integerspin

Integerspin is a term used to describe particles whose intrinsic angular momentum, or spin, takes an integer value in units of the reduced Planck constant (ħ). In quantum mechanics, spin is an intrinsic form of angular momentum carried by elementary particles and composite systems. The spin quantum number s can be integer or half-integer; when s ∈ {0,1,2,...}, the particle is said to have integer spin, or integerspin.

Mathematically, spins are described by representations of the rotation group SU(2). Each value of s labels a representation of dimension 2s+1. For integer s, there are 2s+1 polarization states with magnetic quantum numbers m = -s, -s+1, ..., s.

Physical consequences: Particles with integer spin are bosons; they obey Bose-Einstein statistics and have symmetric wavefunctions under particle exchange, enabling phenomena like Bose-Einstein condensation. By the spin-statistics theorem, half-integer spin particles are fermions and obey Fermi-Dirac statistics.

Examples: Photons (spin 1), gluons (spin 1), Z and W bosons (spin 1) and gravitons (hypothetical spin 2) fall into integerspin. The Higgs boson has spin 0. Composite particles like deuterons can also have integer spin. In theories of higher spin, fields with spin greater than 1, including integer spins, are studied in various contexts.

In practice, integerspin is contrasted with half-integer spin, and the term is more common in older or specialized literature; in modern discussions, people usually speak of integer-spin bosons or half-integer-spin fermions.