Pion form factor with higher-twist effects

The authors present the next-to-leading twist hard scattering amplitude of the pion form factor calculation. They include the quark mass effect and its internal fermi motion effect. Pion form factor is calculated as the convolution of the resulting scattering amplitude with the Dziembowski type light-cone quark model wavefunction. The implication of these higher-twist effects in relation to the interpretation of the frozen coupling constant and the question of dominance of soft and hard contributions is discussed.