Perturbative QCD correction to the hard-scattering amplitude for the meson form factor

1987 ◽  
Vol 35 (7) ◽  
pp. 2255-2256 ◽  
Author(s):  
Eric Braaten ◽  
Sze-Man Tse
Keyword(s):  
Form Factor ◽  
Perturbative Qcd ◽  
Scattering Amplitude ◽  
Hard Scattering

scholarly journals Hard scattering amplitude for the higher helicity components of the pion form factor

1997 ◽  
Vol 55 (11) ◽  
pp. 7107-7113 ◽  
Author(s):  
Fu-Guang Cao ◽  
Jun Cao ◽  
Tao Huang ◽  
Bo-Qiang Ma
Keyword(s):  
Form Factor ◽  
Scattering Amplitude ◽  
Pion Form Factor ◽  
Hard Scattering

CALCULATION OF SCALAR FORM FACTORS OF NONTOPOLOGICAL SOLITONS

1990 ◽  
Vol 05 (08) ◽  
pp. 1509-1527
Author(s):  
L.S. CELENZA ◽  
A. PANTZIRIS ◽  
C.M. SHAKIN
Keyword(s):  
Wave Function ◽  
Form Factor ◽  
Perturbative Qcd ◽  
Soft Part ◽  
Form Factors ◽  
Bound State ◽  
Mass Scale ◽  
Hard Scattering ◽  
Scalar Form ◽  
The Individual

We study a “toy” model which describes the bound state of two scalar particles. We parameterize the “soft” part of the wave function of the bound state using results obtained in the study of a nontopological soliton model. (This part of the wave function has predominantly lowmomentum components.) We improve this wave function by considering a single “hard” scattering, which we treat in perturbation theory. Thus, we have a model in which the wave function has both “soft” and “hard” parts, in the language used when performing perturbative QCD studies. (The relation of these results to those obtained for electromagnetic form factors in perturbative QCD studies requires further analysis.) We find that the form factor calculated using the “soft” part of the wave function behaves as F(Q2)=F(0)/(1+λ2Q2), where Q2=−q2>0. The individual hard scattering terms yield form factors which have the same form, except for a change of the scale factor, λ. We discuss the approach to the asymptotic form, F(Q2)~Q−2, for the various amplitudes which are summed to obtain the complete form factor. We also discuss the modification of the form factor under a change in mass scale. This modification is relatively simple to study since, in our model, there is only a single dimensionful parameter, κ, which sets the scale for all other dimensional parameters.

INFRARED RENORMALON EFFECTS ON LIGHT MESONS ELECTROMAGNETIC TRANSITION FORM FACTOR FMγ*(Q2, ω)

2003 ◽  
Vol 18 (07) ◽  
pp. 1023-1050 ◽  
Author(s):  
YEGANA V. MAMEDOVA
Keyword(s):  
Form Factor ◽  
Perturbative Qcd ◽  
Transition Form Factor ◽  
Form Factors ◽  
Transition Form ◽  
Coupling Constant ◽  
Electromagnetic Transition ◽  
Qcd Factorization ◽  
Factorization Formula ◽  
Light Mesons

The light pseudoscalar π0, η and η′ mesons electromagnetic transition γ* + γ* → M form factors FMγ*(Q2,ω) are calculated, applying the perturbative QCD factorization formula and the frozen coupling constant approximation. In the computations the O(αS) order expression for FMγ*(Q2,ω) and the mesons' infrared renormalon corrected distribution amplitudes are used. In the case of the η and η′ mesons, the SUf(3) ordinary octet-singlet mixing scheme is utilized. Comparisons are made with the results obtained, employing the mesons' ordinary distribution amplitudes and with γ + γ* → M transition form factors.

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