1,071 research outputs found
Peculiar properties of the cluster-cluster interaction induced by the Pauli exclusion principle
Role of the Pauli principle in the formation of both the discrete spectrum
and multi-channel states of the binary nuclear systems composed of clusters is
studied in the Algebraic Version of the resonating-group method. Solutions of
the Hill-Wheeler equations in the discrete representation of a complete basis
of the Pauli-allowed states are discussed for 4He+n, 3H+3H, and 4He+4He binary
systems. An exact treatment of the antisymmetrization effects are shown to
result in either an effective repulsion of the clusters, or their effective
attraction. It also yields a change in the intensity of the centrifugal
potential. Both factors significantly affect the scattering phase behavior.
Special attention is paid to the multi-channel cluster structure 6He+6He as
well as to the difficulties arising in the case when the two clustering
configurations, 6He+6He and 4He+8He, are taken into account simultaneously. In
the latter case the Pauli principle, even in the absence of a potential energy
of the cluster-cluster interaction, leads to the inelastic processes and
secures an existence of both the bound state and resonance in the 12Be compound
nucleus.Comment: 17 pages, 14 figures, 1 table; submitted to Phys.Rev.C Keywords:
light neutron-rich nuclei, cluster model
Energy deposition from focused terawatt laser pulses in air undergoing multifilamentation
Laser filamentation is responsible for the deposition of a significant part
of the laser pulse energy in the propagation medium. We found that using
terawatt laser pulses and relatively tight focusing conditions in air,
resulting in a bundle of co-propagating multifilaments, more than 60 % of the
pulses energy is transferred to the medium, eventually degrading into heat.
This results in a strong hydrodynamic reaction of air with the generation of
shock waves and associated underdense channels for each short-scale filament.
In the focal zone, where filaments are close to each other, these discrete
channels eventually merge to form a single cylindrical low-density tube over a
timescale. We measured the maximum lineic deposited
energy to be more than 1 J/m.Comment: 7 pages, 7 figure
Improved +He potentials by inversion, the tensor force and validity of the double folding model
Improved potential solutions are presented for the inverse scattering problem
for +He data. The input for the inversions includes both the data of
recent phase shift analyses and phase shifts from RGM coupled-channel
calculations based on the NN Minnesota force. The combined calculations provide
a more reliable estimate of the odd-even splitting of the potentials than
previously found, suggesting a rather moderate role for this splitting in
deuteron-nucleus scattering generally. The approximate parity-independence of
the deuteron optical potentials is shown to arise from the nontrivial
interference between antisymmetrization and channel coupling to the deuteron
breakup channels. A further comparison of the empirical potentials established
here and the double folding potential derived from the M3Y effective NN force
(with the appropriate normalisation factor) reveals strong similarities. This
result supports the application of the double folding model, combined with a
small Majorana component, to the description even of such a loosely bound
projectile as the deuteron. In turn, support is given for the application of
iterative-perturbative inversion in combination with the double folding model
to study fine details of the nucleus-nucleus potential. A -He tensor
potential is also derived to reproduce correctly the negative Li quadrupole
moment and the D-state asymptotic constant.Comment: 22 pages, 12 figures, in Revte
On the Appearance of Families of Efimov States in the Spinor Three-Body Problem
Few-body systems with access to multiple internal levels exhibit richness
beyond that typically found in their single-level counterparts. One example is
that of Efimov states in strongly-correlated spinor three-body systems. In [V.
E. Colussi, C. H. Greene, and J. P. D'Incao, Phys. Rev. Lett. {\bf 113}, 045302
(2014)] this problem was analyzed for spinor condensates finding a complex
level structure as in an early work [Bulgac and Efimov, Sov. J. Nucl. Phys. 22,
153 (1976)] in nuclear physics, and the impact of Efimov physics on the general
form of the scattering observables was worked out. In this paper we discuss the
appearance of novel families of Efimov states in the spinor three-body problem.Comment: Conference proceedings for the 21st International Conference on
Few-Body Problems in Physic
Implications of a J^PC exotic
Recent experimental data from BNL on the isovector J^PC =1^-+ exotic at 1.6
GeV in \rho\pi indicate the existence of a non-quarkonium state consistent with
lattice gauge theory predictions. We discuss how further experiments can
strengthen this conclusion. We show that the \rho\pi, \eta'\pi and \eta\pi
couplings of this state qualitatively support the hypothesis that it is a
hybrid meson, although other interpretations cannot be eliminated.Comment: 10 pages, LaTeX, minor numerical correction
On the nature of the Lambda(1405) as a superposition of two states
We use recent data on the reaction with the
mass distribution of forming the with a peak
at 1420 MeV and a relatively narrow width of MeV, together with
those of the reaction to show that there are two
states instead of one as so far assumed.Comment: Contribution to the PANIC05 Conference, Santa Fe, October 200
Generalized Quark Transversity Distribution of the Pion in Chiral Quark Models
The transversity generalized parton distributions (tGPDs) of the the pion,
involving matrix elements of the tensor bilocal quark current, are analyzed in
chiral quark models. We apply the nonlocal chiral models involving a
momentum-dependent quark mass, as well as the local Nambu--Jona-Lasinio with
the Pauli-Villars regularization to calculate the pion tGPDs, as well as
related quantities following from restrained kinematics, evaluation of moments,
or taking the Fourier-Bessel transforms to the impact-parameter space. The
obtained distributions satisfy the formal requirements, such as proper support
and polynomiality, following from Lorentz covariance. We carry out the
leading-order QCD evolution from the low quark-model scale to higher lattice
scales, applying the method of Kivel and Mankiewicz. We evaluate several
lowest-order generalized transversity form factors, accessible from the recent
lattice QCD calculations. These form factors, after evolution, agree properly
with the lattice data, in support of the fact that the spontaneously broken
chiral symmetry is the key element also in the evaluation of the transversity
observables.Comment: 17 pages, 17 figures, regular pape
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