Distribution Amplitudes Of Pseudoscalar Mesons Research Articles

Addendum to: Light-cone distribution amplitudes of pseudoscalar mesons from lattice QCD

We update our lattice determination of the two lowest Gegenbauer moments of the leading-twist pion and kaon light-cone distribution amplitudes [1]

Light-cone distribution amplitudes of pseudoscalar mesons from lattice QCD

We present the first lattice determination of the two lowest Gegenbauer moments of the leading-twist pion and kaon light-cone distribution amplitudes with full control of all errors: {a}_2^{pi }={0.101}_{-24}^{+24} for the pion; {a}_1^K={0.0533}_{-35}^{+34} and {a}_2^K={0.090}_{-20}^{+19} for the kaon. The calculation is carried out on 35 different CLS ensembles with Nf = 2 + 1 flavors of dynamical Wilson-clover fermions. These cover a multitude of pion and kaon mass combinations (including the physical point) and 5 different lattice spacings down to a = 0.039 fm. The momentum smearing technique and a new operator basis are employed to reduce statistical fluctuations and to improve the overlap with the ground states. The results are obtained from a combined chiral and continuum limit extrapolation that includes three separate trajectories in the quark mass plane.

Moments of pseudoscalar meson distribution amplitudes from the lattice

Based on lattice simulations with two flavors of dynamical, $\mathcal{O}(a)$-improved Wilson fermions we present results for the first two moments of the distribution amplitudes of pseudoscalar mesons at several values of the valence quark masses. By extrapolating our results to the physical masses of up/down and strange quarks, we find the first two moments of the ${K}^{+}$ distribution amplitude and the second moment of the ${\ensuremath{\pi}}^{+}$ distribution amplitude. We use nonperturbatively determined renormalization coefficients to obtain results in the $\overline{\mathrm{MS}}$ scheme. At a scale of $4\text{ }\text{ }{\mathrm{GeV}}^{2}$ we find ${a}_{2}^{\ensuremath{\pi}}=0.201(114)$ for the second Gegenbauer moment of the pion's distribution amplitude, while for the kaon, ${a}_{1}^{K}=0.0453(9)(29)$ and ${a}_{2}^{K}=0.175(18)(47)$.

Transition form factors and light-cone distribution amplitudes of pseudoscalar mesons in the chiral quark model

It is shown that a chiral quark model of the Nambu--Jona-Lasinio type can be used to describe "soft"-momenta parts of the amplitudes with large momentum transfer. As a sample, the processes \gamma^* --> \gamma (\pi,\eta,\eta') where one of the photons, \gamma^*, has large space-like virtuality is investigated. The \gamma^* --> \gamma (\pi,\eta,\eta')$ transition form factors are calculated for a wide region of transferred momenta. The results are consistent with the calculations performed in the instanton-induced chiral quark model and agree with experimental data. The distribution amplitudes of pseudoscalar mesons are derived.