2014/03/17 by V. M. Braun, S. Collins, Sara Collins +13
Physics and Astronomy · #Amplitude #Baryon #Distribution function #Fermion #Helicity #High-Energy Particle Collisions Research #Lattice QCD #Light cone #Nucleon #Parity (physics) #Particle physics #Particle physics theoretical and experimental studies #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Quark #Sum rule in quantum mechanics #hep-lat #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevd.89.094511
published as Phys. Rev. D 89, 094511 (2014) · 19 pages, 11 figures
arxiv created 2014/03/17 · openalex publication_date 2014/05/29 · arxiv updated 2014/06/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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_\ensuremathπ\ensuremath≃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 implies different electroproduction cross sections at large transferred momenta and may be related to the difference in the decay patterns observed in experiment.