FIZIKA B 13 (2004)  1, 193-200

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INSTANTON CONTRIBUTION TO THE PION AND PROTON
ELECTROMAGNETIC FORM FACTORS AT Q2 1 GeV2

P. FACCIOLIa, A. SCHWENKb and E. V. SHURYAKc

aE.C.T., Strada delle Tabarelle 286, Villazzano (Trento), I-38050, Italy
bDepartment of Physics, The Ohio State University, Columbus, OH 43210, USA
cDepartment of Physics and Astronomy, State University of New York,
Stony Brook, NY 11794-3800, USA
E-mail addresses: faccioli@ect.it, aschwenk@mps.ohio-state.edu,
shuryak@tonic.physics.sunysb.edu

Received 1 September 2003;        Accepted 26 April 2004
Online 10 October 2004

Studying the instanton-induced contributions to various hard exclusive reactions provides physical insight into the transition from the non-perturbative to the perturbative regime of QCD. To this end, we calculate the leading-instanton contributions to the electromagnetic and transition form factors using an effective theory of the instanton liquid model. We report predictions for the electromagnetic form factor Fp(Q2) of the pion as well as novel results for the proton Dirac form factor F1(Q2).

PACS numbers: 13.40.Gp, 12.38.Lg, 14.20.Dh
UDC 539.12

Keywords: instanton-induced contributions, strong interactions, electromagnetic form factor, Dirac form factor

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