On the problem of the sigma terms in meson-baryon scattering comments on recent literature.

A recent controversy about the value of the sigma term in pion-nucleon scattering is reviewed, with particular attention to possible attempts to reconcile the large value of Cheng and Dashen with the (3, 3*) + (3*, 3) chiral symmetry breaking model of Gell-Mann. Grounds for reservations may be found for each one of three mechanisms considered here. Thus we confirm the general belief that the conventional theory of chiral symmetry breaking cannot be easily maintained, unless the value of Cheng and Dashen is given up in favour of a reestimate by Höhler, Jakob and Strauss. [ABSTRACT FROM AUTHOR]