17,401 research outputs found
New baryons discovered by LHCb as the members of and states
Inspired by the newly observed 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., ,
, , , and
, could be grouped into the states with negative parity.
Among them, the and states could be the
candidates, while and are
suggested as the states. could be regarded as a
state. Since the the spin-parity, the electromagnetic transitions,
and the possible hadronic decay channels have not been
measured yet, other explanations are also probable for these narrow
states. Additionally, we discuss the possibility of the broad
structure as a state with or .
In our scheme, cannot be a candidate.Comment: 10 pages, 3 figures, 5 tables, typos corrected. Published in Phys.
Rev.
Hamilton cycles in almost distance-hereditary graphs
Let be a graph on vertices. A graph is almost
distance-hereditary if each connected induced subgraph of has the
property for any pair of vertices .
A graph is called 1-heavy (2-heavy) if at least one (two) of the end
vertices of each induced subgraph of isomorphic to (a claw) has
(have) degree at least , and called claw-heavy if each claw of has a
pair of end vertices with degree sum at least . 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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