Recent Developments in Chiral Unitary Theory and Triangle Singularities Involving Baryons

Abstract

We report on several reactions involving baryons that develop triangle singularities. The combination of elements of chiral unitary theory with the triangle mechanisms explain different features of reactions and shed light on some decay modes of several resonances. We address the role of a triangle singularity in the $$\pi N(1535)$$ contribution to $$\gamma p \rightarrow p \pi ^0 \eta $$ , another singularity, producing a peak in the $$\gamma p\rightarrow K^+ \varLambda (1405)$$ reaction which was previously unexplained, the role of a singularity in the $$\pi \varDelta $$ decay of the N(1700), and also discuss the $$N^*(1875)$$ resonance from this perspective.