82,582 research outputs found
Two-body hadronic charmed meson decays
We study in this work the two-body hadronic charmed meson decays, including
both the PP and VP modes. The latest experimental data are first analyzed in
the diagrammatic approach. The magnitudes and strong phases of the flavor
amplitudes are extracted from the Cabibbo-favored (CF) decay modes using
minimization. The best-fitted values are then used to predict the
branching fractions of the singly-Cabibbo-suppressed (SCS) and
doubly-Cabibbo-suppressed decay modes in the flavor SU(3) symmetry limit. We
observe significant SU(3) breaking effects in some of SCS channels. In the case
of VP modes, we point out that the and amplitudes cannot be
completely determined based on currently available data. We conjecture that the
quoted experimental results for both and are overestimated. We compare the sizes of color-allowed and
color-suppressed tree amplitudes extracted from the diagrammatical approach
with the effective parameters and defined in the factorization
approach. The ratio is more or less universal among the , and modes. This feature allows
us to discriminate between different solutions of topological amplitudes. For
the long-standing puzzle about the ratio , we argue that, in addition to the SU(3)
breaking effect in the spectator amplitudes, the long-distance resonant
contribution through the nearby resonance can naturally explain why
decays more copiously to than through the
-exchange topology.Comment: 32 pages, 5 figures. An alternative method for error bar extraction
is used; last columns of Tables~I to VI, and all entries in Tables~VII, VIII
and X are modified. To appear in PRD
Guiding, focusing, and sensing on the sub-wavelength scale using metallic wire arrays
We show that two-dimensional arrays of thin metallic wires can guide
transverse electromagnetic (TEM) waves and focus them to the spatial dimensions
much smaller that the vacuum wavelength. This guiding property is retained for
the tapered wire bundles which can be used as multi-channel TEM endoscopes:
they capture a detailed electromagnetic field profile created by deeply
sub-wavelength features of the studied sample and magnify it for observation.
The resulting imaging method is superior to the conventional scanning
microscopy because of the parallel nature of the image acquisition by multiple
metal wires. Possible applications include terahertz and mid-infrared endoscopy
with nanoscale resolution.Comment: 3 figure
Vacuum ultraviolet photoabsorption of prime ice analogues of Pluto and Charon
Here we present the first Vacuum UltraViolet (VUV) photoabsorption spectra of ice analogues of Pluto and Charon ice mixtures. For Pluto the ice analogue is an icy mixture containing nitrogen (N2), carbon monoxide (CO), methane (CH4) and water (H2O) prepared with a 100:1:1:3 ratio, respectively. Photoabsorption of icy mixtures with and without H2O were recorded and no significant changes in the spectra due to presence of H2O were observed. For Charon a VUV photoabsorption spectra of an ice analogue containing ammonia (NH3) and H2O prepared with a 1:1 ratio was recorded, a spectrum of ammonium hydroxide (NH4OH) was also recorded. These spectra may help to interpret the P-Alice data from New Horizons
Orbitronics: the Intrinsic Orbital Hall Effect in p-Doped Silicon
The spin Hall effect depends crucially on the intrinsic spin-orbit coupling
of the energy band. Because of the smaller spin-orbit coupling in silicon, the
spin Hall effect is expected to be much reduced. We show that the electric
field in p-doped silicon can induce a dissipationless orbital current in a
fashion reminiscent of the spin Hall effect. The vertex correction due to
impurity scattering vanishes and the effect is therefore robust against
disorder. The orbital Hall effect can lead to the accumulation of local orbital
momentum at the edge of the sample, and can be detected by the Kerr effect.Comment: 4 page
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