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Milena Soltysiak

Publications and source records attributed to Milena Soltysiak.

4 recordsLinked to original sources
arXiv2016

A covariant nonlocal Lagrangian for the description of the scalar kaonic sector

Mesons are extended objects, hence their interaction can be described by utilizing form factors. At the Lagrangian level, one can use nonlocal interaction terms. Here we describe two possible nonlocal Lagrangians leading to a 3D form factor: the first one is simple but does not fulfill covariance (if one insists on a 3D cutoff), the second extension is more involved but guarantees covariance. Such form factors are useful when calculating mesonic loops. As an important example, we discuss the scalar kaonic sector, $I(J^{P})=\frac{1}{2}(0^{+})$. The Lagrangian contains a single scalar kaon (the well-establish state $K_{0}^{\ast}(1430)$), but through loops $K_{0}^{\ast}(800)$ emerges as a dynamically generated companion pole (which disappears in the large-$N_{c}$ limit).

hep-ph↗
arXiv2016

$K_{0}^{\ast}(800)$ as a companion pole of $K_{0}^{\ast}(1430)$

We study the light scalar sector up to $1.8$ GeV by using a quantum field theoretical approach which includes a single kaonic state in a Lagrangian with both derivative and non-derivative interactions. By performing a fit to $πK$ phase shift data in the $I=1/2,$ $J=0$ channel, we show that $K_{0}^{\ast}(800)$ (or $κ$) emerges as a dynamically generated companion pole of $K_{0}^{\ast }(1430)$. This is a result of investigating quantum fluctuations with one kaon and one pion circulating in the loops dressing $K_{0}^{\ast}(1430)$. We determine the position of the poles on the complex plane in the context of our approach: for $K_{0}^{\ast}(1430)$ we get $(1.413\pm0.002)-i{0.02cm}(0.127\pm0.003)$ (in GeV), while for $κ$ we get $(0.746\pm0.019)-i{0.02cm}(0.262\pm0.014)$ (in GeV). The model-dependence of these results and related uncertainties are discussed in the paper. A large-$N_{c}$ study confirms that $K_{0}^{\ast}(1430)$ is predominantly a quarkonium and that $K_{0}^{\ast}(800)$ is a molecular-like dynamically generated state.

hep-ph↗
arXiv2016

A study of the resonances $K_{0}^{*}(800)$ and $K_{0}^{*}(1430)$

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: $1.413\pm0.002-i(0.127\pm0.003)$ GeV, which is related to the seed quark-antiquark state $K_{0}^{\ast}(1430),$ and $0.746\pm0.019-i(262\pm0.014)$ 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.

hep-ph↗
arXiv2016

Large-$N_{c}$ pole trajectories of the vector kaon $K^{\ast}(892) $ and of the scalar kaons $K_{0}^{\ast}(800)$ and $K_{0}^{\ast}(1430)$

We study the spectral functions, the poles and their trajectories for increasing $N_{c}$ of the vector kaon state $K^{\ast}(892),$ characterized by $I(J^{P})=\frac{1}{2}(1^{-})$, and of the scalar kaons $K_{0}^{\ast}(800)$ and $K_{0}^{\ast}(1430),$ characterized by $I(J^{P})=\frac{1}{2}(0^{+})$. To this end, we use relativistic QFT's Lagrangians with both derivative and non-derivative terms. In the vector kaonic sector the spectral function is well approximated by a Breit-Wigner function: there is one single peak and, correspondingly, a single pole in the complex plane. On the contrary, in the scalar sector, although the Lagrangian contains only one scalar kaonic field, we find two poles, one corresponding to a standard quark-antiquark ,,seed\textquotedblright\ state $K_{0}^{\ast}(1430),$ and one to a \textquotedblleft companion\textquotedblright\ dynamically generate pole $K_{0}^{\ast}(800)$. The latter does not correspond to any peak in the scalar kaonic spectral function, but only to an enhancement in the low-energy regime.

hep-ph↗