  We investigate experimentally the collective behavior of a wet granular
monolayer under vertical vibrations. The spherical particles are partially wet
such that there are short-ranged attractive interactions between adjacent
particles. As the vibration strength increases, clustering, reorganizing and
melting regimes are identified subsequently through a characterization with the
bond-orientational order parameters and the mean kinetic energy of the
particles. The melting transition is found to be a continuous process starting
from the defects inside the crystal.
