HE-4(PI-;
2N);
(PI-;
NP);
DN);
NT);
E AT REST;
T-PI=0 MEV;
MEASURED PARTICLE PAIRS ENERGY;
SIGMA(THETA);
DEDUCED BRANCHING RATIOS;
D O I:
10.1016/0375-9474(95)00068-C
中图分类号:
O57 [原子核物理学、高能物理学];
学科分类号:
070202 ;
摘要:
The emission of nn, np-, nd- and nt-pairs following pi(-)-capture in gaseous He-4 has been studied in a coincidence experiment. Quasifree 2N-absorption is the dominant absorption mechanism with a ratio of r = 4.0(-1.5)(+0.8) for absorption on a nucleon pair with isospin I = 0 and I = 1. Also collinear processes involving more than two nucleons have been observed, including NN final-state interaction with small relative momenta as well as emission of deuterons and tritons. Upper limits are given for phase-space-distributed, i.e. non-collinear 3N- and nnd-emission.