13,919 research outputs found
Decays of the Meson to a -Wave Charmonium State or
The semileptonic decays,
, and the two-body
nonleptonic decays, , (here and
denote and respectively, and
indicates a meson) were computed. All of the form factors appearing in the
relevant weak-current matrix elements with as its initial state and a
-wave charmonium state as its final state for the decays were precisely
formulated in terms of two independent overlapping-integrations of the
wave-functions of and the -wave charmonium and with proper kinematics
factors being `accompanied'. We found that the decays are quite sizable, so
they may be accessible in Run-II at Tevatron and in the foreseen future at LHC,
particularly, when BTeV and LHCB, the special detectors for B-physics, are
borne in mind. In addition, we also pointed out that the decays may potentially be used as a fresh window to look for the
charmonium state, and the cascade decays,
() with one of the radiative decays
being followed accordingly, may affect
the observations of meson through the decays () substantially.Comment: 24 pages, 3 figures, the replacement for improving the presentation
and adding reference
Three Kinds of Special Relativity via Inverse Wick Rotation
Since the special relativity can be viewed as the physics in an inverse Wick
rotation of 4-d Euclid space, which is at almost equal footing with the 4-d
Riemann/Lobachevski space, there should be important physics in the inverse
Wick rotation of 4-d Riemann/Lobachevski space. Thus, there are three kinds of
special relativity in de Sitter/Minkowski/anti-de Sitter space at almost equal
footing, respectively. There is an instanton tunnelling scenario in the
Riemann-de Sitter case that may explain why \La be positive and link with the
multiverse.Comment: 3 pages, no figures, to appear in Chin. Phys. Let
The Decays to -wave Charmonium by Improved Bethe-Salpeter Approach
We re-calculate the exclusive semileptonic and nonleptonic decays of
meson to a -wave charmonium in terms of the improved Bethe-Salpeter (B-S)
approach, which is developed recently. Here the widths for the exclusive
semileptonic and nonleptonic decays, the form factors, and the charged lepton
spectrums for the semileptonic decays are precisely calculated. To test the
concerned approach by comparing with experimental measurements when the
experimental data are available, and to have comparisons with the other
approaches the results obtained by the approach and those by some approaches
else as well as the original B-S approach, which appeared in literature, are
comparatively presented and discussed.Comment: 33 pages, 5 figures, 3 table
Spectra of Free Diquark in the Bethe-Salpeter Approach
In this work, we employ the Bethe-Salpeter (B-S) equation to investigate the
spectra of free diquarks and their B-S wave functions. We find that the B-S
approach can be consistently applied to study the diqaurks with two heavy
quarks or one heavy and one light quarks, but for two light-quark systems, the
results are not reliable. There are a few free parameters in the whole scenario
which can only be fixed phenomenologically. Thus, to determine them, one has to
study baryons which are composed of quarks and diquarks.Comment: 16 pages, no figure
Search for via the transition at LHCb and factory
It is interesting to study the characteristics of the whole family of
which contains two different heavy flavors. LHC and the proposed factory
provide an opportunity because a large database on the family will be
achieved. and its excited states can be identified via their decay modes.
As suggested by experimentalists, is not easy to be
clearly measured, instead, the trajectories of and occurring in
the decay of () can be unambiguously
identified, thus the measurement seems easier and more reliable, therefore this
mode is more favorable at early running stage of LHCb and the proposed
factory. In this work, we calculate the rate of
in terms of the QCD multipole-expansion and the numerical results indicate that
the experimental measurements with the luminosity of LHC and factory are
feasible.Comment: 12 pages, 1 figures and 4 tables, acceptted by SCIENCE CHINA Physics,
Mechanics & Astronomy (Science in China Series G
Study on the Lowest Energy Density of Welding Heat Source Required by Fusion Welding Metal
AbstractWelding is a common metal-processing method, which uses heating or press or both, at the same time, uses or disuses filled composites to achieve the atomic binding of workpieces. The basic welding methods are usually divided into three classes according to the conjunct property of weld metal, namely fusion welding, press welding and braze welding[1,2]. Powder composite welding rod is constituted with powder and termites, which belongs to fusion welding[3]. In order to make sure that the energy of this welding rod can achieve the requirement of fusion welding, so the lowest energy density required by fusing melt should be determined firstly
Precise Measurement of Gravity Variations During a Total Solar Eclipse
The variations of gravity were measured with a high precision LaCoste-Romberg
D gravimeter during a total solar eclipse to investigate the effect of solar
eclipse on the gravitational field. The observed anomaly m/s during the eclipse implies that there may be a shielding
property of gravitation
Charge-Stripe Order and Superconductivity in
A combined resistivity and hard x-ray diffraction study of superconductivity
and charge ordering in , as a function of Pt
substitution and externally applied hydrostatic pressure, is presented.
Experiments are focused on samples near the critical composition where competition and switching between charge order and
superconductivity is established. We show that charge order as a function of
pressure in is preempted - and hence
triggered - by a structural transition. Charge ordering appears uniaxially
along the short crystallographic (1,0,1) domain axis with a
modulation. Based on these results we
draw a charge-order phase diagram and discuss the relation between stripe
ordering and superconductivity.Comment: 8 pages, 4 figures: Accepted in Scientific Report
Fully Automatic Expression-Invariant Face Correspondence
We consider the problem of computing accurate point-to-point correspondences
among a set of human face scans with varying expressions. Our fully automatic
approach does not require any manually placed markers on the scan. Instead, the
approach learns the locations of a set of landmarks present in a database and
uses this knowledge to automatically predict the locations of these landmarks
on a newly available scan. The predicted landmarks are then used to compute
point-to-point correspondences between a template model and the newly available
scan. To accurately fit the expression of the template to the expression of the
scan, we use as template a blendshape model. Our algorithm was tested on a
database of human faces of different ethnic groups with strongly varying
expressions. Experimental results show that the obtained point-to-point
correspondence is both highly accurate and consistent for most of the tested 3D
face models
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