On Sequential Single-Pion Production in Double-Pionic Fusion

Abstract

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 for the two sequential single-pion production steps $pn(I=0)\to pp{\pi }^{-}$ followed by $pp\to d{\pi }^{+}$. Though this sequential process was aimed to explain the dibaryon resonance $d^{\ast }(2380)$ peak in double-pionic fusion, we demonstrate that this is not the case. It rather fits to a possible broad bump at 2.31 GeV in the energy dependence of the $pn\to d{\pi }^0{\pi }^0$ reaction, which was recently interpreted as a consequence of dibaryonic excitations in isoscalar single-pion production.