English

The mass of the two lightest quarks

High Energy Physics - Phenomenology 2015-06-16 v1

Abstract

The problems encountered in the determination of m_u and m_d are discussed. While their sum is known quite well, the difference m_d-m_u, which measures the breaking of isospin symmetry in the QCD Lagrangian, is still subject to significant uncertainties. I focus on recent work based on the dispersive analysis of the decay eta -> 3 pi, which offers a good handle on isospin breaking, because in that transition, the contributions from the e.m. interaction are suppressed.

Keywords

Cite

@article{arxiv.1305.6839,
  title  = {The mass of the two lightest quarks},
  author = {H. Leutwyler},
  journal= {arXiv preprint arXiv:1305.6839},
  year   = {2015}
}

Comments

Contribution to the proceedings of the workshop "Determination of the Fundamental Parameters of QCD", Nanyang Technological University, Singapore, March 2013