Local CP-violation and electric charge separation by magnetic fields from lattice QCD

G. S. Bali, F. Bruckmann, G. Endrödi, Z. Fodor, S. Katz, A. Schäfer

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We study local CP-violation on the lattice by measuring the local correlation between the topological charge density and the electric dipole moment of quarks, induced by a constant external magnetic field. This correlator is found to increase linearly with the external field, with the coefficient of proportionality depending only weakly on temperature. Results are obtained on lattices with various spacings, and are extrapolated to the continuum limit after the renormalization of the observables is carried out. This renormalization utilizes the gradient flow for the quark and gluon fields. Our findings suggest that the strength of local CP-violation in QCD with physical quark masses is about an order of magnitude smaller than a model prediction based on nearly massless quarks in domains of constant gluon backgrounds with topological charge. We also show numerical evidence that the observed local CP-violation correlates with spatially extended electric dipole structures in the QCD vacuum.

Original languageEnglish
Article number129
JournalJournal of High Energy Physics
Volume2014
Issue number4
DOIs
Publication statusPublished - 2014

Fingerprint

polarization (charge separation)
electric charge
CP violation
quantum chromodynamics
quarks
magnetic fields
electric dipoles
electric moments
correlators
dipole moments
spacing
continuums
gradients
vacuum
coefficients
predictions
temperature

Keywords

  • Lattice gauge field theories
  • Lattice QCD
  • Lattice quantum field theory
  • Quark-gluon plasma

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

Local CP-violation and electric charge separation by magnetic fields from lattice QCD. / Bali, G. S.; Bruckmann, F.; Endrödi, G.; Fodor, Z.; Katz, S.; Schäfer, A.

In: Journal of High Energy Physics, Vol. 2014, No. 4, 129, 2014.

Research output: Contribution to journalArticle

Bali, G. S. ; Bruckmann, F. ; Endrödi, G. ; Fodor, Z. ; Katz, S. ; Schäfer, A. / Local CP-violation and electric charge separation by magnetic fields from lattice QCD. In: Journal of High Energy Physics. 2014 ; Vol. 2014, No. 4.
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AU - Katz, S.

AU - Schäfer, A.

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