Search for Θ+(1540) Pentaquark in High-Statistics Measurement of γp→K¯¯¯0K+n at CLAS

The exclusive reaction γp → K ̅ ⁰ K ⁺ n was studied in the photon energy range between 1.6 and 3.8 GeV searching for evidence of the exotic baryon Θ ⁺ (1540)→ nK ⁺ . The decay to nK ⁺ requires the assignment of strangeness S =+1 to any observed resonance. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility corresponding to an integrated luminosity of 70  pb ^-1 . No evidence for the Θ ⁺ pentaquark was found. Upper limits were set on the production cross section as function of center-of-mass angle and nK ⁺ mass. The 95% C.L. upper limit on the total cross section for a narrow resonance at 1540 MeV was found to be 0.8 nb.