Effect of ELF e.m. fields on metalloprotein redox-active sites

The peculiarity of the distribution and geometry of metallic ions in enzymes pushed us to set the hypothesis that metallic ions in active-site act like tiny antennas able to pick up very feeble e.m. signals. Enzymatic activity of Cu2+, Zn2+ Superoxide Dismutase (SOD1) and Fe2+ Xanthine Oxidase (XO) has been studied, following in vitro generation and removal of free radicals. We observed that Superoxide radicals generation by XO is increased by a weak field having the Larmor frequency fL of Fe2+ while the SOD1 kinetics is sensibly reduced by exposure to a weak field having the frequency fL of Cu2+ ion.Comment: 18 pages, 4 figure

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

Nuclear effects in charged-current quasielastic neutrino-nucleus scattering

After a short review of the recent developments in studies of neutrino-nucleus interactions, the predictions for double-differential and integrated charged current-induced quasielastic cross sections are presented within two different relativistic approaches: one is the so-called SuSA method, based on the superscaling behavior exhibited by electron scattering data; the other is a microscopic model based on relativistic mean field theory, and incorporating final-state interactions. The role played by the meson-exchange currents in the two-particle two-hole sector is explored and the results are compared with the recent MiniBooNE data.Comment: 12 pages, 9 figures, to appear in the Proceedings of "XIII Convegno di Cortona su Problemi di Fisica Nucleare Teorica", Cortona (Italy), April 6-8, 201

Off-shell effects in the relativistic mean field model and their role in CC (anti)neutrino scattering at MiniBooNE kinematics

The relativistic mean field (RMF) model is used to describe nucleons in the nucleus and thereby to evaluate the effects of having dynamically off-shell spinors. Compared with free, on-shell nucleons as employed in some other models, within the RMF nucleons are described by relativistic spinors with strongly enhanced lower components. In this work it is seen that for MiniBooNE kinematics, neutrino charged-current quasielastic cross sections show some sensitivity to these off-shell effects, while for the antineutrino-nucleus case the total cross sections are seen to be essentially independent of the enhancement of the lower components. As was found to be the case when comparing the RMF results with the neutrino-nucleus data, the present impulse approximation predictions within the RMF also fall short of the MiniBooNE antineutrino-nucleus data.Comment: 19 pages, 7 figures, submitted to Physics Letters

Charged-current inclusive neutrino cross sections in the SuperScaling model including quasielastic, pion production and meson-exchange contributions

Charged current inclusive neutrino-nucleus cross sections are evaluated using the superscaling model for quasielastic scattering and its extension to the pion production region. The contribution of two-particle-two-hole vector meson-exchange current excitations is also considered within a fully relativistic model tested against electron scattering data. The results are compared with the inclusive neutrino-nucleus data from the T2K and SciBooNE experiments. For experiments where $\langle E_\nu \rangle \sim 0.8$ GeV, the three mechanisms considered in this work provide good agreement with the data. However, when the neutrino energy is larger, effects from beyond the $\Delta$ also appear to be playing a role. The results show that processes induced by two-body currents play a minor role at the kinematics considered.Comment: 10 pages, 7 figure

Petronius on dreams: 300 years of English translations

No abstract available

Nuclear effects in neutrino and antineutrino CCQE scattering at MINERvA kinematics

We compare the charged-current quasielastic neutrino and antineutrino observables obtained in two different nuclear models, the phenomenological SuperScaling Approximation and the Relativistic Mean Field approach, with the recent data published by the MINERvA Collaboration. Both models provide a good description of the data without the need of an ad hoc increase in the mass parameter in the axial-vector dipole form factor. Comparisons are also made with the MiniBooNE results where different conclusions are reached.Comment: 6 pages, 7 figures, Accepted for publication in Physical Review

Fermion propagators in space-time

The one- and the two-particle propagators for an infinite non-interacting Fermi system are studied as functions of space-time coordinates. Their behaviour at the origin and in the asymptotic region is discussed, as is their scaling in the Fermi momentum. Both propagators are shown to have a divergence at equal times. The impact of the interaction among the fermions on their momentum distribution, on their pair correlation function and, hence, on the Coulomb sum rule is explored using a phenomenological model. Finally the problem of how the confinement is reflected in the momentum distribution of the system's constituents is briefly addressed.Comment: 26 pages, 9 figures, accepted for publication on Phys. Rev.

Superscaling and Neutral Current Quasielastic Neutrino-Nucleus Scattering beyond the Relativistic Fermi Gas Model

The superscaling analysis is extended to include quasielastic (QE) scattering via the weak neutral current of neutrinos and antineutrinos from nuclei. The scaling function obtained within the coherent density fluctuation model (used previously in calculations of QE inclusive electron and charge-changing (CC) neutrino scattering) is applied to neutral current neutrino and antineutrino scattering with energies of 1 GeV from $^{12}$C with a proton and neutron knockout (u-channel inclusive processes). The results are compared with those obtained using the scaling function from the relativistic Fermi gas model and the scaling function as determined from the superscaling analysis (SuSA) of QE electron scattering.Comment: 10 pages, 6 figures, published in Phys. Rev.