79,100 research outputs found
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
Boson Decays to Meson and Its Uncertainties
The programming new collider with high luminosity shall provide
another useful platform to study the properties of the doubly heavy meson
in addition to the hadronic colliders as LHC and TEVATRON. Under the `New Trace
Amplitude Approach', we calculate the production of the spin-singlet and
the spin-triplet mesons through the boson decays, where
uncertainties for the production are also discussed. Our results show
KeV and
KeV, where the errors are caused by
varying and within their reasonable regions.Comment: 11 pages, 5 figures, 2 tables. To be published in Eur.Phys.J.
Production of the -Wave Excited -States through the Boson Decays
In Ref.[7],we have dealt with the production of the two color-singlet
-wave -quarkonium states and
through the boson decays. As an
important sequential work, we make a further discussion on the production of
the more complicated -wave excited -quarkonium states, i.e.
and (with
). More over, we also calculate the channel with the two color-octet
quarkonium states and , whose contributions to the decay width maybe at the same order of
magnitude as that of the color-singlet -wave states according to the naive
nonrelativistic quantum chromodynamics scaling rules. The -wave states shall
provide sizable contributions to the production, whose decay width is
about 20% of the total decay width . After summing up all
the mentioned -quarkonium states' contributions, we obtain
KeV, where the errors are caused
by the main uncertainty sources.Comment: 8 pages, 5 figures and 2 tables. basic formulae in the appendix are
cut off to match the published version, which can be found in v1. to be
published in Eur.Phys.J.
Reconstruction of Fractional Quantum Hall Edges
We study the interplay of interaction, confining potential and effects of
finite temperature at the edge of a quantum Hall liquid. Our exact
diagonalization calculation indicates that edge reconstruction occurs in the
fractional quantum Hall regime for a variety of confining potential, including
ones that correspond to a "sharp" edge. Our finite temperature Hartree-Fock
calculation for integer quantum Hall edges indicates that reconstruction is
suppressed above certain temperature. We discuss the implication of our results
on recent edge tunneling and microwave absorption experiments.Comment: Revised version. 5 papges RevTex with 5 eps figures embedded in the
tex
Hadronic Production of S-wave and P-wave Charmed Beauty Mesons via Heavy Quark Fragmentation
At hadron colliders the dominant production mechanism of mesons
with large transverse momentum is due to parton fragmentation. We compute the
rates and transverse momentum spectra for production of S-wave and P-wave
mesons at the Tevatron via the direct fragmentation of the bottom
antiquark as well as the Altarelli-Parisi induced gluon fragmentation. Since
all the radially and orbitally excited mesons below the
flavor threshold will cascade into the pseudoscalar ground state through
electromagnetic and/or hadronic transitions, they all contribute to the
inclusive production of . The contributions of the excited S-wave and
P-wave states to the inclusive production of are 58 and 23\%,
respectively, and hence significant.Comment: Changes are made in the Discussio
The effect of in-plane magnetic field on the spin Hall effect in Rashba-Dresselhaus system
In a two-dimensional electron gas with Rashba and Dresselhaus spin-orbit
couplings, there are two spin-split energy surfaces connected with a degenerate
point. Both the energy surfaces and the topology of the Fermi surfaces can be
varied by an in-plane magnetic field. We find that, if the chemical potential
falls between the bottom of the upper band and the degenerate point, then
simply by changing the direction of the magnetic field, the magnitude of the
spin Hall conductivity can be varied by about 100 percent. Once the chemical
potential is above the degenerate point, the spin Hall conductivity becomes the
constant , independent of the magnitude and direction of the magnetic
field. In addition, we find that the in-plane magnetic field exerts no
influence on the charge Hall conductivity.Comment: 11 pages, 3 figures, to be published on Phys. Rev.
The magnetic dipole transitions in the binding system
The magnetic dipole transitions between the vector mesons and their
relevant pseudoscalar mesons (, , , ,
and etc, the binding states of system) of
the family are interesting. To see the `hyperfine' splitting due to
spin-spin interaction is an important topic for understanding the spin-spin
interaction and the spectrum of the the binding system. The
knowledge about the magnetic dipole transitions is also very useful for
identifying the vector boson mesons experimentally, whose masses are
just slightly above the masses of their relevant pseudoscalar mesons
accordingly. Considering the possibility to observe the vector mesons via the
transitions at factory and the potentially usages of the theoretical
estimate on the transitions, we fucus our efforts on calculating the magnetic
dipole transitions, i.e. precisely to calculate the rates for the transitions
such as decays and , and particularly
work in the Behte-Salpeter framework. In the estimate, as a typical example, we
carefully investigate the dependance of the rate
on the mass difference as well.Comment: 10 pages, 2 figures, 1 tabl
A statistical technique for determining rainfall over land employing Nimbus-6 ESMR measurements
An empirical method was employed to delineate synoptic scale rainfall over land utilizing Nimbus-6 ESMR measurements
Inclusive production of meson in proton-proton collisions at BNL RHIC
Inclusive cross sections for production in proton-proton collisions
were calculated in the -factorization approach for the RHIC energy.
Several mechanisms were considered, including direct color-singlet mechanism,
radiative decays of mesons, decays of , open-charm associated
production of as well as weak decays of B mesons. Different
unintegrated gluon distributions from the literature were used. We find that
radiative decays and direct color-singlet contributions constitute the
dominant mechanism of production. These process cannot be consistently
treated within collinear-factorization approach. The results are compared with
recent RHIC data. The new precise data at small transverse momenta impose
stringent constraints on UGDFs. Some UGDFs are inconsistent with the new data.
The Kwieci\'nski UGDFs give the best description of the data. In order to
verify the mechanism suggested here we propose -- jet correlation
measurement and an independent measurement of meson production in
and/or decay channels. Finally, we address the issue of
\J spin alignment.Comment: 26 pages, 20 figures, the text was slightly modified, the title was
modified, more discussion was added, one figure was removed, one was adde
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