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WG2 goals (Theory and Calculations)

WG2 goals (Theory and Calculations). How accurately can we calculate the neutrino-nucleus interactions?? How do we vadidate the calculation?

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WG2 goals (Theory and Calculations)

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  1. WG2 goals (Theory and Calculations) • How accurately can we calculate the neutrino-nucleus interactions?? How do we vadidate the calculation? • Note: Neutrino data are not simple: neutrino spectrum is wide and accurate to 10-20%; measured events are the mixture of various neutrino interactions (quasi-elastic, D, DIS). • We are using not only new neutrino scattering data (MiniBOONE, K2K, NOMAD, and MINOS), but also electron scattering data which are new (Jupiter/JLAB) or which already exist, to test/evaluate the accuracy of the calculations. Zeller/Sakuda@NuFact05

  2. We need accurate Electron-nucleon scattering data to test and improve Neutrino-nucleon scattering data • Electromagnetic current (Jaem) and weak hadronic charged current (JaCC=Va1+i2–Aa1+i2) are related through CVC: e e q N N Zeller/Sakuda@NuFact05

  3. Developments in Theoretical Calculations • O. Benhar, Comparison of Electron and Neutrino Nucleus Scattering Data with LDA Calculations, hep-ph/0506116 (PRD) • M. Barbaro, Using Electron Scattering Superscaling to Predict Neutrino-Nucleus Scattering, PRC71,015501,2005 • N. Jachowicz, Relativistic Models for Quasi-Elastic Neutrino-Nucleus Scattering, Nucl-th/0505008 • M. Valverde, Inclusive Nucleon Emission Induced by Quasi-Elastic Neutrino-Nucleus Interactions, PRC70, 05503,2004 • A. Botrugno, Neutrino Nucleus Scattering in Giant Resonance Region and in Quasi-Elastic Peak • Y. Sakemi, Study for the Neutrino Coherent Pion Production Experiment ---experimental proposal • A. Kataev, The Relations Between Bjorken Polarized, Bjorken Unpolarized, and Gross-Llewellyn Smith Sum Rules Zeller/Sakuda@NuFact05

  4. Energy region Physics interest 1. 1-100 MeV Reactor, Supernova Nuclear shell structure is important. 2. 100-500 MeV Supernova, ATMn, LSND 3. 500-2000 MeV MiniBOONE, K2K, ATMn, T2K Quasi-elastic and D production are important. 4. E>5 GeV MINOS, CNGS, ATMn Nulcear effects in DIS Zeller/Sakuda@NuFact05

  5. Achievements Zeller/Sakuda@NuFact05

  6. 1. Energy region: 500-2000 MeV • Considering correct Fermi momentum distribution is important. P(p,E): 10-20% effect in cross section and spectrum wrt a simple relativistic Fermi-gas model. See NuInt04 Proceedings NPB(Proc)139. • We now consider the final state interaction (FSI). Benhar/Jachowicz/Valvelde try to evalate this effect using nulcear transparency data. Zeller/Sakuda@NuFact05

  7. ds/dn O(e,e’), n=Ee-Ee’=Enegy transfer (GeV)Ee=700-1200 MeV Blue: Fermi-gas Green: SP Red: SP+FSI QE D Zeller/Sakuda@NuFact05

  8. Prediction for ds/dQ2of FG, SP, SP+FSI validated by electron scattering data, Benhar et al., hep-ph/0506116, PRD FG SP SP+FSI Zeller/Sakuda@NuFact05

  9. Validation of FSI effect: Calculated transparency compared to data Transparency= Probability that a nucleon can escape from the nucleus without being subject to any interaction. i.e. T=1.0 = Completely transparent=No interaction Benhar et al., hep-ph/0506116 Jachowicz et al., nucl-th/0505008 Zeller/Sakuda@NuFact05

  10. The effect of FSI (rescattering)-Valverde Zeller/Sakuda@NuFact05

  11. Use scaling to understand/parametrize data better and quantify -Barbaro et al Zeller/Sakuda@NuFact05

  12. Zeller/Sakuda@NuFact05

  13. D production –Some differences Benhar (Bodek-Ritchie) Valverde Nakamura (Paschos) QE D Zeller/Sakuda@NuFact05

  14. 500-2000 MeV • Quasi-elastic interaction • Calculation of neutrino-nucleus quasi-elastic interaction (500-2000MeV) is in good shape. Going from a simple FG to spectral function S(p,E) improves the cross section calculation by 10-20%. • FSI (nuclear rescattering) makes the cross section changes by another 5-10%. • Overall, the calculation is good to 10% level, considering those effect. • D production • There are some differences between the calculations at Delta peak. • Dip region between quasi-elastic and Delta need to be studied. • Valverde’s calculation looks good. 30-40% differences exist between the calculations. We need further checks. Zeller/Sakuda@NuFact05

  15. 2. Energy region: 10-500 MeV • Butrogno (CRPA, Lecce) and Valverde (RPA, Granada) seems to reproduce LSND cross sections. • Butrogno (CRPA) can reproduce C(e,e’)C* E=10-50 MeV and O(e,e’) E=300-800 MeV reasonably. Zeller/Sakuda@NuFact05

  16. E Transferred Energy x Continuum Random Phase Approximation +FSI --By Botrugno Collective excitations Zeller/Sakuda@NuFact05

  17. Energy Region: II) Giant Resonance Zeller/Sakuda@NuFact05

  18. Valverde (RPA) Zeller/Sakuda@NuFact05

  19. Energy Region: I) Quasielastic Peak Zeller/Sakuda@NuFact05

  20. 3. Coherent pion production • Rein-Seghal calculation is 20 years old. • New calculations (Mateau, Paschos) seem to predict less. • K2K showed a suppressed cross section. • Sakemi (RCNP) performs a new relevant measurement using proton beam and will compare it with the calculation. p + A → n + π+ + A (g.s.) • We need to update the calculations. Zeller/Sakuda@NuFact05

  21. RCNP Coherent Pion Production at RCNP, Osaka g’ΔΔ ~ extract from Coherent Pion Production p + A → n + π+ + A (g.s.) • Peak shift from Delta residual interaction • ΔE ≈ g’ΔΔ(ћcfpND/mp2)ρ0 • Longitudinal response function :RL~ dominant at 0 degree • scpp(0°) → RL → g’ (g’NN, g’ND, g’DD) Light ion induced CPP experiment status : • RCNP 12C(p,nπ+)12C(G.S.)~ in progress Experiment • Beam ~ proton 400MeV un-polarized ⊿E~100keV • Target ~ 12C (100mg/cm2) • Detector • Netron detector ~ ⊿E~300 keV • π detector ~ ⊿E~1 MeV • Identification of CPP • select the ground state of residual nucleus coherent pion cross section[2]. correlation of cross section and g’ΔΔ[3]. [2] E. Oset, Nucl. Phys. A 592 (1995) 472. [3] T. Udagawa et al., Phys. Rev. C 49 (1994) 6. Zeller/Sakuda@NuFact05

  22. 4. Plans for the next NuFact06 • 500-2000MeV: D cross section and Dip region should be checked. • 10-500 MeV: Validate CRPA, RPA calculations more. • Calculation of coherent pion production will be examined and more comparison with other data (K2K NC, MiniBOONE) will be done. • Non-resonant and DIS will be examined. • First of all, we ask the theorists to make a calculation usable and open for us experimenters, so that we can use/test it in the experiments. Zeller/Sakuda@NuFact05

  23. The 4th Workshop on Neutrino-Nucleus Interactions In the Few-GeV Region (NuInt05) Okayama University, 26-29 September, 2005 Supported by JSPS (Japan) and CNR (Italy) NuInt04 (Gran Sasso) Nucl.Phys.B(Proc.Suppl.)139. Zeller/Sakuda@NuFact05

  24. Spectral Function for Various Nuclei • Spectral Functions P(p,E) for various nuclei, eg.16O, are estimated by Benhar et al. using e-N data. P(p,E) : Probability of removing a nucleon of momentum p from ground state leaving the residual nucleus with excitation energy E. Fermi momemtum Fermi Gas model p Zeller/Sakuda@NuFact05

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