Traces of the new resonance in the reaction

Luciano M. Abreu; Wen-Fei Wang; Eulogio Oset

doi:10.1140/epjc/s10052-023-11384-3

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2023) 83: 243
https://doi.org/10.1140/epjc/s10052-023-11384-3

Regular Article - Theoretical Physics

Traces of the new $a_{0} (1780)$ resonance in the $J / ψ \to ϕ K^{+} K^{-} (K^{0} {\bar{K}}^{0})$ $J/\psi \rightarrow \phi K^+K^-(K^0\bar{K}^0)$ reaction

Luciano M. Abreu¹^,2, Wen-Fei Wang²^,3^b and Eulogio Oset²

¹ Instituto de Física, Universidade Federal da Bahia, Campus Universitário de Ondina, 40170-115, Bahia, Brazil
² Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de Paterna, Aptdo. 22085, 46071, Valencia, Spain
³ Institute of Theoretical Physics, Shanxi University, 030006, Taiyuan, Shanxi, China

^b wfwang@ific.uv.es

Received: 26 January 2023
Accepted: 3 March 2023
Published online: 22 March 2023

Abstract

We study the $J / ψ \to ϕ K \bar{K}$ $J/\psi \rightarrow \phi K \bar{K}$ decay, looking for differences in the production rates of $K^{+} K^{-}$ $$K^+ K^-$$ or $K^{0} {\bar{K}}^{0}$ $K^0 \bar{K}^0$ in the region of 1700–1800 MeV, where two resonances appear dynamically generated from the vector-vector interaction. Two resonances are known experimentally in that region, the $f_{0} (1710)$ $$f_0(1710)$$ and a new resonance reported by the BABAR and BESIII collaborations. The $K \bar{K}$ $K \bar{K}$ should be produced with $I = 0$ $$I=0$$ in that reaction, but due to the different $K^{* 0}$ $K^{*0}$ and $K^{* +}$ $K^{*+}$ masses some isospin violation appears. Yet, due to the large width of the $K^{*}$ $$K^*$$ , the violation obtained is very small and the rates of $K^{+} K^{-}$ $$K^+ K^-$$ or $K^{0} {\bar{K}}^{0}$ $K^0 \bar{K}^0$ production are equal within $5 %$ $5\%$ . However, we also find that due to the step needed to convert two vectors into $K \bar{K}$ $K \bar{K}$ , a shape can appear in the $K \bar{K}$ $K \bar{K}$ mass distribution that can mimic the $a_{0}$ $$a_0$$ production around the $K^{*} {\bar{K}}^{*}$ $K^* \bar{K}^*$ threshold, and is simply a threshold effect.

© The Author(s) 2023

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