Determinations of the πN σ term and s-wave scattering lengths

• Published in: Nuclear physics. B Vol. 103; no. 3; pp. 477 - 496
• Main Authors: Moir, David C., Jacob, Richard J., Hite, Gerald E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.1976
• ISSN: 0550-3213; 1873-1562
• DOI: 10.1016/0550-3213(76)90511-3

Determinations of the σ term and s-wave scattering lengths for pion-nucleon scattering are made using interior dispersion relations. The result for the σ term is obtained by extrapolating to the Cheng-Dashen point in only one variable. It is completely independent of the pion-nucleon coupling constant and insensitive to d and f waves in the resonance region. The use of interior dispersion relations allows a series of s-wave scattering length determinations to be made. It is observed that data at intermediate scattering angles gives more consistent results than data near the forward or backward directions, lending further support to the σ term calculation which utilizes only interior angle information.