Electromagnetic form factors of the pion and kaon from the instanton vacuum

Journal Article · Thu May 01 04:00:00 EDT 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.77.094014· OSTI ID:21250120

Nam, Seung-il ^[1]; Kim, Hyun-Chul ^[2]

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1. Yukawa Institute for Theoretical Physics (YITP), Kyoto University, Kyoto 606-8502 (Japan)
2. Department of Physics, Inha University, Incheon 402-751 (Korea, Republic of)

We investigate the pion and kaon ({pi}{sup +}, K{sup +}, K{sup 0}) electromagnetic form factors in the spacelike region: Q{sup 2} < or approx. 1 GeV, based on the gauged low-energy effective chiral action from the instanton vacuum in the large N{sub c} limit. Explicit flavor SU(3) symmetry breaking is taken into account. The nonlocal contributions turn out to be crucial to reproduce the experimental data. While the pion electromagnetic form factor is in good agreement with the data, the kaon one seems underestimated. We also calculate the electromagnetic charge radii for the pion and kaon: <r{sup 2}>{sub {pi}{sup +}}=0.455 fm{sup 2}, <r{sup 2}>{sub K{sup +}}=0.534 fm{sup 2}, and <r{sup 2}>{sub K{sup 0}}=-0.060 fm{sup 2} without any adjustable free parameter except for the average instanton size and interinstanton distance, and they are compatible with the experimental data. The low-energy constant L{sub 9} in the large N{sub c} limit is estimated to be 8.42x10{sup -3} from the pion charge radius.

• OSTI ID: 21250120
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 9 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CHIRALITY
COMPUTERIZED SIMULATION
DISTANCE
ELECTROMAGNETIC FORM FACTORS
FLAVOR MODEL
GAUGE INVARIANCE
GEV RANGE 01-10
INSTANTONS
KAONS NEUTRAL
KAONS PLUS
PIONS PLUS
QUANTUM CHROMODYNAMICS
SU-3 GROUPS
SYMMETRY BREAKING