On the pion distribution amplitude shape |
| |
Authors: | M V Polyakov |
| |
Institution: | 1.Institut für Theoretische Physik II,Ruhr-Universit?t Bochum,Bochum,Germany |
| |
Abstract: | We argue that the recent BaBar data on γ → π e.m. transition form factor at large photon virtuality supports the idea that
pion distribution amplitude (DA) is close to unity with ϕπ′(0)/6 ≫ 1 at a normalization point of μ = 0.6–0.8 GeV. Such pion DA can be obtained in the effective chiral quark model. The
possible flat shape of the pion DA implies that the standard expansion of the DA in Gegenbauer polynomials can be divergent.
On basis of chiral models we predict that the two-pion DA should exhibit anomalous endpoint behaviour for pions in the S-wave
and that such feature is absent for higher partial waves. The latter implies that the ρ, f
2, etc. meson DAs have no anomalous endpoint behaviour. Possible implications of such pion DA for other hard exclusive processes
are shortly discussed. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|