Continuum bound states K-long, D_{1}(2420), D_{s1}(2536) and their partners K-short, D_{1}(2400), D_{sJ}(2463)

• Published in: arXiv.org 2003-07
• Main Authors: Eef van Beveren, Rupp, George
• Format: Article
• Language: English
• Subjects: Admixtures; Coupling
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0306051

The very recently observed \(D^{\ast}_{sJ}(2463)\) meson is described as a \(J^{P}=1^{+}\) \(c\bar{s}\) bound state in a unitarised meson model, owing its existence to the strong OZI-allowed \(^{3}P_{0}\) coupling to the nearby \(S\)-wave \(D^{\ast}K\) threshold. By the same non-perturbative mechanism, the narrow axial-vector \(D_{s1}(2536)\) resonance shows up as a quasi-bound-state partner embedded in the \(D^{\ast}K\) continuum. With the same model and parameters, it is also shown that the preliminary broad \(1^{+}\) \(D_{1}(2400)\) resonance and the established narrow \(1^{+}\) \(D_{1}(2420)\) may be similar \(c\bar{n}\) partners, as a result of the strong OZI-allowed \(^{3}P_{0}\) coupling to the nearby \(S\)-wave \(D^{\ast}\pi\) threshold. The continuum bound states \(D_{1}\)(2420) and \(D_{s1}(2536)\) are found to be mixtures of 33% \(^{3}P_{1}\) and 67% \(^{1}P_{1}\), whereas their partners \(D_{1}(2400)\) and \(D^{\ast}_{sJ}(2463)\) have more or less the opposite \(^{2S+1}P_1\)-state content, but additionally with some \(D^{\ast}\pi\) or \(D^{\ast}K\) admixture, respectively. The employed mechanism also reproduces the ratio of the \(K_{L}\)-\(K_{S}\) mass difference and the \(K_{S}\) width, by describing \(K_{L}\) as a bound state embedded in the \(\pi\pi\) continuum. The model's results for \(J^{P}=1^{+}\) states containing one \(b\) quark are also discussed.