分类: 物理学 >> 核物理学 提交时间: 2016-09-14
摘要: We propose to study the pentaquark candidates of P+c(4380) and P+c(4450) in J/ψ photoproduction and look for further experimental evidence for their nature. Since the photoproduction process does not satisfy the so-called "anomalous triangle singularity" condition their presence in J/ψ photoproduction would conclude that they should be genuine states and provide further evidence for their existence.
分类: 物理学 >> 核物理学 提交时间: 2016-09-14
摘要: We find that several thresholds can contribute to the enhancements of the newly observed heavy pentaquark candidates P+c(4380) and P+c(4450) via the anomalous triangle singularity (ATS) transitions in the specific kinematics of Λb→J/ψK−p. 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 Σ(∗)c can be produced at leading order in Λb 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.