2019 Impact factor 4.389
Particles and Fields
Eur. Phys. J. C 18, 107-116
DOI 10.1007/s100520000524

Power corrections to the process $\gamma\gamma^*\rightarrow \pi\pi$
in the light-cone sum rules approach

N. Kivel1,2 - L. Mankiewicz3,4

1 Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany
2 Petersburg Nuclear Physics Institute, 188350, Gatchina, Russia
3 N. Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warsaw, Poland
4 The Andrzej Soltan Institute for Nuclear Studies Hoza 69, 00-681 Warsaw, Poland

Received: 23 August 2000 / Published online: 13 November 2000 - © Springer-Verlag 2000

Abstract
We applied QCD light-cone sum rules to estimate power corrections to the helicity-conserving amplitude in the process $\gamma^*\gamma\rightarrow
\pi\pi$. We found that above $Q^2 \sim 4$GeV2 power corrections are numerically small and the twist-2 part dominates.The amplitude can be reliably calculated in this region using models of $2 \pi$ distribution amplitudes as input. We found that the magnitude of the NLO corrections depends rather strongly on the normalization of the gluonic distribution amplitude.


Copyright Società Italiana di Fisica, Springer-Verlag 2000