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Recently a novel hadronic state of mass 6.9 GeV, that decays mainly to a pair of charmonia, was observed in LHCb. The data also reveals a broader structure centered around 6490 MeV and suggests another unconfirmed resonance centered at around 7240 MeV, very near to the threshold of two doubly charmed $Xi_{cc}$ baryons. We argue in this note that these exotic hadrons are genuine tetraquarks and not molecules of charmonia. It is conjectured that they are V-baryonium tetraquarks, namely, have an inner structure of a baryonic vertex with a $cc$ diquark attached to it, which is connected by a string to an anti-baryonic vertex with a $bar c bar c$ anti-diquark. We examine these states as the analogs of the states $Psi(4360)$ and $Y(4630)$/$Psi(4660)$ which are charmonium-like tetraquarks. One way to test these claims is by searching for a significant decay of the state at 7.2 GeV into $Xi_{cc}overlineXi_{cc}$. Such a decay would be the analog of the decay of the state $Y(4630)$ into to $Lambda_coverlineLambda_c$. We further argue that there should be trajectories of both orbital and radial excited states of the $X(6900)$. We predict their masses. It is possible that a few of these states have already been seen by LHCb.
We propose an {it{ab initio}} method to explore the nature of the newly discovered particle $X$(6900). We find that there should exist another state near the resonance at around 6.9 $mathrm{GeV}$, and the ratio of production cross sections of $X$(690
We present the ground and excited state spectra of $Omega^{0}_{c}$ baryons with spin up to 7/2 from lattice quantum chromodynamics with dynamical quark fields. Based on our lattice results, we predict the quantum numbers of five $Omega^{0}_{c}$ baryo
In recent years, hints for multi-lepton anomalies have been accumulated by the analysis of Large Hadron Collider (LHC) data, pointing towards the existence of beyond the Standard Model (SM) Higgs bosons: a new scalar particle $S$ with a mass $m_S$ in
Inspired by the recent observation of $chi_{c0}(3930)$, $X(4685)$ and $X(4630)$ by the LHCb Collaboration and some exotic resonances such as $X(4350)$, $X(4500)$, etc. by several experiment collaborations, the $csbar{c}bar{s}$ tetraquark systems with
The past seventeen years have witnessed tremendous progress on the experimental and theoretical explorations of the multiquark states. The hidden-charm and hidden-bottom multiquark systems were reviewed extensively in [Phys. Rept. 639 (2016) 1-121].