Search for the $$\Theta^+$$ pentaquark in the reaction $$\gamma d \to p K^- K^+ n$$
A search for the {Theta}{sup +} in the reaction {gamma}d {yields} pK{sup -} K{sup +} n was completed using the CLAS detector at Jefferson Lab. An earlier publication of the same reaction by the CLAS Collaboration, with lower statistics, reported the observation of a narrow resonance, identified as the {Theta}{sup +} pentaquark. The present experiment, with more than 30 times the integrated luminosity of our earlier measurement, does not show any evidence for a narrow pentaquark resonance. The upper limit on {Theta}{sup +} production in the mass range of 1.52 to 1.56 GeV/c{sup 2} for the {gamma}d {yields} pK{sup -}{Theta}{sup +} reaction is less than 0.3 nb (95% confidence level), and less than 0.6 nb over the mass range 1.48 to 1.70 GeV/c{sup 2}. Using {Lambda}(1520) production as an empirical measure of rescattering in the deuteron, the cross section upper limit for the elementary {gamma}n {yields} K{sup -}{Theta}{sup +} reaction is estimated to be a factor of 10 higher.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE - Office of Energy Research (ER)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 878472
- Report Number(s):
- JLAB-PHY-06-459; DOE/ER/40150-3830; hep-ex/0603028; TRN: US0602389
- Country of Publication:
- United States
- Language:
- English
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