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Title: Superscaling in electroweak excitation of nuclei

Abstract

Superscaling properties of {sup 12}C, {sup 16}O, and {sup 40}Ca nuclear responses, induced by electron and neutrino scattering, are studied for momentum transfer values between 300 and 700 MeV/c. We have defined two indexes to have quantitative estimates of the scaling quality. We have analyzed experimental responses to get the empirical values of the two indexes. We have then investigated the effects of finite dimensions, collective excitations, meson exchange currents, short-range correlations, and final state interactions. These effects strongly modify the relativistic Fermi gas scaling functions, but they conserve the scaling properties. We used the scaling functions to predict electron and neutrino cross sections and we tested their validity by comparing them with the cross sections obtained with a full calculation. For electron scattering we also made a comparison with data. We have calculated the total charge-exchange neutrino cross sections for neutrino energies up to 300 MeV.

Authors:
; ; ;  [1];  [2]
  1. Dipartimento di Fisica, Universita di Lecce and Istituto Nazionale di Fisica Nucleare sez. di Lecce, I-73100 Lecce (Italy)
  2. (Spain)
Publication Date:
OSTI Identifier:
20995136
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.75.034604; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BOSON-EXCHANGE MODELS; CALCIUM 40; CARBON 12; COLLECTIVE EXCITATIONS; COMPARATIVE EVALUATIONS; CROSS SECTIONS; ELECTRONS; FINAL-STATE INTERACTIONS; MEV RANGE 100-1000; NEUTRINOS; OXYGEN 16; RELATIVISTIC RANGE; SCALING

Citation Formats

Martini, M., Co, G., Anguiano, M., Lallena, A. M., and Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada. Superscaling in electroweak excitation of nuclei. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.034604.
Martini, M., Co, G., Anguiano, M., Lallena, A. M., & Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada. Superscaling in electroweak excitation of nuclei. United States. doi:10.1103/PHYSREVC.75.034604.
Martini, M., Co, G., Anguiano, M., Lallena, A. M., and Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada. Thu . "Superscaling in electroweak excitation of nuclei". United States. doi:10.1103/PHYSREVC.75.034604.
@article{osti_20995136,
title = {Superscaling in electroweak excitation of nuclei},
author = {Martini, M. and Co, G. and Anguiano, M. and Lallena, A. M. and Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada},
abstractNote = {Superscaling properties of {sup 12}C, {sup 16}O, and {sup 40}Ca nuclear responses, induced by electron and neutrino scattering, are studied for momentum transfer values between 300 and 700 MeV/c. We have defined two indexes to have quantitative estimates of the scaling quality. We have analyzed experimental responses to get the empirical values of the two indexes. We have then investigated the effects of finite dimensions, collective excitations, meson exchange currents, short-range correlations, and final state interactions. These effects strongly modify the relativistic Fermi gas scaling functions, but they conserve the scaling properties. We used the scaling functions to predict electron and neutrino cross sections and we tested their validity by comparing them with the cross sections obtained with a full calculation. For electron scattering we also made a comparison with data. We have calculated the total charge-exchange neutrino cross sections for neutrino energies up to 300 MeV.},
doi = {10.1103/PHYSREVC.75.034604},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • We investigate the degree to which the concept of superscaling, initially developed within the framework of the relativistic Fermi gas model, applies to inclusive electron scattering from nuclei. We find that data obtained from the low-energy loss side of the quasielastic peak exhibit the superscaling property; i.e., the scaling functions f({psi}{sup '}) are not only independent of momentum transfer (the usual type of scaling: scaling of the first kind), but coincide for A{>=}4 when plotted versus a dimensionless scaling variable {psi}{sup '} (scaling of the second kind). We use this behavior to study the as yet poorly understood properties ofmore » the inclusive response at large electron energy loss. (c) 1999 The American Physical Society.« less
  • The scaling functions f({psi}{sup '}) and F(y) from the {psi}{sup '}- and y-scaling analyses of inclusive electron scattering from nuclei are explored within the coherent density fluctuation model (CDFM). In addition to the CDFM formulation in which the local density distribution is used, we introduce a new equivalent formulation of the CDFM based on the one-body nucleon momentum distribution (NMD). Special attention is paid to the different ways in which the excitation energy of the residual system is taken into account in y and {psi}{sup '} scaling. Both functions, f({psi}{sup '}) and F(y), are calculated using different NMDs and comparedmore » with the experimental data for a wide range of nuclei. The good description of the data for y<0 and {psi}{sup '}<0 (including {psi}{sup '}<-1) makes it possible to show the sensitivity of the calculated scaling functions to the peculiarities of the NMDs in different regions of momenta. It is concluded that the existing data on {psi}{sup '} and y scaling are informative for NMDs at momenta not larger than 2.0-2.5 fm{sup -1}. The CDFM allows us to study simultaneously and on the same footing the role of both basic quantities--the momentum and density distributions--for the description of scaling and superscaling phenomena in nuclei.« less
  • Superscaling analyses of few-GeV inclusive electron scattering from nuclei are extended to include not only quasielastic processes, but also the region where {delta} excitation dominates. With reasonable assumptions about the basic nuclear scaling function extracted from data and information from other studies of the relative roles played by correlation and meson-exchange-current effects, it is shown that the residual strength in the resonance region can be accounted for through an extended scaling analysis. One observes scaling upon assuming that the elementary cross section by which one divides the residual to obtain a new scaling function is dominated by the N{yields}{delta} transitionmore » and employing a new scaling variable suited to the resonance region. This yields a good representation of the electromagnetic response in both the quasielastic and {delta} regions. The scaling approach is then inverted and predictions are made for charge-changing neutrino reactions at energies of a few GeV, with focus placed on nuclei that are relevant to neutrino oscillation measurements. For this, a relativistic treatment of the required weak interaction vector and axial-vector currents for both quasielastic and {delta}-excitation processes is presented.« less
  • The scaling function f({psi}{sup '}) for medium and heavy nuclei with Z{ne}N for which the proton and neutron densities are not similar is constructed within the coherent density fluctuation model (CDFM) as a sum of the proton and neutron scaling functions. The latter are calculated in the cases of {sup 62}Ni, {sup 82}Kr, {sup 118}Sn, and {sup 197}Au nuclei on the basis of the corresponding proton and neutron density distributions, which are obtained in the deformed self-consistent mean-field Skyrme HF+BCS method. The results are in reasonable agreement with the empirical data from the inclusive electron scattering from nuclei showing superscalingmore » for negative values of {psi}{sup '}, including those smaller than -1. This is an improvement over the relativistic Fermi gas model predictions where f({psi}{sup '}) becomes abruptly zero for {psi}{sup '}{<=}-1. It is also an improvement over the CDFM calculations made in the past for nuclei with Z{ne}N assuming that the neutron density is equal to the proton one and using only the phenomenological charge density.« less
  • No abstract prepared.