Search for Theta+ via pi- p --> K- X reaction near production threshold

Abstract

We have searched for ${\Theta }^{+}$ via ${\pi }^{-}p\to K^{-}X$ reaction using 1.87 and 1.92 GeV/c ${\pi }^{-}$ beam at the K2 beam line of the KEK 12 GeV Proton Synchrotron. In the missing mass spectrum at beam momentum of 1.92 GeV/$c$, a bump has been found at 1530 MeV/$c^2$ which is consistent with the mass reported by several experiments. The statistical significance of this bump, however, is only 2.5$-2.7\sigma$. Therefore we have derived the upper limit of ${\Theta }^{+}$ production cross section via ${\pi }^{-}p\to K^{-}{\Theta }^{+}$ reaction which is 4.3$\mu$b at 90% confidence level assuming that ${\Theta }^{+}$ is produced isotropically in the center of mass system.

12pages, 6figures, to be published in Physics Letters B

Cited by in corpus (9)

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• Theta+ formation in inclusive gamma D -> pK- X
• Quark spin content of the proton, hyperon semileptonic decays, and the decay width of the ${\Theta }^{+}$ pentaquark
• Electric properties of the baryon anti-decuplet in the SU(3) chiral quark-soliton model
• Positive parity pentaquark towers in large Nc QCD
• Magnetic and axial-vector transitions of the baryon antidecuplet
• Photoproduction of Theta^+(1540,1/2^+) reexamined with new theoretical information