© Claude Paris (2008)

Laurent Lellouch

CNRS Research Director

Centre de Physique Théorique
Case 907, CNRS Luminy
F-13288 Marseille Cedex 9

Ph:  +33/0 491 26 95 17
Fax: +33/0 491 26 95 53

lellouch [AT] cpt.univ-mrs.fr

Research interests

  • Elementary particle physics
  • Fundamental quark and hadron properties
  • Physics of flavor and CP violation
  • Quantum chromodynamics
  • Lattice field theory
  • Ab initio methods and simulations


Research highlight

Ab initio calculation of the neutron-proton mass difference

This figure shows how the neutron-proton mass difference depends on two combinations of fundamental parameters. On the horizontal axis, the fine structure constant, proportional to the square of the elementary unit of charge is varied from zero to twice its measured value. Along the vertical axis, it is the difference in mass between down and up quarks that is varied. The blue cross indicates the point corresponding to our universe. The black curves correspond to contours of constant neutron-proton mass difference. Each has a label indicating the value of the neutron-proton mass difference to which it corresponds. Any point in the blue region corresponds to a very different universe from ours, in which the proton could decay into a neutron through the weak interaction. Units are mega-electron-volts (MeV). The mass of a hydrogen atom is approximately 1000 MeV.

All research highlights

The Budapest-Marseille-Wuppertal Collaboration

Up to staff list