Search for the pentaquark candidate Theta(1540)+ in the hyperon beam experiment WA89 (original) (raw)
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Physical Review D, 2006
We search for the charmed pentaquark candidate reported by the H1 collaboration, the c… 3100† 0, in e‡ eÿ interactions at a center-of-mass (cm) energy of 10.58 GeV, using 124 fbÿ1 of data recorded with the BABAR detector at the PEP-II e‡ eÿ facility at SLAC. We find no evidence for such a state in the same pD ÿ decay mode reported by H1, and we set limits on its production cross section times branching fraction into pD ÿ as a function of cm momentum. The corresponding limit on its total rate per e‡ eÿ! qq event, times branching ...
Search for the Θ+(1540) pentaquark using kaon secondary interactions at Belle
2006
Using kaon secondary interactions in the material of the Belle detector, we search for both inclusive and exclusive production of the Θ(1540) +. We set an upper limit of 2.5% at the 90% C.L. on the ratio of the Θ(1540) + to Λ(1520) inclusive production cross sections. We also search for the Θ(1540) + as an intermediate resonance in the charge exchange reaction K + n → pK 0 S. An upper limit of Γ Θ + < 0.64 MeV at the 90% C.L. at m Θ + = 1.539 MeV/c 2 is set. These results are obtained from a 397 fb −1 data sample collected with the Belle detector near the Υ(4S) resonance, at the KEKB asymmetric energy e + e − collider.
Study of the rare hyperon decay
Physics Letters B, 2010
We report a new measurement of the decay Ω − → Ξ − π + π − with 76 events and a first observation of the decay Ω + → Ξ + π + π − with 24 events, yielding a combined branching ratio (3.74 +0.67 −0.56) × 10 −4. This represents a factor 25 increase in statistics over the best previous measurement. No evidence is seen for CP violation, with B(Ω − → Ξ − π + π −) = 4.04 +0.83 −0.71 × 10 −4 and B(Ω + → Ξ + π + π −) = 3.15 +1.12 −0.89 × 10 −4. Contrary to theoretical expectation, we see little evidence for the decays Ω − → Ξ * 0 1530 π − and Ω + → Ξ * 0 1530 π + and place a 90% C.L. upper limit on the combined branching ratio B(Ω − (Ω +) → Ξ * 0 1530 (Ξ * 0 1530)π ∓) < 7.0 × 10 −5 .