Search for the $��^{+}$ pentaquark via the $��^-p\to K^-X$ reaction at 1.92 GeV/$c$
説明
The $��^+$ pentaquark baryon was searched for via the $��^-p\to K^-X$ reaction in a missing-mass resolution of 1.4 MeV/$c^2$(FWHM) at J-PARC. $��^-$ meson beams were incident on the liquid hydrogen target with the beam momentum of 1.92 GeV/$c$. No peak structure corresponding to the $��^+$ mass was observed. The upper limit of the production cross section averaged over the scattering angle of 2$^{\circ}$ to 15$^{\circ}$ in the laboratory frame was obtained to be 0.26 $��$b/sr in the mass region of 1.51$-$1.55 GeV/$c^2$.The upper limit of the $��^+$ decay width using the effective Lagrangian approach was obtained to be 0.72 MeV/$c^2$ and 3.1 MeV/$c^2$ for $J^P_��=1/2^+$ and $J^P_��=1/2^-$, respectively.
5 pages, 3 figures, 1 table