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Asymptotic behavior of nucleon electromagnetic form factors in time-like region

E. Tomasi-Gustafsson·G. I. Gakh
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Abstract

We study the asymptotic behavior of the ratio of Pauli and Dirac electromagnetic nucleon form factors, $F_2/F_1$, in time-like region for different parametrizations built for the space-like region. We investigate how fast the ratio $F_2/F_1$ approaches the asymptotic limits according to the Phragmèn-Lindelöf theorem. We show that the QCD-inspired logarithmic behavior of this ratio results in very far asymptotics, experimentally unachievable. This is also confirmed by the normal component of the nucleon polarization, $P_y$, in $e^++e^-\to N+\bar{N}$ (in collisions of unpolarized leptons), which is a very interesting observable, with respect to this theorem. Finally we observe that the 1/Q parametrization of $F_2/F_1$ contradicts this theorem.

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E. Tomasi-Gustafsson, G. I. Gakh. 2005-11-07. Asymptotic behavior of nucleon electromagnetic form factors in time-like region. https://doi.org/10.1140/epja%2Fi2005-10164-5

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