5 research outputs found
QCD sum rule approach for the light scalar mesons as four-quark states
We study the two point-function for the scalar mesons and as diquak-antidiquark states. We also study the decays
of these mesons into , and . We found that the
couplings are consistent with existing experimental data, pointing in favor of
the four-quark structure for the light scalar mesons.Comment: 6 pages, 4 figure
A QCD sum rule calculation for the Y(4140) narrow structure
We use the QCD sum rules to evaluate the mass of a possible scalar mesonic
state that couples to a molecular current. We find a
mass GeV, which is in a excellent agreement
with the recently observed Y(4140) charmonium state. We consider the
contributions of condensates up to dimension eight, we work at leading order in
and we keep terms which are linear in the strange quark mass .
We also consider a molecular current and we obtain
, around 200 MeV above the mass of the Y(3930)
charmonium state. We conclude that it is possible to describe the Y(4140)
structure as a molecular state.Comment: 7 pages, 4 eps figure
Heavy-Light Mesons Scattering from Nucleons: Quark-Gluon and Meson Exchanges
We investigate the scattering of heavy-light K and D mesons by nucleons at low energies. The short-distance part of the interaction is described by quark-gluon interchange and the longdistance part is described by a one-meson-exchange model that includes the contributions of vector (ρ, ω) and scalar (σ) mesons. The microscopic quark model incorporates a confining Coulomb potential extracted from lattice QCD simulations and a transverse hyperfine interaction consistent with a finite gluon propagator in the infrared. The derived effective meson-nucleon potential is used in a Lippmann-Schwinger equation to obtain s-wave phase shifts. Our final aim is to set up a theoretical framework that can be extended to finite temperatures and baryon densities. © 2010 American Institute of Physics