# Relativistic Angular Momentum?

1. Jul 8, 2009

### referframe

What is the mathematical definition of Angular Momentum in Special Relativity? Is there a definition that does not require knowledge of two-forms, tensors, etc.? As always, thanks in advance.

2. Jul 8, 2009

### meopemuk

The total angular momentum of any system of massive spinless particles is

$$\mathbf{J} = \sum_{i}^N \mathbf{r}_i \times \mathbf{p}_i$$

where $\mathbf{r}_i$ are particles positions and $\mathbf{p}_i$ are their momenta. This definition is valid in both non-relativistic and relativistic mechanics.