On the isospin 0 and 1 resonances from $\pi \Sigma$ photoproduction data

Understand

Recently we presented a successful strategy to extract the position of the two $\Lambda(1405)$ poles from experimental photoproduction data on the $\gamma p \to K^+ \pi^0 \Sigma^0 $ reaction at Jefferson Lab.

• Following a similar strategy, we extend the previous method to incorporate also the isospin 1 component which allows us to consider in addition the experimental data on $\gamma p \to K^+ \pi^\pm \Sigma^\mp$.
• The idea is based on considering a production mechanism as model independent as possible and implementing the final state interaction of the final meson-baryon pair based on small modifications of the unitary chiral perturbation theory amplitudes.
• Good fits to the data are obtained with this procedure, by means of which we can also predict the cross sections for the $K^- p \to \bar K N$, $\pi \Sigma$, $\pi\Lambda$ reactions for the different charge channels.