Reading a scientific article, I came across the following integral $$ \int_0^1 dx \int\dfrac{d^2\vec{k}}{16\pi^3} \psi(x,\vec{k})^2 $$
So, I had a huge question: how to use Mathematica to do integral $ \int d^2\vec{k} $?
Can anyone help me with this? Thanks!
