Atomic nuclei and electrons are attracted each other through the electromagnetic interaction. This enables electrons to surround nuclei, and thus atoms can be formed.
What about the case of nuclei, which are formed by protons and neutrons?
There are four kinds of fundamental interaction in the natural world. The interaction between protons and neutrons is the strong interaction called the nuclear force. Since the strong interaction is attractive force and its strength is about 100 times stronger than the electromagnetic interaction, protons and neutrons can form nuclei.
Now the question is, how the strong interaction acts in the strangeness nuclear matter? Acts as an attractive force same in the nuclei, or repulsive force? How much the strength?
We are aiming to obtain keys for these interesting mysteries with new experiments and to understand properties of the strong interaction which governs the material world.