14,157 research outputs found
Searching a systematics for nonfactorizable contributions to hadronic decays of and mesons
We investigate nonfactorizable contributions to charm meson decays in / / /
/ modes. Obtaining the contributions from spectator-quark
diagrams for = 3, we determine nonfactorizable isospin 1/2 and 3/2
amplitudes required to explain the data for these modes. We observe that ratio
of these amplitudes seem to follow a universal value.Comment: 23 pages, Late
Quantum mechanical study of molecules - Eigenvalues and eigenvectors of real symmetric matrices
Computer methods for calculating eigenvalue and eigenvectors of real symmetric matrices arising in problems of molecular quantum mechanic
Near-infrared spectropolarimetry of a delta-spot
Sunspots harboring umbrae of both magnetic polarities within a common
penumbra (delta-spots) are often but not always related to flares. We present
first near-infrared (NIR) observations (Fe I 1078.3 nm and Si I 1078.6 nm
spectra) obtained with the Tenerife Infrared Polarimeter (TIP) at the Vacuum
Tower Telescope (VTT) in Tenerife on 2012 June 17, which afford accurate and
sensitive diagnostics to scrutinize the complex fields along the magnetic
neutral line of a delta-spot within active region NOAA 11504. We examine the
vector magnetic field, line-of-sight (LOS) velocities, and horizontal proper
motions of this rather inactive delta-spot. We find a smooth transition of the
magnetic vector field from the main umbra to that of opposite polarity
(delta-umbra), but a discontinuity of the horizontal magnetic field at some
distance from the delta-umbra on the polarity inversion line. The magnetic
field decreases faster with height by a factor of two above the delta-umbra.
The latter is surrounded by its own Evershed flow. The Evershed flow coming
from the main umbra ends at a line dividing the spot into two parts. This line
is marked by the occurrence of central emission in the Ca II 854.2 nm line.
Along this line, high chromospheric LOS-velocities of both signs appear. We
detect a shear flow within the horizontal flux transport velocities parallel to
the dividing line.Comment: 4 pages, will appear as Letter in Astronomy & Astrophysic
SU(3)-flavor-analysis of nonfactorizable contributions to D --> PP decays
We study charm D - meson decays to two pseudoscalar mesons in Cabibbo favored mode employing SU(3)-flavor for the nonfactorizable matrix elements. Using D\rightarrow \bar K \pi and D_{s} \rightarrow \bar K K to fix the reduced matrix elements, we obtain a consistent fit for \eta and \eta' emitting decays of D and D_{s} mesons
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