A study of the resonances $K_0^{\ast }(800)$ and $K_0^{\ast }(1430)$

Abstract

We study the scalar kaonic states $K_0^{\ast }(800)$ and $K_0^{\ast }(1430)$ by using a relativistic QFT Lagrangian in which only a single kaonic field corresponding to the well-established scalar state $K_0^{\ast }(1430)$ is considered and in which both derivative and non-derivative interaction terms are taken into account. Even if the scalar spectral function shows a unique peak close to $1.4$ GeV, we find two poles in the complex plane: $1.413\pm 0.002-i(0.127\pm 0.003)$ GeV, which is related to the seed quark-antiquark state $K_0^{\ast }(1430),$ and $0.746\pm 0.019-i(262\pm 0.014)$ GeV, which is an additional companion pole related to $K_0^{\ast }(800)$. As a further investigation for increasing $N_c$ confirms, $K_0^{\ast }(800)$ emerges as a dynamically generated four-quark object as a consequence of pion-kaon loops.

Comments: Based on the presentation given at FAIRNESS 2016, Workshop for young scientists with research interests focused on physics at FAIR, 14-19 February 2016, Garmisch-Partenkirchen, Germany. 5 pages, 5 figures