Have Pentaquark States Been Seen?
نویسنده
چکیده
The status of the search for pentaquark baryon states is reviewed in light of new results from the first two dedicated experiments from CLAS at Jefferson Lab and of new analyses from several labs on the Θ + (1540). Evidence for and against the heavier pentaquark states, the Ξ(1862) and the Θ 0 c (3100) observed at CERN and at HERA, respectively, are also discussed. I conclude that the evidence against the latter two heavier pentaquark baryons is rapidly increasing making their existence highly questionable. I also conclude that the evidence for the Θ + state has significantly eroded with the recent CLAS results, but still leaves room for a state with an intrinsic width of Γ < 0.5 MeV. New evidence in support of a low mass pentaquark state from various experiments will be discussed as well.
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