Beyond leading twist; meson decay constants and distribution amplitudes in a self-consistent light-front quark model

Arifi, A. J.; Choi, H.-M.*; Ji, C.-R.*

Arifi, A. J.; Choi, H.-M.*; Ji, C.-R.*

In this study, we present a comprehensive analysis of decay constants and chiral-even and chiral-odd distribution amplitudes (DAs) up to twist 4 for the meson in the standard light-front quark model (LFQM) based on the Bakamjian-Thomas (BT) construction. For the meson, which possesses both longitudinal and transverse polarizations, two types of decay constants arises accordingly. We demonstrate that these decay constants can be self-consistently extracted from both local and nonlocal matrix elements in a manner independent of current components, polarizations, and reference frames. In particular, we emphasize the role of nonlocal matrix elements involving axial-vector and scalar currents, where mixing between two different decay constants; occurs. We show that this mixing is consistently resolved through the BT construction, ensuring the proper extraction of these decay constants. Additionally, we investigate the structure of chiral-even DAs and chiral-odd DAs beyond leading twists, and present their corresponding -moments and Gegenbauer moments. These results provide deeper insight into the nonperturbative structure of vector mesons and demonstrate the robustness and self-consistency of the LFQM based on the BT framework.