Resonance-Parton Duality in $(e,e^{\prime }\pi )$ off Nucleons

Abstract

Regge-pole based descriptions of pion-electroproduction on nucleons have given a very good description of the longitudinal components of the cross sections. However, these very same models grossly underestimate the transverse components. A related problem appears in QCD-based scaling arguments that predict the predominance of longitudinal over transverse electroproduction of pions by terms $\propto Q^2$. However, data from JLAB, Cornell and DESY, covering a wide kinematical range $1<Q^2<11{\mathrm{GeV}}^2$ and $2\mathrm{GeV}<W<4\mathrm{GeV}$, do not show this expected behavior. We address here this issue of the transverse response in pion-electroproduction by considering the contributions of high-lying ($W>2$ GeV) nucleon resonances to pion production. The coupling strengths and form factors are obtained through resonance-parton duality. We show that in a wide range of electron energies and four-momentum transfers such a model describes all the available data very well.

Proc. Erice School 2001: "From Quarks and Gluons to Hadrons and Nuclei", Sept. 16 - 24, 2011, Erice, Italy

References in corpus (9)

• Determination of the Charged Pion Form Factor at Q2=1.60 and 2.45 (GeV/c)2
• Scaling study of the pion electroproduction cross sections and the pion form factor
• Cross sections for hard exclusive electroproduction of pi+ mesons on a hydrogen target
• Deep exclusive charged $\pi$ electroproduction above the resonance region
• Study of the A(e,e'${\pi }^{+}$) Reaction on ${}^1$H, ${}^2$H, ${}^{12}$C, ${}^{27}$Al, ${}^{63}$Cu and ${}^{197}$Au
• Pionic transparency in semi-exclusive electroproduction off nuclei
• Deeply inelastic pions in the exclusive reaction $p(e,e^{\prime }{\pi }^{+})n$ above the resonance region
• Deep exclusive electroproduction of ${\pi }^{+}$ at HERMES
• Exclusive pion electroproduction off nucleons and nuclei