منابع مشابه
Structure of the rho meson and the pion form-factor
From the electromagnetic form factor of the pion and from the decay modes of the τ lepton involving two or three pions one can see that the isovector–vector quark current couples strongly to the ρ meson whereas the isovector– axial-vector current couples strongly to the a1. Therefore such reactions provide excellent access to studies of the properties of (axial-)vector mesons. It has been shown...
متن کاملThe Pion Form Factor
The pion, and specifically its charge form factor, is of key interest in the study of the quark-gluon structure of hadrons. This is exemplified by the many calculations that treat the pion as one of their prime examples. One of the reasons is that the valence structure of the pion, being 〈qq̄〉, is relatively simple. Hence it is expected that the value of the four-momentum transfer squared Q, dow...
متن کاملQuark structure of the pion and pion form factor.
We consider the pion structure in the region of low and moderately high momentum transfers: at low Q 2 , the pion is treated as a composite system of constituent quarks; at moderately high momentum transfers, Q 2 = 10 ÷ 25 GeV 2 , the pion form factor is calculated within perturbative QCD taking into account one–gluon hard exchange. Using the data on pion form factor at Q 2 < 3 GeV 2 and pion a...
متن کاملThe Electromagnetic Pion Form Factor and Instantons
We calculate the electromagnetic pion form factor at intermediate spacelike momentum transfer from the QCD sum rule for the correlation function of two pseudoscalar interpolating fields and the electromagnetic current. This correlator receives essential contributions from direct (i.e. small-scale) instantons, which we evaluate under the assumption of an instanton size distribution consistent wi...
متن کاملVector meson dominance pion electromagnetic form factor with the σ−model loop corrections
A model is developed for electromagnetic form factor of the pion. One-loop corrections are included in the linear σ−model. The ρ−meson contribution is added in an extended VMD model. The form factor, calculated without fitting parameters, is in a good agreement with experiment for space-like and time-like photon momenta. Loop corrections to the two-pion hadronic contribution a (had,π) μ to the ...
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ژورنال
عنوان ژورنال: Progress of Theoretical Physics
سال: 1968
ISSN: 0033-068X,1347-4081
DOI: 10.1143/ptp.40.911