Abstract
We discuss a low-energy theorem of threshold pion electroproduction which allows one to determine the axial root-mean-square radius rA of the nucleon. We show that at the same order where the radius appears, pion loops induce a small correction to the momentum dependence of the electric dipole amplitude E0+(-). This correction amounts to a decrease of the axial mean-square radius by 5% from the electroproduction data and allows one to explain the small discrepancy to the values determined from (anti)neutrino-proton scattering data.
Original language | English |
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Pages (from-to) | 1877-1879 |
Number of pages | 3 |
Journal | Physical Review Letters |
Volume | 69 |
Issue number | 13 |
DOIs | |
State | Published - 1992 |