On leptonic width of $X(4260)$


Abstract in English

New measurements on cross sections in $e^+e^-to J/psipi^+pi^-$, $h_cpi^+pi^-$, $D^0D^{*-}pi^++c.c.$, $psi(2S)pi^+pi^-$, $omegachi_{c0}$ and $J/psieta$ channels have been carried out by BESIII, Belle and BABAR collaborations, and also in the $D_s^*bar D_s^*$ channel. We perform extensive numerical analyses by combining all these data available, together with those in $Dbar D^*$ and $D^*bar D^*$ channels. Though the latter show no evident peak around $sqrt{s}=4.230$ GeV, the missing $X(4260)$ is explained as that it is concealed by the interference effects of the well established charmonia $psi(4040)$, $psi(4160)$ and $psi(4415)$. Our analyses reveal that the leptonic decay width of $X(4260)$ ranges from $O(10^2)$ eV to $O(1)$ keV, and hence may be explained in the conventional quark model picture. That is, the $X(4260)$ may well be interpreted as a mixture of $4^3S_1$ and $3^3D_1$ states.

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