Original URL: http://www.theregister.co.uk/2011/07/25/higgs_boson_warmer/

Higgs Boson hiding place narrows

Masses of new evidence, apparently

By Richard Chirgwin

Posted in Science, 25th July 2011 00:30 GMT

The particle physicist’s game of “hot, warm, cold” in search of the Higgs Boson seems to be getting a little warmer with preliminary results announced by physicists at the Large Hadron Collider late last week.

Actually, what’s getting closer is an either-or: the Higgs Boson will be identified or it will be ruled out (which would disappoint particle physicists right up until the point they realize they now have brand-new lifetime jobs rewriting just about everything they thought they knew).

The results, announced at the Europhysics Conference on High-Energy Physics, are as interesting for what they don’t see as for what they do see. The latest experiments expand the “exclusions” for the Higgs Boson – a large number of theoretical potential masses for the particle are now ruled out.

That simplifies the task ahead for physicists, since they can narrow down experiments specific to the masses no longer excluded from the search.

These are preliminary results only – they have been reviewed by the 800 scientists in the project, but haven’t yet gone through the long process of a formal peer review. However, the latest results seem to exclude the Higgs Boson from the mass range between 155 and 190 GeV (giga-electron volts), and also from the 295 to 450 GeV range. Anybody going Higgs Boson hunting in those mass ranges will now hear “you’re getting colder!” from their colleagues.

And, although it’s too early to say “there it is!”, the researchers have said there seem to be small amounts of excess particles, somewhere between 120 GeV and 180 GeV (the two detectors report different results: the LHC’s ATLAS detector sees excess particles between 120 and 145 GeV, while the CMS detector puts them between 120 and 180 GeV).

Some masses in this range have been excluded not by CERN, but by late experiments at the Fermilab Tevatron, which last year ruled out the 158 to 175 GeV range. ®