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Register a new userOn tetraquarks with hidden charm and strangeness as phi-psi(2S) hadrocharmonium
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In the hadrocharmonium picture a $bar cc$ state and a light hadron form a bound state. The effective interaction is described in terms of the chromoelectric polarizability of the $bar cc$ state and energy-momentum-tensor densities of the light hadron. This picture is justified in the heavy quark limit, and may successfully account for a hidden-charm pentaquark state recently observed by LHCb. In this work we extend the formalism to the description of hidden-charm tetraquarks, and address the question of whether the resonant states observed by LHCb in the $J/psi$-$phi$ spectrum can be described as hadrocharmonia. This is a non-trivial question because nothing is known about the $phi$ meson energy-momentum-tensor densities. With rather general assumptions about energy-momentum-tensor densities in the $phi$-meson we show that a $psi(2S)$-$phi$ bound state can exist, and obtain a characteristic relation between its mass and width. We show that the tetraquark $X(4274)$ observed by LHCb in $J/psi$-$phi$ spectrum is a good candidate for a hadrocharmonium. We make predictions which will allow testing this picture. Our method can be generalized to identify other potential hadrocharmonia.
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We study the $P_{cs}(4459)^0$ recently observed by LHCb using the method of QCD sum rules. Our results support its interpretation as the $bar D^* Xi_c$ hadronic molecular state of either $J^P=1/2^-$ or $3/2^-$. Within the hadronic molecular picture, the three LHCb experiments observing $P_c$ and $P_{cs}$ states cite{lhcb,Aaij:2015tga,Aaij:2019vzc} can be well understood as a whole. This strongly supports the existence of hadronic molecules, whose studies can significantly improve our understanding on the construction of the subatomic world. To verify this picture, we propose to further investigate the $P_{cs}(4459)^0$ to examine whether it can be separated into two states, and to search for the $bar D Xi_c$ molecular state of $J^P=1/2^-$.
With the spin rearrangement, we have performed a comprehensive investigation of the decay patterns of the S-wave tetraquarks and P-wave tetraquarks where the P-wave excitation exists either between the diquark and anti-diquark pair or inside the diquark. Especially, we compare the decay patterns of $Y(4260)$ with different inner structures such as the conventional charmonium, the molecule, the P-wave tetraquark and the hybrid charmonium. We notice the $J/psi pipi$ mode is suppressed in the heavy quark symmetry limit if $Y(4260)$ is a molecular state. Moreover the hybrid charmonium and hidden-charm tetraquark have very similar decay patterns. Both of them decay into the $J/psi pipi$ and open charm modes easily. We also discuss the decay patterns of $X(3872)$, $Y(4360)$, and several charged states such as $Z_c(4020)$. The $h_cpi^{pm}$ decay mode disfavors the tetraquark assumption of $Z_c(4020)$.
Motivated by the recent discovery of the first hidden charm pentaquark state with strangeness $P_{cs}(4459)$ by the LHCb Collaboration, we study the likely existence of a three-body $Sigma_{c}bar{D}bar{K}$ bound state, which shares the same minimal quark content as $P_{cs}(4459)$. The $Sigma_{c}bar{D}$ and $DK$ interactions are determined by reproducing $P_c(4312)$ and $D_{s0}^*(2317)$ as $Sigma_cbar{D}$ and $bar{D}bar{K}$ molecules, respectively, while the $Sigma_cbar{K}$ interaction is constrained by chiral effective theory. We indeed find a three-body bound state by solving the Schrodinger equation using the Gaussian Expansion Method, which can be viewed as an excited hidden charm pentaquark state with strangeness, $P_{cs}^*(4739)$, with $I(J^P)=1(1/2^+)$ and a binding energy of $77.8^{+25}_{-10.3}$ MeV. We further study its strong decays via triangle diagrams and show that its partial decay widths into $DXi_c$ and $D_s^*Sigma_c$ are of a few tens MeV, with the former being dominant.
In this study, we investigate the discovery potential of double-charm tetraquarks $T^{{cc}}_{[bar{q}bar{q}]}$. We find that their production cross sections at the LHCb with $sqrt{s} = 13$ TeV reach $mathcal{O}(10^4)$ pb, which indicates that the LHCb has collected $mathcal{O}(10^8)$ such particles. Through the decay channels of $T^{{cc}}_{[bar{u}bar{d}]}to D^{+}K^{-}pi^{+}$ or $D^0D^+gamma$ (if stable) or $T^{{cc}}_{[bar{u}bar{d}]}to D^0D^{*+}to D^0D^0pi^+$ (if unstable), it is highly expected that they get discovered at the LHCb in the near future. We also discuss the productions and decays of the double-charm tetraquarks at future Tera-$Z$ factories.
We investigate the decay mechanism in the B^- -> phi phi K^- decay with the phi phi invariant mass below the charm threshold and in the neighborhood of the eta_c invariant mass region. Our approach is based on the use of factorization model and the knowledge of matrix elements of the weak currents. For the B meson weak transition we apply form factor formalism, while for the light mesons we use effective weak and strong Lagrangians. We find that the dominant contributions to the branching ratio come from the eta, eta and eta(1490) pole terms of the penguin operators in the decay chains B^- -> eta (eta, eta(1490)) K^- -> phi phi K^-. Our prediction for the branching ratio is in agreement with the Belles result.
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