arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1111.5949hep-phhep-exnucl-exnucl-th
收藏

eta'和eta到四π介子的反常衰变

Anomalous decays of eta' and eta into four pions

Feng-Kun Guo, Bastian Kubis, Andreas Wirzba

摘要:

我们结合手征微扰理论和矢量介子优势理论,计算了尚未测量的eta'衰变到四个π介子的分支比。衰变eta' --> 2(pi+ pi-)和eta' --> pi+ pi-2 pi 0是P波主导的,可以认为主要是通过两个ρ共振进行的;我们预测分支分数分别为(1.0+-0.3)*10^-4和(2.4+-0.7)*10^-4,比目前的实验上限低不了多少。相反,只要假设CP对称性守恒,衰变eta' --> 4pi 0和eta --> 4pi 0都是D波驱动的,并且被显著地进一步抑制;任何关于衰变eta --> 4pi 0的实验证据几乎可以肯定地被解释为CP破坏的信号。我们还计算了由QCD θ项引起的eta' -> 4pi 0和eta -> 4pi 0的CP破坏振幅。

英文摘要:

We calculate the branching ratios of the yet unmeasured eta' decays into four pions, based on a combination of chiral perturbation theory and vector-meson dominance. The decays eta' --> 2(pi+ pi-) and eta' --> pi+ pi- 2pi0 are P-wave dominated and can largely be thought to proceed via two rho resonances; we predict branching fractions of (1.0+-0.3)*10^-4 and (2.4+-0.7)*10^-4, respectively, not much lower than the current experimental upper limits. The decays eta' --> 4pi0 and eta --> 4pi0, in contrast, are D-wave driven as long as conservation of CP symmetry is assumed, and are significantly further suppressed; any experimental evidence for the decay eta --> 4pi0 could almost certainly be interpreted as a signal of CP violation. We also calculate the CP-violating amplitudes for eta' --> 4pi0 and eta --> 4pi0 induced by the QCD theta-term.

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。

↑