The absorption of pion in 3He

• Published in: Nuclear physics. B Vol. 60; pp. 93 - 109
• Main Authors: Phillips, A.C., Roig, F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1973
• ISSN: 0550-3213; 1873-1562
• DOI: 10.1016/0550-3213(73)90172-7

The two-nucleon absorption model is submitted to a quantitative test by considering pion absorption in 3He. The wave functions of 3He are explicitly constructed in terms of wave functions for the S-wave two-nucleon systems. Several prescriptions for the range dependence of the pion absorption interaction are considered, the effective coupling constant of which are determined from the data on pion production in nucleon-nucleon collisions. We show that the usual assumption of no short-range repulsion and of a zero-range absorption interaction is too naive to give reliable results. When the effects of the nuclear short-range repulsion and the finite range of the pion absorption interaction are included, the model gives a ratio for the nnp and nd production rates which agrees with experiment. The theoretical absorption rates for S-wave pions are W S ( nd)=(0.9±0.4)·10 16 sec −1, W S ( nnp)=(3.2±0.8)·10 16 sec −1 . These results agree with experiment if a radiative absorption rate of 4.43·10 15 sec −1 is assumed and if the ratio for absorption from a 2p and from a ls state is 0.65·10 −4. This agreement indicates that the basic idea of two-nucleon absorption could be correct.