Elsevier

Physics Letters B

Volume 734, 27 June 2014, Pages 290-295
Physics Letters B

Nucleon structure from Lattice QCD using a nearly physical pion mass

https://doi.org/10.1016/j.physletb.2014.05.075Get rights and content
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Abstract

We report the first Lattice QCD calculation using the almost physical pion mass mπ=149 MeV that agrees with experiment for four fundamental isovector observables characterizing the gross structure of the nucleon: the Dirac and Pauli radii, the magnetic moment, and the quark momentum fraction. The key to this success is the combination of using a nearly physical pion mass and excluding the contributions of excited states. An analogous calculation of the nucleon axial charge governing beta decay has inconsistencies indicating a source of bias at low pion masses not present for the other observables and yields a result that disagrees with experiment.

Keywords

Lattice QCD
Nucleon structure
Form factors

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