https://doi.org/10.1140/epjc/s10052-017-5000-9
Regular Article - Theoretical Physics
Higher-twist effects in light-cone sum rule for the 
form factor
1
Theoretische Physik 1, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068, Siegen, Germany
2
Department of Theoretical Physics, P.G. Demidov Yaroslavl State University, Yaroslavl, 150000, Russia
* e-mail: rusov@physik.uni-siegen.de
Received:
12
May
2017
Accepted:
17
June
2017
Published online:
4
July
2017
We calculate the higher-twist corrections to the QCD light-cone sum rule for the 
transition form factor. The light-cone expansion of the massive quark propagator in the external gluonic field is extended to include new terms containing the derivatives of the gluon-field strength. The resulting analytical expressions for the twist-5 and twist-6 contributions to the correlation function are obtained in a factorized approximation, expressed via the product of the lower-twist pion distribution amplitudes and the quark-condensate density. The numerical analysis reveals that new higher-twist effects for the form factor are strongly suppressed. This result justifies the conventional truncation of the operator product expansion in the light-cone sum rules up to twist-4 terms.
© The Author(s), 2017
