Form factors and generalized parton distributions of heavy quarkonia in basis light front quantization

Abstract

We calculate the electromagnetic (charge, magnetic and quadrupole) form factors and the associated static moments of heavy quarkonia (charmonia and bottomonia) using the Basis Light Front Quantization (BLFQ) approach. For this work, we adopt light front wavefunctions (LFWFs) generated by a holographic QCD confining potential and a one-gluon exchange interaction with fixed coupling. We compare our BLFQ results with the limiting case of a single BLFQ basis state description of heavy quarkonia and with other available results. These comparisons provide insights into relativistic effects. Using the same LFWFs generated in the BLFQ approach, we also present the generalized parton distributions (GPDs) for selected mesons including those for radially excited mesons such as ψ and Υ . Our GPD results establish the foundation within BLFQ for further investigating hadronic structure such as probing the spin structure of spin-one hadrons in the off-forward limit. I. INTRODUCTIONExploring the electromagnetic (EM) properties of spin-one hadrons has been of great interest because it provides insight into the spin-sensitive structure and the internal dynamics of the hadrons. In particular, hadronic form factors (FFs) serve as one important tool to understand the structure of bound states in quantum chromodynamics (QCD).The numerous investigations on the structure of the spin-zero and spin-one hadrons that include FFs in different formalisms [1-24] provide a window for understanding hadronic structure at low and medium momentum transfer.The investigations with relativistic approaches [1,[6][7][8][9][10][11][12][13][20][21][22][23][24] have presented results for FFs, decay constants and the distribution amplitudes of spin-zero and spin-one bound-state systems such as the pion (π), kaon (K), rho meson (ρ) and J/ψ meson adopting different light front (LF) models. Note a recent investigation [23] has shown the FFs of (pseudo) scalar mesons calculated in a general frame. That work has also pointed out the differences among the results calculated in the various frames including the Drell-Yan frame.Despite these numerous studies and growing interests, there is little consensus on how to obtain static moments such as the quadrupole moments on the LF. Furthermore, investigations on the EM FFs and the associated static moments of radially excited vector mesons such as ψ and Υ are rare to the best of our knowledge [14,15]. It is *

Radiative transitions between 0−+ and 1−− heavy quarkonia on the light front

“…radii [7], distribution amplitudes and parton distributions as well as diffractive vector meson productions [8] have been directly calculated from the light-front wavefunctions (LFWFs), and are in reasonable agreement with experiments and with other approaches (see also Ref. [9]). Therefore, we are motivated to investigate radiative transitions within this model.…”

“…We could then obtain the transition form factor from such hadron matrix elements according to Eqs. (8) and (9). Ideally,V(Q 2 ) is independent of the spin projection m j and the current components.…”

Parton distribution functions of heavy mesons on the light front

“…(For the reviews related to BLFQ and its other application, see Refs. [67][68][69][70][71][72][73][74][75]. )…”

Scattering in strong electromagnetic fields: Transverse size effects in time-dependent basis light-front quantization

“…BLFQ has the advantage of being able to solve bound state problems involving positronium [37] and hadron structures [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53]. In this paper we follow previous work on the physical electron eigenstates in BLFQ [54].…”