English

Decay of the $\Lambda(1405)$ Hyperon to $\Sigma^0\pi^0$ Measured at GlueX

Nuclear Experiment 2022-11-30 v1 High Energy Physics - Experiment High Energy Physics - Phenomenology

Abstract

Among the light baryons, the Jπ=12J^\pi = \frac{1}{2}^- Λ(1405)\Lambda(1405) hyperon is an important special case as it sits just below the NKˉN\bar{K} threshold and decays almost exclusively to Σπ\Sigma\pi. Some long-standing hypotheses for Λ(1405)\Lambda(1405) are that it could be a NKˉN\bar{K} bound state or a Σπ\Sigma\pi continuum resonance. It may also be considered as a simple quark-model resonance, the PP-wave companion of the Λ(1520)\Lambda(1520). In recent years chiral unitary models have suggested that there are two isospin zero poles present in this mass region, and that the "line shape" of the Λ(1405)\Lambda(1405) depends to what extent each of the two poles are stimulated in a given reaction. Below the NKˉN\bar{K} threshold, the Λ(1405)\Lambda(1405) decays to the three Σπ\Sigma\pi charge combinations. The Σ0π0\Sigma^{0}\pi^{0} mode is purely I=0I=0 and it is uncontaminated by complications arising from I=1I=1 scattering processes contributing to the reaction mechanism in the Σ+π\Sigma^{+}\pi^{-} and Σπ+\Sigma^{-}\pi^{+} decays. It is also not affected from production and decay of the nearby Σ0(1385)\Sigma^{0}(1385) hyperon. The GlueX experiment at Jefferson Lab has been used to study the Λ(1405)Σ0π0\Lambda(1405) \to \Sigma^{0}\pi^{0} decay mode. We focus on the preliminary results of dσ/dMΣ0π0d\sigma/dM_{\Sigma^{0}\pi^{0}} and fits to the line shape of the Λ(1405)\Lambda(1405) region in the (ttmin)-(t-t_{min}) range 0 - 1.5 GeV2^2 from analyzing the reaction γpK+Λ\gamma p \to K^{+}\Lambda^* using the data collected during the first phase of the GlueX program.

Keywords

Cite

@article{arxiv.2209.06230,
  title  = {Decay of the $\Lambda(1405)$ Hyperon to $\Sigma^0\pi^0$ Measured at GlueX},
  author = {Nilanga Wickramaarachchi and Reinhard A. Schumacher and Grzegorz Kalicy},
  journal= {arXiv preprint arXiv:2209.06230},
  year   = {2022}
}

Comments

6 pages, 4 figures, Proceedings of the 14th International Conference on Hypernuclear and Strange Particle Physics (HYP2022), 27 June to 1 July 2022