Search for a Higgs boson produced in association with b quarks and decaying into a b-quark pair

Abstract

This paper presents a search for a neutral Higgs boson decaying to a pair of b quarks and produced in association with at least one additional b quark. We study multijet final states with three b-tagged jets, one of which may include a non-isolated muon. The data used correspond to 2.7- 4.8 collected by the CMS experiment in proton-proton collisions at the LHC at a centre of mass energy of 7 TeV. This search is particularly sensitive to Higgs bosons in MSSM scenarios with large values of tan b. No signal is observed. Stringent upper limits on the cross section are derived, and interpreted as bounds in the MSSM and parameters space, with observed upper limits ranging as low as for in the scenario.

Documentation

CADI HIG-12-033 (restricted)

Main Results

Measurements of this search are the 95% CL limits on the MSSM and .

Cross section limit table:

MSSM Higgs boson limit table: ( scenario at )

MSSM Higgs boson limit table: ( scenario at )

Plots/Tables from CMS Paper HIG-12-033 (click on plot to get .pdf)

Figure	Abbreviated Caption
	Figure 1: The (top) and EventBTag (bottom) projections of five templates, for the low-mass scenario.
	Figure2: Invariant mass of the two leading jets, for Data in the control regions, for low (top) and medium (bottom) mass regions . Prediction with B-tag Matrix (blue histogram), with Hyperball method (green histogram), data (red dots) are overlaid. The predictions are normalized to data.
(a) (b) (c) (d)	Figure3: All-hadronic results. Plots (a), (b) are results of the background-only fit in the triple b-tag samples.The plot (a) shows the distribution of the di-jet mass, the plot (b) the distribution of the EventBTag in the low-mass scenario. The cyan-shaded area corresponds to the template uncertainties. Plots (c), (d) correspond to medium mass scenario. Di-jet mass distribution in the medium-mass scenario, (c) with only background templates, and (d) including a signal template for a Higgs boson with a mass of
(a) (b)	Figure 4: Semi-leptonic results. Data (red) and predicted background (blue) in the signal region, for (a) low mass range (used for ) and medium mass range (used for ; the expected signal for different and for is also plotted. The difference between data and predicted background is also shown.
(a) (b)	Figure 5: Observed and expected upper limits for the cross section times branching ratio at 95% confidence level, with linear and logarithmic scales, including statistical and systematic uncertainties for the combined all-hadronic and semi-leptonic results.
(a) (b)	Figure 6: Observed upper limits at 95% CL on as a function of , including the statistical and systematic uncertainties, in the benchmark scenario, both for (top) and (bottom), for the combined all-hadronic and semileptonic results. One- and two-standard deviation ranges for the expected upper limit are represented by the color bands. The expected upper limits for each of the two signatures are also shown (dashed and dotted lines).
	Figure 7: Observed upper limits at 95% confidence level on as a function of , including the statistical and systematic uncertainties, in the benchmark scenario with for the combined all-hadronic and semileptonic results. One- and two-standard deviation ranges for the expected upper limit are represented by the gray bands. Previous exclusion regions from LEP and Tevatron in the multi-b jet channel are overlaid.

Table 1: Systematic uncertainties on the signal yield from various sources are listed in the first column. The following two columns list the resulting uncertainties in the all-hadronic and semi-leptonic analysis. The first group is for signal, the second for the model-dependent limits. A range indicates the variation across the probed Higgs mass values. The source with + affects also the background, while those with * affect only the model-dependent results in the space of the MSSM parameters and

Additional Plots/Tables for public presentation

Figure	Abbreviated Caption
	Observed and expected upper limits for the cross section times branching ratio at 95% confidence level, with linear and logarithmic scales, including statistical and systematic uncertainties for the semi-leptonic results. finalCLs_Xsec_Logy_FULL_newBM_HB_bjj_bjb.png: finalCLs_Xsec_Logy_FULL_newBM_HB_bjj_bjb.pdf:
	The best fit signal strength, in terms of the MSSM Higgs boson cross section with as a function of for the semi-leptonic analisys. The band corresponds to ±1σ uncertainties on the μ̂ value CLs_SignalStrengh_FULL_newBM_HB_bjj_bjb.png CLs_SignalStrengh_FULL_newBM_HB_bjj_bjb.pdf
	Observed and expected upper limits at 95\% confidence level in the MSSM plane , including the statistical and systematic uncertainties, in the benchmark scenario, for the semi-leptonic results. finalCLs_Tanb_FULL_newBM_HB_bjj_bjb.png finalCLs_Tanb_FULL_newBM_HB_bjj_bjb.pdf
	Observed and expected upper limits at 95\% confidence level in the MSSM plane , including the statistical and systematic uncertainties, in the benchmark scenario, for for the semi-leptonic results. finalCLs_Tanb_FULL_newBM_HB_bjj_bjb_mu-200.png finalCLs_Tanb_FULL_newBM_HB_bjj_bjb_mu-200.pdf
	Figure: The (top) and EventBTag (bottom) projections of signal templates for three different masses of the Higgs boson, with the low-mass selection in the all-hadronic analysis.
(a) (b)	Figure: Observed and expected upper limits at 95% confidence level in the MSSM plane including the statistical and systematic uncertainties, in the benchmark scenario,both for (a) and (b) for the all-hadronic results.