On Sequential Single-Pion Production in Double-Pionic Fusion

Recently a two-step process has been proposed for the double-pionic fusion to deuterium $pn (I=0) \to d\pi^+\pi^-$. Its calculation is solely based on total cross section data two sequential single-pion production steps (I=0)\to pp\pi^-$ followed by $pp d\pi^+$. Though this was aimed explain dibaryon resonance $d^*(2380)$ peak in fusion, we demonstrate that not case. It rather fits possible broad bump at 2.31 GeV energy dependence of d\pi^0\pi^0$ reaction, which recently interpreted as consequence dibaryonic excitations isoscalar production.