If this hot, dense phase happened, then nuclear physics predicts fusion leading to helium nuclei.

Alpha particles, like helium nuclei, have a net spin of zero.

The Sun shines by jamming protons together and turning them into helium nuclei.

Even this ship, although it is much more massive than a helium nucleus, has a half-life.

He watched as the machine fired helium nuclei into a thin piece of gold foil.

This yields helium nuclei and tremendous amounts of energy.

Lithium is also used as a source for alpha particles, or helium nuclei.

By this time, all neutrons have been incorporated into helium nuclei.

Alpha can be stopped quite easily by a few centimetres in air or a piece of paper and is equivalent to a helium nucleus.

But contained inside, say, a helium nucleus, they can last nearly forever.