A Croatian theoretical physicist who specialised in nuclear physics.
In 1955, cooperating with Kurt Alder and Ben Roy Mottelson, Alaga discovered the K-selection rules and intensity rules for beta and gamma transitions in deformed atom nuclei. This discovery was key to the development of new nuclei models which confirmed that subatomic particles can distort the shape of the nucleus. These models challenged Aage Bohr, Ben Roy Mottelson and James Rainwater's earlier (1975 Nobel Prize-winning) theory that the nucleus has a perfect spherical shape.
In the journal Physical Review published Alaga's rules for beta and gamma transitions for heavily damaged atomic orbits. Both discoveries are known as Alaga rules, and are now in everyday use among nuclear scientists and in scientific literature.