The $a_1(1420)$ in a Unitary Coupled-Channel Three-Body Approach

Ajay S. Sakthivasan, Yuchuan Feng, Michael Döring +1

An enhancement in the three-pion energy at around $\sqrt{s}\approx 1.42\text{GeV}$ with $a_1$ quantum numbers was observed at the COMPASS experiment. This was later attributed t…