34,203 research outputs found
Chiral Unitary approach to meson-meson and meson-baryon interactions and nuclear applications
We report on recent nonperturbative techniques that combine the information
of chiral Lagrangians (with and without resonances) with unitarity in coupled
channels and other requirements of the S-matrix theory of the strong
interactions. As a result, the region of applicability of such techniques is
much larger than the one of Chiral Perturbation Theory allowing one to study
also resonance physics. Applications to meson-meson and meson-baryon
scattering, as well as to problems where pairs of mesons or a meson and a
baryon appear in the initial or final state are shown. Implications in several
nuclear problems are also discussed.Comment: 85 pages, Latex, Review paper to appear in Prog. Part. Nucl. Phys.,
vol. 4
Triangle singularities in and
We study the appearance of structures in the decay of the into and final states by forming
invariant mass distributions of and pairs,
respectively. The structure in the distribution is associated to the
kinematical triangle singularity that appears when the () decay process is followed by the decay
of the into and the subsequent rescattering of the () pair forming the ()
resonance. We find this type of non-resonant peaks at 2850 MeV in the invariant
mass of pairs from decays and
around 3000 MeV in the invariant mass of pairs from decays. By employing the measured branching ratios of
the and decays, we
predict the branching ratios for the processes into and , in the vicinity of the
triangle singularity peak, to be about and ,
respectively. The observation of this reaction would also give extra support to
the molecular picture of the and .Comment: 18 pages, 15 figures, accepted version for publication in Eur. Phys.
J.
An analysis of the Lattice QCD spectra for and
In this talk I present the results obtained using effective field theories in
a finite volume from a reanalysis of lattice data on the systems,
where bound states of and are found and associated with the states
and , respectively. We confirm the presence of
such states on the lattice data and determine the weight of the channel in
the wave function of and that of in the wave function
of . Our results indicate a large meson-meson component in both
cases.Comment: Conference Proceedings, Hadron 2017, Salamanca, Spai
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