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.

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

Neutral current (anti)neutrino scattering: relativistic mean field and superscaling predictions

We evaluate the neutral current quasi-elastic neutrino cross section within two nuclear models: the SuSA model, based on the superscaling behavior of electron scattering data, and the RMF model, based on relativistic mean field theory. We also estimate the ratio $(\nu p \to \nu p)/(\nu N \to \nu N)$ and compare with the MiniBooNE experimental data, performing a fit of the parameters $M_A$ and $g_A^{(s)}$ within the two models. Finally, we present our predictions for antineutrino scattering.Comment: 15 pages, 4 figure

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$_{3}$ (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 $^{60}$Co and $^{22}$Na {\gamma}-ray energies against a fast BaF$_{2}$ 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$_{3}$(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

Relativistic Models for Quasi-Elastic Neutrino-Nucleus Scattering

Two relativistic approaches to charged-current quasielastic neutrino-nucleus scattering are illustrated and compared: one is phenomenological and based on the superscaling behavior of electron scattering data and the other relies on the microscopic description of nuclear dynamics in relativistic mean field theory. The role of meson exchange currents in the two-particle two-hole sector is explored. The predictions of the models for differential and total cross sections are presented and compared with the MiniBooNE data.Comment: 3 pages, 3 figures, Proceedings of PANIC 2011, MIT, Cambridge, MA, July 201

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, $^{21}$Ne and $^{25}$Mg, and for one oblate nucleus, $^{37}$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