Related papers: Composite nature of the $T_{cc}$ state
The recently discovered $T_{cc}^+$ is evaluated as a $DD^*$ molecular structure in the $J^P=1^+$ sector. A coupled-channels calculation in charged basis, considering the $D^0D^{*\,+}$, $D^+D^{*\,0}$ and $D^{*\,0}D^{*\,+}$ channels, is done…
We study the $J/\psi \pi$ and $D\bar{D}^*$ coupled-channel system within a covariant framework. The $J/\psi \pi$ and $D\bar{D}^*$ invariant-mass distributions measured at 4.23~GeV and 4.26~GeV by BESIII and the finite-volume energy levels…
Motivated by the first observation of the double-charm tetraquark $T_{cc}^+(3875)$ by the LHCb Collaboration, we investigate the nature of $T_{cc}^+$ as an isoscalar $DD^*$ hadronic molecule in a meson-exchange potential model incorporated…
We introduce a near-threshold parameterization that is more general than the effective-range expansion up to and including the effective-range because it can also handle with a near-threshold zero in the $D^0\bar{D}^{*0}$ $S$-wave. In terms…
The $DD^*$ scattering phase shifts in the $T_{cc}^+=cc\bar{u}\bar{d}$ channel are extracted from lattice QCD for five different charm quark masses and a fixed light-quark mass corresponding to $m_\pi\simeq 280$~MeV. The phase shifts are…
We make use of a unitarized coupled-channel model to analyze the mass distribution data of final states in production processes of $X(4260)$. By analyzing the analytical structures of the decay amplitudes, we find that the line shape of…
In 2012, we investigated the possible molecular states composed of two charmed mesons [Phys.Rev. D 88, 114008 (2013), arXiv:1211.5007 [hep-ph](2012)]. The $D^*D$ system with the quantum numbers of $I(J^P)=0(1^+)$ was found to be a good…
Evaluation of the effective-range parameters for the $T_{cc}^+$ state in the LHCb model is examined. The finite width of $D^*$ leads to a shift of the expansion point into the complex plane to match analytical properties of the expanded…
The so far only known charmed non-strange scalar meson is dubbed as $D_0^*(2400)$ in the Review of Particle Physics. We show, within the framework of unitarized chiral perturbation theory, that there are in fact two $(I=1/2, J^P=0^+)$ poles…
The doubly charmed tetraquark $T^+_{cc}$ recently discovered by the LHCb Collaboration is studied on the basis of $(2+1)$-flavor lattice QCD simulations of the $D^*D$ system with nearly physical pion mass $m_\pi=146$ MeV. The interaction of…
We study the molecular probability of the $X(3872)$ in the $D^0 \bar D^{*0}$ and $D^+ D^{*-}$ channels in several scenarios. One of them assumes that the state is purely due to a genuine nonmolecular component. However, it gets unavoidably…
${T_{cc}(cc\bar{u}\bar{d})}^{+}$ has been reported by the LHCb experiment in 2022. The analysis using the Breit-Wigner parametrization found the small binding energy, $0.273$ MeV, which is measured from the threshold of $D^{*+}D^{0}$. In…
The compositeness of weakly bound states is discussed using the effective field theory from the viewpoint of the low-energy universality. We introduce a model with coupling of the single-channel scattering to the bare state, and study the…
Scattering amplitudes involving three-particle scattering processes are investigated within the isobar approximation which respects constraints from two- and three-body unitarity. The particular system considered is the…
We study the internal structure of exotic hadrons, especially focusing on the relation between the compositeness and physical observables. Defined as the probability of finding hadronic molecular components in the wave function,…
We revisit the compositeness theorem proposed by Weinberg in an effective field theory (EFT) and explore criteria which are sensitive to the structure of $S$-wave threshold states. On a general basis, we show that the wave function…
We investigate potential hadronic molecular states in the $D^{(*)}\bar D^{(*)}$ and $B^{(*)}\bar B^{*}$ systems using light meson exchange interactions. Our analysis focuses on coupled-channel systems with spin-parity quantum numbers…
This article provides a pedagogical exploration of coupled-channel scattering in hadronic physics, focusing on theoretical methodologies, and practical applications. It covers key concepts such as the $N/D$ method, Castillejo-Dalitz-Dyson…
Hadrons and their distributions are the most direct observables in experiment, which would shed light on the non-perturbative mystery of quantum chromodynamics (QCD). As the result, any new hadron will challenge our current knowlege on the…
We discuss the relation between the analytic structure of the scattering amplitude and the origin of an eigenstate represented by a pole of the amplitude.If the eigenstate is not dynamically generated by the interaction in the channel of…