Evidence of the Θ^+ in the γd \to K^+K^-pn reaction

Abstract

The γd \to K^+K^-pn reaction has been studied to search for the evidence of the Θ^+ by detecting K^+K^- pairs at forward angles. The Fermi-motion corrected nK^+ invariant mass distribution shows a narrow peak at 1.524 +- 0.002 + 0.003 GeV/c^2. The statistical significance of the peak calculated from a shape analysis is 5.1 σ, and the differential cross-section for the γn \to K^- Θ^+ reaction is estimated to be 12 +- 2 nb/sr in the photon energy range from 2.0 GeV to 2.4 GeV in the LEPS angular range by assuming the isotropic production of the Θ^+ in the γn center-of-mass system. The obtained results support the existence of the Θ^+.

31 pages, 16 figures, and 1 table. Submitted to Phys. Rev. C

References in corpus (6)

• Further evidence for formation of a narrow baryon resonance with positive strangeness in K+ collisions with Xe nuclei
• Forward coherent $\varphi$-meson photoproduction from deuterons near threshold
• Search for Theta+ via pi- p --> K- X reaction near production threshold
• Improved study of a possible Theta+ production in the pp -> p K0 sigma+ reaction with the COSY-TOF spectrometer
• Theta+ formation in inclusive gamma D -> pK- X
• K*-couplings for the antidecuplet excitation

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