A scalar boson
is a boson
equal to zero. Some mesons
are scalar bosons.
The name scalar boson
arises from quantum field theory
. The component
of such a particle's spin along any axis will always be measured to have only one
possible value: 0. The space of spin states therefore has one degree of freedom, the same as the number of components of a mathematical scalar
. If the scalar boson is taken to be the quantum
of a field, the field is a scalar field
, hence the name.
, such as pion
, are pseudoscalar