A search is presented for the single production of a heavy vector-like quark (B) decaying to a Higgs boson and a bottom quark, $\mathrm{B}\rightarrow\mathrm{H}\mathrm{b}$, with the Higgs boson decaying to a pair of bottom quarks. The decay products of the Higgs boson are highly boosted, hence typically collimated. They are reconstructed as a single, massive jet, with heavy flavour content. The single production of vector-like quarks is characterised by the presence of a light flavour quark emitted in the forward region of the detector. The analysis is performed using a data sample collected in 2016 by the CMS experiment at the LHC in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13~\mathrm{TeV}$, corresponding to an integrated luminosity of $35.9~\mathrm{fb}^{-1}$. The observation is consistent with background expectation and upper limits are placed on the production cross section times the branching ratio of a vector-like quark B decaying to a Higgs boson and a bottom quark. Values of cross section times branching ratio above $0.07$--$1.28~\mathrm{pb}$ are excluded at $95\%$ confidence level for masses of $700$--$1800~\mathrm{GeV}$, assuming a resonance with negligible width with respect to experimental resolution. Similar sensitivity is observed for different assumptions on the intrinsic width of the vector-like quark B.
Distribution in the reconstructed B quark mass after applying all selections to events with no forward jets and in the low mass analysis, compared to the background distributions estimated before fitting.
Distribution in the reconstructed B quark mass after applying all selections to events with at least one forward jet and in the low mass analysis, compared to the background distributions estimated before fitting.
Distribution in the reconstructed B quark mass after applying all selections to events with no forward jets and in the low mass analysis, compared to the background distributions estimated before fitting.
Results are reported from a search for supersymmetric particles in proton-proton collisions in the final state with a single, high transverse momentum lepton; multiple jets, including at least one b-tagged jet; and large missing transverse momentum. The data sample corresponds to an integrated luminosity of 2.3 inverse femtobarns at sqrt(s) = 13 TeV, recorded by the CMS experiment at the LHC. The search focuses on processes leading to high jet multiplicities, such as gluino pair production with gluinos to t t-bar neutralino[1]. The quantity M[J], defined as the sum of the masses of the large-radius jets in the event, is used in conjunction with other kinematic variables to provide discrimination between signal and background and as a key part of the background estimation method. The observed event yields in the signal regions in data are consistent with those expected for standard model backgrounds, estimated from control regions in data. Exclusion limits are obtained for a simplified model corresponding to gluino pair production with three-body decays into top quarks and neutralinos. Gluinos with a mass below 1600 GeV are excluded at a 95% confidence level for scenarios with low neutralino[1] mass, and neutralinos with a mass below 800 GeV are excluded for a gluino mass of about 1300 GeV. For models with two-body gluino decays producing on-shell top squarks, the excluded region is only weakly sensitive to the top squark mass.
Event yields obtained from simulated event samples, as the event selection criteria are applied. The category Other includes Drell-Yan, $t\bar{t}H(\rightarrow b\bar{b})$, $t\bar{t}t\bar{t}$, $WZ$, and $WW$. The yields for $t\bar{t}$ events in fully hadronic final states are included in the QCD multijet category. The category $t\bar{t}{\rm V}$ includes $t\bar{t}W$, $t\bar{t}Z$, and $t\bar{t}\gamma$. The benchmark signal models, T1tttt(NC) and T1tttt(C), are described in Section 3. The event selection requirements listed above the horizontal line in the middle of the table are defined as the baseline selection. The background estimates before the $H_{T}$ requirement are not specified because some of the simulated event samples do not extend to the low $H_{T}$ region. Given the size of the MC samples described in Section 3, rows with zero yield have statistical uncertainties of at most 0.16 events, and below 0.05 events in most cases.
Observed and predicted event yields for the signal regions (R4) and background regions (R1--R3) in data (2.3 $\textrm{fb}^{-1}$) in 200<MET<400 GeV region. Expected yields for the two SUSY T1tttt benchmark scenarios are also given. The results from two types of fits are reported: the predictive fit (PF) and the version of the global fit (GF) performed under the assumption of the null hypothesis ($r=0$). The predictive fit uses the observed yields in regions R1, R2, and R3 only and is effectively just a propagation of uncertainties. The global fit uses all four regions. The values of $\kappa$ obtained from the simulation fit are also listed. The first uncertainty in $\kappa$ is statistical, while the second corresponds to the total systematic uncertainty.
Observed and predicted event yields for the signal regions (R4) and background regions (R1--R3) in data (2.3 $\textrm{fb}^{-1}$) in MET>400 GeV region. Expected yields for the two SUSY T1tttt benchmark scenarios are also given. The results from two types of fits are reported: the predictive fit (PF) and the version of the global fit (GF) performed under the assumption of the null hypothesis ($r=0$). The predictive fit uses the observed yields in regions R1, R2, and R3 only and is effectively just a propagation of uncertainties. The global fit uses all four regions. The values of $\kappa$ obtained from the simulation fit are also listed. The first uncertainty in $\kappa$ is statistical, while the second corresponds to the total systematic uncertainty.
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