Second Moment of the Pion Light-cone Distribution Amplitude from Lattice QCD

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 $m_\pi\sim 150 , \mathrm {MeV}$\mathrm{.}Atlatticespacingsbetween$0.06 , \mathrm {fm}$and$0.08 , \mathrm {fm}$wefindforthesecondGegenbauermomentthevalue$a_2 = 0.1364(154)(145)$atthescale$\mu=2 , \mathrm {GeV}$inthe$\overline{$\mathrm{M}\mathrm{S}$}$ 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.