Θ⁺ baryon, N^* (1685) resonance, and πN sigma term in the context of the LEPS and DIANA experiments

2012/04/25 by Ghil-Seok Yang, Yang, Ghil-Seok, Hyun-Chul Kim +1
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th) #hep-ex #hep-ph #nucl-th

paper · pdf · doi:10.48550/arxiv.1204.5644

10 pages. 5 figures

arxiv created 2012/04/25 · arxiv updated 2012/04/26

Abstract

We reexamine properties of the baryon antidecuplet Θ⁺ and N^*, and the πN sigma term within the framework of a chiral soliton model, focusing on their dependence on the Θ⁺ mass. It turns out that the measured value of the N^* mass, M_N^*=1686 MeV, is consistent with that of the Θ⁺ mass M_Θ⁺=1524 MeV by the LEPS collaboration. The N^*→ Nγ magnetic transition moments are almost independent of the Θ⁺ mass. The ratio of the radiative decay width Γ_nn^* to Γ_pp^* turns out to be around 5. The decay width for Θ⁺→ NK is studied in the context of the LEPS and DIANA experiments. When the LEPS value of the Θ⁺ mass is employed, we obtain Γ_ΘNK =(0.5±0.1) MeV. The πN sigma term is found to be almost independent of the Θ⁺ mass. In addition, we derive a new expression for the πN sigma term in terms of the isospin mass splittings of the hyperon octet as well as that of the antidecuplet N^*.

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