Simultaneous analysis of elastic scattering and transfer/breakup channels for the 6He+208Pb reaction at energies near the Coulomb barrier

The elastic and alpha-production channels for the 6He+208Pb reaction are investigated at energies around the Coulomb barrier (E_{lab}=14, 16, 18, 22, and 27 MeV). The effect of the two-neutron transfer channels on the elastic scattering has been studied within the Coupled-Reaction-Channels (CRC) method. We find that the explicit inclusion of these channels allows a simultaneous description of the elastic data and the inclusive alpha cross sections at backward angles. Three-body Continuum-Discretized Coupled-Channels (CDCC) calculations are found to reproduce the elastic data, but not the transfer/breakup data. The trivially-equivalent local polarization potential (TELP) derived from the CRC and CDCC calculations are found to explain the features found in previous phenomenological optical model calculations for this system.Comment: 7 pages, 6 figures (replaced with updated version

The boundary field theory induced by the Chern-Simons theory

The Chern-Simons theory defined on a 3-dimensional manifold with boundary is written as a two-dimensional field theory defined only on the boundary of the three-manifold. The resulting theory is, essentially, the pullback to the boundary of a symplectic structure defined on the space of auxiliary fields in terms of which the connection one-form of the Chern-Simons theory is expressed when solving the condition of vanishing curvature. The counting of the physical degrees of freedom living in the boundary associated to the model is performed using Dirac's canonical analysis for the particular case of the gauge group SU(2). The result is that the specific model has one physical local degree of freedom. Moreover, the role of the boundary conditions on the original Chern- Simons theory is displayed and clarified in an example, which shows how the gauge content as well as the structure of the constraints of the induced boundary theory is affected.Comment: 10 page

The continuum description with pseudo-state wave functions

Benchmark calculations are performed aiming to test the use of two different pseudo-state bases on the the Multiple Scattering expansion of the total Transition amplitude (MST) scattering framework. Calculated differential cross sections for p-6He inelastic scattering at 717 MeV/u show a good agreement between the observables calculated in the two bases. This result gives extra confidence on the pseudo-state representation of continuum states to describe inelastic/breakup scattering.Comment: 4 pages, 2 figures. Published in Physical Review

Time boundary terms and Dirac constraints

Time boundary terms usually added to action principles are systematically handled in the framework of Dirac's canonical analysis. The procedure begins with the introduction of the boundary term into the integral Hamiltonian action and then the resulting action is interpreted as a Lagrangian one to which Dirac's method is applied. Once the general theory is developed, the current procedure is implemented and illustrated in various examples which are originally endowed with different types of constraints.Comment: 12 page

Influence of Rhizobium and Mycorrhizae in the Production of Seedlings of Caesalpinia Spinosa L. Taya in San Pablo, Peru

This research study evaluated the symbiotic influence of Mycorrhizae in the production of propagating material of Caesalpinia Spinosa L. Taya, as well as the characterization of strains of mycorrhitic fungi in field, nursery, and laboratory work. No nodules were found as a product of nitrifying bacteria in the roots of plants Caesalpinea spinosa L., and ectomycorrhitic fungi were identified in the rhizosphere, such as Basidiomicetes and species of Rhizoctonia sp and Fusarium sp. From the evaluations, T4 exceeded all treatments, such as in height, neck diameter, number of leaves, root length, and the wet and dry weight of Taya seedling. In conclusion, we say that the Caesalpinia Spinosa L. Taya, despite of belonging to the legume family, does not present nodulation; but the presence of ectomycorrhitic fungi such as the basidiomicetes in the rhizosphere and high content of organic matter, positively influences the increase in the volume of seedling in the nursery, also reflected in the absorption of protein and phosphorus. Keywords: mycorrhizal association, seedlings, rhizobium. Resumen En el presente trabajo de investigación se evaluó la influencia simbiótica de micorrizas en la producción de plantones de Caesalpinea spinosa L. Taya, así como la caracterización de cepas de hongos micorríticos, realizándose el trabajo en campo, vivero, y laboratorio. No se encontró nódulos como producto de bacterias nitrificantes en las raíces de las plantas de Caesalpinea spinosa L., y se identificó hongos ectomicorríticos en la rizósfera, tales como Basidiomicetes y especies de Rhizoctonia sp y Fusarium sp. De las evaluaciones el T4, supera a todos los tratamientos como en altura, diámetro de cuello, número de hojas, longitud de raíz, peso húmedo y peso seco de plántula.Concluyendo finalmente, diremos que la Caesalpinea spinosa L. taya, a pesar de pertenecer a la familia de las Leguminosas no presenta nodulación; pero la presencia de los hongos ectomicorríticos como los basidiomicetes en la rizósfera y el alto contenido de materia orgánica, influye positivamente en el incremento del volumen de la plántula en vivero, reflejado también en la absorción de proteínas y fosforo. Palabras clave: asociación micorrítica, plantones, rizobium

Magnetization in AIIIBV semiconductor heterostructures with the depletion layer of manganese

The magnetic moment and magnetization in GaAs/Ga$_{0.84}$In$_{0.16}$As/GaAs heterostructures with Mn deluted in GaAs cover layers and with atomically controlled Mn $\delta$-layer thicknesses near GaInAs-quantum well ($\sim$3 nm) in temperature range T=(1.8-300)K in magnetic field up to 50 kOe have been investigated. The mass magnetization all of the samples of GaAs/Ga$_{0.84}$In$_{0.16}$As/GaAs with Mn increases with the increasing of the magnetic field that pointed out on the presence of low-dimensional ferromagnetism in the manganese depletion layer of GaAs based structures. It has been estimated the manganese content threshold at which the ferromagnetic ordering was found.Comment: 8 pages, 3 figure

Multiple scattering effects in quasi free scattering from halo nuclei: a test to Distorted Wave Impulse Approximation

Full Faddeev-type calculations are performed for $^{11}$Be breakup on proton target at 38.4, 100, and 200 MeV/u incident energies. The convergence of the multiple scattering expansion is investigated. The results are compared with those of other frameworks like Distorted Wave Impulse Approximation that are based on an incomplete and truncated multiple scattering expansion.Comment: 7 pages, 16 figures, to be published in Phys. Rev.