A search for narrow Θ+(1540), a candidate for a pentaquark baryon with positive strangeness, has been performed in an exclusive proton-induced reaction \(p + C(N) \to \Theta ^ + \bar \kappa ^0 + C(N)\) on carbon nuclei or quasifree nucleons at \(E_{beam} = 70GeV(\sqrt s = 11.5GeV)\) studying nK+, pKS0, and pKL0 decay channels of Θ+(1540) in four different final states of the \(\Theta ^ + \bar K^0 \) system. In order to assess the quality of the identification of the final states with neutron or KL0, we reconstructed Λ(1520) → nKS0 and ϕ → KL0KS0 decays in the calibration reactions p + C(N) → Λ (1520)K++C(N) and p+C(N) → pϕ+C(N). We found no evidence for a narrow pentaquark peak in any of the studied final states and decay channels. Assuming that the production characteristics of the \(\Theta ^ + \bar K^0 \) system are not drastically different from those of the Λ(1520)K+ and pϕ systems, we established upper limits on the cross-section ratios \(\sigma (\Theta ^ + \bar K^0 )/\sigma (\Lambda (1520)K^ + ) < 0.02\) and \(\sigma (\Theta ^ + \bar K^0 )/\sigma (p\phi ) < 0.15\) at 90% C.L. and a preliminary upper limit for the forward-hemisphere cross section \(\sigma (\Theta ^ + \bar K^0 )\) nb/nucleon.