Antiproton-deuteron annihilation at low energies

Recent experimental studies of the antiproton-deuteron system at low energies have shown that the imaginary part of the antiproton-deuteron scattering length is smaller than the antiproton-proton one. Two- and three-body systems with strong annihilation are investigated and a mechanism explaining this unexpected relation between the imaginary parts of the scattering lengths is proposed.Comment: 6 pages, 3 figures, to be published in The European Physical Journal

Low energy n-\nuc{3}{H} scattering : a novel testground for nuclear interaction

The low energy n-\nuc{3}{H} elastic cross sections near the resonance peak are calculated by solving the 4-nucleon problem with realistic NN interactions. Three different methods -- Alt, Grassberger and Shandas (AGS), Hyperspherical Harmonics and Faddeev-Yakubovsky -- have been used and their respective results are compared. We conclude on a failure of the existing NN forces to reproduce the n-\nuc{3}{H} total cross section.Comment: To be published in Phys. Rev.

Coulomb corrections to low energy antiproton annihilation cross sections on protons and nuclei

We calculate, in a systematic way, the enhancement effect on antiproton-proton and antiproton-nucleus annihilation cross sections at low energy due to the initial state electrostatic interaction between the projectile and the target nucleus. This calculation is aimed at future comparisons between antineutron and antiproton annihilation rates on different targets, for the extraction of pure isospin channels.Comment: 18 pages, 4 figures (latex format

Manifestation of three-body forces in three-body Bethe-Salpeter and light-front equations

Bethe-Salpeter and light-front bound state equations for three scalar particles interacting by scalar exchange-bosons are solved in ladder truncation. In contrast to two-body systems, the three-body binding energies obtained in these two approaches differ significantly from each other: the ladder kernel in light-front dynamics underbinds by approximately a factor of two compared to the ladder Bethe-Salpeter equation. By taking into account three-body forces in the light-front approach, generated by two exchange-bosons in flight, we find that most of this difference disappears; for small exchange masses, the obtained binding energies coincide with each other.Comment: 24 pages, 8 figures, submitted in Few-Body System

Limits on the low energy antinucleon-nucleus annihilations from the Heisenberg principle

We show that the quantum uncertainty principle puts some limits on the effectiveness of the antinucleon-nucleus annihilation at very low energies. This is caused by the fact that the realization a very effective short-distance reaction process implies information on the relative distance of the reacting particles. Some quantitative predictions are possible on this ground, including the approximate A-independence of antinucleon-nucleus annihilation rates.Comment: 10 pages, no figure

Estabilidade de cultivares e linhagens de feijoeiro em diferentes ambientes no Estado de São Paulo.

O presente trabalho teve como objetivos realizar a avaliação genotípica de linhagens de feijoeiro no Estado de São Paulo pela estimativa dos valores genotípicos das linhagens para cada local e também para o ambiente médio de todos os locais. Estudos da adaptabilidade e estabilidade dos valores genotípicos preditos foram realizados pelo procedimento BLUP. A cultivar Graúna e a linhagem GEN 96A31 apresentaram superioridade média de 10% sobre a média geral dos 15 ambientes. Os valores foram computados já penalizando as linhagens pela instabilidade através dos locais e ao mesmo tempo capitalizando a capacidade de resposta (adaptabilidade) à melhoria do ambiente, usando propriedades intrínsecas ao método MHPRVG (Média Harmônica da Performance Relativa dos Valores Genéticos). Os métodos MHPRVG, Lin & Binns e Annicchiarico selecionaram, praticamente, as mesmas linhagens. Contudo, o método MHPRVG forneceu os resultados na própria escala de medição do caráter avaliado, os quais foram interpretados diretamente como valores genéticos para produtividade, estabilidade e adaptabilidade simultaneamente

Benchmark calculation of n-3H and p-3He scattering

The n-3H and p-3He elastic phase-shifts below the trinucleon disintegration thresholds are calculated by solving the 4-nucleon problem with three different realistic nucleon-nucleon interactions (the I-N3LO model by Entem and Machleidt, the Argonne v18 potential model, and a low-k model derived from the CD-Bonn potential). Three different methods -- Alt, Grassberger and Sandhas, Hyperspherical Harmonics, and Faddeev-Yakubovsky -- have been used and their respective results are compared. For both n-3H and p-3He we observe a rather good agreement between the three different theoretical methods. We also compare the theoretical predictions with the available experimental data, confirming the large underprediction of the p-3He analyzing power.Comment: 18 pages, 9 figure

Finite-frequency Rayleigh wave tomography of the western Mediterranean: Mapping its lithospheric structure

We present a 3-D shear wave velocity model for the crust and upper mantle of the western Mediterranean from Rayleigh wave tomography. We analyzed the fundamental mode in the 20¿167 s period band (6.0¿50.0 mHz) from earthquakes recorded by a number of temporary and permanent seismograph arrays. Using the two-plane wave method, we obtained phase velocity dispersion curves that were inverted for an isotropic Vs model that extends from the southern Iberian Massif, across the Gibraltar Arc and the Atlas mountains to the Saharan Craton. The area of the western Mediterranean that we have studied has been the site of complex subduction, slab rollback, and simultaneous compression and extension during African-European convergence since the Oligocene. The shear velocity model shows high velocities beneath the Rif from 65 km depth and beneath the Granada Basin from ¿¿70 km depth that extend beneath the Alboran Domain to more than 250 km depth, which we interpret as a near-vertical slab dangling from beneath the western Alboran Sea. The slab appears to be attached to the crust beneath the Rif and possibly beneath the Granada Basin and Sierra Nevada where low shear velocities (3.8 km/s) are mapped to >55 km depth. The attached slab is pulling down the Gibraltar Arc crust, thickening it, and removing the continental margin lithospheric mantle beneath both Iberia and Morocco as it descends into the deeper mantle. Thin lithosphere is indicated by very low upper mantle velocities beneath the Alboran Sea, above and east of the dangling slab and beneath the Cenozoic volcanics.This research was funded by the U.S. National Science Foundation EAR-0808939. The deployment of the IberArray broadband seismic network is part of the CONSOLIDER CSD2006-00041 (Geosciences in Iberia: Integrated studies on Topography and 4-D Evolution) grant from the Spanish Ministry of Science and Innovation. Additional funding was provided by the Spanish ministry under grants CGL2010-17280 and by Generalitat de Catalunya under grant 2009 SGR 6.Peer Reviewe

Relativistic approaches to structure functions of nuclei

We employ a propagator technique to derive a new relativistic 1/\qq expansion of the structure function of a nucleus, composed of point-nucleons. We exploit non-relativistic features of low-momentum nucleons in the target and only treat relativistically the nucleon after absorption of a high-momentum virtual photon. The new series permits a 3-dimensional reduction of each term and a formal summation of all Final State Interaction terms. We then show that a relativistic structure function can be obtained from its non-relativistic analog by a mere change of a scaling variable and an addition of an energy shift. We compare the obtained result with an ad hoc generalized Gersch-Rodriguez-Smith theory, previously used in computations of nuclear structure functions.Comment: Comparison with data is included, to be published in PRC, Feb. 200

Nominal or Real? The Impact of Regional Price Levels on Satisfaction with Life

According to economic theory, real income, i.e., nominal income adjusted for purchasing power, should be the relevant source of life satisfaction. Previous work, however, has only studied the impact of inflation adjusted nominal income and not taken into account regional differences in purchasing power. Therefore, we use a novel data set to study how regional price levels affect satisfaction with life. The data set comprises about 7 million data points that are used to construct a price level for each of the 428 administrative districts in Germany. We estimate pooled OLS and ordered probit models that include a comprehensive set of individual level, time-varying and time-invariant control variables as well as control variables that capture district heterogeneity other than the price level. Our results show that higher price levels significantly reduce life satisfaction. Furthermore, we find that a higher price level tends to induce a larger loss in life satisfaction than a corresponding decrease in nominal income. A formal test of neutrality of money, however, does not reject neutrality of money. Our results provide an argument in favor of regional indexation of government transfer payments such as social welfare benefits