Two-photon transitions of charmonia on the light front

Abstract

We investigate the two-photon transitions Hcc → γ * γ of the charmonium system in light-front dynamics. The light-front wave functions were obtained from solving the effective Hamiltonian based on light-front holography and one-gluon exchange interaction within the basis light-front quantization approach. We compute the two-photon transition form factors as well as the twophoton decay widths for S-and P-wave charmonia, ηc and χcJ and their excitations. Without introducing any free parameters, our predictions are in good agreement with the recent experimental measurements by BaBar and Belle, shedding light on the relativistic nature of charmonium.

Opportunities for studying C+ resonances at 3--12 GeV photon collider

“…Two-photon widths are successfully predicted with nonrelativistic quark models [21,22]. In the nonrelativistic limit two-photon widths of the meson are proportional to the square of the wave function or its derivative at the origin.…”

“…In Table 1 and Fig. 1 we list known cc and b b resonances with positive C-parity with experimental data from PDG [16] and summary of theoretical predictions on their masses and two-photon widths [18][19][20][21][22].…”

“…Values of the masses and two-photon width for various charmonium and bottomonium states from PDG and various theoretical predictions[18][19][20][21][22] …”

χc2 tensor meson transition form factors in the light front approach

“…We have already presented the formalism for computing the γ * γ * transition amplitudes to 0 ± , 1 + charmonia using light-front cc wave functions (LFWFs) [9][10][11][12]. The majority of works in the literature concentrates on the transition form factors for spinless quarkonia, and for the χ c2 discusses only the two-photon decay width, see for example results obtained from a Bethe Salpeter equation approach [13], relativistic quark models [14,15], Dyson-Schwinger equations [16] or lattice QCD [17], an exception being the light front approach of [18].…”

“…Here, convenient tables of the wave function from the Basis Light Front Quantization (BLFQ) approach of refs. [18,19] are available in the literature [20].…”