Related papers: Composite nature of the $T_{cc}$ state
We use a near-threshold parameterization with explicit inclusion of the Castillejo-Dalitz-Dyson poles, which is more general than the effective range expansion, to study the bottomonium-like states $Z_b(10610)$ and $Z_b(10650)$. In terms of…
A coupled channel analysis of the $D^{\ast+}D^0$ and $D^{\ast0}D^+$ system is performed to study the doubly charmed $T_{cc}^+$ state recently discovered by the LHCb collaboration. We use a simple model for the scattering amplitude that…
We introduce two basic concepts: the compositeness for resonance and the Castillejo-Dalitz-Dyson (CDD) pole. Applying them to hadron states $X(3872)$, $Z_b(10610)$ and $Z_b(10650)$, and $T_{cc}$, we obtain their compositeness values and…
An exotic narrow state in the $D^0D^0\pi^+$ mass spectrum just below the $D^{*+}D^0$ mass threshold is studied using a data set corresponding to an integrated luminosity of 9 fb$^{-1}$ acquired with the LHCb detector in proton-proton…
A coupled-channel approach is applied to the charged tetraquark state $T_{cc}^+$ recently discovered by the LHCb Collaboration. The parameters of the interaction are fixed by a fit to the observed line shape in the three-body $D^0D^0\pi^+$…
In this paper we study the scattering amplitudes of $D^{0}D^{0}\pi^+$-$D^{*+}D^{0}$ coupled channels based on $K$-matrix within the Chew-Mandelstam formalism. The $D^{0}D^{0}\pi^{+}$ invariant mass spectrum of LHCb is fitted and the pole…
Recently LHCb experimental group find an exotic state $T^+_{cc}$ from the process $p\bar{p} \to D^0D^0\pi^+ + X$. A key question is if it is just a molecule or may have confined tetraquark ingredient. To investigate this, different methods…
Very recently, the LHCb Collaboration reported the doubly charmed tetraquark state $T_{cc}^+$ below the $D^{*+}D^0$ threshold about $273$ keV. As a very near-threshold state, its long-distance structure is very important. In the molecular…
A central question in exotic-hadron physics is their internal structure whether these states are loosely bound hadronic molecules or compact multiquark configurations. To shed light on this issue, we develop a model that incorporates mixing…
The internal structure of the near-threshold exotic hadrons, $T_{cc}$ and $X(3872)$, are studied by respecting the decay and coupled-channel contributions. The effective field theory model is introduced to calculate the compositeness, the…
We perform a fit to the LHCb data on the $T_{cc}(3875)$ state in order to determine its nature. We use a general framework that allows to have the $D^0 D^{*+}$, $D^+ D^{*0}$ components forming a molecular state, as well as a possible…
We discuss a model-independent estimator of the likelihood of the compositeness of a shallow S-wave bound or virtual state. The approach is based on an extension of Weinberg's relations in Phys. Rev. 137, B672 (1965) and it relies only on…
The isospin breaking effect plays an essential role in generating hadronic molecular states with a very tiny binding energy. Very recently, the LHCb Collaboration observed a very narrow doubly charmed tetraquark $T_{cc}^+$ in the…
The LHCb Collaboration announced in 2021 the discovery of a new tetraquark-like state, named $T_{cc}^+$, with minimum quark content $cc\bar u\bar d$, close to the $D^0D^{*+}$ threshold. This has motivated countless theoretical works trying…
The first determination of doubly-charmed isospin-0 coupled-channel $DD^\ast-D^\ast D^\ast$ scattering amplitudes from lattice QCD is presented. The finite-volume spectrum is computed for three lattice volumes with a light-quark mass…
Based on a coupled-channel approach, we investigate the structures of four $P_c$ states through compositeness criteria. Toward a more precise description of the states, we have obtained refined fit results of the LHCb data on the $J/\psi p$…
We study the compositeness of near-threshold states to clarify the internal structure of exotic hadron candidates. Within the framework of effective field theory, we extend the Weinberg's weak-binding relation to include the nearby CDD…
The LHCb Collaboration discovered a double-charm tetraquark $T_{cc}^{+}$ with a very small width. We investigate the $T_{cc}^{+}$ as a $DD^{*}$ molecule with $J^{P}=1^{+}$ in the framework of the one-boson-exchange potential model. The…
We perform a unitary coupled channel study of the interaction of the $D^{*+} D^0, D^{*0} D^+$ channels and find a state barely bound, very close to isospin $I=0$. We take the experimental mass as input and obtain the width of the state and…
Starting from the hypothesis that the $T_{cc}^+$ discovered at LHCb is a $D^{\ast+} D^0/D^{\ast 0}D^+$ hadronic molecule, we consider the partial width of its heavy quark spin partner, the $T_{cc}^{\ast +}$ as a $D^{\ast +} D^{\ast 0}$…