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arXiv · 2605.10946

Continuum-Limit HQET LCDAs from Lattice QCD for Tightening B Decay Uncertainties

Xue-Ying Han·Hao-Fei Gao·Jun Hua·Xiangdong Ji·Xiangyu Jiang·Cai-Dian Lü·Andreas Schäfer·Jin-Xin Tan·Ji-Hao Wang·Wei Wang·Ji Xu·Yi-Bo Yang·Fu-Wei Zhang·Jian-Hui Zhang·Jia-Lu Zhang·Mu-Hua Zhang·Qi-An Zhang·Shuai Zhao
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Abstract

Heavy meson HQET light-cone distribution amplitudes (LCDAs) are critical for precision predictions of $B$ meson weak decays, but currently are one of dominant theoretical uncertainties that obscure interpretations of $B$ anomalies and CP-violating measurements. Building on the established HQLaMET framework, supplemented by lattice QCD calculations of the OPE moments, we present a precise lattice QCD calculation of HQET LCDAs by employing multi-ensemble simulations for continuum and physical pion mass extrapolation, quantifying comprehensive systematic errors, and validating results through OPE moment cross-validation. Details of the lattice calculations are provided in a companion paper \cite{HeavymesonDA_long_paper}. Our final results for key inverse moments (at $\mu=1$ GeV) are $\lambda_B=0.340(20)$ GeV and $\sigma_B^{(1)}=1.685(63)$, with the total uncertainty reduced by a factor of three relative to the previous analysis. These results can greatly reduce the uncertainty in the $B \to K^*$ form factors in the large-recoil region. This work resolves the long-standing bottleneck in first-principles predictions of heavy meson LCDAs, advancing precision flavor physics to new frontiers.

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Xue-Ying Han, Hao-Fei Gao, Jun Hua, Xiangdong Ji, Xiangyu Jiang, Cai-Dian Lü, Andreas Schäfer, Jin-Xin Tan, Ji-Hao Wang, Wei Wang, Ji Xu, Yi-Bo Yang, Fu-Wei Zhang, Jian-Hui Zhang, Jia-Lu Zhang, Mu-Hua Zhang, Qi-An Zhang, Shuai Zhao. 2026-04-29. Continuum-Limit HQET LCDAs from Lattice QCD for Tightening B Decay Uncertainties. https://arxiv.org/abs/2605.10946

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