Distribution amplitudes of vector and axial-vector mesons in a nonperturbatively improved symmetry-preserving framework
Abstract
Using continuum Schwinger-function methods with a nonperturbatively improved, symmetry-preserving kernel, we deliver predictions for the leading-twist light-front distribution amplitudes (DAs) of the ρ, K∗, a1(1260), b1(1235), and the unmixed strange partners of the 1++ and 1+− axial-vector (AV) channels, reconstructed from Mellin moments of the associated Bethe--Salpeter wave functions. For vector mesons, polarisation barely affects longitudinal momentum sharing: the longitudinal and transverse DAs are nearly degenerate, and both narrower than the asymptotic distribution in the second-moment sense. The AV sector is different in kind. Charge conjugation compels one projection -- interchanged between the 1++ and 1+− channels -- to vanish at x=1/2 and change sign; breaking SUF(3) symmetry removes this protection, whereupon the zeroth moments become nonzero and the nodes shift from the midpoint. Under a common weighted normalisation, the 1+− zeroth moment is $1.63$ times that of the 1++ channel, and the profile distortion follows the same pattern. A coupling forbidden by charge conjugation in the symmetric limit, fb1=0, becomes fK1+−=0.019GeV in the strange channel: an independent measure of the same symmetry breaking, obtained from a current matrix element rather than from the DA reconstruction. What distinguishes the two sectors is thus a symmetry-enforced zero, not the size of the flavour asymmetry.
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BibTeX
@misc{xu2026distribution,
title = {{Distribution amplitudes of vector and axial-vector mesons in a nonperturbatively improved symmetry-preserving framework}},
author = {Zhen-Ni Xu and Zhao-Qian Yao and Peng Cheng and Khépani Raya},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.02329},
eprint = {2609.02329},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.02329},
}
RIS
TY - UNPB
TI - Distribution amplitudes of vector and axial-vector mesons in a nonperturbatively improved symmetry-preserving framework
AU - Zhen-Ni Xu
AU - Zhao-Qian Yao
AU - Peng Cheng
AU - Khépani Raya
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.02329
UR - https://arxiv.org/abs/2609.02329
AB - Using continuum Schwinger-function methods with a nonperturbatively improved, symmetry-preserving kernel, we deliver predictions for the leading-twist light-front distribution amplitudes (DAs) of the ρ, K^∗, a_1(1260), b_1(1235), and the unmixed strange partners of the 1^++ and 1^+− axial-vector (AV) channels, reconstructed from Mellin moments of the associated Bethe--Salpeter wave functions. For vector mesons, polarisation barely affects longitudinal momentum sharing: the longitudinal and transverse DAs are nearly degenerate, and both narrower than the asymptotic distribution in the second-moment sense. The AV sector is different in kind. Charge conjugation compels one projection -- interchanged between the 1^++ and 1^+− channels -- to vanish at x=1/2 and change sign; breaking SU_F(3) symmetry removes this protection, whereupon the zeroth moments become nonzero and the nodes shift from the midpoint. Under a common weighted normalisation, the 1^+− zeroth moment is $1.63$ times that of the 1^++ channel, and the profile distortion follows the same pattern. A coupling forbidden by charge conjugation in the symmetric limit, f_b_1=0, becomes f_K_1^+−=0.019GeV in the strange channel: an independent measure of the same symmetry breaking, obtained from a current matrix element rather than from the DA reconstruction. What distinguishes the two sectors is thus a symmetry-enforced zero, not the size of the flavour asymmetry.
ER -