Speaker
Dr
Carlos Granados
(The George Washington University)
Description
Using dispersion theory, we calculate the electromagnetic form factors for the transition of a Sigma to a Lambda hyperon at low energy. In this approach, the imaginary part of the form factors is written as a direct product
of the two-pion-Sigma-Lambda amplitudes and the complex conjugate of the pion form factor. The two-pion-Sigma-Lambda amplitudes is also computed through a
procedure combining dispersion theory and (NLO) chiral perturbation theory including a two pion rescattering contribution.
It is found that the inclusion of decuplet baryons in the intermediate state of the transition
is necessary in order to obtain reasonable results, consistent with overall expectations. The electric transition form factor calculated through this method remains very small while the magnetic form factor obtained
depends strongly on a not well defined low-energy constant of the NLO Lagrangian. The predictive
power of this approach will be enhanced by signicantly constraining this constant from a measurement
of the magnetic transition radius, a measurement that can be performed at the future Facility
for Antiproton and Ion Research (FAIR).
Primary authors
Dr
Carlos Granados
(The George Washington University)
Elisabetta Perotti
(Uppsala University)
Prof.
Stefan Leupold
(Uppsala University)
