Higher-Twist Effects in Light-Cone Sum Rule for the $B\to\pi$ Form Factor

Understand

We calculate the higher-twist corrections to the QCD light-cone sum rule for the $B \to \pi$ 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 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 $B \to \pi$ form factor are strongly suppressed.