ABC Effect and Resonance Structure in the Double-Pionic Fusion to ${}^3$He

Abstract

Exclusive and kinematically complete measurements of the double pionic fusion to ${}^3$He have been performed in the energy region of the so-called ABC effect, which denotes a pronounced low-mass enhancement in the $\pi \pi$-invariant mass spectrum. The experiments were carried out with the WASA detector setup at COSY. Similar to the observations in the basic $pn\to d{\pi }^0{\pi }^0$ reaction and in the $dd{\to }^4$He${\pi }^0{\pi }^0$ reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. Differential cross sections are well described by the hypothesis of $d^{\ast }$ resonance formation during the reaction process in addition to the conventional $t$-channel $\Delta \Delta$ mechanism. The deduced $d^{\ast }$ resonance width can be understood from collision broadening due to Fermi motion of the nucleons in initial and final nuclei.

References in corpus (10)

• ABC Effect in Basic Double-Pionic Fusion --- Observation of a new resonance?
• Double-Pionic Fusion of Nuclear Systems and the ABCEffect -- Aproaching a Puzzle by Exclusive and Kinematically Complete Measurements
• The WASA Detector Facility at CELSIUS
• Quark models of dibaryon resonances in nucleon-nucleon scattering
• Neutron-Proton Scattering in the Context of the $d^{\ast }$(2380) Resonance
• Two-Pion Production in Proton-Proton Collisions -- Experimental Total Cross Sections and their Isospin Decomposition
• Delta Delta Excitation in Proton-Proton Induced pi0pi0 Production
• Nuclear matter at high density: Phase transitions, multiquark states, and supernova outbursts
• Exclusive measurement of two-pion production in the dd --> 4Hepipi reaction
• Isospin effects in the exclusive dp -> 3Heπ+π- reaction

Cited by in corpus (4)

• On the History of Dibaryons and their Final Observation
• Double-charm heptaquark states composed of two charmed mesons and one nucleon
• Isospin symmetry breaking in double-pion production in the region of $d^{\ast }(2380)$ and the scalar $\sigma$ meson
• Study of the pd(dp) -> 3He pi pi reactions close to threshold