Twist-3 contribution to the pion electromagnetic form factor

Fu-Guang Cao, Yuan-Ben Dai, Chao-Shang Huang
1999 European Physical Journal C: Particles and Fields  
Non-leading contribution to the pion electromagnetic form factor which comes from the pion twist-3 wave function is analyzed in the modied hard scattering approach (MHSA) proposed by Li and Sterman. This contribution is enhanced signicantly due to bound state eect (the twist-3 wave function is independent of the fractional momentum carried by the parton and has a large factor m 2 =m 0 with m being the pion meson mass and m 0 being the mean u-and d-quark masses). Consequently, although it is
more » ... ressed by the factor 1=Q 2 , the twist-3 contribution is comparable with and even larger than the leading twist (twist-2) contribution at intermediate energy region of Q 2 being 2 40 GeV 2 .
doi:10.1007/s100529900952 fatcat:vlwrervy5vecphgtaxaionxz54