Near-threshold Lambda(1520) production by the gamma p -> K+Lambda(1520) reaction at forward K+ angles

TL;DR

This study measures differential cross sections and asymmetries for gamma p -> K+ Lambda(1520) reactions, revealing a new bump at W=2.11 GeV that challenges existing theoretical models and suggests possible new resonance or interference effects.

Contribution

First measurement of photon-beam asymmetries and cross sections for this reaction at energies up to 2.4 GeV, discovering a new bump structure not explained by current models.

Findings

Discovery of a bump at W=2.11 GeV in cross sections.

The bump is not reproduced by models with J<=3/2 resonances.

Indicates possible higher-spin resonance or interference effects.

Abstract

Differential cross sections and photon-beam asymmetries for the gamma p -> K+ Lambda(1520) reaction have been measured with linearly polarized photon beams at energies from the threshold to 2.4 GeV at 0.6<cos(theta)<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<=3/2. This result suggests that the bump might be produced by a nucleon resonance possibly with J>=5/2 or by a new reaction process, for example an interference effect with the phi photoproduction having a similar bump structure in the cross sections.