Influence of confining gluon configurations on the P→γ*γ transition form factors

Abstract

Transition form factors F P γ * γ ( * ) of pseudoscalar mesons are studied within the framework of the domain model of confinement, chiral symmetry breaking and hadronization. In this model, the QCD vacuum is described by the statistical ensemble of domain wall networks which represents the almost everywhere homogeneous Abelian (anti-)self-dual gluon field configurations. Calculations of the form factors are performed consistently with mass spectra of light, heavy-light and double-heavy mesons, their weak and strong decay constants. Influence of the nonperturbative intermediate range gluon fields on asymptotic behaviour of pion transition form factor is of particular interest, as it can potentially lead to the growth of Q 2 Fπγ * γ(Q 2 ). It is found that Q 2 Fπγ * γ(Q 2 ) approaches a constant value at asymptotically large Q 2 . However, this limit differs from the standard factorization bound, though for pion form factor complies with Belle data more likely than with BaBar ones. At the same time the generally accepted factorization bound is shown to be satisfied for the case of the symmetric kinematics,

Finite Size Effects in the Free Energy Density for Abelian (Anti-)Self-Dual Gluon Field in SU(3) Gluodynamics

“…There exists certain evidence that physical QCD vacuum can be rather efficiently represented by the statistical ensemble of almost everywhere homogeneous Abelian (anti-)self-dual gluon field configurations. Indications come from study of QCD effective action by various methods [1][2][3][4][5][6][7] and application of the model of confinement, chiral symmetry breaking and hadronization in QCD, which is based on this representation of QCD vacuum, to calculation of hadron spectra, decay constants and formfactors [8][9][10][11][12]. In particular, study of the effective action demonstrated that homogeneous Abelian (anti-)self-dual field appears to be a good candidate for a global minimum of the effective action [1,7], and that there exist kink-like defects in the Abelian (anti-)self-dual homogeneous gluon background field [6] allowing one to explicitly represent general almost everywhere homogeneous Abelian (anti-)self-dual field configurations in the form of domain wall networks [13].…”

Dispersive approach to non-Abelian axial anomaly

“…Note, that at s < s 0 there is a NP QCD contribution following from (25): h0jGGjγγi ∝ α e α s . So, unlike the second KHLEBTSOV, KLOPOT, OGANESIAN, and TERYAEV PHYS.…”

“…This approach was used to study the transition form factors of the π 0 , η and η 0 mesons in the spacelike [10][11][12][13][14][15] and timelike [16] regions. Along with the study based on the ASRs, the transition form factors have been a subject of extensive investigation within other frameworks recently, such as light cone sum rules [17][18][19], constituent [20], light-front [21] and nonlocal chiral quark models [22], light-front holographic QCD [23] as well as in some other models [24][25][26] and model-independent analyses [27][28][29].…”

Soft gluon fields and anomalous magnetic moment of muon

“…which provides explicit invariance of the effective meson action with respect to the background gauge transformations. Calculation of pion transition form factor F πγ * γ within the model has demonstrated [8] that the Wilson lines are responsible for deviation of F πγ * γ from Brodsky-Lepage limit [11] at large photon virtuality. The Wilson lines were FIG.…”

“…Specifically, we will touch this issue by calculating the lowest order in the number of intermediate mesons contributions (quark loop and one intermediate meson) within the domain model of QCD vacuum and hadronization developed in Refs. [4][5][6][7][8][9][10]. The driving feature of the model is the vacuum mean field represented by domain-structured configurations of almost everywhere homogeneous Abelian (anti-)self-dual gluon field which is treated nonperturbatively.…”