We study the effects of instantons on the charged pion electromagnetic form factor at intermediate momenta. In the single instanton approximation (SIA), we predict the pion form factor in the kinematic region [Formula Presented] By developing the calculation in a mixed time-momentum representation, it is possible to maximally reduce the model dependence and to calculate the form factor directly. We find the intriguing result that the SIA calculation coincides with the vector dominance monopole form, up to a surprisingly high momentum transfer [Formula Presented] This suggests that vector dominance for the pion holds beyond low energy nuclear physics.
Faccioli, P., Schwenk, A., Shuryak, E. (2003). Instanton contribution to the pion electromagnetic form factor at Q(2)> 1 GeV2. PHYSICAL REVIEW D, 67(11) [10.1103/PhysRevD.67.113009].
Instanton contribution to the pion electromagnetic form factor at Q(2)> 1 GeV2
Faccioli, P;
2003
Abstract
We study the effects of instantons on the charged pion electromagnetic form factor at intermediate momenta. In the single instanton approximation (SIA), we predict the pion form factor in the kinematic region [Formula Presented] By developing the calculation in a mixed time-momentum representation, it is possible to maximally reduce the model dependence and to calculate the form factor directly. We find the intriguing result that the SIA calculation coincides with the vector dominance monopole form, up to a surprisingly high momentum transfer [Formula Presented] This suggests that vector dominance for the pion holds beyond low energy nuclear physics.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.