194 research outputs found
Relativistic descriptions of quasielastic charged-current neutrino-nucleus scattering: application to scaling and superscaling ideas
The analysis of the recent experimental data on charged-current
neutrino-nucleus scattering cross sections measured at MiniBooNE requires fully
relativistic theoretical descriptions also accounting for the role of final
state interactions. In this work we evaluate inclusive quasielastic
differential neutrino cross sections within the framework of the relativistic
impulse approximation. Results based on the relativistic mean field potential
are compared with the ones corresponding to the relativistic Green function
approach. An analysis of scaling and superscaling properties provided by both
models is also presented.Comment: 11 pages, 8 figures, version accepted for publication in Physical
Review
Final-State Interactions in the Superscaling Analysis of Neutral-Current Quasielastic Neutrino Scattering
Effects of strong final-state interactions in the superscaling properties of
neutral-current quasielastic neutrino cross sections are investigated using the
Relativistic Impulse Approximation as guidance. First- and second-kind scaling
are analyzed for neutrino beam energies ranging from 1 to 2 GeV for the cases
of 12C, 16O and 40Ca. Different detection angles of the outgoing nucleon are
considered in order to sample various nucleon energy regimes. Scaling of the
second kind is shown to be very robust. Validity of first-kind scaling is found
to be linked to the kinematics of the process. Superscaling still prevails even
in the presence of very strong final-state interactions, provided that some
kinematical restrains are kept, and the conditions under which superscaling can
be applied to predict neutral-current quasielastic neutrino scattering are
determined.Comment: 39 pages, 16 figures, accepted for publication in Phys. Rev.
Spin dependent Momentum Distributions in Deformed Nuclei
We study the properties of the spin dependent one body density in momentum
space for odd--A polarized deformed nuclei within the mean field approximation.
We derive analytic expressions connecting intrinsic and laboratory momentum
distributions. The latter are related to observable transition densities in
{\bf p}--space that can be probed in one nucleon knock--out reactions from
polarized targets. It is shown that most of the information contained in the
intrinsic spin dependent momentum distribution is lost when the nucleus is not
polarized. Results are presented and discussed for two prolate nuclei,
Ne and Mg, and for one oblate nucleus, Ar. The effects of
deformation are highlighted by comparison to the case of odd--A nuclei in the
spherical model.Comment: Latex 2.09. 25 pages and 6 figures (available from
[email protected]), to appear in Ann. of Phy
Enhanced time response of 1-in. LaBr3(Ce) crystals by leading edge and constant fraction techniques
We have characterized in depth the time response of three detectors equipped
with cylindrical LaBr (Ce) crystals with dimensions of 1-in. in height
and 1-in. in diameter, and having nominal Ce doping concentration of 5%, 8% and
10%. Measurements were performed at Co and Na {\gamma}-ray
energies against a fast BaF reference detector. The time resolution was
optimized by the choice of the photomultiplier bias voltage and the fine tuning
of the parameters of the constant fraction discriminator, namely the
zero-crossing and the external delay. We report here on the optimal time
resolution of the three crystals. It is observed that timing properties are
influenced by the amount of Ce doping and the crystal homogeneity. For the
crystal with 8% of Ce doping the use of the ORTEC 935 CFD at very shorts delays
in addition to the Hamamatsu R9779 PMT has made it possible to improve the
LaBr(Ce) time resolution from the best literature value at 60Co photon
energies to below 100 ps.Comment: Article submitted to Nuclear Instruments and Methods in Physics
Research Section A: Accelerators, Spectrometers, Detectors and Associated
Equipmen
Relativistic descriptions of final-state interactions in charged-current quasielastic neutrino-nucleus scattering at MiniBooNE kinematics
The results of two relativistic models with different descriptions of the
final-state interactions are compared with the MiniBooNE data of
charged-current quasielastic cross sections. The relativistic mean field model
uses the same potential for the bound and ejected nucleon wave functions. In
the relativistic Green's function (RGF) model the final-state interactions are
described in the inclusive scattering consistently with the exclusive
scattering using the same complex optical potential. The RGF results describe
the experimental data for total cross-sections without the need to modify the
nucleon axial mass.Comment: 5 pages 3 figure
Nuclear transparencies in relativistic A(e,e'p) models
Relativistic and unfactorized calculations for the nuclear transparency
extracted from exclusive A(e,e'p) reactions for 0.3 \leq Q^2 \leq 10 (GeV/c)^2
are presented for the target nuclei C, Si, Fe and Pb. For Q^2 \geq 0.6
(GeV/c)^2, the transparency results are computed within the framework of the
recently developed relativistic multiple-scattering Glauber approximation
(RMSGA). The target-mass and Q^2 dependence of the RMSGA predictions are
compared with relativistic distorted-wave impulse approximation (RDWIA)
calculations. Despite the very different model assumptions underlying the
treatment of the final-state interactions in the RMSGA and RDWIA frameworks,
they predict comparable nuclear transparencies for kinematic regimes where both
models are applicable.Comment: 15 pages, 4 figure
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