Magnetic Polarisability of Octet Baryons via Lattice QCD

Abstract

Drawing on recent advances in lattice-QCD background-field techniques, the magnetic polarisability of octet baryons is calculated from the first principles of QCD. The results are presented in the context of new constituent quark-model calculations providing a framework for understanding the lattice results and a direct comparison with simulation results at unphysical quark masses. Using smeared quark sources, low-lying Laplacian eigenmode projection and final-state Landau mode projection, considerable attention is devoted to ensuring single-state isolation in the lattice correlation functions. We also introduce new weighting methods to reduce the sensitivity to correlation-function fits, averaging over many fits based on merit drawn from the full correlated ${\chi }^2$ of the fits. The techniques are implemented on the $32^3\times 64$, 2+1-flavour dynamical-fermion lattices provided by the PACS-CS collaboration following the introduction of uniform magnetic fields quantised to the lowest nontrivial values available. After some fine tuning of the constituent quark model parameters, we find the model captures the patterns observed in the lattice QCD results very well, providing important insights into the physics underpinning the magnetic polarisabilities. Finally, comparison with the most recent results from experiment proceeds through an effective field theory formalism which incorporates estimates of finite-volume corrections and small electro-quenching corrections as the results are brought to the physical point. We find excellent agreement with experiment where available, including the proton and neutron polarisabilities.

arXiv comment32 pages, 15 figures

References in corpus (46)

• A New Way to Set the Energy Scale in Lattice Gauge Theories and its Application to the Static Force and ${\alpha }_s$ in SU(2) Yang--Mills Theory
• Analytic Smearing of SU(3) Link Variables in Lattice QCD
• 2+1 Flavor Lattice QCD toward the Physical Point
• 50 Years of Quantum Chromodynamics
• Precise determination of the strangeness magnetic moment of the nucleon
• Using effective field theory to analyse low-energy Compton scattering data from protons and light nuclei
• Chiral Analysis of Quenched Baryon Masses
• Convergence of chiral effective field theory
• Measurement of the Electric and Magnetic Polarizabilities of the Proton
• Precision Electromagnetic Structure of Octet Baryons in the Chiral Regime
• Baryon Octet to Decuplet Electromagnetic Transitions
• Strange Electric Form Factor of the Proton
• Isolating the Λ(1405) in Lattice QCD
• The Magnetic Structure of Light Nuclei from Lattice QCD
• Compton scattering from the proton in an effective field theory with explicit Delta degrees of freedom
• Magnetic polarizability of hadrons from lattice QCD in the background field method
• Quark Contributions to Baryon Magnetic Moments in Full, Quenched and Partially Quenched QCD
• Strange magnetic form factor of the proton at $Q^2=0.23$ GeV${}^2$
• Chiral extrapolation of octet-baryon charge radii
• Landau levels in QCD
• New Measurement of Compton Scattering from the Deuteron and an Improved Extraction of the Neutron Electromagnetic Polarizabilities
• Magnetic properties of the nucleon in a uniform background field
• Quasi-free Compton Scattering and the Polarizabilities of the Neutron
• Charged multi-hadron systems in lattice QCD+QED
• Neutron polarizabilities investigated by quasi-free Compton scattering from the deuteron
• Finite-volume and partial quenching effects in the magnetic polarizability of the neutron
• Nucleon Polarisabilities at and Beyond Physical Pion Masses
• Magnetic polarisability of the nucleon using a Laplacian mode projection
• Chiral extrapolations for nucleon electric charge radii
• Chiral extrapolations for nucleon magnetic moments
• Strong contribution to octet baryon mass splittings
• Elastic Form Factors of Nucleon Excitations in Lattice QCD
• Nucleon Polarizabilities from Low-Energy Compton Scattering
• Magnetic polarizability of hadrons from lattice QCD
• Proton scalar dipole polarizabilities from real Compton scattering data, using fixed-t subtracted dispersion relations and the bootstrap method
• Power Counting Regime of Chiral Effective Field Theory and Beyond
• A Method to Extract Charged Hadron Properties from Lattice QCD in Magnetic Fields
• Neutron magnetic polarisability with Landau mode operators
• Sum rule for the Compton amplitude and implications for the proton-neutron mass difference
• Octet Baryons in Large Magnetic Fields
• Pion in a uniform background magnetic field with clover fermions
• Towards charged hadron polarizabilities from four-point functions in lattice QCD
• Wave Functions of the Proton Ground State in the Presence of a Uniform Background Magnetic Field in Lattice QCD
• Hyperon Polarizabilities in the Bound State Soliton Model
• Dynamical Polarizabilities of SU(3) Octet of Baryons
• SU(3) Symmetry Breaking and Octet Baryon Polarizabilities