Magnetic and quadrupole moments of the $Z_c(3900)$

Understand

The electromagnetic properties of the tetraquark state $Z_c(3900)$ are investigated in the diquark-antidiquark picture and its magnetic and quadrupole moments are extracted.

• To this end, the light-cone QCD sum rule in electromagnetic background field is used.
• The magnetic and quadrupole moments encode the spatial distributions of the charge and magnetization in the particle.
• The result obtained for the magnetic moment is quite large and can be measured in future experiments.