ABC effect and resonance structure in the double-pionic fusion to He-3

作者：Adlarson P; Augustyniak W; Bardan W; Bashkanov M; Bergmann F S; Berlowski M; Bhatt H; Bondar A; Buescher M; Calen H; Ciepal I; Clement H^*; Coderre D; Czerwinski E; Demmich K; Doroshkevich E; Engels R; Erven A; Erven W; Eyrich W; Fedorets P; Foehl K; Fransson K; Goldenbaum F; Goslawski P; Goswami A; Grigoryev K; Gullstrom C O; Hauenstein F; Heijkenskjold L; Hejny V; Hoistad B; Huesken N; Jarczyk L; Johansson T; Kamys B

来源：Physical Review C, 2015, 91(1): 015201.

DOI：10.1103/PhysRevC.91.015201

Exclusive and kinematically complete measurements of the double pionic fusion to He-3 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 (the cooler synchrotron at Forschungszentrum Julich). Similar to the observations in the basic pn -> d pi(0)pi(0) reaction and in the dd -> He-4 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* resonance formation during the reaction process in addition to the conventional t-channel Delta Delta mechanism. The deduced d* resonance width can be understood from collision broadening due to Fermi motion of the nucleons in initial and final nuclei.

• 出版日期2015-1-6