Weyl equation
= Weyl equation
{c}
{title2=$i(\partial_t\mp\boldsymbol\sigma\cdot\boldsymbol\nabla)\chi_{L/R}=0$}
{wiki}
The free <massless particle>[massless] relativistic field equation for one chiral two-component <spinor>. With mostly-minus metric, the left-chiral equation has the minus sign and the right-chiral equation the plus sign. The positive-energy <particle> <helicities> are respectively $-1/2$ and $+1/2$; antiparticle <helicities> are opposite.