Differential Cross Sections for Neutron-Proton Scattering in the Region of the $d^{\ast }(2380)$ Dibaryon Resonance

Abstract

Differential cross sections have been extracted from exclusive and kinematically complete high-statistics measurements of quasifree polarized $\vec{n}p$ scattering performed in the energy region of the $d^{\ast }(2380)$ dibaryon resonance covering the the range of beam energies $T_n$ = 0.98 - 1.29 GeV ($\sqrt{s}$ = 2.32 - 2.44 GeV). The experiment was carried out with the WASA-at-COSY setup having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process $dp\to np+p_{spectator}$. That way the $np$ differential cross section $\ddot{I}ƒ(\hat{I}˜)$ was measured over a large angular range. The obtained angular distributions complement the corresponding analyzing power $A_y(\hat{I}˜)$ measurements published previously. A SAID partial-wave analysis incorporating the new data strengthens the finding of a resonance pole in the coupled ${}^3{D}_3{-}^3{G}_3$ waves.