$P$-wave dibaryon resonances in $pp$ elastic scattering and near-threshold pion production

TL;DR

This paper shows that dibaryon resonances significantly influence proton-proton scattering in P waves and are crucial for understanding near-threshold neutral pion production, challenging traditional models.

Contribution

It introduces a dibaryon-induced model that explains P-wave scattering and pion production, highlighting the role of recently discovered dibaryon resonances.

Findings

Dibaryon resonances determine elastic phase shifts and inelasticities in $pp$ scattering.

The $^3P_0$ dibaryon is key in near-threshold $ ext{pi}^0$ production.

Traditional models fail to account for dibaryon contributions.

Abstract

It is demonstrated within the dibaryon-induced model for $NN$ interaction that $pp$ scattering in $P$ waves is governed mainly by the production of the intermediate dibaryon resonances. Two dibaryon resonances with a mass of about 2200 MeV discovered recently by the ANKE-COSY Collaboration are shown to determine both elastic $pp$ phase shifts and inelasticities in the $^3P_0$ and $^3P_2$-$^3F_2$ channels from zero energy up to $T_p=0.7$-$0.9$ GeV. It is also demonstrated clearly that the $^3P_0$ dibaryon plays a decisive role in near-threshold neutral pion production in $pp$ collisions which is poorly understood to date. The missing dibaryon contribution is found to be the very possible reason for the failure of traditional approaches to explain near-threshold $\pi^0$ production.