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Q 2 dependence of charged current π + production data vs. theory

Q 2 dependence of charged current π + production data vs. theory. JAROSLAW NOWAK For the MiniBooNE Collaboration LOUISIANA STATE UNIVERSITY Sixth International Workshop on Neutrino-Nucleus Interactions in the Few- GeV Region May 18th - 22nd, 2009 Sitges , Barcelona (Spain).

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Q 2 dependence of charged current π + production data vs. theory

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  1. Q2 dependence of charged current π+ productiondata vs. theory JAROSLAW NOWAK For the MiniBooNE Collaboration LOUISIANA STATE UNIVERSITY Sixth International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region May 18th - 22nd, 2009 Sitges, Barcelona (Spain)

  2. CC π+ sample #events / 5.58E20POT/bin Rein-Sehgal model of resonance excitations with MA=1.1GeV [Annals of Physics, 133, 79 (1981)] The Q2 distribution has been presented by Bonnie Fleming at NuInt 07 No muon mass in dynamics in CCπ+ Rein-Sehgal model for coherent π+ production with MA=1.03 GeV [Nucl. Phys. B223, 29, (1983)] Rescale to reproduce MiniBooNE NCπ0 results (PLB 664, 1, 2008) J. Nowak - NuInt09

  3. Recent theoretical predictions All models are described by the Rarita-Schwinger formalism Vector form factors from Lalakulich et al. Phys.Rev.D74:014009,2006 ANL Lalakulich et al., Phys.Rev.D71:074003,2005 Hernandez et al, Phys.Rev.D76:033005,2007 Axial-vector form factors: Adler model – used also in The analyses for ANL and BNL With the biggest contribution From C5A(Q2) Graczyk and SobczykPhys.Rev.D77:053001,2008

  4. Necessary improvement – muon mass Muon mass in resonace excitation model • Muon mass included only in the leptonic current –KLN model [Kuzmin, Lyubushkin and Naumov, Phys. Part. Nucl. 35, S133 (2004)] • Improving the KLN model by adding the pion-pole terms – BRS model [Berger and Sehgal, Phys. Rev. D 76, 113004 (2007)] • Similar prediction by Graczyk & Sobczyk [Phys.Rev.D77:053003,2008] With muon mass partial cross sections depend on the helicity Only three Functions Modified • Muon mass in coherent π+ production is introduced by applying • Adler’s screening factor • [D. Rein and L. M. Sehgal, Phys. Lett. B 657, 207 (2007) ] Multiply by Adler’s screening factor J. Nowak - NuInt09

  5. Improvements – form factors The relationship between vector form factor in the Rein-Sehgal model and the Rarita-Schwinger form factors taken from Graczyk and Sobczyk, Phys.Rev.D77:053001,2008 Vector form factor Axial vector form factor J. Nowak - NuInt09

  6. Improvement of the model of pion production Improvement In the agreement With data for Q2 And for Eν vs. Q2 #events /5.58E20POT/bin PRELIMINARY Reconstructed Q2 (GeV2) PRELIMINARY Data/MC (absolutely normalized)

  7. Comparison to other models All models but the Rein-Sehgal are with muon mass effect and new vector form factor #events for 5.58E20POT/bin Lalakulich v.1 Hernandez Lalakulich v.2 PRELIMINARY PRELIMINARY Reconstructed Q2 (GeV2) Graczyk v.1 Graczyk v.2 J. Nowak - NuInt09

  8. MiniBooNE results for the MA1π fit • The fit for the MA1π has been performed • for the improved Rein-Sehgal model: • Absolutely normalized distributions • Fit for entire range of Q2 and without • the coherent π+ production MA1π=1.16±0.15 GeV with χ2/ndf =22/39 For 0.0<Q2/GeV2<1.0 MA1π=1.17±0.13 GeV with χ2/ndf =14/32 For Q2>0.2 GeV2 PRELIMINARY The same analysis for the default model In Nuance gives Rein-Sehgal MA1π=1.77±0.27 GeV with χ2/ndf =22/39 J. Nowak - NuInt09

  9. Two-parameter fit Keeping the dipole form of the C5A we performed two-parameter fits MA1π GA MA1π and C5A(0) MA1π and coherent contribution Best fit MA1π=1.15 GeV Coherent<0.04 Best fit MA1π=1.37 GeV C5A(0)=0.97 PRELIMINARY PRELIMINARY GARS(0)=0.764 1σ contour MA only fit Default contribution to CCπ+ events J. Nowak - NuInt09

  10. Conclusions • The new model of charged • Current pion production • Improved agreement with data • We performed fits for three models Best fit values obtained for the new model with BRS (muon mass), new GV and C5A #events / 5.58E20POT/bin The fit result for MA1π for Q2>0.2GeV2 MA1π=1.17±0.13 GeV. PRELIMINARY PRELIMINARY 2a. Coherent contribution and MA1π MA1π=1.15 GeV Coherent<0.04 2b. MA1π and C5A(0) MA1π=1.37 GeV C5A(0)=0.97 J. Nowak - NuInt09

  11. Backup slides J. Nowak - NuInt09

  12. MA1π for the shape MA1π=1.16±0.15 GeV with χ2/ndf =22/39 For 0.0<Q2/GeV2<1.0 MA1π=1.17±0.13 GeV with χ2/ndf =14/39 For Q2>0.2 GeV2 MA1π=1.06±0.1 GeV For shape Q2>0.2 GeV2 with χ2/ndf =110/39 (absolutely normalized) J. Nowak - NuInt09

  13. Recent experimental results • SciBooNE MiniBooNE, PHLTA,B664,41 1.3 GeV NC coherent pion production is Of all NC π0 (19.5 ±1.1 (stat) ±2.5 (sys))% K2K, PRL 95, 252301 (2005) 1.1 GeV 2.2 GeV J. Nowak - NuInt09

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