The possible existence of a ($ s\bar s$) S = 0 meson at M $\approx$ 762 MeV is discussed through a critical analysis of the existing data. Different experimental results are considered and show the possibility that the presence of such meson is not excluded by the data, but may be hidden by more excited mesons at nearby masses.
Study of the neutrino-oxygen cross sections of the charged-current reaction 16O($\barν_e,e^+$)16N(0 MeV,$2^-$) and the neutral-current reaction 16O($ν,ν$')16O(12.97/12.53 MeV,$2^-$), producing high-energy gamma rays
Several compact $sssc\bar c$ pentaquark resonances are predicted in a potential quark model. The Hamiltonian is the best available one, which reproduces the masses of the low-lying charmed and strange hadrons well. Full five-body calculations are carried out by the use of the Gaussian expansion method, and the relevant baryon-meson thresholds are taken into account explicitly. Employing the real scaling method, we predict four sharp resonances, $J^P=1/2^-$ ($E=5180$ MeV, $Γ=20$ MeV), $5/2^-$ (5645 MeV, 30 MeV), $5/2^-$ (5670 MeV, 50 MeV), and $1/2^+$ (5360 MeV, 80 MeV). These are the candidate…
We calculate the masses of the $QQ\bar{q}\bar{q}$ ($Q=c,b$; $q=u,d,s$) tetraquark states with the aid of heavy diquark-antiquark symmetry (HDAS) and the chromomagnetic interaction (CMI) model. The masses of the highest-spin ($J=2$) tetraquarks that have only the $(QQ)_{\bar{3}_c}(\bar{q}\bar{q})_{3_c}$ color structure are related with those of conventional hadrons using HDAS. Thereafter, the masses of their partner states are determined with the mass splittings in the CMI model. Our numerical results reveal that: (i) the lightest $cc\bar{n}\bar{n}$ ($n=u,d$) is an $I(J^P)=0(1^+)$ state around …
The three-body $ηK^*\bar{K}^*$, $πK^*\bar{K}^*$ and $KK^*\bar{K}^*$ systems are investigated within the framework of fixed-center approximation to the Faddeev equations, where $K^*\bar{K}^*$ is treated as the scalar meson $f_0(1710)$. The interactions between $π$, $η$, $K$ and $K^*$ are taking from the chiral unitary approach. By scattering the $η$ meson on the clusterized $(K^*\bar{K}^*)_{f_0(1710)}$ system, we find a peak in the modulus squared of the three-body scattering amplitude and it can be associated as a bound state with quantum numbers $I^G(J^{PC})=0^+(0^{-+})$. Its mass and width a…
We investigate the $η\bar{K}K^*$ three body system in order to look for possible $I^G(J^{PC})=0^+(1^{-+})$ exotic states in the framework of the fixed center approximation to the Faddeev equation. We assume the scattering of $η$ on a clusterized system $\bar{K}K^*$, which is known to generate the $f_1(1285)$, or a $\bar{K}$ on a clusterized system $ηK^*$, which is shown to generate the $K_1(1270)$. In the case of the $η$-$(\bar{K}K^*)_{f_1(1285)}$ scattering, we find evidence of a bound state $I^G(J^{PC})=0^+(1^{-+})$ below the $η{f_1(1285)}$ threshold with mass around 1700 MeV and width about…
We investigate a doubly-bottomed tetraquark state $T_{bb}$ $(bb \bar{u}\bar{d})$ with quantum number $I(J^P)=0(1^+)$ in $(2+1)$-flavor lattice QCD. Using the Non-Relativistic QCD (NRQCD) quark action for $b$ quarks, we have extracted the coupled channel potential between $\bar{B}\bar{B}^*$ and $\bar{B}^* \bar{B}^*$ in the HAL QCD method at $a \approx 0.09$ {fm} on $32^3\times 64$ lattices. The potential predicts an existence of a bound $T_{bb}$ below the $\bar{B}\bar{B}^*$ threshold. At the physical pion mass $m_π\approx140$ {MeV} extrapolated from $m_π\approx 410,\, 570,\, 700$ {MeV}, a bindi…
New calculations of the quasi-bound state positions in $K^{-}K^{-}pp$ kaonic nuclear cluster are performed using non-relativistic four-body Faddeev-type equations in AGS form. The corresponding separable approximation for the integral kernels in the three- and four-body kaonic clusters is obtained by using the Hilbert-Schmidt expansion procedure. Different phenomenological models of $\bar{K}N-πΣ$ potentials with one- and two-pole structure of $Λ$(1405) resonance and separable potential models for $\bar{K}$-$\bar{K}$ and nucleon-nucleon interactions, are used. The dependence of the resulting fo…
In the molecular picture the hidden-charm, pentaquark-like $P_c(4450)$ resonance is a $\bar{D}^* Σ_c$ bound state with quantum numbers $I=\tfrac{1}{2}$ and $J^P = \tfrac{3}{2}^-$. If this happens to be the case, it will be natural to expect the existence of $\bar{D}^* \bar{D}^* Σ_c$ three-body bound states. The most probable quantum numbers for a bound $\bar{D}^* \bar{D}^* Σ_c$ trimer are the isoscalar $J^P = \tfrac{1}{2}^+$, $\tfrac{5}{2}^+$ and the isovector $J^P = \tfrac{3}{2}^+$, $\tfrac{5}{2}^+$ configurations. Calculations within a contact-range theory indicate a trimer binding energy $B…
In this presentation we discuss the generation of hadrons with an exotic quark content and hidden charm emerging from three-body interactions. To be more specific, we have studied the $KD\bar{D}^*/K\bar D D^*$ and $ND\bar{D}^*/N\bar{D}D^*$ systems and predicted states generated from the respective three-body dynamics. In the case of the $KD\bar{D}^*/K\bar D D^*$ system we predict the formation of a meson state with mass around $4307$ MeV and quantum numbers $I(J^P) = 1/2(1^-)$, $K^*(4307)$, and from the study of the $ND\bar{D}^*/N\bar{D}D^*$ system we found $N^*$ states with masses in the rang…
Motivated by the recent finding of five $Ω_c$ states by the LHCb collaboration, and the successful reproduction of three of them in a recent approach searching for molecular states of meson-baryon with the quantum numbers of $Ω_c$, we extend these ideas and make predictions for the interaction of meson-baryon in the beauty sector, searching for poles in the scattering matrix that correspond to physical states. We find several $Ω_b$ states: two states with masses 6405~MeV and 6465~MeV for $J^P= \frac{1}{2}^-$; two more states with masses 6427~MeV and 6665~MeV for $\frac{3}{2}^-$; and three stat…
Invoked by the recent observation of $Y(4390)$ at BESIII, which is about 40 MeV below the $D^*(2010)\bar{D}_1(2420)$ threshold, we investigate possible bound and resonance states from the $D^*(2010)\bar{D}_1(2420)$ interaction with the one-boson-exchange model in a quasipotential Bethe-Salpeter equation approach. A bound state with quantum number $0^-(1^{--})$ is produced at 4384 MeV from the $D^ (2010)\bar{D}_1(2420)$ interaction, which can be related to experimentally observed $Y(4390)$. Another state with quantum number $1^+(1^{+})$ is also produced at $4461+i39$ MeV from this interaction. …
In this work, we calculate meson-baryon scattering phase shifts in four channels using lattice QCD methods. From a set of calculations at four volumes, corresponding to spatial sizes of 2, 2.5, 3, and 4 fm, and a pion mass of m_pi ~ 390 MeV, we determine the scattering lengths and effective ranges for these systems at the corresponding quark masses. We also perform the calculation at a lighter quark mass, m_pi ~ 230 MeV, on the largest volume. Using these determinations, along with those in previous work, we perform a chiral extrapolation of the scattering lengths to the physical point after c…
In this work we extend our formalism to study meson-baryon interactions by including $s$- and $u$-channel diagrams for pseudoscalar-baryon systems. We study the coupled systems with strangeness $-1$ and focus on studying the isospin-1 resonance(s), especially in the energy region around 1400 MeV. By constraining the model parameters to fit the cross section data available on several processes involving relevant channels, we find resonances in the isoscalar as well as the isovector sector in the energy region around 1400 MeV.
In this talk we discuss the formation of exotic hadrons with hidden charm arising from three-body interactions. To be more specific, in the strangeness sector, we predict the existence of a mesonic state, $K^*(4307)$, which is dynamically generated from the three-body interactions of the $KD\bar{D}^*$ system, has mass around $4307$ MeV and quantum numbers $I(J^P) = 1/2\,(1^-)$. In the baryonic sector, we predict the existence of $N^*$ states, which are generated from the three-body interactions of the $ND\bar{D}^*$ system, with masses around $4400\sim 4600$ MeV, widths of $2\sim 20$ MeV and po…
Recently the Belle collaboration has discovered a narrow $S=-3$ baryon, the $Ω(2012)$. We explore the possibility that the $Ω(2012)$ is a $Ξ(1530)\,\bar K$ molecule, where the binding mechanism is the coupled channel dynamics with the $Ω\,η$ channel. The characteristic signature of a molecular $Ω(2012)$ will be its decay into the three body channel $Ξπ\bar{K}$, for which we expect a partial decay width of $2-3\,{\rm MeV}$. The partial decay width into the $Ξ\bar{K}$ channel should lie in the range of $1-11\,{\rm MeV}$, a figure compatible with experiment and which we have deduced from the assu…
