A Gamow–Teller transition is a type of nuclear beta decay in which the spins of the emitted electron (positron) and antineutrino (neutrino) couple to total spin , leading to an angular momentum change between the initial and final states of the nucleus. This is in contrast to a Fermi transition, in which the spins of the emitted particles couple to and so the angular momentum of the initial and final states are unchanged (). Gamow-Teller and Fermi transitions correspond to two different forms of leading order behavior of the weak interaction Hamiltonian in the non-relativistic limit:

= isospin transition matrix which turn protons to neutrons and vise-versa

= Pauli spin matrices, which lead to .

= identity operator in spin space, leaving unchanged.

= Weak vector coupling constant.

= Weak axial-vector coupling constant.