论文标题
$ j/ψ\toγη_{（2）} $的辐射衰减宽度来自$ n_f = 2 $ lattice qcd
Radiative Decay Width of $J/ψ\to γη_{(2)}$ from $N_f=2$ Lattice QCD
论文作者
论文摘要
$ j/ψ$辐射衰减中伪级介子的辐射生产率仍然难以捉摸。我们介绍了$ j/ψ$的第一个晶格QCD计算$ j/ψ$辐射衰减成$η_{（2）} $，$ \ mathrm {su（2）} $ sight singlet singlet pseudlecs pseudleccalar erson，确认qcd $ \ m mathrm {u_a（1）$ a anm and and a nom and and and and con。单身伪凯尔斯介子。使用$ n_f = 2 $ lattice QCD量规配置进行晶格仿真，pion质量$m_π\ 350 $ mev。特别是，已经利用了蒸馏方法来计算光夸克环。在此报告的结果与质量$ m_ {η_ {（2）}} = 718（8）$ MEV和衰减宽度$γ（j/ψ\toγη_ {（2）}）= 0.385（45）$ kev。通过假设$ \ mathrm {u_a（1）} $异常和味道单链式混合角$θ= -24.5^\ circ $，物理$η$和$最j/ψ$辐射衰减的生产率为1.15美元10^{ - 3} $，与实验测量数据非常吻合。我们的研究表明了晶格QCD研究对$ j/ψ$辐射衰变的潜力。
The large radiative production rate for pseudoscalar mesons in the $J/ψ$ radiative decay remains elusive. We present the first lattice QCD calculation of partial decay width of $J/ψ$ radiatively decaying into $η_{(2)}$, the $\mathrm{SU(2)}$ flavor singlet pseudoscalar meson, which confirms QCD $\mathrm{U_A(1)}$ anomaly enhancement to the coupling of gluons with flavor singlet pseudoscalar mesons. The lattice simulation is carried out using $N_f=2$ lattice QCD gauge configurations at the pion mass $m_π \approx 350$ MeV. In particular, the distillation method has been utilized to calculate light quark loops. The results are reported here with the mass $m_{η_{(2)}}= 718(8)$ MeV and the decay width $Γ(J/ψ\toγη_{(2)})=0.385(45)$ keV. By assuming the dominance of $\mathrm{U_A(1)}$ anomaly and flavor singlet-octet mixing angle $θ=-24.5^\circ$, the production rates for the physical $η$ and $η'$ in $J/ψ$ radiative decay are predicted to be $1.15(14)\times 10^{-3}$ and $4.49(53)\times 10^{-3}$, respectively, which agree well with the experimental measurement data. Our study manifests the potential of lattice QCD studies on the light hadron production in $J/ψ$ radiative decays.
