标题： $K_1$轴矢量介子的混合角 显示英文标题

标题： Mixing angle of $K_1$ axial vector mesons

摘要： 各种实验测量的分析都表明，$K_1(1270)$和$K_1(1400)$的混合角$\theta_{K_1}$接近$33^\circ$或$57^\circ$。 然而，$\theta_{K_1}$是否大于或小于$45^\circ$仍然存在很大争议。 例如，最近有两项关于$K_1$介子强衰变的研究。 一个小组声称$\theta_{K_1}\approx 60^\circ$，而另一个小组得到$\theta_{K_1}=(33.6\pm4.3)^\circ$。 由于通过质量关系确定混合角$\alpha_{^3\!P_1}$和$\alpha_{^1\!P_1}$，前者（后者）是$f_1(1285)$（$h_1(1170)$）和$f_1(1420)$（$h_1(1380)$）在味基下的混合角，这取决于$\theta_{K_1}$，我们表明$\theta_{K_1}\approx 57^\circ$被排除，因为它导致$^1\!P_1$区域的理想混合出现过大偏差，与$\alpha_{^1\!P_1}$的格点计算以及$h_1(1170)$和$h_1(1380)$的强衰变观测结果不一致。 我们发现对于$\theta_{K_1}\approx (28-30)^\circ$，相应的$\alpha_{^3\!P_1}$和$\alpha_{^1\!P_1}$与所有晶格和现象学分析结果一致。 这再次强化了$\theta_{K_1}\sim 33^\circ$比$57^\circ$更受青睐的结论。 显示英文摘要

摘要： Analyses of various experimental measurements all indicate that the mixing angle $\theta_{K_1}$ of $K_1(1270)$ and $K_1(1400)$ is in the vicinity of $33^\circ$ or $57^\circ$. However, whether $\theta_{K_1}$ is greater or less than $45^\circ$ is still quite controversial. For example, there were two very recent studies of the strong decays of $K_1$ mesons. One group claimed that $\theta_{K_1}\approx 60^\circ$, while the other group obtained $\theta_{K_1}=(33.6\pm4.3)^\circ$. Since the determination of the mixing angles $\alpha_{^3\!P_1}$ and $\alpha_{^1\!P_1}$ with the former (latter) being the mixing angle of $f_1(1285)$ ($h_1(1170)$) and $f_1(1420)$ ($h_1(1380)$) in the flavor basis through mass relations depend on $\theta_{K_1}$, we show that $\theta_{K_1}\approx 57^\circ$ is ruled out as it leads to a too large deviation from ideal mixing in the $^1\!P_1$ sector, inconsistent with the lattice calculation of $\alpha_{^1\!P_1}$ and the observation of strong decays of $h_1(1170)$ and $h_1(1380)$. We find that for $\theta_{K_1}\approx (28-30)^\circ$, the corresponding $\alpha_{^3\!P_1}$ and $\alpha_{^1\!P_1}$ agree well with all lattice and phenomenological analyses. This again reinforces the statement that $\theta_{K_1}\sim 33^\circ$ is much more favored than $57^\circ$.