How small was the smallest particle that you have discovered?

Question: How small was the smallest particle that you have discovered?
- Keywords:
  discovery,
  particle,
  smallest
Asked by Georgina to Jackie on 16 Mar 2015.
- Jaclyn Bell answered on 16 Mar 2015:
  
  Personally I haven’t discovered any particles as I just do theory and not experimental physics. The main particles I work with are the smallest constituents of the atom – they are called quarks and gluons. In my research I use a lot of maths to model what these particles are doing when they collide. It is then up to other theories and experimental data to confirm my results 🙂 but so far I haven’t discovered anything ‘new’ – just confirmed what we know already.

Question: How small was the smallest particle that you have discovered?