A unitarity analysis on the I=0 $d$ wave $\pi \pi$ scattering amplitude

Jian-jun Wang, Z. Y. Zhou, H. Q. Zheng

We study I=0 $d$ wave $\pi \pi$ scattering phase shift using a proper unitarization approach. It is verified that the $f_2(1270)$ resonance corresponds to a twin pole structure: one on…