1,264 research outputs found
Effects of mass renormalization on the surface properties of heavy-ion fusion potential
We discuss the effects of fast nuclear excitations on heavy-ion fusion
reactions at energies near and below the Coulomb barrier. Using the fusion of
two Ca nuclei as an example and the inversion method, we show that the
mass renormalization induced by fast nuclear excitations leads to a large
surface diffuseness in the effective potential for heavy-ion fusion reactions.Comment: 13 pages, Late
Anharmonic phonon excitations in subbarrier fusion reactions
Recently measured high precision data of fusion excitation function have
enabled a detailed study on the effects of nuclear collective excitations on
fusion reactions. Using such highly accurate data of the O +
Sm reactions, we discuss the anharmonic properties of collective
phonon excitations in Sm nuclei. It is shown that subbarrier fusion
reactions are strongly affected by the anharmonic effects and thus offer an
alternative method to extract the static quadrupole moments of phonon states in
a spherical nucleus.Comment: 10 pages, To be published in the Proceedings of the Tours Symposium
on Nuclear Physics III, Tours, France, September 1997 (American Institute of
Physics
Spatially Resolved NMR Relaxation Rate in a Noncentrosymmetric Superconductor
We numerically study the spatially-resolved NMR around a single vortex in a
noncentrosymmetric superconductor such as CePt3Si.
The nuclear spin-lattice relaxation rate 1/T1 under the influence of the
vortex core states is calculated for an s+p-wave Cooper pairing state.
The result is compared with that for an s-wave pairing state.Comment: 2 pages; submitted to Proc. of SCES'0
17O NMR study of q=0 spin excitations in a nearly ideal S=1/2 1D Heisenberg antiferromagnet, Sr2CuO3, up to 800 K
We used 17O NMR to probe the uniform (wavevector q=0) electron spin
excitations up to 800 K in Sr2CuO3 and separate the q=0 from the q=\pm\pi/a
staggered components. Our results support the logarithmic decrease of the
uniform spin susceptibility below T ~ 0.015J, where J=2200 K. From measurement
of the dynamical spin susceptibility for q=0 by the spin-lattice relaxation
rate 1/T_{1}, we demonstrate that the q=0 mode of spin transport is ballistic
at the T=0 limit, but has a diffusion-like contribution at finite temperatures
even for T << J.Comment: Submitted to Phys. Rev. Lett. 4 pages, 4 figure
Applicability of the orientation average formula in heavy-ion fusion reactions of deformed nuclei
In heavy-ion fusion reactions involving a well deformed nucleus, one often
assumes that the orientation of the target nucleus does not change during the
reaction. We discuss the accuracy of this procedure by analyzing the excitation
function of the fusion cross section and the fusion barrier distribution in the
reactions of Sm target with various projectiles ranging from C
to Ar. It is shown that the approximation gradually looses its accuracy
with increasing charge product of the projectile and target nuclei because of
the effects of finite excitation energy of the target nucleus. The relevance of
such inaccuracy in analyzing the experimental data is also discussed.Comment: 5 pages and 3 figure
Effect of the Vortices on the Nuclear Spin Relaxation Rate in the Unconventional Pairing States of the Organic Superconductor (TMTSF)PF
This Letter theoretically discusses quasiparticle states and nuclear spin
relaxation rates in a quasi-one-dimensional superconductor
(TMTSF)PF under a magnetic field applied parallel to the conduction
chains. We study the effects of Josephson-type vortices on by
solving the Bogoliubov de Gennes equation for -, - or -wave pairing
interactions. In the presence of line nodes in pairing functions, is
proportional to in sufficiently low temperatures because quasiparticles
induced by vortices at the Fermi energy relax spins. We also try to identify
the pairing symmetry of (TMTSF)PF.Comment: 4+ pages, 4 figure
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