Spatial distribution of local density of states in vicinity of impurity on semiconductor surface

We present the results of detailed theoretical investigations of changes in local density of total electronic surface states in 2D anisotropic atomic semiconductor lattice in vicinity of impurity atom for a wide range of applied bias voltage. We have found that taking into account changes in density of continuous spectrum states leads to the formation of a downfall at the particular value of applied voltage when we are interested in the density of states above the impurity atom or even to a series of downfalls for the fixed value of the distance from the impurity. The behaviour of local density of states with increasing of the distance from impurity along the chain differs from behaviour in the direction perpendicular to the chain.Comment: 6 pages, 5 figure

Quasielastic contribution to antineutrino-nucleus scattering

We report on a calculation of cross sections for charged-current quasielastic antineutrino scattering off $^{12}$C in the energy range of interest for the MiniBooNE experiment. We adopt the impulse approximation (IA) and use the nonrelativistic continuum random phase approximation (CRPA) to model the nuclear dynamics. An effective nucleon-nucleon interaction of the Skyrme type is used. We compare our results with the recent MiniBooNE antineutrino cross-section data and confront them with alternate calculations. The CRPA predictions reproduce the gross features of the shape of the measured double-differential cross sections. The CRPA cross sections are typically larger than those of other reported IA calculations but tend to underestimate the magnitude of the MiniBooNE data. We observe that an enhancement of the nucleon axial mass in CRPA calculations is an effective way of improving on the description of the shape and magnitude of the double-differential cross sections. The rescaling of $M_{A}$ is illustrated to affect the shape of the double-differential cross sections differently than multinucleon effects beyond the IA.Comment: 10 pages, 10 figures. Version published in Physical Review

Impact of low-energy nuclear excitations on neutrino-nucleus scattering at MiniBooNE and T2K kinematics

[Background] Meticulous modeling of neutrino-nucleus interactions is essential to achieve the unprecedented precision goals of present and future accelerator-based neutrino-oscillation experiments. [Purpose] Confront our calculations of charged-current quasielastic cross section with the measurements of MiniBooNE and T2K, and to quantitatively investigate the role of nuclear-structure effects, in particular, low-energy nuclear excitations in forward muon scattering. [Method] The model takes the mean-field (MF) approach as the starting point, and solves Hartree-Fock (HF) equations using a Skyrme (SkE2) nucleon-nucleon interaction. Long-range nuclear correlations are taken into account by means of the continuum random-phase approximation (CRPA) framework. [Results] We present our calculations on flux-folded double differential, and flux-unfolded total cross sections off $^{12}$C and compare them with MiniBooNE and (off-axis) T2K measurements. We discuss the importance of low-energy nuclear excitations for the forward bins. [Conclusions] The CRPA predictions describe the gross features of the measured cross sections. They underpredict the data (more in the neutrino than in the antineutrino case) because of the absence of processes beyond pure quasielastic scattering in our model. At very forward muon scattering, low-energy nuclear excitations ($\omega <$ 50 MeV) account for nearly 50% of the flux-folded cross section.Comment: 8 pages, 9 figures. Version published in Physical Review