Relativistic Models of Quasielastic Electron and Neutrino-Nucleus Scattering Carlotta Giusti

1. Relativistic Models of Quasielastic Electron and Neutrino-Nucleus Scattering Carlotta Giusti University and INFN Pavia in collaboration with: A. Meucci (Pavia) F.D. Pacati (Pavia) J.A. Caballero (Sevilla) J.M. Udías (Madrid) XXVIII International Workshop in Nuclear Theory, Rila Mountains June 21st-27th 2009

2. nuclear response to the electroweak probe QE-peak QE-peak dominated by one-nucleon knockout

3. QE e-nucleus scattering

4. QE e-nucleus scattering • both e’ and N detected one-nucleon-knockout (e,e’p) • (A-1) is a discrete eigenstaten exclusive (e,e’p)

5. QE e-nucleus scattering • both e’ and N detected one-nucleon-knockout (e,e’p) • (A-1) is a discrete eigenstaten exclusive (e,e’p) • only e’ detected inclusive (e,e’)

6. QE e-nucleus scattering • both e’ and N detected one-nucleon knockout (e,e’p) • (A-1) is a discrete eigenstaten exclusive (e,e’p) • only e’ detected inclusive (e,e’) QE -nucleus scattering NC CC

7. QE e-nucleus scattering • both e’ and N detected one-nucleon knockout (e,e’p) • (A-1) is a discrete eigenstaten exclusive (e,e’p) • only e’ detected inclusive (e,e’) QE -nucleus scattering NC CC • only N detected semi-inclusive NC and CC

8. QE e-nucleus scattering • both e’ and N detected one-nucleon knockout (e,e’p) • (A-1) is a discrete eigenstaten exclusive (e,e’p) • only e’ detected inclusive (e,e’) QE -nucleus scattering NC CC • only N detected semi-inclusive NC and CC • only final lepton detected inclusive CC

9. electron scattering PVES neutrino scattering NC CC

10. electron scattering PVES neutrino scattering NC CC kinfactor

11. electron scattering PVES neutrino scattering NC CC lepton tensor contains lepton kinematics

12. electron scattering PVES neutrino scattering NC CC hadron tensor

13. Direct knockout DWIA (e,e’p) n p exclusive reaction: n DKO mechanism: the probe interacts through a one-body current with one nucleon which is then emitted the remaining nucleons are spectators |f > e’ ,q e |i > 0

14. Direct knockout DWIA (e,e’p) p n |f > e’ • j one-body nuclear current • (-) = < n|f> s.p. scattering w.f. H+(+Em) • n= <n|0> one-nucleon overlap H(-Em) • n spectroscopic factor • (-) and  consistently derived as eigenfunctions of a Feshbach-type optical model Hamiltonian • phenomenological ingredients used in the calculations for (-) and  ,q e |i > 0

15. RDWIA: (e,e’p) comparison to data 16O(e,e’p) NIKHEF parallel kin e=520 MeV Tp = 90 MeV n = 0.7 n =0.65 rel RDWIA nonrel DWIA JLab (,q) const kin e=2445 MeV  =439 MeV Tp= 435 MeV RDWIA diff opt.pot. n = 0.7

16. RDWIA: NC and CC  –nucleus scattering N n |f > k’ • transition amplitudes calculated with the same model used for (e,e’p) • the same phenomenological ingredients are used for (-) and  • j one-body nuclear weak current ,q k |i > 0

17. One-body nuclear weak current NC K anomalous part of the magnetic moment

18. One-body nuclear weak current CC induced pseudoscalar form factor CC The axial form factor NC possible strange-quark contribution

19. One-body nuclear weak current The weak isovector Dirac and Pauli FF are related to the Dirac and Pauli elm FF by the CVC hypothesis CC NC strange FF

20.  –nucleus scattering • only the outgoing nucleon is detected: semi inclusive process • cross section integrated over the energy and angle of the outgoing lepton • integration over the angle of the outgoing nucleon • final nuclear state is not determined : sum over n

21. calculations • pure Shell Model description: n one-hole states in the target with an unitary spectral strength • n over all occupied states in the SM: all the nucleons are included but correlations are neglected • the cross section for the -nucleus scattering where one nucleon is detected is obtained from the sum of all the integrated one-nucleon knockout channels • FSI are described by a complex optical potential with an imaginary absorptive part

22. CC NC FSI the imaginary part of the optical potential gives an absorption that reduces the calculated cross sections RPWIA RDWIA RPWIA RDWIA FSI FSI

23. FSI for the inclusive scattering : Green’s Function Approach • (e,e’) nonrelativistic • F. Capuzzi, C. Giusti, F.D. Pacati, Nucl. Phys. A 524 (1991) 281 • F. Capuzzi, C. Giusti, F.D. Pacati, D.N. Kadrev Ann. Phys. 317 (2005) 492(AS CORR) • (e,e’) relativistic • Meucci, F. Capuzzi, C. Giusti, F.D. Pacati, PRC (2003) 67 054601 • A. Meucci, C. Giusti, F.D. Pacati Nucl. Phys. A 756 (2005) 359(PVES) • CC relativistic • A. Meucci, C. Giusti, F.D. Pacati Nucl. Phys. A739 (2004) 277

24. FSI for the inclusive scattering : Green’s Function Approach • the components of the inclusive response are expressed in terms of theGreen’s operators • under suitable approximations can be written in terms of thes.p. optical model Green’s function • the explicit calculation of the s.p. Green’s function can be avoided by its spectral representation which is based on a biorthogonal expansion in terms of anon Herm optical potential V and V+ • matrix elements similar to RDWIA • scattering states eigenfunctions of V and V+(absorption and gain of flux): the imaginary part redistributes the flux and the total flux is conserved • consistent treatmentof FSI in the exclusive and in the inclusive scattering

25. FSI for the inclusive scattering : Green’s Function Approach interference between different channels

26. FSI for the inclusive scattering : Green’s Function Approach eigenfunctions of V and V+

27. FSI for the inclusive scattering : Green’s Function Approach gain of flux loss of flux Flux redistributed and conserved The imaginary part of the optical potential is responsible for the redistribution of the flux among the different channels

28. FSI for the inclusive scattering : Green’s Function Approach gain of flux loss of flux For a real optical potential V=V+ the second term vanishes and the nuclear response is given by the sum of all the integrated one-nucleon knockout processes (without absorption)

29. 16O(e,e’) Green’s function approach GF data from Frascati NPA 602 405 (1996) A. Meucci, F. Capuzzi, C. Giusti, F.D. Pacati, PRC 67 (2003) 054601

30. 16O(e,e’) e = 1080 MeV =320 RPWIA GF 1NKO FSI e = 1200 MeV =320 data from Frascati NPA 602 405 (1996)

31. FSI FSI RPWIA GF rROP 1NKO GF

32. COMPARISON OF RELATIVISTIC MODELS PAVIA MADRID-SEVILLA • consistency of numerical results • comparison of different descriptions of FSI

33. 12C(e,e’) relativistic models e = 1 GeV FSI RPWIA rROP GF1 GF2 RMF Relativistic Mean Field: same real energy-independent potential of bound states Orthogonalization, fulfills dispersion relations and maintains the continuity equation

34. 12C(e,e’) relativistic models e = 1 GeV q=500 MeV/c q=800 MeV/c q=1000 MeV/c FSI GF1 GF2 RMF

35. 12C(e,e’) relativistic models GF1 GF2 RMF

36. SCALING PROPERTIES GF RMF

37. SCALING FUNCTION Scaling properties of the electron scattering data At sufficiently high q the scaling function depends only upon one kinematical variable (scaling variable) (SCALING OF I KIND) is the same for all nuclei (SCALING OF II KIND) I+II SUPERSCALING

38. Scaling variable (QE) + (-) for  lower (higher) than the QEP, where =0 • Reasonable scaling of I kind at the left of QEP • Excellent scaling of II kind in the same region • Breaking of scaling particularly of I kind at the right of QEP (effects beyond IA) • The longitudinal contribution superscales fQE extracted from the data

39. Experimental QE superscaling function M.B. Barbaro,J.E. Amaro, J.A. Caballero, T.W. Donnelly, A. Molinari, and I. Sick, Nucl. Phys Proc. Suppl 155 (2006) 257

40. SCALING FUNCTION The properties of the experimental scaling function should be accounted for by microscopic calculations The asymmetric shape of fQE should be explained The scaling properties of different models can be verified The associated scaling functions compared with the experimental fQE

41. QE SUPERSCALING FUNCTION: RFG Relativistic Fermi Gas

42. QE SUPERSCALING FUNCTION: RPWIA, rROP, RMF only RMF gives an asymmetric shape J.A. CaballeroJ.E. Amaro, M.B. Barbaro, T.W. Donnelly, C.Maieron, and J.M. Udias PRL 95 (2005) 252502

43. QE SCALING FUNCTION: GF, RMF q=500 MeV/c q=800 MeV/c q=1000 MeV/c GF1 GF2 RMF asymmetric shape

44. Analysis first-kind scaling : GF RMF GF1 GF2 RMF q=500 MeV/c q=800 MeV/c q=1000 MeV/c

45. DIFFERENT DESCRIPTIONS OF FSI RMF GF real energy-independent MF reproduces nuclear saturation properties, purely nucleonic contribution, no information from scattering reactions explicitly incorporated complex energy-dependent phenomenological OP fitted to elastic p-A scattering information from scattering reactions the imaginary part includes the overall effect of inelastic channels not univocally determined from elastic phenomenology different OP reproduce elastic p-A scattering but can give different predictions for non elastic observables

46. COMPARISON RMF-GF • RESULTS : • GF1, GF2, RMF similar results for the cross section and QE scaling function for q=500-700 MeV/c, differences increase increasing q • WHY ? • At higher q and energies the phenomenological OP can include contributions from non nucleonic d.o.f. (flux lost into inelastic  excitation with or without real  production) • GF can give better description of (e,e’) experimental c.s. at higher q, where QE and  peak approach and overlap • Non nucleonic contributions in the OP break scaling, they should not be included in the QE longitudinal scaling function (purely nucleonic)

47. FUTURE WORK….. • deeper understanding of the differences • disentangle nucleonic and non nucleonic contributions in the OP, extract purely nucleonic OP, use it in the GF approach and compare the results with the QE experimental scaling function • extend the comparison to different situations, neutrino scattering…