at a particle collider a pentaquark was discovered. My question in short is what does the discovery of a pentaquark signify? Is there a theory that it supports or something like that?
You're asking about the significance of the discovery of the Pentaquark. It would shed light on some mysteries surrounding the nuclear force, to begin with. It could perhaps lead to a change in what we understand about Neutron stars, too.
In terms of "some theory it supports or something like that", generally the stuff we already think still makes sense. Good!