Strange hidden-charm tetraquarks in constituent quark model

In the framework of the chiral quark model (ChQM), we systematically investigate the strange hidden-charm tetraquark systems $$cs{\bar{c}}{\bar{u}}$$ c s c ¯ u ¯ with two structures: $$q{\bar{q}}-q{\bar{q}}$$ q q ¯ - q q ¯ and $$qq-{\bar{q}}{\bar{q}}$$ q q - q ¯ q ¯ . The bound-state calculation shows that there is no any bound state in present work, which excludes the molecular state explanation ($$D^{0}D_{s}^{*-}/D^{*0}D_{s}^{-}/D^{*0}D_{s}^{*-}$$ D 0 D s ∗ - / D ∗ 0 D s - / D ∗ 0 D s ∗ - ) of the reported $$Z_{cs}(3985)^{-}$$ Z cs ( 3985 ) - or $$Z_{cs}(4000)^{+}$$ Z cs ( 4000 ) + . However, the effective potentials for the $$cs-{\bar{c}}{\bar{u}}$$ c s - c ¯ u ¯ systems show the possibility of some resonance states. By applying a stabilization calculation and coupling all channels of both two structures, two new resonance states are obtained, which are the $$IJ^{P}=\frac{1}{2} 0^{+}$$ I J P = 1 2 0 + state with the energy around 4111–4116 MeV and the $$IJ^{P} =\frac{1}{2} 1^{+}$$ I J P = 1 2 1 + state with energy around 4113–4119 MeV, respectively. Both of them are worthy of search in future experiments. Our results show that the coupling calculation between the bound channels and open channels is indispensable to provide the necessary information for experiments to search for exotic hadron states.

BESIII future prospects in exotic hadron spectroscopy

Recent BESIII results on exotic hadron candidates, the heavy charmonium-like states, will be reviewed, as well as a short introductions to the BEPCII collider and the BEESIII detector. Future BESIII running plans, specially the physics program for the exotic hadron spectroscopy, will be discussed.

Tomography and gravitational radii for hadrons by three-dimensional structure functions

Three-dimensional tomography of hadrons can be investigated by generalized parton distributions (GPDs), transverse-momentum-dependent parton distributions (TMDs), and generalized distribution amplitudes (GDAs). The GDA studies had been only theoretical for a long time because there was no experimental measurement until recently, whereas the GPDs and TMDs have been investigated extensively by deeply vir- tual Compton scattering and semi-inclusive deep inelastic scattering. Here, we report our studies to determine pion GDAs from recent KEKB measurements on the differen- tial cross section of γ*γ → π0π0. Since an exotic-hadron pair can be produced in the final state, the GDAs can be used also for probing internal structure of exotic hadron candidates in future. The other important feature of the GDAs is that the GDAs contain information on form factors of the energy-momentum tensor for quarks and gluons, so that gravitational form factors and radii can be calculated from the determined GDAs. We show the mass (energy) and the mechanical (pressure, shear force) form factors and radii for the pion. Our analysis should be the first attempt for obtaining gravitational form factors and radii of hadrons by analysis of actual experimental measurements. We believe that a new field of gravitational physics is created from the microscopic level in terms of elementary quarks and gluons.

Light exotic hadrons at BESIII

We review the recent results for the light exotic hadron states, which are obtained using the data recorded with the BESIII detector at the BEPCII e+e- collider in Beijing, China.