J.A. Caballero

Relativistic mean field approximation to the analysis of 16 O ( e , e ′ p ) 15 N data at | Q 2 | 0.4 ( GeV / c ) 2

We use the relativistic distorted wave impulse approximation to analyze data on 16 O(e,ep) 15 N at |Q 2 | ≤ 0.4 (GeV/c) 2 that were obtained by differ- ent groups and seemed controversial. Results for differential cross-sections, response functions and ATL asymmetry are discussed and compared to dif- ferent sets of experimental data for proton knockout from p1/2 and p3/2 shells in 16 O. We compare with a nonrelativistic approach to better identify rel- ativistic effects. The present relativistic approach is found to accommodate most of the discrepancy between data from different groups, smoothing a long standing controversy.

RPWIA analysis of dynamical relativistic contributions in 16O(e→,e′p→) reactions

Abstract Coincidence scattering of polarized electrons from nuclei with polarization transfer to outgoing nucleons is studied within the context of relativistic mean field theory. Effects introduced by the dynamical enhancement of the lower components of the bound nucleon wave function are analyzed for the polarized response functions and transferred polarization asymmetries assuming the relativistic plane-wave impulse approximation (RPWIA). Results obtained by projecting out the negative-energy components are compared with the fully relativistic calculation for proton knockout from p 1/2 and p 3/2 shells in 16 O for a variety of kinematic situations. The crucial role played by the relativistic dynamics in some spin-dependent observables is clearly manifested even for low/medium values of the missing momentum. The degree to which knowledge about nucleon form factors can be extracted from analyses of this type of process is also discussed.

RPWIA analysis of dynamical relativistic contributions in

Abstract Coincidence scattering of polarized electrons from nuclei with polarization transfer to outgoing nucleons is studied within the context of relativistic mean field theory. Effects introduced by the dynamical enhancement of the lower components of the bound nucleon wave function are analyzed for the polarized response functions and transferred polarization asymmetries assuming the relativistic plane-wave impulse approximation (RPWIA). Results obtained by projecting out the negative-energy components are compared with the fully relativistic calculation for proton knockout from p 1/2 and p 3/2 shells in 16 O for a variety of kinematic situations. The crucial role played by the relativistic dynamics in some spin-dependent observables is clearly manifested even for low/medium values of the missing momentum. The degree to which knowledge about nucleon form factors can be extracted from analyses of this type of process is also discussed.

^{16}O(\vec{e},e'\vec{p})

Abstract We consider ratios of elastiv ν ( ovrarr / BC )-proton cross sections measured by the Brookhaven BNL-734 experiment and use them to obtain the neutral current (NC) over charged current (CC) neutrino-antineutrino asymmetry. We discuss the sensitivity of these ratios and of the asymmetry to the electric, magnetic and axial strange form factors of the nucleon and to the axial cutoff mass M A . We show that the effects of the nuclear structure and interactions on the asymmetry and, in general, on ratios of cross sections are negligible. We find some restrictions on the possible values of the parameters characterizing the strange form factors. We show that a precise measurement of the neutrino-antineutrino asymmetry would allow the extraction of the axial and vector magnetic strange form factors in a model independent way. The neutrino-antineutrino asymmetry turns out to be almost independent on the electric strange form factor and on the axial cutoff mass.

reactions

We study the occurrence of factorization in polarized and unpolarized observables in coincidence quasielastic electron scattering. Starting with the relativistic distorted wave impulse approximation, we reformulate the effective momentum approximation and show that the latter leads to observables which factorize under some specific conditions. Within this framework, the role played by final state interactions and, in particular, by the spin-orbit term is explored. Connection with the nonrelativistic formalism is studied in depth. Numerical results are presented to illustrate the analytical derivations and to quantify the differences between factorized and unfactorized approaches.

Strange form factors of the proton: a new analysis of the ν (ovrarr/BC) data of the BNL-734 experiment

The phenomenon of superscaling for quasielastic lepton induced reactions at energies of a few GeV is investigated within the framework of the relativistic impulse approximation. A global analysis of quasielastic inclusive electron and charged-current neutrino scattering reactions on nuclei is presented. Scaling and superscaling properties are shown to emerge from both types of processes. The crucial role played by final state interactions is evaluated by using different approaches. The asymmetric shape presented by the experimental scaling function, with a long tail in the region of positive values of the scaling variable, is reproduced when the interaction in the final state between the knockout nucleon and the residual nucleus is described within the relativistic mean field approach. The impact of gauge ambiguities and off-shell effects in the scaling function is also analyzed.

A(e, e'p)B responses: From bare nucleons to complex nuclei

Abstract Kinematical relativistic effects are analyzed within the plane-wave impulse approximation for outgoing nucleon polarized responses in coincidence electron scattering. Following recent approaches for semi-relativistic reductions of the electromagnetic current operator, here an exact treatment of the problem for the transferred energy and momentum is presented. Rather than employing existing semi-relativistic expressions for the single-nucleon matrix elements, in this work the response functions are expanded directly. Results are compared for different kinematical situations with the fully-relativistic PWIA calculation as well as with previous expansions. Off- and on-shell prescriptions are also studied in detail, and a systematic analysis of the various kinematical variables involved in the process is presented.

General study of superscaling in quasielastic ( e , e ' ) and ( ν , μ ) reactions using the relativistic impulse approximation

Recoil nucleon transferred polarization observables in coincidence quasielastic electron scattering are studied within the relativistic distorted wave impulse approximation. Results for response functions and polarization asymmetries are discussed for proton knockout from

Kinematical relativistic effects in (e→,e′N→) reactions

p_{1/2}

Analysis of polarizedO16(e⃗,e′p⃗)observables within the relativistic distorted wave impulse approximation

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