Vector Algebra

If $\mathbf{a}=2 \hat{\mathbf{i}}+\hat{\mathbf{j}}-\hat{\mathbf{k}}, \mathbf{b}=\hat{\mathbf{i}}-\hat{\mathbf{j}}+3 \hat{\mathbf{k}}, \mathbf{x}=\left(\frac{\mathbf{a b}}{|\mathbf{b}|^2}\right) \mathbf{b}, \mathbf{y}=\left(\frac{\mathbf{a b}}{|\mathbf{a}|^2}\right) \mathbf{a}$ and $\theta$ is angle between $\mathbf{a}$ and $\mathbf{b}$, then $x^2+y^2=$