Measurement of the mass of the top quark in decays with a J/psi meson in pp collisions at 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
JHEP 12 (2016) 123, 2016.
Inspire Record 1480862 DOI 10.17182/hepdata.75539

A first measurement of the top quark mass using the decay channel t to (W to l nu) (b to J/psi + X to mu+ mu- + X) is presented. The analysis uses events selected from the proton-proton collisions recorded with the CMS detector at the LHC at a center-of-mass energy of 8 TeV. The data correspond to an integrated luminosity of 19.7 inverse femtobarns, with 666 t t-bar and single top quark candidate events containing a reconstructed J/psi candidate decaying into an oppositely-charged muon pair. The mass of the (J/psi + l) system, where l is an electron or a muon from W boson decay, is used to extract a top quark mass of 173.5 +/- 3.0 (stat) +/- 0.9 (syst) GeV.

2 data tables

Number of selected events from simulations and observed in data. The uncertainties are statistical.

Summary of the impact of systematic uncertainties on the top quark mass according to the contributions from each source.


Search for two Higgs bosons in final states containing two photons and two bottom quarks

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev.D 94 (2016) 052012, 2016.
Inspire Record 1431986 DOI 10.17182/hepdata.77003

A search is presented for the production of two Higgs bosons in final states containing two photons and two bottom quarks. Both resonant and nonresonant hypotheses are investigated. The analyzed data correspond to an integrated luminosity of 19.7 inverse femtobarns of proton-proton collisions at sqrt(s) = 8 TeV collected with the CMS detector. Good agreement is observed between data and predictions of the standard model (SM). Upper limits are set at 95% confidence level on the production cross section of new particles and compared to the prediction for the existence of a warped extra dimension. When the decay to two Higgs bosons is kinematically allowed, assuming a mass scale Lambda[R] = 1 TeV for the model, the data exclude a radion scalar at masses below 980 GeV. The first Kaluza-Klein excitation mode of the graviton in the RS1 Randall-Sundrum model is excluded for masses between 325 and 450 GeV. An upper limit of 0.71 pb is set on the nonresonant two-Higgs-boson cross section in the SM-like hypothesis. Limits are also derived on nonresonant production assuming anomalous Higgs boson couplings.

3 data tables

Observed $m_\mathrm{jj}$ spectrum (black points) compared with a background estimate (black line), obtained in background only hypothesis, for HPHP category. The simulated radion resonances of $m_\mathrm{X} = 1.5$ and 2 TeV are also shown. Observed and expected 95% CL upper limits on the product of cross section and the branching fraction sigma(pp->X)*B(X->HH) obtained through a combination of the two event categories. The limits for mX = 400 GeV are shown for both Low mass and High mass signal extraction methods.

Observed and expected 95% CL upper limits on the product of cross section and the branching fraction sigma(pp->X)*B(X->HH->gamma gamma b b ) for the nonresonant BSM analysis, performed by changing the parameters $kappa_$lambda, y_t and c_2 while keeping all other parameters fixed at the SM predictions.

Signal efficiencies in the four different signal regions for the nonresonant BSM analysis, performed by changing the parameters $kappa_$lambda, y_t and c_2 while keeping all other parameters fixed at the SM predictions. The four signal regions are made in b-tag and m_HH categries, being those: "Low-purity, High-mass" (LPHM), "Low-purity, Low-mass" (LPLM), "High-purity, High-mass" (HPHM) and "High-purity, Low-mass" (HPLM).


Search for heavy Majorana neutrinos in e+/- e+/- plus jets and e+/- mu+/- plus jets events in proton-proton collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
JHEP 04 (2016) 169, 2016.
Inspire Record 1426525 DOI 10.17182/hepdata.77059

A search is performed for heavy Majorana neutrinos (N) decaying into a W boson and a lepton using the CMS detector at the Large Hadron Collider. A signature of two jets and either two same sign electrons or a same sign electron-muon pair is searched for using 19.7 inverse femtobarns of data collected during 2012 in proton-proton collisions at a centre-of-mass energy of 8 TeV. The data are found to be consistent with the expected standard model (SM) background and, in the context of a Type-1 seesaw mechanism, upper limits are set on the cross section times branching fraction for production of heavy Majorana neutrinos in the mass range between 40 and 500 GeV. The results are additionally interpreted as limits on the mixing between the heavy Majorana neutrinos and the SM neutrinos. In the mass range considered, the upper limits range between 0.00015 - 0.72 for |V[eN]|^2 and 6.6E-5 - 0.47 for |V[eN] V*[muN]|^2 / ( |V[eN]|^2 + |V[muN]|^2 ), where V[lN] is the mixing element describing the mixing of the heavy neutrino with the SM neutrino of flavour l. These limits are the most restrictive direct limits for heavy Majorana neutrino masses above 200 GeV.

10 data tables

Selection requirements for the low- and high-mass signal regions.

ee channel. Selection requirements on discriminating variables determined by the optimization for each Majorana neutrino mass point. The last column shows the overall signal acceptance. Different selection criteria are used for low- and high-mass search regions. The "-" indicates that no selection requirement is made.

e$\mu$ channel. Selection requirements on discriminating variables determined by the optimization for each Majorana neutrino mass point. The last column shows the overall signal acceptance. Different selection criteria are used for low- and high-mass search regions. The ''-'' indicates that no selection requirement is made.

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Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Eur.Phys.J.C 76 (2016) 371, 2016.
Inspire Record 1424833 DOI 10.17182/hepdata.73976

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at sqrt(s) = 8 TeV. The data correspond to an integrated luminosity of 19.7 inverse femtobarns. The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t t-bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95% confidence level for the product of the production cross section and branching fraction sigma(gg to X) B(X to HH to b b-bar b b-bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with a mass scale Lambda[R] = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV.

7 data tables

Observed $m_\mathrm{jj}$ spectrum (black points) compared with a background estimate (black line), obtained in background only hypothesis, for HPHP category. The simulated radion resonances of $m_\mathrm{X} = 1.5$ and 2 TeV are also shown.

Observed $m_\mathrm{jj}$ spectrum (black points) compared with a background estimate (black line), obtained in background only hypothesis, for HPLP category. The simulated radion resonances of $m_\mathrm{X} = 1.5$ and 2 TeV are also shown.

Observed $m_\mathrm{jj}$ spectrum (black points) compared with a background estimate (black line), obtained in background only hypothesis, for LPHP category. The simulated radion resonances of $m_\mathrm{X} = 1.5$ and 2 TeV are also shown.

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Measurements of t t-bar spin correlations and top quark polarization using dilepton final states in pp collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, V. ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev.D 93 (2016) 052007, 2016.
Inspire Record 1413748 DOI 10.17182/hepdata.70879

Measurements of the top quark-antiquark (t t-bar) spin correlations and the top quark polarization are presented for t t-bar pairs produced in pp collisions at sqrt(s) = 8 TeV. The data correspond to an integrated luminosity of 19.5 inverse femtobarns collected with the CMS detector at the LHC. The measurements are performed using events with two oppositely charged leptons (electrons or muons) and two or more jets, where at least one of the jets is identified as originating from a bottom quark. The spin correlations and polarization are measured from the angular distributions of the two selected leptons, both inclusively and differentially, with respect to the invariant mass, rapidity, and transverse momentum of the t t-bar system. The measurements are unfolded to the parton level and found to be in agreement with predictions of the standard model. A search for new physics in the form of anomalous top quark chromo moments is performed. No evidence of new physics is observed, and exclusion limits on the real part of the chromo-magnetic dipole moment and the imaginary part of the chromo-electric dipole moment are evaluated.

106 data tables

Inclusive values of the asymmetry variables.

Values of the 12 bins of the normalized differential cross section as a function of $\left|\Delta \phi_{\ell^+\ell^-}\right|$.

Statistical covariance matrix for the 12 bins of the normalized differential cross section as a function of $\left|\Delta \phi_{\ell^+\ell^-}\right|$.

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Observation of top quark pairs produced in association with a vector boson in pp collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
JHEP 01 (2016) 096, 2016.
Inspire Record 1396140 DOI 10.17182/hepdata.69486

Measurements of the cross sections for top quark pairs produced in association with a W or Z boson are presented, using 8 TeV pp collision data corresponding to an integrated luminosity of 19.5 inverse femtobarns, collected by the CMS experiment at the LHC. Final states are selected in which the associated W boson decays to a charged lepton and a neutrino or the Z boson decays to two charged leptons. Signal events are identified by matching reconstructed objects in the detector to specific final state particles from ttW or ttZ decays. The ttW cross section is measured to be 382 +117 -102 fb with a significance of 4.8 standard deviations from the background-only hypothesis. The ttZ cross section is measured to be 242 +65 -55 fb with a significance of 6.4 standard deviations from the background-only hypothesis. These measurements are used to set bounds on five anomalous dimension-six operators that would affect the ttW and ttZ cross sections.

6 data tables

Expected yields after the final fit, compared to the observed data for OS t$\bar{\mathrm{t}}$Z final states. Here ``hf'' and ``lf'' stand for heavy and light flavors, respectively.

Expected yields after the final fit, compared to the observed data for SS t$\bar{\mathrm{t}}$W final states. The multiboson process includes WWW, WWZ, and W$^{\pm}$W$^{\pm}$; t$\mathrm{\bar{t}}$+X includes t$\mathrm{\bar{t}}\gamma$, t$\mathrm{\bar{t}}\gamma^{*}$, and t$\bar{\mathrm{t}}$WW.

Expected yields after the final fit, compared to the observed data for 3$\ell$ t$\bar{\mathrm{t}}$W and three and 4$\ell$ t$\bar{\mathrm{t}}$Z final states. The 4$\ell$ ``Z-veto'' channel has exactly one lepton pair consistent with a Z boson decay; the ``Z'' channel has two. The multiboson process includes WWW and WWZ; t$\mathrm{\bar{t}}$+X includes t$\mathrm{\bar{t}}\gamma$, t$\mathrm{\bar{t}}\gamma^{*}$, and t$\bar{\mathrm{t}}$WW.

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Angular analysis of the decay B0 to K*0 mu mu from pp collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett.B 753 (2016) 424-448, 2016.
Inspire Record 1385600 DOI 10.17182/hepdata.17057

The angular distributions and the differential branching fraction of the decay B0 to K*0(892) mu mu are studied using data corresponding to an integrated luminosity of 20.5 inverse femtobarns collected with the CMS detector at the LHC in pp collisions at sqrt(s) = 8 TeV. From 1430 signal decays, the forward-backward asymmetry of the muons, the K*0(892) longitudinal polarization fraction, and the differential branching fraction are determined as a function of the dimuon invariant mass squared. The measurements are among the most precise to date and are in good agreement with standard model predictions.

2 data tables

The measured values of signal yield, FL, AFB, and differential branching fraction in bins of the dimuon invariant mass squared. The (FL,AFB) correlation factors are also shown.

The measured values of FL, AFB, and differential branching fraction in bins of the dimuon invariant mass squared, combining the 7 TeV and 8 TeV results.


Search for resonances and quantum black holes using dijet mass spectra in proton-proton collisions at sqrt(s)=8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev.D 91 (2015) 052009, 2015.
Inspire Record 1340084 DOI 10.17182/hepdata.66764

A search for resonances and quantum black holes is performed using the dijet mass spectra measured in proton-proton collisions at sqrt(s) = 8 TeV with the CMS detector at the LHC. The data set corresponds to an integrated luminosity of 19.7 inverse femtobarns. In a search for narrow resonances that couple to quark-quark, quark-gluon, or gluon-gluon pairs, model-independent upper limits, at 95% confidence level, are obtained on the production cross section of resonances, with masses above 1.2 TeV. When interpreted in the context of specific models the limits exclude: string resonances with masses below 5.0 TeV; excited quarks below 3.5 TeV; scalar diquarks below 4.7 TeV; W' bosons below 1.9 TeV or between 2.0 and 2.2 TeV; Z' bosons below 1.7 TeV; and Randall-Sundrum gravitons below 1.6 TeV. A separate search is conducted for narrow resonances that decay to final states including b quarks. The first exclusion limit is set for excited b quarks, with a lower mass limit between 1.2 and 1.6 TeV depending on their decay properties. Searches are also carried out for wide resonances, assuming for the first time width-to-mass ratios up to 30%, and for quantum black holes with a range of model parameters. The wide resonance search excludes axigluons and colorons with mass below 3.6 TeV, and color-octet scalars with mass below 2.5 TeV. Lower bounds between 5.0 and 6.3 TeV are set on the masses of quantum black holes.

10 data tables

Inclusive dijet mass spectrum from wide jets (points) compared to a fit (solid curve) and to predictions including detector simulation of multijet events and signal resonances. The predicted multijet shape (QCD MC) has been scaled to the data (see text). The vertical error bars are statistical only and the horizontal error bars are the bin widths. For comparison,the signal distributions for a W resonance of mass 1900 GeV and an excited quark of mass 3.6 TeV are shown. The bin-by-bin fit residuals scaled to the statistical uncertainty of the data , (data - fit)/$\sigma_{data}$, are shown at the bottom and compared with the expected signal contributions.

Observed 95% CL upper limits on $\sigma B A$ for narrow qq, qg, and gg resonances, from the inclusive analysis for signal masses between 1.2 and 5.5 TeV.

Observed 95% CL upper limits on $\sigma B A$ for narrow gg/bb, qq/bb, and bg resonances from the b-enriched analysis, for signal masses between 1.2 and 4.0 TeV. The upper limits are given for different ratios $f_{bb}$ for gg/bb and qq/bb resonances, and for 100% branching fraction into bg.

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Search for Displaced Supersymmetry in events with an electron and a muon with large impact parameters

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev.Lett. 114 (2015) 061801, 2015.
Inspire Record 1317640 DOI 10.17182/hepdata.66763

A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at sqrt(s) = 8 TeV. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7 inverse femtobarns. Events are selected with an electron and a muon that have transverse impact parameter values between 0.02 cm and 2 cm. The search has been designed to be sensitive to a wide range of models with nonprompt e-mu final states. Limits are set on the "displaced supersymmetry" model, with pair production of top squarks decaying into an e-mu final state via R-parity-violating interactions. The results are the most restrictive to date on this model, with the most stringent limit being obtained for a top squark lifetime corresponding to c tau = 2 cm, excluding masses below 790 GeV at 95% confidence level.

8 data tables

Electron transverse impact parameter distribution for data and expected background processes after the preselection requirements have been applied. The event yields per bin have been rescaled to account for the varying bin sizes. The rightmost bin contains the overflow entries.

Muon transverse impact parameter distribution for data and expected background processes after the preselection requirements have been applied. The event yields per bin have been rescaled to account for the varying bin sizes. The rightmost contains the overflow entries.

Numbers of expected and observed events in the three search regions (see the text for the definitions of these regions). Background and signal expectations are quoted as $N_{\text{exp}} \pm 1\sigma$ stat $\pm 1\sigma$ syst. If the estimated background is zero in a particular search region, the estimate is instead taken from the preceding region. Since this should always overestimate the background, we denote this by a preceding "<".

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Search for pair production of third-generation scalar leptoquarks and top squarks in proton-proton collisions at sqrt(s) = 8 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett.B 739 (2014) 229-249, 2014.
Inspire Record 1309874 DOI 10.17182/hepdata.66933

A search for pair production of third-generation scalar leptoquarks and supersymmetric top quark partners, top squarks, in final states involving tau leptons and bottom quarks is presented. The search uses events from a data sample of proton-proton collisions corresponding to an integrated luminosity of 19.7 inverse femtobarns, collected with the CMS detector at the LHC with sqrt(s) = 8 TeV. The number of observed events is found to be in agreement with the expected standard model background. Third-generation scalar leptoquarks with masses below 740 GeV are excluded at 95% confidence level, assuming a 100% branching fraction for the leptoquark decay to a tau lepton and a bottom quark. In addition, this mass limit applies directly to top squarks decaying via an R-parity violating coupling lambda'[333]. The search also considers a similar signature from top squarks undergoing a chargino-mediated decay involving the R-parity violating coupling lambda'[3jk]. Each top squark decays to a tau lepton, a bottom quark, and two light quarks. Top squarks in this model with masses below 580 GeV are excluded at 95% confidence level. The constraint on the leptoquark mass is the most stringent to date, and this is the first search for top squarks decaying via lambda'[3jk].

9 data tables

The estimated backgrounds, observed event yields, and expected number of signal events for the leptoquark search. For the simulation-based entries, the statistical and systematic uncertainties are shown separately, in that order.

The estimated backgrounds, observed event yields, and expected number of signal events for the top squark search. For the simulation-based entries, the statistical and systematic uncertainties are shown separately, in that order.

Selection efficiencies in % for the signal in the leptoquark search, estimated from the simulation.

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