论文标题
$ b^ - \ to k^-x（3872）; x \toπ^0π^+π^ - $和x（3872）质量的三角奇异性
Triangle singularity in $B^-\to K^-X(3872);X\to π^0π^+π^-$ and the X(3872) mass
论文作者
论文摘要
我们从三角形机制中评估了$ x（3872）$宽度的贡献，其中$ x $在$ x $中陷入$ d^{*0} \ bar {d}^0 -cc $，然后$ d^{*0}（\ bar {d}}^}^{*0} $ d^0} $ d^0 $ d^0 $（ $ d^0 \ bar {d}^0 $ fuse产生$π^+π^ - $。这种机制从$π^+π^ - $不变质量中的三角奇异性产生了一个不对称的峰，对$ x $质量非常敏感。我们评估了一个反应的分支比，其中可以在$ b^ - \至k^ - π^0π^0π^+π^ - $反应中看到这种效果，并表明确定$π^+π^ - $的峰的确定是确定$ x $质量的不变质量分布。鉴于$ x $质量中的当前不确定性，不允许知道$ d^{*0} \ bar {d}^0 $状态是否受到限制，如下所建议的测量值应非常欢迎澄清此问题。
We evaluate the contribution to the $X(3872)$ width from a triangle mechanism in which the $X$ decays into $D^{*0}\bar{D}^0 -cc$, then the $D^{*0} (\bar{D}^{*0})$ decays into $D^0 π^0$ ($\bar{D}^0 π^0$) and the $D^0 \bar{D}^0$ fuse to produce $π^+ π^-$. This mechanism produces an asymmetric peak from a triangle singularity in the $π^+ π^-$ invariant mass with a shape very sensitive to the $X$ mass. We evaluate the branching ratios for a reaction where this effect can be seen in the $B^- \to K^- π^0 π^+ π^-$ reaction and show that the determination of the peak in the invariant mass distribution of $π^+ π^-$ is all that is needed to determine the $X$ mass. Given the present uncertainties in the $X$ mass, which do not allow to know whether the $D^{*0} \bar{D}^0$ state is bound or not, measurements like the one suggested here should be most welcome to clarify this issue.
