Abstract.
Non-leading contribution to the pion electromagnetic form factor which comes from the pion twist-3 wave function is analyzed in the modified hard scattering approach (MHSA) proposed by Li and Sterman. This contribution is enhanced significantly due to bound state effect (the twist-3 wave function is independent of the fractional momentum carried by the parton and has a large factor \(\sim m_\pi^2/m_0\) with \(m_\pi\) being the pion meson mass and \(m_0\) being the mean u- and d-quark masses). Consequently, although it is suppressed 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 \(2 \sim 40 \,{\rm GeV}^2\).
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Received: 23 March 1998 / Published online: 3 November 1999
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Cao, FG., Dai, YB. & Huang, CS. Twist-3 contribution to the pion electromagnetic form factor. Eur. Phys. J. C 11, 501–506 (1999). https://doi.org/10.1007/s100529900952
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DOI: https://doi.org/10.1007/s100529900952