis - Radiative Meeting 30/05/0721 of 18 Amplitude current term Form factor Inverse propagator

22. A.De Santis - Radiative Meeting 30/05/0722 of 18 Major change in GEANFI

23. A.De Santis - Radiative Meeting 30/05/0723 of 18 Kinematic fit Input parameters: Constraints:

24. A.De Santis - Radiative Meeting 30/05/0724 of 18 Measured visible cross section

25. A.De Santis - Radiative Meeting 30/05/0725 of 18 Tracking efficiency

26. A.De Santis - Radiative Meeting 30/05/0726 of 18 Vertex efficiency

27. A.De Santis - Radiative Meeting 30/05/0727 of 18 Eta filter and Bhabha filter