ATLAS Sensitivity Prospects for Higgs Boson Production at the LHC Running at 7, 8 or 9 TeV

Figure 1: The cross-section of the most significant processes for Standard Model Higs boson production at the LHC. Details are in the text.

Figure 2: The ratio of the production cross-sections at different centre-of-mass energies for the most important Standard Model Higgs production processes. Details are in the text.

Figure 3: The transverse mass as defined in Equation 1 for signal and background events in the analysis after all cuts for the Higgs boson masses = 200, 300, 400, 500 and 600 GeV.

Figure 4: Left: The expected signal rate, as a multiple of the Standard Model rate, which could be excluded by the search at 7 TeV. For example, if the median line is at '2' for some then a hypothetical particle, behaving exactly like the Standard Model Higgs boson but with twice the rate, would be excluded at 95% CL in 50% of experiments. Right is the same for the channel. The by itself has a small region of expected exclusion. The green and yellow bands indicate the range in which the limits are expected to lie. depending upon the data.

Figure 5: Left: The mass, of the b-jet pair in the analysis for the Higgs boson signal ( = 400 GeV) and the main backgrounds. Right: The invariant mass of the system for events with 2 b-tagged jets and < 50 GeV. The vertical dashed lines indicate the area used to define the signal region.

Figure 6: The invariant mass of the system for the Higgs boson masses = 200, 300, 400, 500 and 600 GeV.

Figure 7: The expected signal rate, as a multiple of the Standard Model rate, which could be excluded by teh channel at 7 TeV and 1 fb^-1 of integrated luminosity. The green and yellow bands indicate the range in which the lmits are expected to lie, depending upon the data.

Figure 8: Expected 95% CL upper limits on the Standard Model Higgs boson production in the channel as a function of the Higgs boson mass, for 7 TeV centre-of-mass energy. The green and yellow bands indicate the range in which the limits are expected to lie, depending upon the data. Variation of the background estimate in the toy Monte Carlo trials changes the limit calculated when zero events are observed. This gives rise to narrow downward-fluctuation band even when every few background events are expected.

Figure 9: The estimated multiple of the Standard model signal cross-section excluded by the search at 95% CL as a function of the Higs boson mass for an integrated luminosity of 1 fb^-1 at 7 TeV. The green and yellow bands represent the range in which the limit is expected to lie, depending upon the data.

Figure 10: The expected signal rate, as a multiple of the standard Model rate, which could be excluded at 95% CL by the search at 7 TeV. The green and yellow bands indicate the range in which the limits are expected to lie. depending upon the data.

Figure 11: The expected signal rate, as a multiple of the Standard Model rate, which could be excluded at 95% CL by the search at 7 TeV. The green and yellow bands indicate the range in which the limits are expected to lie, depending upon the data.

Figure 12: Top: The multiple of the cross-section of a Standard Model Higgs boson which can be excluded using 1 fb^-1 of data at 7 TeV. At each mass, every channel giving reporting on it is used. The plot at the left is the same as the right except truncated to 200 GeV. The green and yellow bands indicate th range in which we expect the limit will lie, depending upon the data.

Figure 13: Combined sensitivity for different integrated luminosity scenarios. Left shows the 95% CL median sensitivities and right gives the 3σ sensitivity. Public limits from LEP [39] and the Tevatron [38] are shown for comparison.

Figure 14: Combined sensitivity for different centre-of-mass energies. The top two plots compare the evolution at 1 and 2 fb^-1. The top right also shows the impact of an aggressive analysis strategy explained in the text. Bottom plot shows the 1 fb^-1 result over the full mass range. Public results from LEP [39] and the Tevatron [38] are shown for comparison.

Figure 15: The amount of integrated luminosity at 8 or 9 TeV which gives the same median sensitivity as a function of Higgs boson mass as 1 fb^-1 at 7 TeV.