A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider

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Science  21 Dec 2012:
Vol. 338, Issue 6114, pp. 1569-1575
DOI: 10.1126/science.1230816
  • Fig. 1

    Schematic view of the CMS detector showing its main components.

  • Fig. 2

    Diphoton (γγ) invariant mass distribution for the 7- and 8-TeV data collected by CMS in 2011 and 2012, respectively (black points with error bars). The data are weighted by the ratio of the signal to signal plus background for each event class. The solid red line shows the fit result for signal-plus-background; the dashed red line with color bands shows only the background with its uncertainties at 1σ (yellow) or 2σ (cyan). (Inset) The central part of the unweighted invariant mass distribution. Integrated luminosity was 5.1 fb−1 in 2011 and 5.3 fb−1 in 2012.

  • Fig. 3

    Event recorded with the CMS detector in 2012 at a proton-proton center-of-mass energy of 8 TeV. The event shows characteristics expected from the decay of the SM Higgs boson to a pair of Z bosons, one of which subsequently decays to a pair of electrons (green lines in the tracker matched to green towers in the ECAL in the central region of the detector) and the other decays to a pair of muons (red lines). The event could also be due to known SM background processes.

  • Fig. 4

    Distribution of the four-lepton reconstructed invariant mass for the sum of the 4e, 4μ, and 2e2μ channels. Points represent the data, shaded histograms represent the background, and the empty histogram the signal expectations. The distributions are presented as stacked histograms. The measurements are presented for the sum of the data collected at center-of-mass energies of 7 and 8 TeV during 2011 and 2012, respectively. Error bars represent standard deviations. (Inset) The four-lepton invariant mass distribution after selection of events with signal-like kinematics, as described in the text.

  • Fig. 5

    Distribution of the invariant mass of lepton pairs for the zero-jet eμ category in the search at 8 TeV for the SM Higgs boson decay to a pair of W bosons. The signal expected from the SM Higgs boson with a mass mH = 125 GeV is shown added to the background. Error bars indicate standard deviations.

  • Fig. 6

    The observed probability (local P value) that the background-only hypothesis would yield as many (or more) events as seen in the CMS data, as a function of the mass of the SM Higgs boson for each of the five search channels individually and the combination of all five channels. The dashed line shows the median expected local P values for the SM Higgs boson with a mass mH.

  • Fig. 7

    (Left) 68% CL contours for the relative signal strength σ/σSMH versus the Higgs boson mass for the high-precision decay modes (γγ and ZZ). (Right) The relative signal strength σ/σSMH for the five Higgs boson decay modes examined by CMS. The symbol σ/σSM denotes the production cross section multiplied by the relevant branching fraction, relative to the SM expectation.

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