Abstract
We consider pion electroproduction at threshold to one loop order in chiral perturbation theory. We derive novel contributions to the low-energy theorems for the S-wave multipoles E0+ and L0+ at threshold to order O(μ2, v) with μ=Mπ/m the ratio of the pion and nucleon mass and v=k2/m2 related to the four-momentum of the virtual photon. At next-to-leading order, the effect of infrared singularities generated by virtual pions becomes visible. We also discuss the inclusion of photon-nucleon vertex form factors.
Original language | English |
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Pages (from-to) | 448-452 |
Number of pages | 5 |
Journal | Physics Letters B |
Volume | 282 |
Issue number | 3-4 |
DOIs | |
State | Published - 28 May 1992 |