Soft-Pion Theorem for Hard Near-Threshold Pion Production
/ Authors
/ Abstract
We prove a new soft-pion theorem for the near-threshold pion production by a hard electromagnetic probe. This theorem relates various near-threshold pion-production amplitudes to the nucleon distribution amplitudes. The new soft-pion theorem is in good agreement with the SLAC data for the structure function F{sup p}{sub 2}(W,Q{sup 2}) for W{sup 2}{<=}1.4 GeV{sup 2} and 9{<=}{<=}Q{sup 2}{<=}30.7 GeV{sup 2} .
Journal: Physical Review Letters