143 research outputs found
Signature of strange dibaryon in kaon-induced reaction
We examine how the signature of the strange-dibaryon resonances in the
barKNN-piSigmaN system shows up in the scattering amplitude on the physical
real energy axis within the framework of Alt-Grassberger-Sandhas (AGS)
equations. The so-called point method is applied to handle the three-body
unitarity cut in the amplitudes. We also discuss the possibility that the
strange-dibaryon production reactions can be used for discriminating between
existing models of the two-body barKN-piSigma system with Lambda(1405).Comment: 4 pages, 6 figures, talk given at The Fifth Asia-Pacific Conference
on Few-Body Problems in Physics 2011 (APFB2011), held in Seoul, Korea, August
22-26, 201
Chiral perturbation theory calculation for pn -> dpipi at threshold
We investigate the reaction pn -> dpipi in the framework of Chiral
Perturbation Theory. For the first time a complete calculation of the leading
order contributions is presented. We identify various diagrams that are of
equal importance as compared to those recognized in earlier works. The diagrams
at leading order behave as expected by the power counting. Also for the first
time the nucleon-nucleon interaction in the initial, intermediate and final
state is included consistently and found to be very important. This study
provides a theoretical basis for a controlled evaluation of the non-resonant
contributions in two-pion production reactions in nucleon-nucleon collisions.Comment: 24 pages, 3 figures, 3 table
Evaluation of the polarization observables I^S and I^C in the reaction gamma p --> pi^0 eta p
We evaluate the polarization observables I^S and I^C for the reaction gamma p
--> pi^0 eta p, using a chiral unitary framework developed earlier. The I^S and
I^C observables have been recently measured for the first time by the
CBELSA/TAPS collaboration. The theoretical predictions of I^S and I^C, given
for altogether 18 angle dependent functions, are in good agreement with the
measurements. Also, the asymmetry dSigma/dcos(theta) evaluated here agrees with
the data. We show the importance of the Delta(1700)D33 resonance and its S-wave
decay into eta Delta(1232). The result can be considered as a further
confirmation of the dynamical nature of this resonance. At the highest
energies, deviations of the predictions from the data start to become
noticeable, which leaves room for additional processes and resonances such as a
Delta(1940)D33. We also point out how to further improve the calculation.Comment: Version accepted for publication by the European Physical Journal A,
9 pages, 7 figure
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