منابع مشابه
Baryon-Pion Couplings from Large-Nc QCD
We derive a set of consistency conditions for the pion-baryon coupling constants in the large-Nc limit of QCD. The consistency conditions have a unique solution which are precisely the values for the pion-baryon coupling constants in the Skyrme model. We also prove that non-relativistic SU(2Nf ) spin-flavor symmetry (where Nf is the number of light flavors) is a symmetry of the baryon-pion coup...
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The electromagnetic form factor of the pion is obtained using a particular realization of QCD in the large Nc limit, which sums up the infinite number of zero-width resonances to yield an Euler’s Beta function of the Veneziano type. This form factor agrees with space-like data much better than single rho-meson dominance. A simple unitarization ansatz is illustrated, and the resulting vector spe...
متن کاملPion Form Factor in QCD at Intermediate Momentum Transfers
We present a quantitative analysis of the electromagnetic pion form factor in the light-cone sum rule approach, including radiative corrections and higher-twist effects. The comparison to the existing data favors the asymptotic profile of the pion distribution amplitude and allows to estimate the deviation: ( ∫ du/uφπ(u))/( ∫ du/uφas π (u)) = 1.1± 0.1 at the scale 1 GeV. Special attention is pa...
متن کاملPion form factor from local-duality QCD sum rule
We present our recent results for the pion elastic form factor [1] obtained within a local-duality three-point sum rule (a Borel sum rule in the limit of an infinite Borel parameter). Our analysis [1] includes the O(1) and O(αs) contributions and is therefore applicable in a broad range of spacelike momentum transfers. Our results demonstrate in essentially model-independent way that the O(1) t...
متن کاملTwisted mass QCD for the pion electromagnetic form factor
The pion form factor is computed using quenched twisted mass QCD and the GMRES-DR matrix inverter. The momentum averaging procedure of Frezzotti and Rossi is used to remove leading lattice spacing artifacts, and numerical results for the form factor show the expected improvement with respect to the standard Wilson action. Although some matrix inverters are known to fail when applied to twisted ...
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ژورنال
عنوان ژورنال: Physics Letters B
سال: 2001
ISSN: 0370-2693
DOI: 10.1016/s0370-2693(01)00576-7