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Issues in the Quasi-free Delta Production Region

Issues in the Quasi-free Delta Production Region. Ryoichi Seki (CSUN/Caltech) in collaboration with Hiroki Nakamura (Waseda) RCCN International Workshop; Kahiwa, Japan; December 11, 2004. Q = (  , q ) . Structure/ Response Function (  , q ).

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Issues in the Quasi-free Delta Production Region

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  1. Issues in the Quasi-free Delta Production Region Ryoichi Seki (CSUN/Caltech) in collaboration with Hiroki Nakamura (Waseda) RCCN International Workshop; Kahiwa, Japan; December 11, 2004

  2. Q = (,q)  Structure/ Response Function (,q) 1. Nucleonic reactions + Ν  ℓ + Δ(1232) ℓ + Ν* a) (e,e’) SLAC J-Lab b) (,ℓ) Axial transition form factors 2. Nuclear reactions + A  ℓ + A* ℓ + A* +  …………. a) Spectral function b) Final state interaction c) Exchange current e) Other approaches

  3. Dufner-Tsai (1968), Fogli-Nardulli (1979) Paschos-Yu-Sakuda (2004) Dufner-Tsai(1968), Fogli-Nardulli (1979)(Res2) Paschos-Yu-Sakuda (2004)(Res1)

  4. Nucleonic reactions a) (e,e’) SLAC • Target: p, d and inclusive  p and n responses • A. Bodek et al., Phys. Rev. D20, 1471 (1979) • A. Bodek and J. L. Richie, Phys. Rev. D23, 1070 (1981)

  5. b) p (e,e’) J-Lab

  6. Theoretical models 1)Unitary isobar model, MAID and Jlab/Yeveran D. Drechsel, S. S. Kamalov, and L.Tiator, Nucl. Phys. A645,145(‘99) I. G. Aznauryan, Phys. Rev. C68,065204 (‘03); C67,015209 (‘03) 2) Multi-channel K-matrix model, SAID R. A. Arndt et al., Phys. Rev. C52, 2120 (1995) Int. J. Mod. Phys. A18, 449 (2003) 3) Dynamical model, SL (Sato-Lee) and DMT (Dubna-Mainz-Taiwan) T. Sato and T.-S. H. Lee, Phys. Rev. C54, 2660 (1996) Phys. Rev. C63, 055201 (2001) S. S. Kamalov and S. N. Young, Phys. Rev. Lett. 83, 4494 (‘99) + D. Drechsel, O. Hanstein, L. Tiator, Phys. Rev. C64, 032201(’02) * A recent review: V. D. Burkert and T.-S. H. Lee, nucl-ex/0407020 (July’04) Phenomenological model H2 model, C. Keppel (1995) http://hallcweb.jlab.org/resdata/

  7. a) n (e,e’) J-Lab 1) D (e,e’p) for Ee = 5.765 GeV and Q2 = 1.2 – 5 GeV2 A. V. Klimenko, PhD thesis (Old Dominion Univ., 2004) 2) D (e,e’p) BONUS (2005)

  8. Inclusive Neutron Resonance Electroproduction Again, a large uncertainty in neutron extraction….. …must consider deuteron wave function, Fermi smearing, off-shell effects, neutron structure function shape,... Courtesy of Thia Keppel

  9. So, what will BONUS measure?…Inclusive Neutron Measurements in the JLab (large x, low Q) Kinematic Regime • Elastic form factors • Resonance structure • Transition form factors • Quark-hadron duality • Data over a range of Q2, x • Structure function moments • Large x nucleon structure Courtesy of Thia Keppel

  10. Courtesy of Thia Keppel BONUS RTPC Design 4mm x 10 cm 7.5 atm F, z from pads r from time dE/dx from charge along track (particle ID) 4 cm He neonDME

  11. Courtesy ofThia KeppelTransition Form Factors from Inclusive Data – Projected Results Neutron n ->D Statistical uncertainties only Model uncertainty dominant, comparable to proton extractions

  12. b) Nucleonic (,ℓ) * D. Rein and L. Sehgal, Ann. Phys. 133, 79 (1981) D. Rein, Z. Phys. C 35, 43 (1987)  BNL data (1990) and Int. Workshop on N* Physics (1997) * Alverez-Russo, Singh,and Vincent Vacas, Phys. Rev. C57, 2693 (‘98) E. Paschos, J.-Y. Yu, and M. Sakuda, Phys. Rev. D69, 014013 (‘04) * T. Sato, D. Uno, and T.-S. H. Lee, Phys. Rev. C67, 065201 (2003) p ( , ¯) p Data: BNL(1990) Data:ANL(1979) • *Scaling: A. Bodek, I. Park, and U. ki Yang, hep/ph/0411202 (16 Nov 2004)

  13. 2. Nuclear reactions a) Spectral function: * O. Benhar et al. (H. Nakamura’s talk in this workshop) Many-body nuclear matter calculation (correlated nuclear-state basis) + Shell model, in local density approx. * C. Ciofi degli Atti and S. Simula, Phys. Rev. C53, 1689 (‘96) b) Final state interaction: * Nucleon: Eikonal approx. of Lorentzian with optical potential * Pion: L. L. Salcedo, E. Oset et al., Nucl. Phys. A484, 557 (“88) (Note: Importance of the real part of the potential for low-E pions)

  14. p nuclear effects in 16O p+ – 16O cross section (NEUT vs. Data) Probability of p0 – 16Ointeraction in NEUT

  15. c) Exchange current 1) Current conservation + Off-energy/mass shell contributions * Electromagnetic  meson exchange models * Axial  Δ(1232) and pions in intermediate states modified propagators with their self-energy 2) Warning: 20 - 30% quenching of gA (GT) in beta decays Kirchbach and D. Riska, Nucl. Phys. A578, 511 (‘94) M. Hjorth-Jensen et al. Nucl. Phys. A563, 525 (1993) D. O. Riska, Phys. Rep. 181, 208 (1989) Effects on the form factors?

  16. d) Other approaches 1) Valencia/Granadamany-body calculations: A. Gil, J. Nieves, and E. Oset, Nucl. Phys. A627, 543 (1997) Many-body approach to the inclusive (e,e’) reaction … J. Nieves, J. E. Amaro, and M. Valverde, nucl-th/0408008 (3 Aug 2004) Nuclear many-body theory of electroweak interactions … 2) Donnelly/I. Sick superscaling (RFG + phenomenological modifying function) J. E. Amaro et al., nucl-th/0409078 (30 Set 2004) Using electron scattering superscaling to predict charge- changing neutrino cross sections in nuclei C. Maieron, T. W. Donnelly, I. Sick, Phys. Rev. C65, 025502 (2002) Extended superscaling of electron scattering from nuclei

  17. 16O(e , e’)Effects of form factor (Res1:Paschos et al.)Data (@Frascati): M. Anghinolfi et al. Nucl. Phys. A602, 405 (1996)

  18. Conclusion: Assessment of the present status of the Delta region 1) Quality: Presently available calculations and codes include all important physics except for that associated with the current (partial) conservation. 2) Predictability: More tuning of the calculations is desirable to the electron-scattering precision data, currently available or becoming available. 3) Experiment: More precise neutrino-nucleon data are critically needed 4) Codes: It is perhaps the best time for creating codes of higher quality than the presently available, by putting all together.

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