A study of the $$\gamma ^*$$ γ ∗ – $$f_{0}(980)$$ f 0 ( 980 ) transition form factors

Abstract

The γ * -f 0 (980) transition form factors are calculated within the QCD factorization framework. The f 0 -meson is assumed to be mainly generated through its ss Fock component. The corresponding spin wave function of the f 0 (980) meson is constructed and, combined with a model light-cone wave function for this Fock component, used in the calculation of the form factors. In the real-photon limit the results for the transverse form factor are compared to the large momentum-transfer data measured by the BELLE collaboration recently. It turns out that, for the momentum-transfer range explored by BELLE, the collinear approximation does not suffice, power corrections to it, modeled as quark transverse moment effects, seem to be needed. Mixing of the f 0 with the σ (500) is also briefly discussed.

Hadron tomography by generalized distribution amplitudes in the pion-pair production process γ*γ→π0π0Kumano1, Song2, Teryaev3 2018Phys. Rev. D126811601View full textAdd to dashboardCite

“…However, it appears in the total cross section [7] and the γ → f 0 ð980Þ transition form factor is investigated by using the Belle data [66]. Such studies indicate that f 0 ð980Þ is consistent with the qq configuration, which is different from our finding in Fig.…”

“…However, the pion distribution amplitude is related to the C-odd GDAs as shown in Eq. (66), and our current analysis is for the C-even GDAs, so that there is no direct connection.…”

QCD constituent counting rules for neutral vector mesons

“…[21], the exclusive production processes of scalar S ¼ 0 þþ and tensor T ¼ 2 þþ mesons through single-photon annihilation e þ e − → γ Ã → γSðTÞ were analyzed. Here, the transition form factors of γ Ã → γS and γ Ã → γT are not constants, and they scale as F γ Ã γS ðsÞ ∼ 1/s and F γ Ã γT ðsÞ ∼ 1/s 2 at large s, consistent with the scaling of the corresponding form factors at large values of virtual-photon squared Euclidean momentum Q 2 : F γ Ã γS ðQ 2 Þ ∼ 1/Q 2 [22] and F γ Ã γT ðQ 2 Þ ∼ 1/Q 4 [23]. The scaling of the form factors follows directly from using the differing twist counting for the S-and Tcreating operators [12].…”

On some implications of the BaBar data on the γ⁎η′ transition form factor

“…In [7] it has been shown that, for the γ * π 0 form factor, this property of the ω-expansion even holds to NNLO 3 . The correlation between the power of ω and the Gegenbauer coefficients also holds for the γ * f 0 (980) [8] to LO and, exploiting the NLO corrections given in [6], also to that order. For the axialvector, e.g.…”

“…4. Expansion of the NLO leading-twist γ * η and γ * η ′ form factors: Expanding the form factor (8) upon ω leads to…”