Speaker
Description
This talk is based two recent papers, [BESIII, arXiv:2601.01817] and [Y. Tang et al., CPC:10.1088/1674-1137/ae5c70]. Using $20.3~\text{fb}^{-1}$ of $e^+e^-$ annihilation data collected at $\sqrt{s}=3.773~\text{GeV}$ with the BESIII detector, we report the first observation of the semileptonic decays $D^0\to K^-\omega e^+\nu_e$ and $D^+\to K_S^0\omega e^+\nu_e$. This leads to the first direct determination of $\mathcal B(K_1(1270)\to K\omega) = (8.4\pm 1.4 \pm 0.5)\%$. Furthermore, the $\bar{K}_1(1270)$ mass is measured to be $(1336 \pm 9 \pm 2)$ MeV/$c^2$, providing unique experimental support for the two-pole structure of the $\bar{K}_1(1270)$ resonance. In additional, a sensitivity study has been carried out recently based on four $D \to \bar{K}\pi\pi e^+\nu_e$ decay channels, based on a novel model-independent method. The branching fractions of different $K_1(1270)$ decay modes are expected to be measured with much reduced systematic uncertainties, which could be pursued in further facilities such as STCF.
| 请选择分会 | 强子物理与味物理 |
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