Pion in a uniform background magnetic field with clover fermions

Abstract

Background field methods provide an important nonperturbative formalism for the determination of hadronic properties which are complementary to matrix-element calculations. However, new challenges are encountered when utilising a fermion action exposed to additive mass renormalisations. In this case, the background field can induce an undesired field-dependent additive mass renormalisation that acts to change the quark mass as the background field is changed. For example, in a calculation utilising Wilson fermions in a uniform background magnetic field, the Wilson term introduced a field-dependent renormalisation to the quark mass which manifests itself in an unphysical increase of the neutral-pion mass for large magnetic fields. Herein, the clover fermion action is studied to determine the extent to which the removal of $\mathcal{O}(a)$ discretisation errors suppresses the field-dependent changes to the quark mass. We illustrate how a careful treatment of nonperturbative improvement is necessary to resolve this artefact of the Wilson term. Using the $32^3\times 64$ dynamical-fermion lattices provided by the PACS-CS Collaboration we demonstrate how our technique suppresses the unphysical mass renormalisation over a broad range of magnetic field strengths.

arXiv comment10 pages, 7 figures, version published in Phys. Rev. D

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Cited by in corpus (9)

• Pion magnetic polarisability using the background field method
• Magnetic polarisability of the nucleon using a Laplacian mode projection
• QCD Thermodynamics and Neutral Pion in a Uniform Magnetic Field: Finite Volume Effects
• Chiral extrapolation of the charged-pion magnetic polarizability with Padé approximant
• Chiral extrapolation of the magnetic polarizability of the neutral pion
• Structure of heavy quarkonia in a strong magnetic field
• Magnetic Polarisability of Octet Baryons via Lattice QCD
• Landau-Zener-Stückelberg-Majorana dynamics of magnetized quarkonia
• Quarkonium spectra with magnetically induced anisotropic confinement