CMS-PAS-HIG-15-008

CMS-PAS-HIG-15-008
Search for $\mathrm{ t \bar{t} H }$ production in multilepton final states at $\sqrt{s} =$ 13 TeV
CMS Collaboration
March 2016

Abstract: A search for the standard model Higgs boson produced in association with a top quark pair is presented. Data collected by the CMS experiment in pp collisions at a center of mass energy of $\sqrt{s}=$ 13 TeV and corresponding to an integrated luminosity of 2.3 fb $^{-1}$ are used. The analysis targets the $\mathrm{WW}^{}$ , $\mathrm{ZZ}^{}$ and $\tau\tau$ decay channels of the Higgs boson by selecting final states with two same-sign leptons or more than three leptons, produced in association with b jets. The signal strength is measured to be 0.6 $^{+1.4}_{-1.1}$ times the standard model expectation. The observed 95% confidence level upper limit on the $\mathrm{t} \overline{\mathrm{t}} \mathrm{H}$ production cross section is 3.3 times the standard model expectation, compared to the 2.6 expected in absence of a signal. The combination of ttH results with CMS data at 13 TeV is summarized at this url.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ;

Figures & Tables	CMS Publications

Figures
png pdf	Figure 1-a: Feynman diagrams for ${ {\mathrm{ t \bar{t} } } \mathrm{ H } }$ production at pp colliders, with the Higgs boson decaying to $\mathrm {WW}^{}$ , $\mathrm {ZZ}^{}$ , and $\tau \tau$ (from a to c). They represent examples of final states with four leptons, three leptons, and two same-sign leptons, respectively.
png pdf	Figure 1-b: Feynman diagrams for ${ {\mathrm{ t \bar{t} } } \mathrm{ H } }$ production at pp colliders, with the Higgs boson decaying to $\mathrm {WW}^{}$ , $\mathrm {ZZ}^{}$ , and $\tau \tau$ (from a to c). They represent examples of final states with four leptons, three leptons, and two same-sign leptons, respectively.
png pdf	Figure 1-c: Feynman diagrams for ${ {\mathrm{ t \bar{t} } } \mathrm{ H } }$ production at pp colliders, with the Higgs boson decaying to $\mathrm {WW}^{}$ , $\mathrm {ZZ}^{}$ , and $\tau \tau$ (from a to c). They represent examples of final states with four leptons, three leptons, and two same-sign leptons, respectively.
png pdf	Figure 2-a: a,b,c: number of selected jets in the same-sign $\mu \mu$ , $\mathrm{e} \mathrm{e}$ , and $\mathrm{e} \mu$ channels. d,e,f: distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the two lepton same-sign selection inclusive in lepton flavor. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 2-b: a,b,c: number of selected jets in the same-sign $\mu \mu$ , $\mathrm{e} \mathrm{e}$ , and $\mathrm{e} \mu$ channels. d,e,f: distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the two lepton same-sign selection inclusive in lepton flavor. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 2-c: a,b,c: number of selected jets in the same-sign $\mu \mu$ , $\mathrm{e} \mathrm{e}$ , and $\mathrm{e} \mu$ channels. d,e,f: distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the two lepton same-sign selection inclusive in lepton flavor. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 2-d: a,b,c: number of selected jets in the same-sign $\mu \mu$ , $\mathrm{e} \mathrm{e}$ , and $\mathrm{e} \mu$ channels. d,e,f: distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the two lepton same-sign selection inclusive in lepton flavor. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 2-e: a,b,c: number of selected jets in the same-sign $\mu \mu$ , $\mathrm{e} \mathrm{e}$ , and $\mathrm{e} \mu$ channels. d,e,f: distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the two lepton same-sign selection inclusive in lepton flavor. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 2-f: a,b,c: number of selected jets in the same-sign $\mu \mu$ , $\mathrm{e} \mathrm{e}$ , and $\mathrm{e} \mu$ channels. d,e,f: distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the two lepton same-sign selection inclusive in lepton flavor. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 3-a: Number of selected jets, distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the three-lepton channel. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 3-b: Number of selected jets, distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the three-lepton channel. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 3-c: Number of selected jets, distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the three-lepton channel. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 3-d: Number of selected jets, distributions of the BDT kinematic discriminants and result of their combination in the bins used for signal extraction, for the three-lepton channel. Pre-fit distributions are shown. Uncertainties are statistical only.
png pdf	Figure 4-a: a: asymptotic 95% CL upper limits on the signal strength parameter. b: best fit of the signal strength parameter.
png pdf	Figure 4-b: a: asymptotic 95% CL upper limits on the signal strength parameter. b: best fit of the signal strength parameter.

Tables
png pdf	Table 1: Expected and observed yields after the selection in 2lss and three-lepton final states. The rare SM backgrounds include ${\mathrm{Z} } {\mathrm{Z} }$ , $\mathrm{W} ^\pm \mathrm{W} ^\pm \mathrm {qq}$ , $\mathrm{W} \mathrm{W}$ produced in double-parton interactions, and triboson production. Uncertainties are statistical only. The backgrounds from non-prompt leptons and charge flips are extracted from data.
png pdf	Table 2: Asymptotic 95% CL upper limits on the signal strength parameter.
png pdf	Table 3: Best fit of the signal strength parameter.