In the $B^+\to D^+ D^-K^+$ decay, LHCb has reported the observation of the open-charm exotic states $X_{0,1}^0\equiv X_{0,1}(2900)^0$ with four different quark flavors~$(ud\bar s \bar c)$, where the subscripts (0,1) denote the spins. To confirm the discovery, we propose $Λ_b\to Σ_c^{0(++)} X_{0,1}^{\prime\,0(--)}$ in the final state interaction, where $X_{0,1}^{\prime\,0(--)}$ with $s u\bar d \bar c$ ($ds\bar u \bar c$) are the new $X_{0,1}$-like exotic states. More specifically, $Λ_c^+D_s^-$ in $Λ_b\to Λ_c^+D_s^-$ are transformed as $Σ_c^{0(++)} X_{0,1}^{\prime\,0(--)}$, by exchanging $π^{+(-)}$. As the order of magnitude estimates, we calculate ${\cal B}(Λ_b\to Σ_c^{0(++)} X_{0,1}^{\prime\,0(--)}) =(2.3\pm 0.6,4.3\pm 0.8^{+3.3}_{-2.5})\times 10^{-4}$. In addition, we estimate other $b$-baryon decays with the $X_{0,1}$-like states, such as ${\cal B}(Ξ_{b}^{0(-)}\to Ξ_{c}^{0(+)}(2645)X_{0}^{\prime\,0(--)}, Λ_{b}\to Ξ_{c}^{\prime\,0}X_{0,1}^{0})\sim 10^{-5}$. While one needs $Λ_b\to Σ_c^{0(++)}M_c M$ to observe $X_{0,1}^{\prime\,0(--)}\to M_c M$ with $M_c M=D_s^-π^+$, $\bar D^0 \bar K^0$ $(D_s^-π^-$, $D^-K^-)$, ${\cal B}(Λ_b\to Σ_c^{0(++)} X_{0,1}^{\prime\,0(--)}, X_{0,1}^{\prime\,0(--)}\to M_c M)\sim 10^{-4}$ are accessible to the LHCb experiment.
We predict several new exotic doubly-heavy hadronic resonances, inferring from the observed exotic bottomonium-like and charmonium-like narrow states $X(3872)$, $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$, and $Z_c(4020/4025)$. We interpret the binding mechanism as mostly molecular-like isospin-exchange attraction between two heavy-light mesons in a relative S-wave state. We then generalize it to other systems containing two heavy hadrons which can couple through isospin exchange. The new predicted states include resonances in meson-meson, meson-baryon, baryon-baryon, and baryon-antibaryon channel…
We point out that the new exotic resonances recently reported by LHCb in the $J/ψp$ channel are excellent candidates for photoproduction off a proton target. This test is crucial to confirming the resonant nature of such states, as opposed to their being kinematical effects. We specialize to an interpretation of the heavier narrow state as a molecule composed of $Σ_c$ and $\bar D^*$, and estimate its production cross section using vector dominance. The relevant photon energies and fluxes are well within the capabilities of the GlueX and CLAS12 detectors at Thomas Jefferson National Accelerator…
The heavy quarks $c$ and $b$ stabilize exotic meson $(qq\bar q \bar q)$ and baryon $(qqqq \bar q)$ states. We discuss work with M. Karliner on molecules containing $c \bar c$ and $b \bar b$; the first doubly charmed baryon; isospin splittings; $Ξ_{cc}^+ = ccd$ and $Ω_{cc} = ccs$ masses; lifetimes; tetraquarks stable under strong and electromagnetic decay; excited $Ω_{c}$ states; and P-wave excitation energies.
In the large $N_c$ limit both heavy and light baryons are described by the universal mean field, which allows us to relate the properties of heavy baryons to light ones. With the only input from the decays of light octet baryons (due to the universality of the chiral mean field), excellent description of strong decays of both charm and bottom sextets is obtained. The parameter-free prediction for the widths of exotic anti-decapentaplet ($\overline{\boldsymbol{15}}$) baryons is also made. The exotic heavy baryons should be anomalously narrow despite of large phase space available. In particular…
The infinite chain of transitions of one pair of mesons (channel I) into another pair of mesons (channel II) can produce bound states and resonances in both channels even if no interactions inside channels exist. These resonances which can occur also in meson-baryon channels are called channel-coupling (CC) resonances. A new mechanism of CC resonances is proposed where transitions occur due to a rearrangement of confining strings inside each channel -- the recoupling mechanism. The amplitude of this recoupling mechanism is expressed via overlap integrals of the wave functions of participating …
The significantly screened heavy-quark potential in hot medium provides the possibility to study exotic quantum states of three-heavy-quark systems. By solving the Schrödinger equation for a three-charm-quark system at finite temperature, we found that, there exist Borromean states which might be realized in high energy nuclear collisions, and the binding energies of the system satisfy precisely the scaling law for Efimov states in the resonance limit.
We employ the chiral quark-soliton model to describe excited baryons with one heavy quark. Identifying known charmed baryons with multiplets allowed by the model, we argue that apart from regular excitations of the ground state multiplets, some of recently reported by the LHCb collaboration narrow $Ω^{0}_{c}$ states, may correspond to the exotic pentaquarks. This interpretation can be easily verified experimentally, since exotic $Ω^{0}_{c}$ states -- contrary to the regular excitations -- form isospin triplets, rather than singlets.
We cautiously review the treatment of pentaquark exotic baryons in chiral soliton models. We consider two examples and argue that any consistent and self-contained description must go beyond the mean field approximation that only considers the classical soliton and the canonical quantization of its (would-be) zero modes via collective coordinates.
On some properties of Exotic Baryons in Quasi particle diquark model
The properties of the Theta^{+} and Xi^{--}_{3/2} exotic baryons have been investigated in the framework of diquark- diquark-antiquark system. A model for diquark suggested in an analogy with the quasi-particle in a crystal lattice has been used. The mass of the exotics have been computed. The Decay width of the Theta^{+} has been estimated to be ~ 11 MeV using effective diquark theory. The radius of the Xi^{--}_{3/2} has been extracted as 0.94fm using the experimental value of the frac{Γ_{Θ^{+}}}{Γ_{Ξ^{--}_{3/2}}}. The results obtained are found to be in good agreement with the present experi…
In this work we study the possible QCD exotic states in the doubly charmed baryon sector. Within chiral effective theory, it is predicted that several excited baryons result from the $S$-wave scattering of ground-state doubly charmed baryons ($Ξ_{cc}^{++}, Ξ_{cc}^{+}, Ω_{cc}^{+}$) and light pseudoscalar mesons ($π, K, η$). The excited doubly charmed baryons can be classified by the strangeness ($S$) and isospin ($I$) quantum numbers. Two of the excited states are clearly exotic, in the sense that they cannot be explained by the conventional baryons with three quarks, since their quantum number…
