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Twist-3 contribution to the pion electromagnetic form factor

Fu-Guang Cao·Yuan-Ben Dai·Chao-Shang Huang
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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 $\sim m_π^2/m_0$ with $m_π$ 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 $2 \sim 40 {GeV}^2$.

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Fu-Guang Cao, Yuan-Ben Dai, Chao-Shang Huang. 1998-06-01. Twist-3 contribution to the pion electromagnetic form factor. https://doi.org/10.1007/s100520050650

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