Near-Threshold $\ensuremath{\Lambda}(1520)$ Production by the $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}p\ensuremath{\rightarrow}{K}^{+}\ensuremath{\Lambda}(1520)$ Reaction at Forward ${K}^{+}$ Angles

Near-Threshold $Λ (1520)$ Production by the $\vec{γ} p \to K^{+} Λ (1520)$ Reaction at Forward $K^{+}$ Angles

H. Kohri et al. (LEPS Collaboration)

Phys. Rev. Lett. 104, 172001 – Published 26 April 2010

Abstract

Differential cross sections and photon-beam asymmetries for the $\vec{γ} p \to K^{+} Λ (1520)$ reaction have been measured with linearly polarized photon beams at energies from the threshold to 2.4 GeV at $0.6 < \cos θ_{c . m .}^{K} < 1$ . A new bump structure was found at $W ≃ 2.11 GeV$ in the cross sections. The bump is not well reproduced by theoretical calculations introducing a nucleon resonance with $J \leq \frac{3}{2}$ . This result suggests that the bump might be produced by a nucleon resonance possibly with $J \geq \frac{5}{2}$ or by a new reaction process, for example, an interference effect with the $ϕ$ photoproduction having a similar bump structure in the cross sections.