AI 中文总结
本研究探讨$B^0 \to D^- π^+ a_0(980)(π^0 η)$衰变中的三角机制，发现其能产生与$a_1(1420)$相关的特征峰，为验证$a_1(1420)$的三角奇异性本质提供了可在LHCb等实验检验的平台。
AI 中文摘要
COMPASS合作组观测到的$a_1(1420)$的三角奇异性解释已被广泛接受。本工作研究衰变$B^0 \to D^- π^+ a_0(980)(π^0 η)$中的三角机制，其中$a_0(980)$被视为动力学产生态。$\bar{K}^{*0}$-$K^+$-$K^-$三角圈源于Belle合作组已观测到的衰变$B^0 \to D^- K^+ \bar{K}^{*0}$，随后$\bar{K}^{*0} \to K^- π^+$衰变。三角振幅在1420 MeV附近形成明显峰值，反映在$π a_0(980)$系统的不变质量谱中。计算得到的微分衰变宽度在$π^0 η$不变质量分布中于980 MeV附近呈现窄峰；此外，$π^+ π^0 η$系统的不变质量分布在1420 MeV附近显示清晰峰值，进一步证实了$a_1(1420)$的三角奇异性解释。我们预期所提出的$B^0$衰变模式可为进一步探索$a_1(1420)$的三角奇异性本质提供潜在平台，并可在LHCb、BESIII和Belle II等未来实验中得到检验。
英文摘要
The triangle singularity interpretation of the \replyhe{$a_1(1420)$} observed by the COMPASS Collaboration has been widely accepted. In this work, we investigate the triangle mechanism in the decay $B^0 \to D^- π^+ a_0(980)(π^0 η)$, where the $a_0(980)$ is treated as a dynamically generated state. The $\bar{K}^{*0}$-$K^+$-$K^-$ triangle loop originates from the decay $B^0 \to D^- K^+ \bar{K}^{*0}$, which has been observed by the Belle Collaboration, followed by the subsequent decay $\bar{K}^{*0} \to K^- π^+$. The triangle amplitude develops a pronounced peak around 1420 MeV, which is reflected in the invariant mass spectrum of the $πa_0(980)$ system. The differential decay width is calculated and exhibits a narrow peak around $980~\mathrm{MeV}$ in the $π^0 η$ invariant mass distribution. Furthermore, the invariant mass distribution of the $π^+ π^0 η$ system shows a clear peak around $1420~\mathrm{MeV}$, which further \replyhe{confirms} the triangle singularity explanation of the \replyhe{$a_1(1420)$}. We expect that the proposed $B^0$ decay mode could provide a potential platform for further exploring the triangle-singularity nature of the \replyhe{$a_1(1420)$} and could be tested in future experiments such as LHCb, BESIII, and Belle~II.
