论文标题
$ 1^{ - +} $ hybrid in $ j/ψ$辐射的衰减来自晶格QCD
$1^{-+}$ Hybrid in $J/ψ$ Radiative Decays from Lattice QCD
论文作者
论文摘要
我们介绍了$ 1^{ - +} $ Light Meson $η_1$ in $ J/ψ$辐射衰减的第一个理论预测。在$ n_f = 2 $晶格QCD形式主义带有式质量$m_π\大约350 $ meV中，相关的电磁多极形式是从涉及必须是夸克歼灭图的三点函数中提取的，这些函数是通过蒸馏方法计算得出的。 $ j/ψ\至γη_1$的部分宽度确定为$ 2.29（77）〜\ mathrm {ev} $ at $η_1$ subs $ mass $ m_ {η_1} = 2.23（4）$ gev。如果$η_1$对应于该过程中最近观察到的$η_1（1855）$，则$ j/ψ\toγη_1（1855）\ to besiii by besiii，然后分支分数$ \ mathrm {brm {br}（br}（J/ψ\ togγ）（1855555）$ 6. 10^{ - 5} $，这意味着$ \ mathrm {br}（η_1（1855）\至ηη'）\ sim 4.3 \％$。
We present the first theoretical prediction of the production rate of $1^{-+}$ light hybrid meson $η_1$ in $J/ψ$ radiative decays. In the $N_f=2$ lattice QCD formalism with the pion mass $m_π\approx 350$ MeV, the related electromagnetic multipole form factors are extracted from the three-point functions that involve necessarily quark annihilation diagrams, which are calculated through the distillation method. The partial width of $J/ψ\to γη_1$ is determined to be $2.29(77)~\mathrm{eV}$ at the $η_1$ mass $m_{η_1}=2.23(4)$ GeV. If $η_1$ corresponds to the recently observed $η_1(1855)$ in the process $J/ψ\to γη_1(1855)\to γηη'$ by BESIII, then the branching fraction $\mathrm{Br}(J/ψ\to γη_1(1855))$ is estimated to be $6.2(2.2)\times 10^{-5}$, which implies $\mathrm{Br}(η_1(1855)\to ηη')\sim 4.3\%$.
