Large corrections to asymptotic $F_{{\eta }_c\gamma }$ and $F_{{\eta }_b\gamma }$ in the light-cone perturbative QCD

Abstract

The large-$Q^2$ behavior of ${\eta }_c$-$\gamma$ and ${\eta }_b$-$\gamma$ transition form factors, $F_{{\eta }_c\gamma }(Q^2)$ and $F_{{\eta }_b\gamma }(Q^2)$ are analyzed in the framework of light-cone perturbative QCD with the heavy quark ($c$ and $b$) mass effect, the parton's transverse momentum dependence and the higher helicity components in the light-cone wave function are respected. It is pointed out that the quark mass effect brings significant modifications to the asymptotic predictions of the transition form factors in a rather broad energy region, and this modification is much severer for $F_{{\eta }_b\gamma }(Q^2)$ than that for $F_{{\eta }_c\gamma }(Q^2)$ due to the $b$-quark being heavier than the $c$-quark. The parton's transverse momentum and the higher helicity components are another two factors which decrease the perturbative predictions. For the transition form factor $F_{{\eta }_c\gamma }(Q^2)$, they bring sizable corrections in the present experimentally accessible energy region ($Q^2\le 10Ge{V}^2$). For the transition form factor $F_{{\eta }_b\gamma }(Q^2)$, the corrections coming from these two factors are negligible since the $b$-quark mass is much larger than the parton's average transverse momentum. The coming $e^{+}{e}^{-}$ collider (LEP2) will provide the opportunity to examine these theoretical predictions.

8 pages, RevTex, 5 PostScript figures

References in corpus (6)

• Transverse Momentum and Sudakov Effects in Exclusive QCD Processes: gamma* gamma pi0 Form Factor
• Melosh rotation: source of the proton's missing spin
• A perturbative approach to the eta_c-gamma transition form factor
• Decay Constant Ratios $f_{{\eta }_c}/f_{J/\psi }$ and $f_{{\eta }_b}/f_{{\rm Y}}$
• The hard scattering amplitude for the higher helicity components of the pion form factor
• Possible effects of quark and gluon condensates in quarkonium spectra

Cited by in corpus (23)

• Semileptonic $B_c$ decays and Charmonium distribution amplitude
• An Implication on the Pion Distribution Amplitude from the Pion-Photon Transition Form Factor with the New BABAR Data
• Measurement of the gamma gamma* --> eta_c transition form factor
• Can NRQCD explain the $\gamma {\gamma }^{\ast }\to {\eta }_c$ transition form factor data?
• An improved light-cone harmonic oscillator model for the pionic leading-twist distribution amplitude
• Determination of the $\eta$ and ${\eta }^{\prime }$ Mixing Angle from the Pseudoscalar Transition Form Factors
• Determination of the pion distribution amplitude
• The cross section of the process $e^{+}+e^{-}\to J/\psi +{\eta }_c$ within the QCD light-cone sum rules
• The $\rho$-meson longitudinal leading-twist distribution amplitude within QCD background field theory
• Heavy and light meson wavefunctions
• Information on the Pion Distribution Amplitude from the Pion-Photon Transition Form Factor with the Belle and BaBar Data
• The ${\gamma }^{\ast }{\gamma }^{\ast }\to {\eta }_c(1S,2S)$ transition form factors for spacelike photons
• $K_0^{\ast }(1430)$ Twist-2 Distribution Amplitude and $B_s,D_s\to K_0^{\ast }(1430)$ Transition Form Factors
• $B\to \rho$ transition form factors within the QCD light-cone sum rules and the $\rho$-meson leading-twist distribution amplitude
• $B\to K^{\ast }$ Transition Form Factors and the Semi-leptonic Decay $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$
• Finding a way to determine the pion distribution amplitude from the experimental data
• $a_0(980)$-meson twist-2 distribution amplitude within the QCD sum rules and investigation of $D\to a_0(980)(\to \eta \pi )e^{+}{\nu }_e$
• Reconsideration of the $B\to K^{\ast }$ Transition Form Factors within the QCD Light-Cone Sum Rules
• Systematic twist expansion of $({\eta }_c,{\eta }_b)\to {\gamma }^{\ast }\gamma$ transition form factors in light-front quark model
• The $B\to \rho$ helicity form factors within the QCD light-cone sum rules
• Form factors of ${\eta }_c$ in light front quark model
• Footprint in fitting $B\to D$ vector form factor and determination for $D$-meson leading-twist LCDA
• Radiative Decays of Vector Mesons with Light-Cone Sum Rules