7,778 research outputs found
photoproduction on the quasi-free nucleons in the chiral quark model
A chiral quark-model approach is adopted to study the photoproduction
off the quasi-free neutron and proton from a deuteron target. Good descriptions
of the differential cross sections, total cross sections and beam asymmetries
for these two processes are obtained in the low energy region. For , the dominant resonances are ,
, , and . While for
the process, the dominant resonances are
, , , and
. Furthermore, the channel backgrounds have significant
contributions to the photoproduction processes. The configuration
mixings in the and can be extracted,
i.e. and . It shows that the
narrow bump-like structure around GeV observed in can be naturally explained by the constructive
interferences between and . In contrast, the
destructive interference between and produces the
shallow dip around GeV in . The wave
interfering behaviors in the proton and neutron reactions are correlated with
each other in the quark model framework, and no new exotic nucleon resonances
are needed in these two reactions.Comment: 12 pages, 11 figures, helicity amplitudes are added, to be published
in PR
Hyperbolic Chaos of Turing Patterns
We consider time evolution of Turing patterns in an extended system governed
by an equation of the Swift-Hohenberg type, where due to an external periodic
parameter modulation long-wave and short-wave patterns with length scales
related as 1:3 emerge in succession. We show theoretically and demonstrate
numerically that the spatial phases of the patterns, being observed
stroboscopically, are governed by an expanding circle map, so that the
corresponding chaos of Turing patterns is hyperbolic, associated with a strange
attractor of the Smale-Williams solenoid type. This chaos is shown to be robust
with respect to variations of parameters and boundary conditions.Comment: 4 pages, 4 figure
Entanglement in the Process of Stimulated Brillouin Scattering of Light
The process of stimulated Brillouin scattering is described by the model of
two-dimensional oscillator. The phenomenon of entanglement which appears in the
photon-phonon modes after the interaction with matter is discussed.Comment: 4 pages, LaTe
Derivation And Solution Of The System Of Equations Describing intense beams, For Nonstationary Distribution Of Transverse Phase Space density
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