70 research outputs found
A new vibrational level of the H molecular ion
A new state of the H molecular ion with binding energy of
1.09 a.u. below the first dissociation limit is predicted, using
highly accurate numerical nonrelativistic quantum calculations. It is the first
L=0 excited state, antisymmetric with respect to the exchange of the two
protons. It manifests itself as a huge p-H scattering length of
Bohr radii.Comment: 6 pages + 3 figure
Testing Non-local Nucleon-Nucleon Interactions in the Four-Nucleon Systems
The Faddeev-Yakubovski equations are solved in configuration space for the -particle and n-H continuum states. We test the ability of nonlocal
nucleon-nucleon interaction models to describe 3N and 4N systems.Comment: 16 pages, 6 figure
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
Critical Temperature for -Particle Condensation within a Momentum Projected Mean Field Approach
Alpha-particle (quartet) condensation in homogeneous spin-isospin symmetric
nuclear matter is investigated. The usual Thouless criterion for the critical
temperature is extended to the quartet case. The in-medium four-body problem is
strongly simplified by the use of a momentum projected mean field ansatz for
the quartet. The self-consistent single particle wave functions are shown and
discussed for various values of the density at the critical temperature
Benchmark calculation of p-3H and n-3He scattering
p-3H and n-3He scattering in the energy range above the n-3He but below the
d-d thresholds is studied by solving the 4-nucleon problem with a realistic
nucleon-nucleon interaction. Three different methods -- Alt, Grassberger and
Sandhas, Hyperspherical Harmonics, and Faddeev-Yakubovsky -- have been employed
and their results for both elastic and charge-exchange processes are compared.
We observe a good agreement between the three different methods, thus the
obtained results may serve as a benchmark. A comparison with the available
experimental data is also reported and discussed.Comment: 13 pages, 6 figures. arXiv admin note: text overlap with
arXiv:1109.362
Parity violation in low energy neutron deuteron scattering
Parity violating effects for low energy elastic neutron deuteron scattering
are calculated for DDH and EFT-type of weak potentials in a Distorted Wave Born
Approximation, using realistic hadronic strong interaction wave functions,
obtained by solving three-body Faddeev equations in configuration space. The
results of relation between physical observables and low energy constants can
be used to fix low energy constants from experiments. Potential model
dependencies of parity violating effects are discussed.Comment: version accepted for publication in Phys. Rev.
Time Reversal Invariance Violation in Neutron Deuteron Scattering
Time reversal invariance violating (TRIV) effects for low energy elastic
neutron deuteron scattering are calculated for meson exchange and EFT-type of
TRIV potentials in a Distorted Wave Born Approximation, using realistic
hadronic strong interaction wave functions, obtained by solving three-body
Faddeev equations in configuration space. The relation between TRIV and parity
violating observables are discussed
Free-surface pressure distributions with minimum wave resistance
The wave resistance of distributions of excess pressure over a rectangular region on the surface of a steady stream is minimised by choice of spatial variation in pressure. Both unconstrained and constrained (non-negative) pressures are studied. Results with impressive resistance reductions are provided, both via discretisation to a large number of step pressures, and via optimisation within a low-order continuous family
Three-neutron resonance trajectories for realistic interaction models
Three-neutron resonances are investigated using realistic nucleon-nucleon
interaction models. The resonance pole trajectories are explored by first
adding an additional interaction to artificially bind the three-neutron system
and then gradually removing it. The pole positions for the three-neutron states
up to J=5/2 are localized in the third energy quadrant-Im (E)<=0, Re
(E)<=0-well before the additional interaction is removed. Our study shows that
realistic nucleon-nucleon interaction models exclude any possible experimental
signature of three-neutron resonances.Comment: 13 pages ; 8 figs ; 5 table
Description of He tetramer bound and scattering states
Faddeev-Yakubovski equations are solved numerically for 4He tetramer and
trimer states using realistic helium-helium interaction models. We describe the
properties of ground and excited states, and we discuss with a special emphasis
the 4He-4He3 low energy scattering
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