76 research outputs found
Isospin quantum number of D_{s0}^+(2317)
The D_s^+ pi^0 and D_s^{*+} gamma decays of the D_{s0}^+(2317) are studied by
assigning it to various charmed strange scalar mesons. As a result, it is found
that its assignment to an iso-triplet four-quark meson is favored by the
severest experimental constraint on the ratio of the rates for these decays,
while assigning it to an I=0 state (a four-quark or a conventional {c\bar{s}})
is inconsistent with this constraint.Comment: 6 pages, no figure, RevTeX4, references added and clarification of
tex
Diffractive heavy pseudoscalar-meson productions by weak neutral currents
A first theoretical study for neutrino-induced diffractive productions of
heavy pseudoscalar-mesons, \eta_c and \eta_b, off a nucleon is performed based
on factorization formalism in QCD. We evaluate the forward diffractive
production cross section in perturbative QCD in terms of the light-cone wave
functions of Z boson and \eta_{c,b} mesons, and the gluon distribution of the
nucleon. The diffractive production of \eta_c is governed by the axial vector
coupling of the longitudinally polarized Z boson to Q\bar{Q} pair, and the
resulting \eta_c production cross section is larger than the J/\psi one by one
order of magnitude. The bottomonium \eta_b production, which shows up for
higher beam energy, is also discussed.Comment: 5 pages with 3 embedded figures. Talk presented at the 15th
International Spin Physics Symposium, Spin 2002, Brookhaven National
Laboratory, September 9-14, 200
Low-energy J/psi-Hadron Interactions from Quenched Lattice QCD
The J/psi-hadron interaction is a key ingredient in analyzing the J/psi
suppression in hot hadronic matter as well as the propagation of J/psi in
nuclei. As a first step to clarify the J/psi-hadron interactions at low
energies, we have calculated J/psi-pi, J/psi-rho and J/psi-nucleon scattering
lengths by the quenched lattice QCD simulations with Wilson fermions for
beta=6.2 on 24^3*48 and 32^3*48 lattices. Using the Luscher's method to extract
the scattering length from the simulations in a finite box, we find an
attractive interaction in the S-wave channel for all three systems: Among
others, the J/psi-nucleon interaction is most attractive. Possibility of the
J/psi-nucleon bound state is also discussed.Comment: 6 pages, 6 figures, talk presented at Lattice 2005 (Heavy quark
physics), Trinity College, Dublin, Ireland, 25-30 July 200
QCD sum rules for \rho, \omega, \phi meson-nucleon scattering lengths and the mass shifts in nuclear medium
A new QCD sum rule analysis on the spin-isospin averaged , and
meson-nucleon scattering lengths is presented. By introducing the
constraint relation on the the low energy limit of the vector-current nucleon
forward scattering amplitude, we get fm,
fm and fm, which suggests that
these V-N interactions are attractive. It is also proved that the previous
studies on the mass shift of these vector mesons in the nuclear medium are
essentially the ones obtained from these scattering lengths in the linear
density approximation.Comment: Revised version. 21 pages + 5 figures. Latex. Prog. Theor. Phys. in
press. More discussions adde
Properties of the DsJ states
Recent measurements involving the newly discovered D_sJ particles are
reported. The results of D_sJ production and decay branching fraction
measurements are shown. Possible spin-parity and quark content assignments of
D_sJ mesons are discussed. The results are based on a large data sample
recorded by the Belle detector at the KEKB e^+ e^- collider.Comment: 4 pages, 3 figures, proceedings to the talk given on behalf of the
Belle Collaboration at the First Meeting of the APS Topical Group on Hadron
Physic
Analysis of the vertex with the light-cone QCD sum rules
In this article, we analyze the vertex with the light-cone QCD
sum rules. The strong coupling constant is an important
parameter in evaluating the charmonium absorption cross sections in searching
for the quark-gluon plasmas. Our numerical value for the is
consistent with the prediction of the effective SU(4) symmetry and vector meson
dominance theory.Comment: 6 pages, 1 figure, revised versio
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