Neutron Beta Decay in a Strong Magnetic Field

The $\beta$ decay of a neutron in a strong quantizing magnetic field is studied by making use of the exact Dirac wave function for the electron in a magnetic field of arbitrary strength. The general conclusion is that the lifetime is unaffected by the magnetic field for $H<\mathrm{}{10}^{12}$ G. For $H>\mathrm{}{10}^{12}$ G, the lifetime in a vacuum is appreciably decreased. This conclusion is still valid when the decay takes place in a degenerate electron gas at densities lower than ${10}^6$ g/${\mathrm{cm}}^3$. At higher densities, the lifetime in a magnetic field tends to reach the value in the absence of the field, for any field strength.