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Twist-3 contribution to the pion electromagnetic form factor

  • Fu-Guang Cao
  • Yuan-Ben Dai
  • Chao-Shang Huang
Theoretical physics

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 \(2 \sim 40 \,{\rm GeV}^2\).

Keywords

Form Factor Energy Region State Effect Intermediate Energy Fractional Momentum 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Fu-Guang Cao
    • 1
  • Yuan-Ben Dai
    • 1
  • Chao-Shang Huang
    • 1
  1. 1.CCAST (World Laboratory), P.O. Box 8730, Beijing 100080, P.R. China CN

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