Finn M. Stokes

Search for low-lying lattice QCD eigenstates in the Roper regime

Adrian L. Kiratidis, Waseem Kamleh, Derek B. Leinweber, Zhan-Wei Liu, Finn M. Stokes and Anthony W. Thomas

N* Spectroscopy from Lattice QCD: The Roper Explained

Derek Leinweber, Waseem Kamleh, Adrian Kiratidis, Zhan-Wei Liu, Selim Mahbub, Dale Roberts, Finn Stokes, Anthony W. Thomas and Jiajun Wu

Parity-expanded variational analysis for nonzero momentum

Finn M. Stokes, Waseem Kamleh, Derek B. Leinweber, M. Selim Mahbub, Benjamin J. Menadue, and Benjamin J. Owen

Visualizations of coherent center domains in local Polyakov loops

Abstract Quantum Chromodynamics exhibits a hadronic confined phase at low to moderate temperatures and, at a critical temperature T C , undergoes a transition to a deconfined phase known as the quark–gluon plasma. The nature of this deconfinement phase transition is probed through visualizations of the Polyakov loop, a gauge independent order parameter. We produce visualizations that provide novel insights into the structure and evolution of center clusters. Using the HMC algorithm the percolation during the deconfinement transition is observed. Using 3D rendering of the phase and magnitude of the Polyakov loop, the fractal structure and correlations are examined. The evolution of the center clusters as the gauge fields thermalize from below the critical temperature to above it are also exposed. We observe deconfinement proceeding through a competition for the dominance of a particular center phase. We use stout-link smearing to remove small-scale noise in order to observe the large-scale evolution of the center clusters. A correlation between the magnitude of the Polyakov loop and the proximity of its phase to one of the center phases of SU(3) is evident in the visualizations.

Structure of the Nucleon and its Excitations

The structure of the ground state nucleon and its finite-volume excitations are examined from three different perspectives. Using new techniques to extract the relativistic components of the nucleon wave function, the node structure of both the upper and lower components of the nucleon wave function are illustrated. A non-trivial role for gluonic components is manifest. In the second approach, the parity-expanded variational analysis (PEVA) technique is utilised to isolate states at finite momenta, enabling a novel examination of the electric and magnetic form factors of nucleon excitations. Here the magnetic form factors of low-lying odd-parity nucleons are particularly interesting. Finally, the structure of the nucleon spectrum is examined in a Hamiltonian effective field theory analysis incorporating recent lattice-QCD determinations of low-lying two-particle scattering-state energies in the finite volume. The Roper resonance of Nature is observed to originate from multi-particle coupled-channel interactions while the first radial excitation of the nucleon sits much higher at approximately 1.9 GeV.

Study of Low-Lying Baryons with Hamiltonian Effective Field Theory

Drawing on experimental data for baryon resonances, Hamiltonian effective field theory (HEFT) is used to predict the positions of the finite-volume energy levels to be observed in lattice QCD simulations. We have studied the low-lying baryons

Spectroscopy with Local Multi-hadron Interpolators in Lattice QCD

N^*(1535)

Electromagnetic Form Factors Of Nucleon Eexcitations from Lattice QCD

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Electromagnetic Form Factors through Parity-Expanded Variational Analysis

N^*(1440)

Hamiltonian effective field theory study of the

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