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Observation of new $\Omega_c^{0}$ states decaying to the $\Xi_c^+ K^-$ final state

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Abstract

Two new excited states, $\Omega_c(3185)^0$ and $\Omega_c(3327)^0$, are observed in the $\Xi_c^{+}K^{-}$ invariant-mass spectrum using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of $9 {\rm fb}^{-1}$. Five previously observed excited $\Omega_c^0$ states are confirmed, namely $\Omega_c(3000)^0$, $\Omega_c(3050)^0$, $\Omega_c(3065)^0$, $\Omega_c(3090)^0$, and $\Omega_c(3119)^0$. The masses and widths of these seven states are measured with the highest precision to date.

Figures and captions

Invariant-mass distribution of the $\Omega_c(X)^{0}$ candidates in (a) data set 1 and (b) data set 2, with the fit results overlaid. A bin width of 5 $\text{ Me V}$ is used for plotting. The previously observed excited $\Omega_c^0$ states are shown in blue dashed lines. The $\Omega_c(3185)^{0}$ state is shown in the brown area, and the $\Omega_c(3327)^{0}$ state is shown in the red area. Three feed-down components are shown as the yellow areas, while the green long-dashed line corresponds to the combinatorial background.

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Tables and captions

Fit results of the mass, width, and yield for each state, and for each data set. Uncertainties are statistical only.

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Systematic uncertainties on the measured masses and natural widths.

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Measured mass and natural width for each of the seven $\Omega_c(X)^{0}$ states. The first uncertainty is statistical and the second is systematic, the third (mass only) arises from the uncertainty of the known $\Xi_{c}^{+}$ mass.

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Created on 23 March 2024.