First principles calculations of the form factors of baryon excitations are now becoming accessible through advances in Lattice QCD techniques. In this paper, we explore the utility of the parity-expanded variational analysis (PEVA) technique in calculating the Sachs electromagnetic form factors for excitations of the proton and neutron. We study the two lowest-lying odd-parity excitations and demonstrate that at heavier quark masses, these states are dominated by behaviour consistent with constituent quark models for the N∗(1535) and N∗(1650), respectively. We also study the lowest-lying localised even-parity excitation, and find that its form factors are consistent with a radial excitation of the ground state nucleon. A comparison of the results from the PEVA technique with those from a conventional variational analysis exposes the necessity of the PEVA approach in baryon excited-state studies.
@article{arxiv.1907.00177,
title = {Elastic Form Factors of Nucleon Excitations in Lattice QCD},
author = {Finn M. Stokes and Waseem Kamleh and Derek B. Leinweber},
journal= {arXiv preprint arXiv:1907.00177},
year = {2020}
}