Last week, one of the detectors at the Large Hadron Collider (LHC) made a quiet step towards discovering the Higgs particle — part of the mechanism that physicists think endows things with mass.

The Compact Muon Solenoid (CMS) detector announced that it had detected its first pair of Z bosons. Z bosons are relatively little-known particles that mediate the weak nuclear force, in the same way that photons (i.e. light particles) moderate electromagnetism and gluons moderate the strong nuclear force.

If the Higgs particle is heavy, then it is likely to decay into a pair of Zs. The Zs in turn decay into high-energy muons (think heavy electrons), which cut a straight line through CMS’s powerful magnetic fields. That means the four little lines to the right COULD be a signature of a Higgs decay.

That could is important. There are other things that could cause a pair of Zs to appear in the machine. CMS physicist Tomasso Dorigo announced the ZZ result on his blog, and also made quite clear that this ZZ pair could have been produced directly by the proton-proton collisions.

As with so many things in high-energy physics, stats matter. Over the next run (to come in early 2011), physicists are going to collect more of these ZZ decays. Dorigo thinks it may take perhaps 100 pairs to determine where they are coming from. Further measurements over the next year should clarify the picture.

Credit: CMS