Exotic resonant structures found in Λ0 b and B0 decays into charmonium in the LHCb experiment are discussed. Examination of the J/Ψ p system in Λ0 b→ J/ΨK-p decays shows two states each of which must be composed of uudcc quarks, and thus are called charmonium pentaquarks. Their masses are 4380 ± 8 ± 29 MeV and 4449.8 ± 1.7 ± 2.5 MeV, and their corresponding widths (Γ) are 205 ± 18 ± 86 MeV, and 39 ± 5 ± 19 MeV. The preferred JP assignments are of opposite parity, with one state having spin 3/2 and the other 5/2. Models of internal binding of the pentaquark states are discussed. Finally, another mesonic state is discussed, the Z(4430)- that decays into Ψφπ- and was first observed by the Belle collaboration in B0 → Ψ′K+π- decays. Using a sample of approximately 25,000 signal events, LHCb determines the JP to be 1+.
|Original language||English (US)|
|State||Published - 2015|
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