Arie Bodek, Univ. of Rochester1 [P13.011] Modeling Neutrino Quasi-elastic Cross Sections Using Up to Date Nucleon Form Factors Howard Budd, Arie Bodek (Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627), John Arrington (Argronne National Laboratory, Argonne, IL) Arie Bodek, Howard Budd, Univ. of Rochester and John Arrington Argonne National Laboratory FormFactors-DPF03.ppt A Review of Weak and Electromagnetic Form Factors

Arie Bodek, Univ. of Rochester2 Need to update - Axial Form Factor extraction This Talk (What is the difference in the quasi-elastic cross sections if: 1. We use the most recent very precise value of g A = F A (Q 2 ) = (instead of 1.23 used in earlier analyses.) Sensitivity to g A and m A, 2. Use the most recent Updated G E P.N (Q 2 ) and G M P.N ((Q 2 ) from Electron Scattering (instead of the dipole form assumed in earlier analyses) In additionThere are new precise measurments of G E P.N (Q 2 ) Using polarization transfer experiments 3. How much does m A, measured in previous experiments change if current up to date form factors are used instead --- Begin updating m A e +i k2. r e +i k1.r Mp

Arie Bodek, Univ. of Rochester3 They implemented The Llewellyn-Smith Formalism for NUMI Non zero

Arie Bodek, Univ. of Rochester4 Fp important for Muon neutrinos only at Very Low Energy Q 2 =-q 2 UPDATE: Replace by G E V = G E P -G E N g A,M A need to Be updated UPATE: Replace by G M V = G M P -G M N From C.H. Llewellyn Smith (SLAC). SLAC-PUB-0958 Phys.Rept.3:261,1972

Arie Bodek, Univ. of Rochester5 Neutron G M N is negativeNeutron (G M N / G M N dipole ) At low Q2 Our Ratio to Dipole similar to that nucl-ex/ G. Kubon, et al Phys.Lett. B524 (2002) Neutron (G M N / G M N dipole )

Arie Bodek, Univ. of Rochester6 Neutron G E N is positive New Polarization data gives Precise non zero G E N hep-ph/ (2002) Neutron, G E N is positive - Imagine N=P+pion cloud Neutron (G E N / G E P dipole ) Krutov (G E N ) 2 show_gen_new.pict Galster fit Gen

Arie Bodek, Univ. of Rochester7 Extract Correlated Proton G M P, G E P simultaneously from e-p Cross Section Data with and without Polarization Data Proton G M P Compare Rosenbluth Cross section Form Factor Separation Versus new Hall A Polarization measurements Proton G E P /G M P Proton G M P / G M P -DIPOLE

Arie Bodek, Univ. of Rochester8 Effect of G M N + (G M P,G E P using POLARIZATION data AND non zero G E N Krutov) - Versus Dipole Form -> Discrepancy between G E P Cross Section and Polarization Data Not significant for Neutrino Cross Sections G M P,G E P extracted With e-p Cross Section data only G M P,G E P extracted with both e-p Cross section and Polarization data ratio_JhaKJhaJ_D0DD.pict ratio_JKJJ_D0DD.pict using cross section data AND G E N Krutov Using Polarization Transfer data AND G E N Krutov +n->p+  - +p->n+  + +n->p+  - +p->n+  +

Arie Bodek, Univ. of Rochester9  quasi-elastic neutrinos on Neutrons-( - Calculated  quasi-elastic Antineutrinos on Protons - Calculated From H. Budd -U of Rochester (NuInt02) (with Bodek and Arrington) DATA - FLUX ERRORS ARE 10% With the most Up to date Form Factors The agreement With data is not spectacular Antineutrino data mostly on nuclear targets

Arie Bodek, Univ. of Rochester10 Reanalysis of

Arie Bodek, Univ. of Rochester11 Type in their d  /dQ2 histogram. Fit with our best Knowledge of their parameters : Get M A = (A different central value, but they do event likelihood fit And we do not have their the event, just the histogram. If we put is best knowledge of form factors, then we get M A = or  M A = So all their Values for M A. should be reduced by 0.025

Hep-ph/ (2001) For updated M A expt. need to be reanalyzed with new g A, and G E N Difference In Ma between Electroproduction And neutrino Is understood M A from neutrino expt. No theory corrections needed 1.11=M A

Arie Bodek, Univ. of Rochester13 Using these data we get  M A to update to for latest ga+form factors. (note different experiments have different neutrino energy Spectra, different fit region, different targets, so each experiment requires its own study). A Pure Dipole analysis, with ga=1.23 (Shape analysis) - if redone with best know form factors -->  M A = (I.e. results need to be reduced by 0.055) for different experiments can get  M A from to Change ga=1.23 to best known ga= (shape analysis) --->  M A = Dipole-> better Gmn, Gep, Gmp -->  M A = Gen=0-> non zero Gen --->  M A = Total-0.055

Arie Bodek, Univ. of Rochester14 Low-Q2 suppression or Larger M A ? T.Ishida’s From Ito NuInt02 K2K fits this With larger Ma=1.11 instead Of nominal 1.02 GeV First result done at NuInt02

Arie Bodek, Univ. of Rochester15 Effect is Low Q2 suppression from non Zero Gen Wrong Gen /Best Form Factors (Ratio) Wrong Ma=1.1 (used by K2K) Over Ma=1.02 (Ratio) If One Uses Both wrong Form Factors (used in K2K MC) ( Wrong Gen =0 +Wrong Ma=1.1) Over Best Form Factors (Ratio) --> Get right shape But wrong normalization of 10% ANSWER - Neutrino Community Using Outdated Form Factors For E=1 GeV