2013/11/14 by Jonna Koponen, Francis Bursa, Koponen, Jonna +7
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #hep-lat
paper · pdf · doi:10.48550/arxiv.1311.3513
Presented at the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, Germany
arxiv created 2013/11/14 · arxiv updated 2013/11/15
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 nf=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 q2 range from 0 to -0.12 GeV2 and extract the mean square radius, <r2v>. The shape of the vector form factor and the resulting radius is compared with experiment.