Light-cone Distribution Amplitudes of the Nucleon and Negative Parity Nucleon Resonances from Lattice QCD

Abstract

We present the results of a lattice study of light-cone distribution amplitudes (DAs) of the nucleon and negative parity nucleon resonances using two flavors of dynamical (clover) fermions on lattices of different volumes and pion masses down to m_pi = 150 MeV. We find that the three valence quarks in the proton share their momentum in the proportion 37% : 31% : 31%, where the larger fraction corresponds to the u-quark that carries proton helicity, and determine the value of the wave function at the origin in position space, which turns out to be small compared to the existing estimates based on QCD sum rules. Higher-order moments are constrained by our data and are all compatible with zero within our uncertainties. We also calculate the normalization constants of the higher-twist DAs that are related to the distribution of quark angular momentum. Furthermore, we use the variational method and customized parity projection operators to study the states with negative parity. In this way we are able to separate the contributions of the two lowest states that, as we argue, possibly correspond to N*(1535) and a mixture of N*(1650) and the pion-nucleon continuum, respectively. It turns out that the state that we identify with N*(1535) has a very different DA as compared to both the second observed negative parity state and the nucleon, which may explain the difference in the decay patterns of N*(1535) and N*(1650) observed in experiment.

19 pages, 11 figures

References in corpus (7)

• Nucleon Form Factors in QCD
• Nucleon mass and sigma term from lattice QCD with two light fermion flavors
• Baryon Operators of Higher Twist in QCD and Nucleon Distribution Amplitudes
• Electroproduction of the N*(1535) resonance at large momentum transfer
• Nucleon distribution amplitudes from lattice QCD
• Non-perturbative renormalization of three-quark operators
• Irreducible Multiplets of Three-Quark Operators on the Lattice: Controlling Mixing under Renormalization

Cited by in corpus (9)

• Baryons as relativistic three-quark bound states
• Empirical Consequences of Emergent Mass
• Light-cone distribution amplitudes of octet baryons from lattice QCD
• Measurements of $ep\to e^{\prime }{\pi }^{+}{\pi }^{-}{p}^{\prime }$ Cross Sections with CLAS at $1.40<W<2.0$ GeV and $2.0<Q^2<5.0$ GeV${}^2$
• Second moment of the pion distribution amplitude with the momentum smearing technique
• Axial form factor of the nucleon at large momentum transfers
• QCD description of backward vector meson hard electroproduction
• Study of the ${\Lambda }_b\to N^{\ast }{\ell }^{+}{\ell }^{-}$ decay in light cone sum rules
• Light-cone sum rule approach for Baryon form factors