1,360 research outputs found
Muon capture in nuclei: an ab initio approach based on quantum Monte Carlo methods
An ab initio quantum Monte Carlo method is introduced for calculating total
rates of muon weak capture in light nuclei with mass number . As a
first application of the method, we perform a calculation of the rate in He
in a dynamical framework based on realistic two- and three-nucleon interactions
and realistic nuclear charge-changing weak currents. The currents include one-
and two-body terms induced by - and -meson exchange, and
-to- excitation, and are constrained to reproduce the empirical
value of the Gamow-Teller matrix element in tritium. We investigate the
sensitivity of theoretical predictions to current parametrizations of the
nucleon axial and induced pseudoscalar form factors as well as to two-body
contributions in the weak currents. The large uncertainties in the measured
values obtained from bubble-chamber experiments (carried out over 50 years ago)
prevent us from drawing any definite conclusions.Comment: 6 pages, 1 figur
Properties of nuclei up to using local chiral interactions
We report accurate quantum Monte Carlo calculations of nuclei up to
based on local chiral two- and three-nucleon interactions up to
next-to-next-to-leading order. We examine the theoretical uncertainties
associated with the chiral expansion and the cutoff in the theory, as well as
the associated operator choices in the three-nucleon interactions. While in
light nuclei the cutoff variation and systematic uncertainties are rather
small, in O these can be significant for large coordinate-space cutoffs.
Overall, we show that chiral interactions constructed to reproduce properties
of very light systems and nucleon-nucleon scattering give an excellent
description of binding energies, charge radii, and form factors for all these
nuclei, including open-shell systems in and 12.Comment: 6 pages, 4 figure
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