The nucleon sigma term from threshold parameters

A new sum rule determines the nucleon sigma term by the pi N elastic scatte ring threshold parameters alone. This "threshold" value of sigma(2 mu(2)) p rovides an independent check of existing values obtained from global disper sive analyses, and also provides a realistic error assignment. Employing a recent analysis of low energy (T-pi < 100 MeV) pi N data our sum rule impli es sigma(2 mu(2)) = 71 +/- 9 MeV. (C) 2000 Published by Elsevier Science B. V. All rights reserved.