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arXiv · 1311.3513

Pion electromagnetic form factor from full lattice QCD

Jonna Koponen·Francis Bursa·Christine Davies·Gordon Donald·Rachel Dowdall
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Abstract

We present preliminary results from the first calculation of the pion electromagnetic form factor at physical light quark masses. This form factor parameterises the deviations from the behaviour of a point-like particle when a photon hits the pion. These deviations result from the internal structure of the pion and can thus be calculated in QCD. We use three sets (different lattice spacings) of n_f=2+1+1 lattice configurations generated by the MILC collaboration. The Highly Improved Staggered Quark formalism (HISQ) is used for all of the sea and valence quarks. Using lattice configurations with u/d quark masses very close to the physical value is an advantage, as we avoid the chiral extrapolation. We study the shape of the vector (f_+) form factor in the q^2 range from 0 to -0.12 GeV^2 and extract the mean square radius, . The shape of the vector form factor and the resulting radius is compared with experiment.

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Jonna Koponen, Francis Bursa, Christine Davies, Gordon Donald, Rachel Dowdall. 2013-11-14. Pion electromagnetic form factor from full lattice QCD. https://arxiv.org/abs/1311.3513

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