Scalar boson

A scalar boson is a boson whose spin equals zero. Boson means that it has an integer-valued spin; the scalar fixes this value to 0.

The name "scalar boson" arises from quantum field theory. It refers to the particular transformation properties under Lorentz transformation.

Examples

• Various known composite particles are scalar bosons, e.g. the alpha particle and the pi meson. Among the scalar mesons, one distinguishes between the scalar and pseudoscalar mesons, which refers to their transformation property under parity.

• The only fundamental scalar boson in the standard model of elementary particle physics is the Higgs boson. It is the only elementary particle in the Standard Model that has not yet been experimentally measured (February 2012). There are various other hypothetical fundamental scalar bosons, including the inflaton.

• One very popular quantum field theory, which uses scalar bosonic fields and is introduced in many introductory books to quantum field theories for pedagogical reasons, is the so called $\Phi^4$-theory. It usually serves as a toy model to introduce into the basic concepts of the field.

See also

• Scalar meson
• Pseudoscalar meson
• Quantum field theory
• Scalar field theory
• Vector boson