Last year’s run of the LHC has set a cutoff for the expected mass of the Higgs boson. This important result came out of the recently concluded Europhysics Conference 2011.
CMS has excluded the mass ranges of 149-206 GeV and 300-440 GeV for the Higgs with a confidence level of 95%. It has also excluded the masses from 145-480 GeV with a lower confidence level of 90%. This excludes a huge part of the expected mass range, and has gotten particle physicists both excited and demoralised.
The Higgs Boson, also called ‘God Particle’ is the only particle predicted by the Standard Model but has not been detected in any collider. It has been assigned the function of endowing all particles in the Universe with mass. Any particle interacting with the Higgs field, mediated by the Higgs boson, is said to have mass. The boson is named after physicist Peter Higgs, the person who came up with the idea. Unfortunately, the Standard Model says little more than the lower limit of the mass of the Higgs Boson. CERN has given itself till 2012 for proving the existence of the Higgs.
Further news is that is the results of the 2010 and 2011 runs are interpreted in the light of a Standard Model having four generation of fermions (SM4), instead of just three, scientists put a 95% confidence level on the exclusion of the Higgs boson in the mass range of 120-600 GeV.
There are also many particle physics theories not involving any Higgs boson called Higgless theories and they may now come to the forefront, if the Higgs remains elusive.
CMS is carrying on the search using decays of different particles. It is trying to produce the Higgs using two photons, two tau leptons, two W bosons and two Z bosons.