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Since few years, a new family of exotic states has been appearing above the open-heavy meson thresholds: the so-called $XYZ$ states. BESIII at the BEPCII $e^+e^-$ collider plays a unique role in the study of those particles in the charmonium sector. Changing the beam energy, BESIII can collect large data samples by means of scans of the resonant region, accessing directly to all vector states. As part of a larger upgrade program, BESIII has planned to increase the center of mass energy to reach $4.7$ GeV: this will allow BESIII to investigate the nature of the $Y(4660)$, that was at first observed by Belle and BaBar after Initial State Radiation only in $pipi psi(2s)$ and $Lambda_c$ $bar{Lambda}_c$ final states. The relative branching ratio seems to point toward a baryonium interpretation of the resonance, as expected in Rossi-Veneziano model. BESIII can directly measure the cross sections around the expected peak position and verify this prediction. In this presentation, the status of the $XYZ$ searches at BESIII will be presented, with a focus also on the plans for the newest data taking and for the $Y(4660)$ studies.
At present very large data samples in the energy region of 2.0-4.6 GeV were accumulated by the BESIII detector, which is operated in the upgraded Beijing electron positron collider (BEPCII). These data samples provide an unprecedented opportunity in
The standard model of particle physics is a well-tested theoretical framework, but there are still a number of issues that deserve further experimental and theoretical investigation. For quark physics, such questions include: the nature of quark conf
The search for multi-quark states beyond the constituent quark model (CQM) has resulted in the discovery of many new exotic states, starting with the observation of the X(3872), discovered by Belle in 2003. Also in the sector of charm-strange physics
There has recently been a dramatic renewal of interest in the subjects of hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like $XYZ$ states at BESIII and $B$ factories, and
The BESIII experiment in Beijing takes data in $tau$-charm domain since 2009. For the moment the world largest samples of $J/psi$, $psi(3686)$, $psi(3770)$ and $psi(4040)$ data have been collected. Hadron spectroscopy is a unique way to access QCD, w