Work

Next-to-Next-to-Leading-Order QCD Prediction for the Pion Form Factor

Year: 2025

Type: article

Abstract: We accomplish for the first time the two-loop computation of the leading-twist contribution to the pion form factor by employing the effective field theory formalism rigorously. The next-to-next-to-leading-order hard function is determined by evaluating the appropriate five-point QCD amplitude with the modern multiloop technique and by implementing the ultraviolet renormalization and infrared subtractions in the presence of evanescent operators. The yielding two-loop correction to this fundamental quantity turns out to be numerically significant at experimentally accessible momentum transfers. We further demonstrate that the newly computed two-loop QCD correction is highly beneficial for an improved determination of the leading-twist pion distribution amplitude.

Source: Physical Review Letters

DOI: 10.1103/yx51-lc3q

Authors: Yao Ji, Bo-Xuan Shi, Jian Wang, Ye-Fan Wang, Yu-Ming Wang, Hui-Xin Yu