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Register a new userObservation of five new narrow $Omega_c^0$ states decaying to $Xi_c^+ K^-$
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The $Xi_c^+ K^-$ mass spectrum is studied with a sample of $pp$ collision data corresponding to an integrated luminosity of 3.3 fb$^{-1}$, collected by the LHCb experiment. The $Xi_c^+$ is reconstructed in the decay mode $p K^- pi^+$. Five new, narrow excited $Omega_c^0$ states are observed: the $Omega_c(3000)^0$, $Omega_c(3050)^0$, $Omega_c(3066)^0$, $Omega_c(3090)^0$, and $Omega_c(3119)^0$. Measurements of their masses and widths are reported.
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The $Lambda_c^+K^-$ mass spectrum is studied with a data sample of $pp$ collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 5.6 fb$^{-1}$ collected by the LHCb experiment. Three $Xi_c^0$ states are observed with a large significance and their masses and natural widths are measured to be begin{eqnarray*} m(Xi_c(2923)^0)&=& 2923.04 pm 0.25 pm 0.20 pm 0.14 ~mathrm{MeV}, Gamma(Xi_c(2923)^0) &=& 7.1 pm 0.8 pm 1.8 ~mathrm{MeV}, end{eqnarray*} begin{eqnarray*} m(Xi_c(2939)^0) &=& 2938.55 pm 0.21 pm 0.17 pm 0.14 ~mathrm{ MeV}, Gamma(Xi_c(2939)^0) &=& 10.2 pm 0.8 pm 1.1 ~mathrm{ MeV}, end{eqnarray*} begin{eqnarray*} m(Xi_c(2965)^0) &=& 2964.88 pm 0.26 pm 0.14 pm 0.14~mathrm{ MeV}, Gamma(Xi_c(2965)^0) &=& 14.1 pm 0.9 pm 1.3~mathrm{ MeV}, end{eqnarray*} where the uncertainties are statistical, systematic, and due to the limited knowledge of the $Lambda_c^+$ mass. The $Xi_c(2923)^0$ and $Xi_c(2939)^0$ baryons are new states. The $Xi_c(2965)^0$ state is in the vicinity of the known $Xi_c(2970)^0$ baryon; however, their masses and natural widths differ significantly.
The first observation of the $Omega_b^-toXi_c^+ K^- pi^-$ decay is reported using proton-proton collision data at centre-of-mass energies of $7$, $8$ and $13,mathrm{TeV}$ collected by the LHCb experiment, corresponding to an integrated luminosity of $9,mathrm{fb}^{-1}$. Four excited $Omega_c^0$ baryons are observed in the $Xi_c^+ K^-$ mass projection of the $Omega_b^-toXi_c^+ K^- pi^-$ decays with significance exceeding five standard deviations. Their relative production rates, masses and natural widths are measured, and a test of spin hypotheses is performed. Moreover, the branching ratio of $Omega_b^-toXi_c^+ K^- pi^-$ is measured relative to the $Omega_b^-to Omega_c^0 pi^-$ decay mode and a precise measurement of the $Omega_b^-$ mass of $6044.3 pm 1.2 pm 1.1^{,+0.19}_{,-0.22},mathrm{MeV}$ is obtained.
Using a data sample of 980 ${rm fb}^{-1}$ of $e^+e^-$ annihilation data taken with the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider, we report the results of a study of excited $Xi_c$ states that decay, via the emission of photons and/or charged pions, into $Xi_c^0$ or $Xi_c^+$ ground state charmed-strange baryons. We present new measurements of the masses of all members of the $Xi_c^{prime}$, $Xi_c(2645)$, $Xi_c(2790)$, $Xi_c(2815)$, and $Xi_c(2980)$ isodoublets, measurements of the intrinsic widths of those that decay strongly, and evidence of previously unknown transitions.
Using 13.7 fb^{-1} of data recorded by the CLEO detector at CESR, we report preliminary evidence for two new charmed baryons; one decaying into Xi_c^{0prime} pi^+ with the subsequent decay Xi_c^{0prime} to Xi_c^0 gamma, and its isospin partner decaying into Xi_c^{+prime} pi^- followed by Xi_c^{+prime} to Xi_c^+ gamma. We measure the following mass differences for the two states: M(Xi_c^0 gamma pi^+)-M(Xi_c^0)=318.4+-1.5+-2.9 MeV, and M(Xi_c^+ gamma pi^-)-M(Xi_c^+)=323.9+-pm1.4+-pm3.0 MeV. We interpret these new states as the J^P = (1/2)^-1 Xi_{c1} particles, the charmed-strange analogues of the Lambda_{c1}^+(2593).
We study the weak decay $Omega_b^- to (Xi_c^+ , K^-) , pi^-$, in view of the narrow $Omega_c$ states recently measured by the LHCb collaboration and later confirmed by the Belle collaboration. The $Omega_c(3050)$ and $Omega_c(3090)$ are described as meson-baryon molecular states, using an extension of the local hidden gauge approach in coupled channels. We investigate the $Xi D$, $Xi_c bar K$ and $Xi_c^prime bar K$ invariant mass distributions making predictions that could be confronted with future experiments, providing useful information that could help determine the quantum numbers and nature of these states.
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