The interacting boson model (IBM) is a
model innuclear physics in which
nucleons (
protons or
neutrons) pair up, essentially
acting as a single
particle with
boson properties, with
integral
spin of either 2 (d-boson) or 0 (s-boson). They correspond to a quintuplet and singlet, i.e. 6 states.
It is sometimes known as the Interacting boson approximation (IBA).[1]: 7
The IBM1/IBM-I model treats both types of
nucleons the same and considers only pairs of nucleons coupled to
total angular momentum 0 and 2, called respectively, s and d
bosons.
The IBM2/IBM-II model treats
protons and
neutrons separately.
Both models are restricted to nuclei with even numbers of protons and neutrons.[1]: 9
The model can be used to predict vibrational and rotational modes of non-spherical nuclei.[2]