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arXiv 1110.2249hep-phhep-ex
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再论轴矢量介子混合

Revisiting Axial-Vector Meson Mixing

Hai-Yang Cheng

摘要:

各种唯象学研究表明,轴矢量介子$a_1(1260)$和$b_1(1235)$的奇异伙伴$K_{1A}$和$K_{1B}$的混合角$θ_{K_1}$分别位于$35^\circ$或$55^\circ$附近,但该角是否大于或小于$45^\circ$仍存在争议。当从质量关系确定$f_1(1285)$ - $f_1(1420)$混合角$θ_{^3P_1}$和$h_1(1170)$ - $h_1(1380)$混合角$θ_{^1P_1}$时,它们取决于$K_{1A}$和$K_{1B}$的质量,而$K_{1A}$和$K_{1B}$的质量又取决于混合角$θ_{K_1}$。我们证明了轻$q\bar q$态与重$s \bar s$态的近似解耦,这对矢量介子、张量介子和$3^{--}$介子都是经验有效的,当应用于等轴矢量介子时,将使我们能够区分$θ_{^3P_1}$和$θ_{^1P_1}$的不同解,并获得$θ_{K_1}\sim 35^\circ$。事实上,对于$θ_{K_1}\sim 55^\circ$,预测的$θ_{^1P_1}$与最近的晶格计算不一致,并且$h_1(1170)$和$h_1(1380)$的$q\bar q$组分中隐含的大的$s\bar s$含量不能解释它们的强衰变的观察。我们得出结论,$θ_{K_1}$小于$45^\circ$。

英文摘要:

Various phenomenological studies indicate that the mixing angle $θ_{K_1}$ of $K_{1A}$ and $K_{1B}$, the strange partners of the axial-vector mesons $a_1(1260)$ and $b_1(1235)$, respectively, lies in the vicinity of $35^\circ$ or $55^\circ$, but whether this angle is larger or smaller than $45^\circ$ still remains controversial. When the $f_1(1285)$-$f_1(1420)$ mixing angle $θ_{^3P_1}$ and the $h_1(1170)$-$h_1(1380)$ mixing angle $θ_{^1P_1}$ are determined from the mass relations, they depend on the masses of $K_{1A}$ and $K_{1B}$, which in turn depend on the mixing angle $θ_{K_1}$. We show that the approximate decoupling of the light $q\bar q$ state from the heavier $s \bar s$ state, which is empirically valid for vector, tensor and $3^{--}$ mesons, when applied to isoscalar axial-vector mesons, will enable us to discriminate different solutions of $θ_{^3P_1}$ and $θ_{^1P_1}$ and pick up $θ_{K_1}\sim 35^\circ$. Indeed, for $θ_{K_1}\sim 55^\circ$, the predicted $θ_{^1P_1}$ disagrees sharply with the recent lattice calculation and the implied large $s\bar s$ content of $h_1(1170)$ and $q\bar q$ component of $h_1(1380)$ cannot explain the observation of their strong decays. We conclude that $θ_{K_1}$ is smaller than $45^\circ$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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