3,997 research outputs found
How to understand the underlying structures of , , and
We investigate the possible rescattering effects which may contribute to the
process . It is shown that the
rescattering via the open-charmed meson loops, and
rescattering via the loops may simulate the structures of
and , respectively. However, if the quantum numbers of
() are (), it is hard to to ascribe the
observation of and to the -wave threshold rescattering
effects, which implies that and could be genuine
resonances. We also suggest that may be the conventional orbitally
excited state .Comment: 14 pages, 5 figures, 1 tabl
Investigating possible decay modes of under the molecular state ansatz
By assuming that is a molecular state, we investigate
some hidden-charm and charmed pair decay channels of via intermediate
meson loops with an effective Lagrangian approach. Through
investigating the -dependence of branching ratios and ratios between
different decay channels, we show that the intermediate meson
loops are crucial for driving these transitions of studied here. The
coupled channel effects turn out to be more important in , which can be tested in the future experiments.Comment: 8 pages, 6 figures; The width effects of Y(4260) considered; Revised
version accepted by Phys. Rev.
Searching for observable effects induced by anomalous triangle singularities
We investigate the anomalous triangle singularity (ATS) and its possible
manifestations in various processes. We show that the ATS should have important
impact on our understanding of the nature of some newly observed threshold
states. Discussions on how to distinguish the ATS phenomena from genuine
dynamic pole structures are presented.Comment: 13 pages, 5 figures, 1 table, version to appear in Phys. Lett.
Understanding the newly observed heavy pentaquark candidates
We find that several thresholds can contribute to the enhancements of the
newly observed heavy pentaquark candidates and via
the anomalous triangle singularity (ATS) transitions in the specific kinematics
of . Apart from the observed two peaks we find that
another peaks around 4.5 GeV can also be produced by the ATS. We also show that
the can be produced at leading order in decay.
This process is different from the triangle diagram and its threshold
enhancement only appears as CUSP effects if there is no pole structure or the
ATS involved. The threshold interaction associated with the presence of the ATS
turns out to be a general phenomenon and plays a crucial role in the
understanding of candidates for exotic states.Comment: 9 pages, 6 figures, 4 tables; published version in PL
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