5,565 research outputs found
Design of Spacecraft Formation Orbits Relative to a Stabilized Trajectory
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76533/1/AIAA-8433-932.pd
Equivalent approaches for two-body anti-triplet charmed baryon decays
For the two-body anti-triplet charmed baryon decays, there exist two
theoretical analyses based on the flavor () symmetry. One is
the irreducible approach (IRA), which depends on the irreducible
representation of the effective Hamiltonian. The other is the
topological-diagram approach (TDA), where the decays are drawn to consist of
-boson emission and -boson exchange topologies. We demonstrate that IRA
and TDA can be equivalent, such that the IRA parameters can be seen to mix with
the TDA topologies. The current observations of might cause theoretical difficulties. With the
symmetry breaking, we explain . It is
found that a specific -boson exchange topology denoted by only appears
in , by which we explain . In addition, we predict for future
measurements to test if can be a significant contribution.Comment: 13 pages, 7 tables, 1 figure, introduction rephrased, reference
added, typos correcte
Pictorial approach for two-body weak decays
We explore two-body non-leptonic weak decays of into final
states and , where denotes an
octet (a decuplet) baryon, and represents a pseudoscalar (vector) meson.
Based on the flavor symmetry, we depict and parameterize
the -emission and -exchange processes using the topological diagram
approach, establishing strict relations for possible decay channels.
We identify dominant topological parameters, determined by available data,
allowing us to explain the experimental ratios , , and . We also calculate the branching fractions of the
Cabibbo-allowed decays, such as . In particular, we establish
approximate isospin relations: and , where
is accessible
to the Belle and LHCb experiments.Comment: 16 pages, 3 tables, 2 figure
Critical behavior of the 3-state Potts model on Sierpinski carpet
We study the critical behavior of the 3-state Potts model, where the spins
are located at the centers of the occupied squares of the deterministic
Sierpinski carpet. A finite-size scaling analysis is performed from Monte Carlo
simulations, for a Hausdorff dimension . The phase
transition is shown to be a second order one. The maxima of the susceptibility
of the order parameter follow a power law in a very reliable way, which enables
us to calculate the ratio of the exponents . We find that the
scaling corrections affect the behavior of most of the thermodynamical
quantities. However, the sequence of intersection points extracted from the
Binder's cumulant provides bounds for the critical temperature. We are able to
give the bounds for the exponent as well as for the ratio of the
exponents , which are compatible with the results calculated from
the hyperscaling relation.Comment: 13 pages, 4 figure
Coherent-State Approach to Two-dimensional Electron Magnetism
We study in this paper the possible occurrence of orbital magnetim for
two-dimensional electrons confined by a harmonic potential in various regimes
of temperature and magnetic field. Standard coherent state families are used
for calculating symbols of various involved observables like thermodynamical
potential, magnetic moment, or spatialdistribution of current. Their
expressions are given in a closed form and the resulting Berezin-Lieb
inequalities provide a straightforward way to study magnetism in various limit
regimes. In particular, we predict a paramagnetic behaviour in the
thermodynamical limit as well as in the quasiclassical limit under a weak
field. Eventually, we obtain an exact expression for the magnetic moment which
yields a full description of the phase diagram of the magnetization.Comment: 21 pages, 6 figures, submitted to PR
Accretion and photodesorption of CO ice as a function of the incident angle of deposition
Non-thermal desorption of inter- and circum-stellar ice mantles on dust
grains, in particular ultraviolet photon-induced desorption, has gained
importance in recent years. These processes may account for the observed gas
phase abundances of molecules like CO toward cold interstellar clouds. Ice
mantle growth results from gas molecules impinging on the dust from all
directions and incidence angles. Nevertheless, the effect of the incident angle
for deposition on ice photo-desorption rate has not been studied. This work
explores the impact on the accretion and photodesorption rates of the incidence
angle of CO gas molecules with the cold surface during deposition of a CO ice
layer. Infrared spectroscopy monitored CO ice upon deposition at different
angles, ultraviolet-irradiation, and subsequent warm-up. Vacuum-ultraviolet
spectroscopy and a Ni-mesh measured the emission of the ultraviolet lamp.
Molecules ejected from the ice to the gas during irradiation or warm-up were
characterized by a quadrupole mass spectrometer. The photodesorption rate of CO
ice deposited at 11 K and different incident angles was rather stable between 0
and 45. A maximum in the CO photodesorption rate appeared around
70-incidence deposition angle. The same deposition angle leads to the
maximum surface area of water ice. Although this study of the surface area
could not be performed for CO ice, the similar angle dependence in the
photodesorption and the ice surface area suggests that they are closely
related. Further evidence for a dependence of CO ice morphology on deposition
angle is provided by thermal desorption of CO ice experiments
Study of and decays
We study the three-body baryonic decays with
representing the or meson. Particularly, we predict that or , where the errors arise
from the non-factorizable effects as well as the uncertainties in the and transition form factors, while the two
different results are due to overall relative signs between the form factors,
causing the constructive and destructive interference effects. For the
corresponding baryonic decays, we find that or with the errors
similar to those above. The decays in question are accessible to the
experiments at BELLE and LHCb.Comment: 15 pages, 5 figures, revised version accepted by EPJ
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