17,511 research outputs found

    New Ωc0\Omega_c^0 baryons discovered by LHCb as the members of 1P1P and 2S2S states

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    Inspired by the newly observed Ωc0\Omega_c^0 states at LHCb, we decode their properties by performing an analysis of mass spectrum and decay behavior. Our studies show that the five narrow states, i.e., Ωc(3000)0\Omega_c(3000)^0, Ωc(3050)0\Omega_c(3050)^0, Ωc(3066)0\Omega_c(3066)^0, Ωc(3090)0\Omega_c(3090)^0, and Ωc(3119)0\Omega_c(3119)^0, could be grouped into the 1P1P states with negative parity. Among them, the Ωc(3000)0\Omega_c(3000)^0 and Ωc(3090)0\Omega_c(3090)^0 states could be the JP=1/2−J^P=1/2^- candidates, while Ωc(3050)0\Omega_c(3050)^0 and Ωc(3119)0\Omega_c(3119)^0 are suggested as the JP=3/2−J^P=3/2^- states. Ωc(3066)0\Omega_c(3066)^0 could be regarded as a JP=5/2−J^P=5/2^- state. Since the the spin-parity, the electromagnetic transitions, and the possible hadronic decay channels Ωc(∗)π\Omega_c^{(\ast)}\pi have not been measured yet, other explanations are also probable for these narrow Ωc0\Omega_c^0 states. Additionally, we discuss the possibility of the broad structure Ωc(3188)0\Omega_c(3188)^0 as a 2S2S state with JP=1/2+J^P=1/2^+ or JP=3/2+J^P=3/2^+. In our scheme, Ωc(3119)0\Omega_c(3119)^0 cannot be a 2S2S candidate.Comment: 10 pages, 3 figures, 5 tables, typos corrected. Published in Phys. Rev.

    Hamilton cycles in almost distance-hereditary graphs

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    Let GG be a graph on n≥3n\geq 3 vertices. A graph GG is almost distance-hereditary if each connected induced subgraph HH of GG has the property dH(x,y)≤dG(x,y)+1d_{H}(x,y)\leq d_{G}(x,y)+1 for any pair of vertices x,y∈V(H)x,y\in V(H). A graph GG is called 1-heavy (2-heavy) if at least one (two) of the end vertices of each induced subgraph of GG isomorphic to K1,3K_{1,3} (a claw) has (have) degree at least n/2n/2, and called claw-heavy if each claw of GG has a pair of end vertices with degree sum at least nn. Thus every 2-heavy graph is claw-heavy. In this paper we prove the following two results: (1) Every 2-connected, claw-heavy and almost distance-hereditary graph is Hamiltonian. (2) Every 3-connected, 1-heavy and almost distance-hereditary graph is Hamiltonian. In particular, the first result improves a previous theorem of Feng and Guo. Both results are sharp in some sense.Comment: 14 pages; 1 figure; a new theorem is adde
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