Further evidence for formation of a narrow baryon resonance with positive strangeness in K+ collisions with Xe nuclei

Abstract

We have continued our investigation of the charge-exchange reaction K^+ Xe --> K^0 p Xe' in the bubble chamber DIANA. In agreement with our previous results based on part of the present statistics, formation of a narrow p K^0 resonance with mass of 1537+-2 MeV/c^2 is observed in the elementary transition K^+ n --> K^0 p on a neutron bound in the Xenon nucleus. Visible width of the peak is consistent with being entirely due to instrumental resolution and allows to place an upper limit on its intrinsic width: Γ< 9 MeV/c^2. A more precise estimate of the resonance intrinsic width, Γ= 0.36+-0.11 MeV/c^2, is obtained from the ratio between the numbers of resonant and non-resonant charge-exchange events. The signal is observed in a restricted interval of incident K^+ momentum, that is consistent with smearing of a narrow p K^0 resonance by Fermi motion of the target neutron. Statistical significance of the signal is some 7.3, 5.3, and 4.3 standard deviations for the estimators S/sqrt{B}, S/sqrt{S+B}, and S/sqrt{S+2B}, respectively. This observation confirms and reinforces our earlier results, and offers strong evidence for formation of a pentaquark baryon with positive strangeness in the charge-exchange reaction K^+ n --> K^0 p on a bound neutron.

13 pages, 8 figures, some chenges in text and references, more precise estimate of Theta(1540) to add, submitted to Phys.Atom.Nucl(Yad.Fiz.)

Cited by in corpus (16)

• Evidence of the Θ^+ in the γd \to K^+K^-pn reaction
• Improved study of a possible Theta+ production in the pp -> p K0 sigma+ reaction with the COSY-TOF spectrometer
• Experimental Review on Pentaquarks
• New Narrow Nucleon N*(1685)
• Present status on experimental search for pentaquarks
• High-resolution search for the ${\Theta }^{+}$ pentaquark via a pion-induced reaction at J-PARC
• An explanation why the Theta+ is seen in some experiments and not in others
• Axial-vector transitions and strong decays of the baryon antidecuplet in the self-consistent SU(3) chiral quark-soliton model
• Vector transition form factors of the $N{K}^{\ast }\to {\Theta }^{+}$ and $N{\bar{K}}^{\ast }\to {\Sigma }_{\overline{10}}^{\ast -}$ in the SU(3) chiral quark-soliton model
• Quark spin content of the proton, hyperon semileptonic decays, and the decay width of the ${\Theta }^{+}$ pentaquark
• To see the exotic Theta^+ baryon from interference
• Exotic baryons in two-dimensional QCD and the generalized sine-Gordon solitons
• K*-couplings for the antidecuplet excitation
• SU(6), Triquark states, and the pentaquark
• Vector and axial-vector structures of the Theta^+
• Photoproduction of Theta^+(1540,1/2^+) reexamined with new theoretical information