Supersymmetry theorises the existence of more massive versions of particles that have already been detected. Their existence would help explain why galaxies appear to rotate faster than the Standard Model would suggest. Physicists have speculated that as well as the particles we know about, galaxies contain invisible, undetected dark matter made up of super particles. The galaxies therefore contain more mass than we can detect and so spin faster.
Researchers at the LHCb detector have dealt a serious blow to this idea. They have measured the decay between a particle known as a Bs Meson into two particles known as muons. It is the first time that this decay has been observed and the team has calculated that for every billion times that the Bs Meson decays it only decays in this way three times.
If superparticles were to exist the decay would happen far more often. This test is one of the "golden" tests for supersymmetry and it is one that on the face of it this hugely popular theory among physicists has failed.