| Autor: |
JLQCD, collaborations, TWQCD, Aoki, S., Chiu, T. W., Fukaya, H., Hashimoto, S., Hsieh, T. H., Kaneko, T., Matsufuru, H., Noaki, J., Onogi, T., Shintani, E., Yamada, N. |
| Rok vydání: |
2009 |
| Předmět: |
|
| Zdroj: |
Phys.Rev.D80:034508,2009 |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1103/PhysRevD.80.034508 |
| Popis: |
We calculate pion vector and scalar form factors in two-flavor lattice QCD and study the chiral behavior of the vector and scalar radii _{V,S}. Numerical simulations are carried out on a 16^3 x 32 lattice at a lattice spacing of 0.12 fm with quark masses down to \sim m_s/6, where m_s is the physical strange quark mass. Chiral symmetry, which is essential for a direct comparison with chiral perturbation theory (ChPT), is exactly preserved in our calculation at finite lattice spacing by employing the overlap quark action. We utilize the so-called all-to-all quark propagator in order to calculate the scalar form factor including the contributions of disconnected diagrams and to improve statistical accuracy of the form factors. A detailed comparison with ChPT reveals that the next-to-next-to-leading-order contributions to the radii are essential to describe their chiral behavior in the region of quark mass from m_s/6 to m_s/2. Chiral extrapolation based on two-loop ChPT yields _V=0.409(23)(37)fm and _S=0.617(79)(66)fm, which are consistent with phenomenological analysis. We also present our estimates of relevant low-energy constants.
Comment: 32 pages, 18 figures, typos corrected |
| Databáze: |
arXiv |
| Externí odkaz: |
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