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ppg Large Angle analysis & Off Peak

ppg Large Angle analysis & Off Peak. f decays WG meeting, Frascati, 28 February 2007. ppg Large Angle analysis. f decays WG meeting, Frascati, 28 February 2007. Analysis cuts. LA acceptance 50° < q p < 130° 50° < q g < 130°, E g > 50 MeV Likelihood ( .and. )

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ppg Large Angle analysis & Off Peak

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  1. ppg Large Angle analysis & Off Peak fdecays WG meeting, Frascati, 28 February 2007

  2. ppg Large Angle analysis fdecays WG meeting, Frascati, 28 February 2007

  3. Analysis cuts • LA acceptance 50° < qp < 130° 50° < qg < 130°, Eg > 50 MeV • Likelihood (.and.) • Kinematic fit in ppp hypothesis • Mtrk vs. Mpp2 cut • W vs. Mpp2 cut • Systematic effects evaluated • Efficiencies evaluated • Contribution of scalar meson evaluated • Systematic effect on the f0(980) evaluated (major step forward with respect the KGM) • Pion form factor extracted

  4. 2ppp>200 2ppp Systematic on analysis cuts Shifting the cuts, run the full selection for Data and MC (for each ‘shifted cut’) and looked at the change in the ratio Data/MC with respect to the standard selection c2ppp 2ppp > 200: maximum inefficiency of the signal: 1% RDtMC 2ppp 2pppfrom 100 to 600, in steps of 100 Each double ratio RDtMC fitted with a straight line 0.2% effect

  5. Maximum shift Analysis cut Mtrk [MeV] 1 MeV Step Minimum shift Mpp2 [GeV2] Mtrk vs. Mpp2 Mtrk(Kine)-Mtrk(Reco): more than 95% well described by a single gaussian of s = 3.5 MeV For each step, RDtMC fitted with a straight line RDtMC 0.2% effect Mtrk [MeV]

  6. W vs. Mpp2 Actual cut [o] Mpp2 [GeV2] Moving the cut in steps of 0.1o, in the interval -0.5o - +0.5o Negligible effect for Mpp2 > 0.4 GeV2

  7. 3s RDtMC RDtMC qp & qg Moving qp,g in step of 1o between 45o and 155o Ratio RDtMC fitted with a straight line qpResolution: 0.5° 3s → 1.5° 0.2% effect Bigger range for qg 0.1% effect

  8. 0.25 < Mpp2 < 0.3 [GeV2] Mtrk [MeV] Mtrk 0.35 < Mpp2 < 0.4 [GeV2] Mtrk [MeV] Systematic on background subtraction ppp-MC rescaling New ppgtag version  higher p-p+p0 background (before cut on Trackmass) rescaling factor for 3p-MC Data ppg mmg 3p-norm to L 3p-rescaled

  9. , Mtrk>150 MeV Mpp2 [GeV2] ppp Looking at the difference DATA-MC in ‘safe’ regions and multiplied by the background contamination DATA-MC relative difference fit: 2% 0.3% error at 0.3 GeV2 0.1% error at 0.4 GeV2 Negligible from 0.5 GeV2

  10. Mpp2 [GeV2] Mpp2 [GeV2] mmg Number of events for Mtrk < 120 MeV for DATA and MC in bin of Mpp2 multiplying MC-DATA relative difference times the muon contamination  systematic error on the mmg subtraction Negligible up to 0.6 GeV2 0.2% at high masses

  11. Scalar meson subtraction Choice of the f0 model: 1st step Different models implemented in Phokhara5.1. Differences between the models. Check using forward-backward asymmetry Models excluded by the F-B asymmetry check N.B. No rpp+p-g contribution simulated in Phokhara. Effects al low Q

  12. Chrg asymmetry (p+) [o] Chrg asymmetry (p+) [o] Choice of the f0 model: 2nd step Check using charge asymmetry in bin of Mpp2 “No structure” model excluded

  13. Choice of the Kaon-loop model parameters Strategy Parameters in the K+K- loop: m(f0), g(f0kk), g(f0pp) 1. Fix a set of parameters for the f0(980) – K+K- loop model – referring to the FB-asymmetry agreement. 2. Look at the maximun and minimum variation in the cross section • Covered the full range 4m2p-1GeV2 to observe the effect the f0(980) contribution • Averaged the FB-ASY from p+ and p- to make the smaller the statistical error

  14. FB asym FB asym FB asym Varying systematically the two couplings: g(f0kk), g(f0pp)  Comparison data/MC of the F-B Asymmetry

  15. g(f0kk) g(f0pp) Plateau of minima • Coupling values chosen for the reference cross section: g(f0kk)=-4.39, g(f0pp)=3.6(2=98)  Cross section for the threered values

  16. ds/dQ2 ds/dQ2 ds/dQ2 relatively big effect at low Q2 Small effect on the r-peak (as expected) relatively big effect at high Q2

  17. g(f0kk)=-4.39, g(f0pp)=3.6 (2=98)  ds/dMpp2 Ref To check the stability two more coupling combinations (blue values) have been considered. RErr actually does not change.

  18. Q2 [GeV2] rpp+p-g contribution The LA selection run on ALL_PHYS ntuples: From kine identified what passes as rpp+p-g Q2(rpp+p-g) / (Q2-Data) Q2 [GeV2] Influence on the systematic error on f0 subtraction?

  19. Systematic on the efficiencies Shifting each single cut used to select the sample  diffence data/MC • Tracking p+p-p0 sample 0.4% dissagreement with MC • Inefficiency contains p-decay and nuclear interaction effects • Difference Data-MC: limted description of track splitting in MC Varying • c2ppp, Minv(gg) • rpca, |zpca|, rfirst hit • Systematic: maximun deviation 0.2% • Vertex • p+p-g sample • 0.3% disagreement with MC • Difference Data-MC: limted description of track splitting in MC Varying • W, rpca, |zpca|, rfirst hit • Systematic: maximun deviation 0.1%

  20. FB Asymmetry (average of p+ and p-) Q2 [GeV2] Systematic on the FSR contribution FSR contribution Data 2006 Data-MC fitted with a line (0.4-0.85 GeV2) 0.04  0.01 (2 = 1.9) • FSR (LO+NLO) contribution estimated from Phokhara version • Cut-off for Eg  0.05 • Systematic maximun deviation • 0.4% at 0.4 GeV2 • 0.2% at 0.6 GeV2 • ~1% at 0.85 GeV2 Q2 [GeV2]

  21. Pion Form Factor extraction Global approach Version 5 of Phokhara in GEANFI  distinguish between gISR and gFSR and evaluate inefficiecny of cuts on NLO-events • Global efficiency from MC • Analysis cuts efficiencies • acceptance correction • unshifting (from Mpp to Mg*) • rejection of FSR-LO • reconstructions effect • Correct for eglobal • Correct for e(data)/e(MC) • Normalize to L • Divide by H • Correct for vacuum polarization • Correct for f0(980) contribution Q2 [GeV2]

  22. after all cuts Q2 [GeV2] Exclusive approach Phokhara5.1 (version inclusive of f0(980) according to K+K- loop) in GEANFI • Correct for (FSR+f0) efficiency eFSR+f0 • Correct for global efficiency for pure ISR events eISRglobal • Correct for e(data)/e(MC) • Normalize to L • Divide by H • Correct for vacuum polarization • Add back FSR-NLO contribution (Schwinger) f0(980) contribution simulated in GEANFI

  23. M(g*) [GeV2] M(g*) [GeV2] Global Exclusive g(f0kk)=-5.89 g(f0pp)=3.6 Global / Exclusive

  24. M(g*) [GeV2] Scalars correction according to Phohara5.1 Scalars correction according to Feva Systematic error on scalar correction on the F(p) from difference between scalar contribution predicted from the two curves Large Angle 2002 Small Angle 2001 Mpp2 [GeV2]

  25. Total systematic error

  26. Values parameters

  27. Conclusions and future steps • Analysis has got a solid “conclusive” point - systematic error well below 1% • … apart the f0 issue  repeat the study with Feva

  28. … & Off Peak fdecays WG meeting, Frascati, 28 February 2007

  29. pS [MeV] The pS cut Using DVFS bank Cut, downscaling… ? ppgsubstream requirements: 1. DVFS bank: Mtrk > 80 MeV and Mpp2 < 1.02 GeV2 if DVFS does not satisfy the conditions 2. DTFS bank: Mtrk > 80 MeV and Mpp2 < 1.02 GeV2

  30. DTFS bank DVFS bank Mtrk [MeV] Mtrk [MeV] Mpp2 [GeV2] Mpp2 [GeV2] pS [MeV] Events with the ppgsubstream requirements are not satisfied by DVFS enter thanks to the DTFS “recovering procedure” Events in which DVFS has not passed ppgsubstream

  31. pS [MeV] Mpp2 [GeV2] pS [MeV] The cut on Mpp2 < 1.02 GeV2 (DVFS)corresponds to the “fake” cut on pS at ~ 970 MeV Removing the ppgsubstream requirement the cut at pS disappears

  32. Status of the production • DATA stentu ntuples already done since before Xtmas (apart the data which have to be reprocessed) - dsts spread between Frascati and Karlsruhe - ntuples stored in Karlsruhe • ppg and mmg off peak MC stentu ntuples production completed - stored in Frascati (phidec15) - small sample in Karlsruhe • Ntuples for efficiency studies to be produced

  33. Mtrk [MeV] Mtrk [MeV] 2006 ppg 2006 mmg Mpp2 [GeV2] Mpp2 [GeV2] Some analysis cuts (work in progress) Trackmass Same Mtrk vs. Mpp2 cutting function of 2002 LA Mtrk [MeV] Histograms are in log scale on the z-axis New ppgtag applied with DVFS information Mpp2 [GeV2]

  34. Wp [] Wp [] 2006 ppg 2006 mmg Mpp2 [GeV2] Mpp2 [GeV2] 2006 DATA Wp [] Mpp2 [GeV2] Omega - 2002 LA W cut - 2006 W cut Histograms are in log scale on the z-axis

  35. mmg / ppg+mmg Mtrk [MeV] mmg / ppg+mmg Mtrk [MeV] Mtrk [MeV] mmg contamination after all the analysis cuts • ppgtag • LA acceptance • Likelihood (.and.) • Mtrk vs. Mpp2 cut • Mpp2 • W vs. Mpp2 cut • ppp hypothesis Kinematic fit

  36. 2006 ppg 2006 Data 2006 ppg 2006 Data Mtrk [MeV] sMtrk [MeV] Mpp2 [GeV2] Mpp2 [GeV2] MC /Data -1 MC /Data -1 Mpp2 [GeV2] Mpp2 [GeV2] Optimization of the 2006 MC Bini-Valeriani’s procedure • Systematic shift in momenta as function of qp • Momentum resolution corrected by Gaussian smearing functions Mtrk vs. Mpp2 Data and MC systematically different in Mtrk mean values (Mtrk) (sMtrk)

  37. 2006 ppg 2006 Data sMtrk [MeV] Mtrk [MeV] 2006 ppg 2006 Data qp [] qp [] MC /Data -1 MC /Data -1 qp [] qp [] Mtrk vs. qp Data and MC systematically different in Mtrk mean values (Mtrk) (sMtrk) B-V’s procedure is not good DATA-MC discrepancies (specially) the Mtrk mean values

  38. No Monte Carlo tuning 2006 ppg 2006 Data Mtrk [MeV] sMtrk [MeV] 2006 ppg 2006 Data Mtrk vs. Mpp2 Data and MC in good agreement in Mtrk mean values but not in the width Mpp2 [GeV2] Mpp2 [GeV2] MC /Data -1 (Mtrk) (sMtrk) MC /Data -1 Mpp2 [GeV2] Mpp2 [GeV2]

  39. 2006 ppg 2006 Data Mtrk [MeV] sMtrk [MeV] 2006 ppg 2006 Data qp [] qp [] (Mtrk) MC /Data -1 MC /Data -1 (sMtrk) qp [] qp [] Mtrk vs. qp Similar to the situation of Mtrk vs. Mpp2 Without any MC tuning DATA-MC discrepancy in Mtrk resolutions

  40. (Mtrk) (Mtrk) MC /Data -1 MC /Data -1 qp+ [rad] qp- [rad] • Fine tuning of Mtrk mean values (vs. Mpp2 and vs. qp)  qp correcting function • Fine tuning of the momenta resolution  different Gaussian smearing sets • …

  41. (sMtrk) (sMtrk) MC /Data -1 MC /Data -1 qp+ [rad] qp- [rad] Different combination of Gaussian smearing sets: different multiplicative factors for different qpand Mpp2 ranges … Still try and try iterative procedure (?)

  42. A glance at the future steps • Track calibration • Fix the DATA-MC comparisons • Work out a dedicated analysis cut set • Start the efficiencies (vertex and tracking) studies

  43. Mtrk –mp [MeV] Data 2006 ppg MC 2006 Mpp2 [GeV2] First steps along track calibration Mtrk –mp [MeV] Mpp2 [GeV2]

  44. ppg MC 2006 Kine Mtrk –mp [MeV] Mpp2 [GeV2]

  45. Backup

  46. Check on background contamination (ppp and mmg) after ppp MC rescaling MC = mmg + ppg + ppp

  47. Systematic on the background subtraction: muon Negligible up 0.6 GeV2 0.2% at high masses (relatively high contribution But good description from MC)

  48. 2ppp cuts inefficiencies Kinematic fit

  49. Trackmass Zoomed in the talk Mtrk [MeV] Max and min shift Mpp2 [GeV2]

  50. FB-Asy g(f0kk) = -4.39 g(f0pp) = 3.6 Q2 [GeV2] Check of pion Form Factor parameterization effect Parameters of the f0(980) fixed, varying the parameters the F(p) parametrization (Kühn-Santamaria)  F-B Asymmetry

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