1,061 research outputs found

    Few body Calculation of Neutrino Neutral Inelastic scattering on 4He

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    The inelastic neutral reaction of neutrino on 4He is calculated using two modern nucleon--nucleon potentials. Full final state interaction among the four nucleons is considered, via the Lorentz integral transform (LIT) method. The effective interaction hyperspherical-harmonic (EIHH) approach is used to solve the resulting Schrodinger like equations. A detailed energy dependent calculation is given in the impulse approximation.Comment: 4 pages; talk at 18th International Conference on Few-Body Problems in Physics (FB18), Santos, SP, Brazil, August 200

    Neutrino Breakup of A=3 Nuclei in Supernovae

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    We extend the virial equation of state to include 3H and 3He nuclei, and predict significant mass-three fractions near the neutrinosphere in supernovae. While alpha particles are often more abundant, we demonstrate that energy transfer cross-sections for muon and tau neutrinos at low densities are dominated by breakup of the loosely-bound 3H and 3He nuclei. The virial coefficients involving A=3 nuclei are calculated directly from the corresponding nucleon-3H and nucleon-3He scattering phase shifts. For the neutral-current inelastic cross-sections and the energy transfer cross sections, we perform ab-initio calculations based on microscopic two- and three-nucleon interactions and meson-exchange currents.Comment: 6 pages, 2 figures, minor additions, to appear in Phys. Rev.

    Effects of three-nucleon forces and two-body currents on Gamow-Teller strengths

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    We optimize chiral interactions at next-to-next-to leading order to observables in two- and three-nucleon systems, and compute Gamow-Teller transitions in carbon-14, oxygen-22 and oxygen-24 using consistent two-body currents. We compute spectra of the daughter nuclei nitrogen-14, fluorine-22 and fluorine-24 via an isospin-breaking coupled-cluster technique, with several predictions. The two-body currents reduce the Ikeda sum rule, corresponding to a quenching factor q^2 ~ 0.84-0.92 of the axial-vector coupling. The half life of carbon-14 depends on the energy of the first excited 1+ state, the three-nucleon force, and the two-body current

    Correlation between Charge Inhomogeneities and Structure in Graphene and Other Electronic Crystalline Membranes

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    Only one atom thick and not inclined to lattice defects, graphene represents the ultimate crystalline membrane. However, its structure reveals unique features not found in other crystalline membranes, in particular the existence of ripples with wavelength of 100-300 Angstroms. Here, I trace the origin of this difference to the free electrons in the membrane. The deformation energy of the lattice creates a coupling between charge fluctuations and the structure, resulting in ripples on the membrane, correlated with charge inhomogeneities. In graphene this mechanism reproduces the experimental result for both charge puddles and ripples.Comment: Accepted for publication in PRB as Rapid Communicatio

    Solar fusion cross sections II: the pp chain and CNO cycles

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    We summarize and critically evaluate the available data on nuclear fusion cross sections important to energy generation in the Sun and other hydrogen-burning stars and to solar neutrino production. Recommended values and uncertainties are provided for key cross sections, and a recommended spectrum is given for 8B solar neutrinos. We also discuss opportunities for further increasing the precision of key rates, including new facilities, new experimental techniques, and improvements in theory. This review, which summarizes the conclusions of a workshop held at the Institute for Nuclear Theory, Seattle, in January 2009, is intended as a 10-year update and supplement to Reviews of Modern Physics 70 (1998) 1265.Comment: 54 pages, 20 figures, version to be published in Reviews of Modern Physics; various typos corrected and several updates mad
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