Mass-squared difference
= Mass-squared difference
{title2=$\Delta m_{ij}^2=m_i^2-m_j^2$}
The difference between the squared <masses> of two propagation states. In vacuum its contribution to a <neutrino oscillation> <probability> has phase $\Delta m_{ij}^2L/(4E)$ in <natural units>. The exact identity $\Delta m_{13}^2=\Delta m_{12}^2+\Delta m_{23}^2$ constrains any proposed three-state numerical inputs.