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تسجيل مستخدم جديدSearch for $eta$ and $eta^primeto pi^+ e^- bar{ u}_e +c.c.$ decays in $jpsi to phi eta$ and $phi eta^prime$
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Using a sample of 225.3 million $jpsi$ events collected with the BESIII detector at the BEPCII $e^+e^-$ collider in 2009, searches for the decays of $eta$ and $eta^primetopi^+ e^- bar{ u}_e +c.c.$ in $jpsi to phi eta$ and $phieta^prime$ are performed. The $phi$ signals, which are reconstructed in $K^+K^-$ final states, are used to tag $eta$ and $eta^prime$ semileptonic decays. No signals are observed for either $eta$ or $eta^prime$, and upper limits at the 90% confidence level are determined to be $7.3times 10^{-4}$ and $5.0times 10^{-4}$ for the ratios $frac{{mathcal B}(etato pi^+ e^- bar{ u}_e +c.c.)}{{mathcal B}(eta to pippimpiz)}$ and $frac{{mathcal B}(eta^primeto pi^+ e^-bar{ u}_e +c.c.)}{{mathcal B}(eta^prime to pippimeta)}$, respectively. These are the first upper limit values determined for $eta$ and $eta^prime$ semileptonic weak decays.
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