The CMS search for the Higgs boson is being carried out using a range of decay products: two photons; two τ leptons; two b quarks; two W bosons; and two Z bosons. Analysing all of these channels ensures that the search is sensitive to observing the Higgs irrespective of its mass. The CMS collaboration presented the first results from a combination of Higgs searches in these channels at the EPS-HEP 2011 conference in Grenoble at the end of July. For Lepton Photon 2011, held in Mumbai a month later, they were able to update several key analyses, using additional data collected during the summer.
The CMS results presented in Mumbai were based on data-sets corresponding to 1.1–1.7 fb–1 (integrated luminosity), depending on the channel. The figure shows the result of all of the search channels combined. It indicates that CMS observes no convincing excess of events in the explored mass range of 110–600 GeV.
The analysis excludes, with a confidence level (CL) of 95% the existence of a Standard Model Higgs boson in three Higgs mass ranges: 145–216 GeV, 226–288 GeV and 310–400 GeV. For the quantity of data collected so far, the CMS collaboration would expect to exclude the Higgs boson in the range 130–440 GeV in the absence of a signal. The two gaps between the three excluded mass ranges observed in the data are consistent with statistical fluctuations. At 90% CL, the results exclude the Standard Model Higgs boson in the mass range from 144–440 GeV, without interruptions. All exclusion regions were obtained using CLs from the modified frequentist construction .
A modest excess of events is, however, apparent for Higgs boson masses below 145 GeV. With the data due to be collected in the coming months, CMS will be able to distinguish between the possible interpretations: either the production of a Higgs boson or a statistical fluctuation of the backgrounds. During the ongoing proton–proton data-taking period at the LHC, which is expected to terminate at the end of 2012, CMS will record substantially more data, leading to a significantly increased sensitivity to the Standard Model Higgs boson – if it exists – over the full range of possible masses.
More information can be found in CMS-HIG-11-011.
