The quark model was formulated in 1964 to classify mesons as bound states made of a
quark–antiquark pair, and baryons as bound states made of three quarks. For a long time all …

A large number of experimental discoveries especially in the heavy quarkonium sector that
did not meet the expectations of the until then very successful quark model led to a …

Multiquark resonances are undoubtedly experimentally observed. The number of states and
the amount of details on their properties have been growing over the years. It is very recent …

In the past decade many charmonium-like states were observed experimentally. Especially
those charged charmonium-like Z c states and bottomonium-like Z b states cannot be …

The last decade has seen a marked shift in how the internal structure of hadrons is
understood. Modern experimental facilities, new theoretical techniques for the continuum …

In the past two decades, a plethora of hadronic states beyond the conventional quark model
of qq ̄ mesons and qqq baryons have been observed experimentally, which motivated …

Using a relativized diquark model Hamiltonian, we calculate the masses of J^ PC= 0^++ J
PC= 0++ ground-state tetraquarks in the following systems: bs ̄ b ̄ s bsb¯ s¯, bb ̄ n ̄ n …

The past decade witnessed a remarkable proliferation of exotic charmonium-like
resonances discovered at accelerators. In particular, the recently observed charged states …

We discuss the possible existence of the fully-heavy tetraquarks. We calculate the ground-
state energy of the bb ̄ b ̄ b bbb¯ b¯ bound state, where b stands for the bottom quark, in …

According to the classification of the quark model, the hadrons going beyond three-quark
baryon and quark-antiquark meson pictures are called exotic hadrons. Many new hadrons …