1,061 research outputs found
Few body Calculation of Neutrino Neutral Inelastic scattering on 4He
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
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
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
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
Lattice calculations for A=3,4,6,12 nuclei using chiral effective field theory
We present lattice calculations for the ground state energies of tritium,
helium-3, helium-4, lithium-6, and carbon-12 nuclei. Our results were
previously summarized in a letter publication. This paper provides full details
of the calculations. We include isospin-breaking, Coulomb effects, and
interactions up to next-to-next-to-leading order in chiral effective field
theory.Comment: 38 pages, 11 figures, final publication versio
Solar fusion cross sections II: the pp chain and CNO cycles
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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