We present the results of a lattice study of the second moment of the light-cone pion distribution amplitude using two flavors of dynamical (clover) fermions on lattices of different volumes and pion masses down to $m_{\pi }\sim 150\mathrm{MeV}$. At lattice spacings between 0.06 and 0.08 fm we find for the second Gegenbauer moment the value $a_2=0.1364(154)(145)$ at the scale $\mu =2\mathrm{GeV}$ in the $\overline{\mathrm{MS}}$ scheme, where the first error is statistical including the uncertainty of the chiral extrapolation, and the second error is the estimated uncertainty coming from the nonperturbatively determined renormalization factors. The error due to the continuum extrapolation cannot be quantified yet and is the only remaining significant source of uncertainty.

• Received 16 March 2015

DOI:https://doi.org/10.1103/PhysRevD.92.014504