Q2 dependence of charged current p production data vs' theory

1
Q2 dependence of charged current p
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 p sample
events / 5.58E20POT/bin
Rein-Sehgal model of resonance excitations with
MA1.1GeV Annals of Physics, 133, 79 (1981)
The Q2 distribution has been presented by Bonnie
Fleming at NuInt 07
No muon mass in dynamics in CCp
Rein-Sehgal model for coherent p production
with MA1.03 GeV Nucl. Phys. B223, 29, (1983)
Rescale to reproduce MiniBooNE NCp0 results
(PLB 664, 1, 2008)
3
Recent theoretical predictions
All models are described by the Rarita-Schwinger
formalism
Vector form factors from Lalakulich et al.
Phys.Rev.D74014009,2006
ANL
Lalakulich et al., Phys.Rev.D71074003,2005
Hernandez et al, Phys.Rev.D76033005,2007
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.D77053001,2008
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.D77053003,2008

With muon mass partial cross sections depend on
the helicity
Only three Functions Modified
Muon mass in coherent p production is
introduced by applying Adlers screening factor
D. Rein and L. M. Sehgal, Phys. Lett. B 657,
207 (2007)
Multiply by Adlers screening factor
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.D77053001,2008

Vector form factor
Axial vector form factor
6
Improvement of the model of pion production
Improvement In the agreement With data for Q2 And
for E? 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
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MiniBooNE results for the MA1p fit

• The fit for the MA1p has been performed
• for the improved Rein-Sehgal model
• Absolutely normalized distributions
• Fit for entire range of Q2 and without
• the coherent p production

MA1p1.160.15 GeV with ?2/ndf 22/39 For
0.0ltQ2/GeV2lt1.0
MA1p1.170.13 GeV with ?2/ndf 14/32 For Q2gt0.2
GeV2
PRELIMINARY
The same analysis for the default model In
Nuance gives
Rein-Sehgal
MA1p1.770.27 GeV with ?2/ndf 22/39
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Two-parameter fit
Keeping the dipole form of the C5A we performed
two-parameter fits
GA
MA1p
MA1p and C5A(0)
MA1p and coherent contribution
Best fit MA1p1.37 GeV C5A(0)0.97
Best fit MA1p1.15 GeV Coherentlt0.04
PRELIMINARY
PRELIMINARY
GARS(0)0.764
1s contour
MA only fit
Default contribution to CCp events
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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 MA1p
• for Q2gt0.2GeV2
• MA1p1.170.13 GeV.

PRELIMINARY
PRELIMINARY
2a. Coherent contribution and MA1p MA1p1.15
GeV Coherentlt0.04
2b. MA1p and C5A(0) MA1p1.37
GeV C5A(0)0.97
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Backup slides
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MA1p for the shape
MA1p1.160.15 GeV with ?2/ndf 22/39 For
0.0ltQ2/GeV2lt1.0
MA1p1.170.13 GeV with ?2/ndf 14/39 For Q2gt0.2
GeV2
MA1p1.060.1 GeV For shape Q2gt0.2 GeV2 with
?2/ndf 110/39 (absolutely normalized)
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Recent experimental results

• SciBooNE

MiniBooNE, PHLTA,B664,41
1.3 GeV
NC coherent pion production is Of all NC p0
(19.5 1.1 (stat) 2.5 (sys))
1.1 GeV
2.2 GeV