7,751 research outputs found
A new method to study the number of colors in the final-state interactions of hadrons
We match the scattering amplitudes of Chiral Perturbation
Theory with those from dispersion relations that respect analyticity and
coupled channel unitarity, as well as accurately describing experiment. Their
dependence on the number of colors () is obtained. By varying the
trajectories of the poles and residues (the couplings to ) of light
mesons, the , , and are investigated.
Our results show that the method proposed is a reliable way to study the
dependence in hadron-hadron scattering with final-state interactions.Comment: 7 pages, 3 figures, improved behaviou
Two photon couplings of the lightest isoscalars from BELLE data
Amplitude Analysis of two photon production of and ,
using S-matrix constraints and fitting all available data, including the latest
precision results from Belle, yields a single partial wave solution up to 1.4
GeV. The two photon couplings of the , and
are determined from the residues of the resonance poles.Comment: 11 pages, 3 figures, extended for detail
and the structure observed around the threshold
We analyze the origin of the structure observed in the reaction for invariant masses close to the
antiproton-proton () threshold, commonly associated with the
resonance. Specifically, we explore the effect of a possible contribution from
the two-step process .
The calculation is performed in distorted-wave Born approximation which allows
an appropriate inclusion of the interaction in the transition
amplitude. The amplitude itself is generated from a corresponding
potential recently derived within chiral effective field theory. We are able to
reproduce the measured spectra for the reactions
and for invariant masses around the threshold. The structure seen in the spectrum emerges as
a threshold effect due to the opening of the channel.Comment: 9 pages, 5 figure
Re-examining the resonance in the reaction
The reaction is investigated
at energies close to the threshold with emphasis on the role played by the
resonance. The interaction in the final
system, constructed within chiral effective field theory and supplemented by a
pole diagram that represents a bare resonance, is taken into account
rigorously. The pole parameters of the are extracted and found to be
compatible with the ones of the resonance that have been established
in the reaction . The actual result for the
is MeV and MeV.
Predictions for the electromagnetic form factors in the timelike
region are presented.Comment: 11 pages, 3 figure
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