Hard Exclusive Electroproduction of Pions(4)

We investigate the exclusive electroproduction of pi^+ mesons from nucleons. To leading twist, leading order alpha_s accuracy the corresponding production amplitude can be decomposed into pseudovector and pseudoscalar parts. Both can be expressed in terms

anonlocalquarkoperatorsandwichedbetweenprotonandneutronstates:

¯d(0)γ5n n(P′,S′)|ψ [0,z]ψu(z)|p(P,S) z2=0=

¯(P,S)γ5nN N(P,S)′′

¯(P′,S′)γ5N(P,S)r·n N d[x,y]e ix(P·z) iy(r·z) Fdu+eix(P·z) iy¯(r·z)¯du F

fπ

8Ncπ(τ)P¯·n 10dτΦ

x+2y+xω¯ i +ω¯

ω¯x+2y+xω¯ i