## 05.11.2009 17:15

# Renormalising nuclear forces

## M. Birse

Effective field theory is now an important tool for the construction of nuclear forces. It offers the promise both of a systematic expansion of these forces in powers of low-energy scales and of a consistent treatment three-body forces and other effective operators. The terms in this expansion are organised according to a "power counting" of low-energy scales. The original suggestion of Weinberg, naive dimensional analysis, works well in the mesonic sector. However it cannot handle strong interactions leading to low-energy bound states and so it needs to be modified. This has led to a long-running debate about the appropriate power counting for each channel. Clear answers can be obtained by using the renormalisation group (RG) to analyse the scale dependence of nuclear forces. I outline how the RG is being applied to this problem and summarise results from several RG analyses of nuclear forces. I also comment on how this approach can be applied to other systems with large scattering lengths, such as ultracold atoms.