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Progress report on p 0 p 0 g analysis

Progress report on p 0 p 0 g analysis. S. Giovannella, S.Miscetti (LNF-INFN). Final fits to the √ s-dependence of visible cross sections Status of KLOE memos … Plans for the fitting of the Dalitz-plot. f decays meeting – 22 Nov 2005. Status and plan.

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Progress report on p 0 p 0 g analysis

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  1. Progress report on p0 p0 g analysis S. Giovannella, S.Miscetti (LNF-INFN) • Final fits to the √s-dependence of visible cross sections • Status of KLOE memos … • Plans for the fitting of the Dalitz-plot f decays meeting – 22 Nov 2005

  2. Status and plan • As shown in the July phidec meeting, we have reached a stable • conclusive result for the data analysis while we are completing • the fit on the dalitz-plot. • Today we show the results of the fits to the ppg visible cross • section obtained by repeating the analysis “as in 2001” i.e. • neglecting any interference between VDM and scalar terms . • From these fits we will extract the parameters describing the • e+e-→wp0 and the BR( f → ppg). • To understand how well we do all of this ( + for checking the • normalization of our main background ) we have also analized • a large sample of → decays in 7 photons (prescaling 1/50 • while running our 5-photon selection).

  3. wp vs Sg events (Masses) • With our new, process • independent, photon pairing • procedure, we build the • best omega mass. • As in 2001, we then count • as : • - wp events the ones in • within 3 sigma from Mw • - Sg all the others

  4. wp vs Sg events (Angular distributions) wp events Clear S=1 angular dependence Sg events Clear S=0 angular dependence

  5. wp events vs √s (angular distributions)

  6. wp: energy dependence of the xsec • Linear dependence • - s = s0× (1+a (s’-Mf)) • B) Model /’ mesons • - 2 different parametrizations of r r‘ used

  7. wp: Fit to the visible xsec Fit A Fit B Fit C

  8. wp: FIT RESULTS to the visible xsec

  9.  → : energy dependence of the cross sections 3 Fit parameters : - a normalization - Mf , Gf We use Gfll(KLOE) = 1.320 0.017 0.015 keV c2 = 16.8/17 a= 1.014  0.010 Mf = 1019.4X  0.01 MeV Gf = 4.36  0.09 MeV

  10.  →f0  : energy dependence of the xsec

  11. f0g : Determination of BR (f→ f0g → p0p0g) We get G(f→ p0p0g) = (0.498 0.005 0.022) keV BR( f→ p0p0g ) = (1.057  0.046fit0.017norm) 10 -4

  12. First conclusions .. • As shown in this presentation, when neglecting the interference • between wp and Sg we are able to distinguish the most relevant • features of the ppgevents: • - There is a clear resonant – not resonant component • - The not resonant component is dominated by e+e- →wp →ppg • events with a well defined spin 1 angular dependence. • - The resonant component is a scalar • - If we fit the not-resonant component we find the parameters • describing the interference with the f meson to be in • reasonable agreement with SND. • - If we fit the resonant component we find that the two points far • away the f peak are not perfectly described by our model. • However we extract the BR ( f → ppg) • - All of this work has been summarized in a KLOE Memo 319 • - Submitted today!

  13. Improved K-loop parametrization N.N.Achasov, private communication • Insertion of a KK phase: • Beyond to its contribution in the interference term, • IT CHANGES THE SCALAR TERM AMPLITUDE • IN THE Mpp<2MK+ REGION • New parametrization of the pp phase:

  14. Results with the new parametrization Achasov-Kiselev: combined fit to KLOE 2000 + pp scattering data dBR/dMpp (KLOE 2000 data) dBR/dMpp× 108 (MeV-1) Mpp(MeV)

  15. Results with the new parametrization Achasov-Kiselev: combined fit to KLOE 2000 + pp scattering data d00 h00 Mpp(GeV) Paper ready in a short time Mpp(GeV)

  16. Fit results: new K-loop parametrization

  17. Fit results: new K-loop parametrization f0 only f0 + s (Msfixed)

  18. K-loop fit results: f0 + s (Msfixed) The fit parameters obtained in the f0+s case do not give a good parametrization of d00 ─ Achasov ─ This analysis Achasov: some theoretical restrictions(analyticity of the amplitudes…) have to be imposed in the fit. We have to include them!

  19. K-loop fit results: f0 + s • Discussing with Achasov we realized that the parameters of s • and the kk, pp phases are very much related. • To let them vary freely we should either fit also 00 or impose • a lot of theory restrictions which are not so easy to implement • in our fitting function. • We therefore followed a much more simple approach: • - (Fit A) we left free only the f0 parameters + VDM • - (Fit B) as (Fit A) leaving the sigma mass to vary

  20. K-loop fit results: f0 + s (MASSES) f0 + Vdm + Sigma FIXED f0 + Vdm + Sigma Free

  21. K-loop fit results: f0 + s (phases) f0 + Vdm + Sigma FIXED f0 + Vdm + Sigma Free

  22. K-loop fit results: f0 + s (phases) f0 + Vdm + Sigma FIXED f0 + Vdm + Sigma Free

  23. K-loop fit results: f0 + s (compositions) f0 + Vdm + Sigma FIXED f0 + Vdm + Sigma Free

  24. Fit results:

  25. Conclusions • S-dependence of p0 p0 g x-sec done! • KLOE memo submitted. • Fit results to the Dalitz at 1019.6 with KL improved parametrization is reasonable ! • + It has a good pp phase behaviour. • Other points at different √s to be fit …. We will proceed with the writing of the dalitz-fit Documentation and then go for the final blessing

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