Dispersive analysis of the scalar form factor of the nucleon

作者：Hoferichter M^*; Ditsche C; Kubis B; Meissner U G

来源：The Journal of High Energy Physics, 2012, 2012(6): 063.

DOI：10.1007/JHEP06(2012)063

• Chiral Lagrangians
• QCD

Based on the recently proposed Roy-Steiner equations for pion-nucleon (pi N) scattering [1], we derive a system of coupled integral equations for the pi pi -%26gt; (N) over barN and (K) over barK -%26gt; (N) over barN S-waves. These equations take the form of a two-channel Muskhelishvili-Omnes problem, whose solution in the presence of a finite matching point is discussed. We use these results to update the dispersive analysis of the scalar form factor of the nucleon fully including _(K) over barK intermediate states. In particular, we determine the correction Delta(sigma) = sigma(2M(pi)(2)) - sigma(pi N), which is needed for the extraction of the pion-nucleon sigma term from pi N scattering, as a function of pion-nucleon subthreshold parameters and the pi N coupling constant.

• 出版日期2012-6