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تسجيل مستخدم جديدResonant parameters of the $Y(4220)$
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The vector charmoniumlike state $Y(4220)$ was reported recently in the cross sections of $e^+e^-to omega chi_{c0}$, $pi^+pi^-h_c$, $pi^+pi^- J/psi$, and $D^0 D^{*-}pi^+ + c.c.$ measured by the BESIII experiment. A combined fit is performed to the cross sections of these four final states to extract the resonant parameters of the $Y(4220)$. We determine a mass $M=(4219.6pm 3.3pm 5.1)$~MeV/$c^2$ and a total width $Gamma=(56.0pm 3.6pm 6.9)$~MeV for the $Y(4220)$, where the first uncertainties are statistical and the second ones systematic. Assuming the $Y(4220)$ decays dominantly to the above four modes and their isospin symmetric modes, we also estimate its leptonic decay width and decay branching fractions. These information is essential for the understanding of the nature of this state.
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Many vector charmonium-like states have been reported recently in the cross sections of $e^+e^- rightarrow omegachi_{c0}$, $pi^{+}pi^{-}h_c$, $pi^{+}pi^{-}J/psi$, $pi^{+}pi^{-}psi(3686)$ and $pi^{+}D^{0}D^{*-}+c.c.$ To better understand the nature of
these states, a combined fit is performed to these cross sections by using three resonances $Y(4220)$, $Y(4390)$ and $Y(4660)$. The resonant parameters for the three resonances are obtained. We emphasize that two resonances $Y(4220)$ and $Y(4390)$ are sufficient to explain these cross sections below 4.6 GeV. The lower limits of $Y(4220)$ and $Y(4390)$s leptonic decay widths are also determined to be $(36.4pm2.0pm4.2)$ and $(123.8pm6.5pm9.0)$ eV.
The cross sections of the process $e^{+}e^{-} to eta J/psi$ at center-of-mass energies ($sqrt{s}$) between 3.81 and 4.60 GeV are measured with high precision by using data samples collected with the BESIII detector operating at the BEPCII storage rin
g. Three structures are observed by analyzing the lineshape of the measured cross sections, and a maximum-likelihood fit including three resonances is performed by assuming the lowest lying structure is the $psi(4040)$. For the other resonances, we obtain masses of $(4218.7 pm 4.0 pm 2.5)$ and $(4380.4 pm 14.2 pm 1.8)$ MeV/c$^{2}$ with corresponding widths of $(82.5 pm 5.9 pm 0.5)$ and $(147.0 pm 63.0 pm 25.8)$ MeV, respectively, where the first uncertainties are statistical and the second ones systematic. The measured resonant parameters are consistent with those of the $Y(4220)$ and $Y(4360)$ from pr evious measurements of different final states. For the first time, we observe the decays of the $Y(4220)$ and $Y(4360)$ into $eta J/psi$ final states.
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