A search for the production of heavy partners of the top quark with charge 5/3 is performed in events with a pair of same-sign leptons. The data sample corresponds to an integrated luminosity of 19.5 inverse femtobarns and was collected at sqrt(s) = 8 TeV by the CMS experiment. No significant excess is observed in the data above the expected background and the existence of top-quark partners with masses below 800 GeV is excluded at a 95% confidence level, assuming they decay exclusively to tW. This is the first limit on these particles from the LHC, and it is significantly more restrictive than previous limits.
The distribution of HT for all channels combined after the full selection except for the HT requirement itself.
Expected and observed 95% CL limits on the $\mathrm{T}_{5/3}$ production cross section times the branching fraction for decay to same-sign dileptons.
The distribution of HT for all channels combined, after the requirement of same- sign dileptons, the Z-boson veto, and a requirement of at least two jets.
The ratio between the prompt psi(2S) and J/psi yields, reconstructed via their decays into muon pairs, is measured in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV. The analysis is based on PbPb and pp data samples collected by CMS at the LHC, corresponding to integrated luminosities of 150 inverse microbarns and 5.4 inverse picobarns, respectively. The double ratio of measured yields, (N[psi(2S)]/N[J/psi])[PbPb] / (N[psi(2S)]/ N[J/psi])[pp], is computed in three PbPb collision centrality bins and two kinematic ranges: one at midrapidity, abs(y) < 1.6, covering the transverse momentum range 6.5 < pt < 30 GeV/c, and the other at forward rapidity, 1.6 < abs(y) < 2.4, extending to lower pt values, 3 < pt < 30 GeV/c. The centrality-integrated double ratio changes from 0.45 +/- 0.13 (stat) +/- 0.07 (syst) in the first range to 1.67 +/- 0.34 (stat) +/- 0.27 (syst) in the second. This difference is most pronounced in the most central collisions.
Double ratio of measured yields, $(N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{\mathrm{PbPb}} / (N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{pp}$, as a function of centrality, for the midrapidity analysis bin.
Double ratio of measured yields, $(N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{\mathrm{PbPb}} / (N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{pp}$, as a function of centrality, for the forward rapidity analysis bin.
Double ratio of measured yields, $(N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{\mathrm{PbPb}} / (N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{pp}$, integrated over centrality, for the midrapidity and forward rapidity analysis bins.
The first study of W boson production in pPb collisions is presented, for bosons decaying to a muon or electron, and a neutrino. The measurements are based on a data sample corresponding to an integrated luminosity of 34.6 inverse nanobarns at a nucleon-nucleon centre-of-mass energy of sqrt(s[NN]) = 5.02 TeV, collected by the CMS experiment. The W boson differential cross sections, lepton charge asymmetry, and forward-backward asymmetries are measured for leptons of transverse momentum exceeding 25 GeV, and as a function of the lepton pseudorapidity in the abs(eta[lab]) < 2.4 range. Deviations from the expectations based on currently available parton distribution functions are observed, showing the need for including W boson data in nuclear parton distribution global fits.
Lepton charge asymmetry, $(N_{\ell}^+ - N_{\ell}^-)/(N_{\ell}^+ + N_{\ell}^-)$ as a function of the lepton pseudorapidity.
Production cross section for $\textrm{pPb} \to W^+ + X \to \ell \nu + X$ for positively (top) and negatively (bottom) charged leptons of $p_T$ larger than 25 GeV$/c$, in nanobarns, as a function of the lepton pseudorapidity. Values are given first for muons and electrons separately, then combined. The global normalization uncertainty of 3.5\% is not included in the listed uncertainties.
Production cross section for $\textrm{pPb} \to W^- + X \to \ell \nu + X$ for positively (top) and negatively (bottom) charged leptons of $p_T$ larger than 25 GeV$/c$, in nanobarns, as a function of the lepton pseudorapidity. Values are given first for muons and electrons separately, then combined. The global normalization uncertainty of 3.5\% is not included in the listed uncertainties.
The relative yields of $\Upsilon$ mesons produced in pp and PbPb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV and reconstructed via the dimuon decay channel are measured using data collected by the CMS experiment. Double ratios are formed by comparing the yields of the excited states, $\Upsilon$(2S) and $\Upsilon$(3S), to the ground state, $\Upsilon$(1S), in both PbPb and pp collisions at the same center-of-mass energy. The double ratios, [$\Upsilon$(nS)/$\Upsilon$(1S)]$_\mathrm{PbPb}$ / [$\Upsilon$(nS)/$\Upsilon$(1S)]$_\mathrm{pp}$, are measured to be 0.308 $\pm$ 0.055 (stat) $\pm$ 0.019 (syst) for the $\Upsilon$(2S) and less than 0.26 at 95% confidence level for the $\Upsilon$(3S). No significant $\Upsilon$(3S) signal is found in the PbPb data. The double ratios are studied as a function of collision centrality, as well as dimuon transverse momentum and rapidity. No significant dependencies are observed.
Double ratio of measured yields, $(N_{\varUpsilon(2S)} / N_{\varUpsilon(1S)})_{\mathrm{PbPb}} / (N_{\varUpsilon(2S)} / N_{\varUpsilon(1S)})_{pp}$, as a function of centrality, for upsilon $|y|<2.4$ and $p_T<30$GeV, and $p_{T}^{\mu}>4$GeV.
Double ratio of measured yields, $(N_{\varUpsilon(2S)} / N_{\varUpsilon(1S)})_{\mathrm{PbPb}} / (N_{\varUpsilon(2S)} / N_{\varUpsilon(1S)})_{pp}$, as a function of pT, for upsilon $|y|<2.4$, $p_{T}^{\mu}>4$GeV, and 0--100\% event centrality.
Double ratio of measured yields, $(N_{\varUpsilon(2S)} / N_{\varUpsilon(1S)})_{\mathrm{PbPb}} / (N_{\varUpsilon(2S)} / N_{\varUpsilon(1S)})_{pp}$, as a function of rapidity, for upsilon $pT<30$GeV, $p_{T}^{\mu}>4$GeV, and 0--100\% event centrality.
The nuclear modification factor RAA and the azimuthal anisotropy coefficient v[2] of prompt and nonprompt (i.e. those from decays of b hadrons) J/psi mesons, measured from PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV at the LHC, are reported. The results are presented in several event centrality intervals and several kinematic regions, for transverse momenta pt > 6.5 GeV/c and rapidity abs(y) < 2.4, extending down to pt = 3 GeV/c in the 1.6 < abs(y) < 2.4 range. The v[2] of prompt J/psi is found to be nonzero, but with no strong dependence on centrality, rapidity, or pt over the full kinematic range studied. The measured v[2] of nonprompt J/psi is consistent with zero. The RAA of prompt J/psi exhibits a suppression that increases from peripheral to central collisions but does not vary as a function of either y or pt in the fiducial range. The nonprompt J/psi RAA shows a suppression which becomes stronger as rapidity or pt increase. The v[2] and nuclear suppression of open and hidden charm, and of open charm and beauty, are compared.
Prompt J/$\psi$ $v_{2}$ as a function of centrality. The average ${N}_{\rm part}$ values correspond to events flatly distributed across centrality.
Prompt J/$\psi$ $v_{2}$ as a function of rapidity.
Prompt J/$\psi$ $v_{2}$ as a function of $p_{T}$.
The production yields of Upsilon(1S), Upsilon(2S), and Upsilon(3S) quarkonium states are measured through their decays into muon pairs in the CMS detector, in PbPb and pp collisions at the centre-of-mass energy per nucleon pair of 2.76 TeV. The data correspond to integrated luminosities of 166 inverse microbarns and 5.4 inverse picobarns for PbPb and pp collisions, respectively. Differential production cross sections are reported as functions of Upsilon rapidity y up to 2.4, and transverse momentum pT up to 20 GeV/c. A strong centrality-dependent suppression is observed in PbPb relative to pp collisions, by factors of up to approximately 2 and 8, for the Upsilon(1S) and Upsilon(2S) states, respectively. No significant dependence of this suppression is observed as a function of y or pT. The Upsilon(3S) state is not observed in PbPb collisions, which corresponds to a suppression for the centrality-integrated data by at least a factor of approximately 7 at a 95% confidence level. The observed suppression is in agreement with theoretical scenarios modeling the sequential melting of quarkonium states in a quark gluon plasma.
Differential cross section for Y(1S) states as a function of their transverse momentum and per unit of rapidity in pp collisions. Statistical (systematic) uncertainties are displayed as error bars (boxes). Global relative uncertainties of 3.7% are not displayed.
Differential cross section for Y(2S) states as a function of their transverse momentum and per unit of rapidity in pp collisions. Statistical (systematic) uncertainties are displayed as error bars (boxes). Global relative uncertainties of 3.7% are not displayed.
Differential cross section for Y(3S) states as a function of their transverse momentum and per unit of rapidity in pp collisions. Statistical (systematic) uncertainties are displayed as error bars (boxes). Global relative uncertainties of 3.7% are not displayed.
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.
Interpretation of results in the T1tttt model. The colored regions show the upper limits (95\% CL) on the production cross section for $pp\rightarrow \tilde{g}\tilde{g},\tilde{g}\rightarrow t\bar{t}\tilde{\chi}^0_1$ in the $m_{\tilde{g}}$-$m_{\tilde{\chi}^0_1}$ plane.
Interpretation of results in the T1tttt model. The colored regions show the upper limits (95\% CL) on the production cross section for $pp\rightarrow \tilde{g}\tilde{g},\tilde{g}\rightarrow t\bar{t}\tilde{\chi}^0_1$ in the $m_{\tilde{g}}$-$m_{\tilde{\chi}^0_1}$ plane. The curve shows the observed limit on the corresponding SUSY particle masses obtained by comparing the excluded cross section with theoretical cross sections.
Interpretation of results in the T1tttt model. The colored regions show the upper limits (95\% CL) on the production cross section for $pp\rightarrow \tilde{g}\tilde{g},\tilde{g}\rightarrow t\bar{t}\tilde{\chi}^0_1$ in the $m_{\tilde{g}}$-$m_{\tilde{\chi}^0_1}$ plane. The curve shows the observed limit on the corresponding SUSY particle masses obtained by comparing the excluded cross section with $+1\sigma$ theoretical cross sections.
The relative modification of the prompt psi(2S) and J/psi yields from pp to PbPb collisions, at the center of mass energy of 5.02 TeV per nucleon pair, is presented. The analysis is based on pp and PbPb data samples collected by the CMS experiment at the LHC in 2015, corresponding to integrated luminosities of 28.0 inverse picobarns and 464 inverse microbarns, respectively. The double ratio of measured yields of prompt charmonia reconstructed through their decays into muon pairs, (N[psi(2S)]/N[J/psi])[PbPb] / (N[psi(2S)]/N[J/psi])[pp], is determined as a function of PbPb collision centrality and charmonium transverse momentum pt, in two kinematic intervals: abs(y) < 1.6 covering 6.5 < pt < 30 GeV/c and 1.6 < abs(y) < 2.4 covering 3 < pt < 30 GeV/c. The centrality-integrated double ratios are 0.36 +/- 0.08 (stat) +/-0.05 (syst) in the first interval and 0.24 +/- 0.22 (stat) +/- 0.09 (syst) in the second. The double ratio is lower than unity in all the measured bins, suggesting that the psi(2S) yield is more suppressed than the J/psi yield in the explored phase space.
Double ratio of measured yields, $(N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{\mathrm{PbPb}} / (N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{pp}$, as a function of pT, for the midrapidity analysis bin.
95% CL intervals on the double ratio of measured yields, $(N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{\mathrm{PbPb}} / (N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{pp}$, as a function of pT, for the midrapidity analysis bin.
Double ratio of measured yields, $(N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{\mathrm{PbPb}} / (N_{\psi\mathrm{(2S)}} / N_{J/\psi})_{pp}$, as a function of pT, for the forward rapidity analysis bin.
A search is performed for anomalous interactions of the recently discovered Higgs boson using matrix element techniques with the information from its decay to four leptons and from associated Higgs boson production with two quark jets in either vector boson fusion or associated production with a vector boson. The data were recorded by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 38.6 inverse femtobarns. These data are combined with the data collected at center-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 inverse femtobarns, respectively. All observations are consistent with the expectations for the standard model Higgs boson.
Observed and expected likelihood scans $f_{a3}\cos\phi_{a3}$. See Section 2 of the paper for more details.
Observed and expected likelihood scans $f_{a2}\cos\phi_{a2}$. See Section 2 of the paper for more details.
Observed and expected likelihood scans $f_{\Lambda1}\cos\phi_{\Lambda1}$. See Section 2 of the paper for more details.
A search for new physics in events with a Z boson produced in association with large missing transverse momentum at the LHC is presented. The search is based on the 2016 data sample of proton-proton collisions recorded with the CMS experiment at $\sqrt{s} = $ 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The results of this search are interpreted in terms of a simplified model of dark matter production via spin-0 or spin-1 mediators, a scenario with a standard-model-like Higgs boson produced in association with the Z boson and decaying invisibly, a model of unparticle production, and a model with large extra spatial dimensions. No significant deviations from the background expectations are found, and limits are set on relevant model parameters, significantly extending the results previously achieved in this channel.
Expected event yields in each $p_{\mathrm{T}}^{\mathrm{miss}}$ bin for the sum of background processes in the signal region (SR). The background yields and their corresponding uncertainties are obtained after performing a fit to data. Two sets of background yields are reported: one from a background-only fit to data in both the SR and the control regions (CRs), and one from a fit to data in all CRs, but excluding data in the SR. The observed numbers of events in each bin are also included. The last bin includes overflow.
Limit on the signal strength of the DM signal in a simplified model with a vector mediator.
Limit on the signal strength of the DM signal in a simplified model with an axial-vector mediator.
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