972 research outputs found
Multifragmentation calculated with relativistic force
A saturating hamiltonian is presented in a relativistically covariant
formalism. The interaction is described by scalar and vector mesons, with
coupling strengths adjusted to the nuclear matter. No explicit density depe
ndence is assumed. The hamiltonian is applied in a QMD calculation to determine
the fragment distribution in O + Br collision at different energies (50 -- 200
MeV/u) to test the applicability of the model at low energies. The results are
compared with experiment and with previous non-relativistic calculations.
PACS: 25.70Mn, 25.75.+rComment: 23 pages, latex, with 10 PS figures, available at
http://www.gsi.de/~papp
Verfassungsgeschichte des Alten Reiches (Basistexte – Frühe Neuzeit Band 1) Szerk. Gabriele Haug-Moritz Steiner, Stuttgart 2014. 283 oldal
Stadt und Öffentlichkeit in der Frühen Neuzeit. Hrsg. Schwerhoff, Gerd (Städteforschung. Reihe A, Darstellungen, Bd. 83.) Köln–Weimar–Wien, 2011. Böhlau VI u. 219 p.
Au+Au central collisions at 150, 250 and 400 AMeV energies in QMD with relativistic forces
An extensive comparison of the recent experimental data published by the FOPI
collaboration at GSI with the results of a relativistically covariant
formulation of a QMD code is presented. For most of the quantities we find
agreement with the experimental results showing that the derived force has a
reasonable momentum dependence.Comment: 33 pages with 18 EPSF figures included. Final version to appear in
Nucl. Phys.
Looking at the bright side - The story of AA Dor as revealed by its cool companion
Irradiation effects in close binaries are crucial for a reliable
determination of system parameters and understanding the close binary
evolution. We study irradiated light originating from the low mass component of
an eclipsing system comprising a hot subdwarf primary and a low mass companion,
to precisely interpret their high precision photometric and spectroscopic data,
and accurately determine their system and surface parameters. We re-analyse the
archival VLT/UVES spectra of AA Dor system where irradiation features have
already been detected. After removing the predominant contribution of the hot
subdwarf primary, the residual spectra reveal more than 100 emission lines from
the heated side of the secondary with maximum intensity close to the phases
around secondary eclipse. We analyse 22 narrow emission lines of the irradiated
secondary, mainly of OII, with a few CII lines. Their phase profiles constrain
the emission region of the heated side to a radius 95% of the radius of
the secondary. The shape of their velocity profiles reveals two distinct
asymmetry features one at the quadrature and the other at the secondary
eclipse. We identify more than 70 weaker emission lines originating from HeI,
NII, SiIII, CaII and MgII. We correct the radial velocity semi-amplitude of the
center-of-light to the centre-of-mass of the secondary and calculate accurate
masses of both components. The resulting masses =0.46
0.01 and =0.079 0.002 are in perfect
accordance with those of a canonical hot subdwarf primary and a low mass star
just at the substellar limit for the companion. We compute a first generation
atmosphere model of the irradiated low mass secondary, which matches the
observed spectrum well. We find an indication of an extended atmosphere of the
irradiated secondary star.Comment: 13 pages, 9 figures, accepted for publication in A&
Correlation functions of small-scale fluctuations of the interplanetary magnetic field
The Interplanetary Magnetic Field shows complex spatial and temporal
variations. Single spacecraft measurements reveal only a one dimensional
section of this rich four dimensional phenomenon. Multi-point measurements of
the four Cluster spacecraft provide a unique tool to study the spatiotemporal
structure of the field. Using Cluster data we determined three dimensional
correlation functions of the fluctuations. By means of the correlation function
one can describe and measure field variations. Our results can be used to
verify theoretical predictions, to understand the formation and nature of solar
wind turbulence. We found that the correlation length varies over almost six
orders of magnitude. The IMF turbulence shows significant anisotropy with two
distinct populations. In certain time intervals the ratio of the three axes of
the correlation ellipse is 1/2.2/6 while in the remaining time we found
extremely high correlation along one axis. We found favoured directions in the
orientation of the correlation ellipsoids.Comment: accepted to Solar Physics on June 14, 2010. 10 pages, 8 figure
The interplay between environmental and magmatic conditions in eruption style transitions within a fissure-aligned monogenetic volcanic system of Auckland, New Zealand
Effect of a lattice upon an interacting system of electrons: Breakdown of scaling and decay of persistent currents
For an interacting system of N electrons, we study the conditions under which
a lattice model of size L with nearest neighbor hopping t and U/r Coulomb
repulsion has the same ground state as a continuum model. For a fixed value of
N, one gets identical results when the inter-electron spacing to the Bohr
radius ratio r_s < r_s^*. Above r_s^*, the persistent current created by an
enclosed flux begins to decay and r_s ceases to be the scaling parameter. Three
criteria giving similar r_s^* are proposed and checked using square lattices.Comment: 7 pages, 5 postscript figure
- …