This paper presents distributions of topological observables in inclusive three- and four-jet events produced in pp collisions at a centre-of-mass energy of 7 $\,\text {TeV}$ with a data sample collected by the CMS experiment corresponding to a luminosity of 5.1 $\,\text {fb}^{-1}$ . The distributions are corrected for detector effects, and compared with several event generators based on two- and multi-parton matrix elements at leading order. Among the considered calculations, MadGraph interfaced with pythia6 displays the overall best agreement with data.

A search is reported for massive resonances decaying into a quark and a vector boson (W or Z), or two vector bosons (WW, WZ, or ZZ). The analysis is performed on an inclusive sample of multijet events corresponding to an integrated luminosity of 19.7 inverse femtobarns, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. The search uses novel jet-substructure identification techniques that provide sensitivity to the presence of highly boosted vector bosons decaying into a pair of quarks. Exclusion limits are set at a confidence level of 95% on the production of: (i) excited quark resonances q* decaying to qW and qZ for masses less than 3.2 TeV and 2.9 TeV, respectively, (ii) a Randall-Sundrum graviton G[RS] decaying into WW for masses below 1.2 TeV, and (iii) a heavy partner of the W boson W' decaying into WZ for masses less than 1.7 TeV. For the first time mass limits are set on W' to WZ and G[RS] to WW in the all-jets final state. The mass limits on q* to qW, q* to qZ, W' to WZ, G[RS] to WW are the most stringent to date. A model with a "bulk" graviton G[Bulk] that decays into WW or ZZ bosons is also studied.

Measurements of $W\gamma$ and $Z\gamma$ production in proton-proton collisions at $\sqrt{s}$ = 7 TeV are used to extract limits on anomalous triple gauge couplings. The results are based on data recorded by the CMS experiment at the LHC that correspond to an integrated luminosity of 5.0 inverse femtobarns. The cross sections are measured for photon transverse momenta $p_T^{\gamma} \gt$ 15 GeV, and for separations between photons and final-state charged leptons in the pseudorapidity-azimuthal plane of $\Delta R(l, \gamma) \gt$ 0.7 in $l \nu \gamma$ and $ll \gamma$ final states, where l refers either to an electron or a muon. A dilepton invariant mass requirement of $m_{ll} \gt$ 50 GeV is imposed for the Z$\gamma$ process. No deviations are observed relative to predictions from the standard model, and limits are set on anomalous WW$\gamma$, ZZ$\gamma$, and Z$\gamma\gamma$ triple gauge couplings.

A search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks is presented. Events with hadronic jets and one or two oppositely charged leptons are selected from a data sample corresponding to an integrated luminosity of 19.5 $\,\text {fb}^\text {-1}$ collected by the CMS experiment at the LHC in $\mathrm {p}\mathrm {p}$ collisions at a centre-of-mass energy of 8 $\,\hbox {TeV}$ . In order to separate the signal from the larger $\hbox {t}\overline{\hbox {t}}$  + jets background, this analysis uses a matrix element method that assigns a probability density value to each reconstructed event under signal or background hypotheses. The ratio between the two values is used in a maximum likelihood fit to extract the signal yield. The results are presented in terms of the measured signal strength modifier, $\mu $ , relative to the standard model prediction for a Higgs boson mass of 125 $\,\hbox {GeV}$ . The observed (expected) exclusion limit at a 95 % confidence level is $\mu <4.2$ (3.3), corresponding to a best fit value $\hat{\mu }=1.2^{+1.6-1.5}$ .

Measurements are presented of the t-channel single-top-quark production cross section in proton-proton collisions at $ \sqrt{s} $ = 8 TeV. The results are based on a data sample corresponding to an integrated luminosity of 19.7 fb$^{−1}$ recorded with the CMS detector at the LHC. The cross section is measured inclusively, as well as separately for top (t) and antitop $ \left(\overline{\mathrm{t}}\right) $ , in final states with a muon or an electron. The measured inclusive t-channel cross section is σ$_{t-ch.}$ = 83.6 ± 2.3 (stat.) ± 7.4 (syst.) pb. The single t and $ \overline{\mathrm{t}} $ cross sections are measured to be σ$_{t-ch.}$(t) = 53.8 ± 1.5 (stat.) ± 4.4 (syst.) pb and σ$_{t-ch.}$ $ \left(\overline{t}\right) $ = 27.6 ± 1.3 (stat.) ± 3.7 (syst.) pb, respectively. The measured ratio of cross sections is R$_{t-ch.}$ = σ$_{t-ch.}$(t)/σ$_{t-ch.}$ $ \left(\overline{\mathrm{t}}\right) $ = 1.95 ± 0.10 (stat.) ± 0.19 (syst.), in agreement with the standard model prediction. The modulus of the Cabibbo-Kobayashi-Maskawa matrix element V$_{tb}$ is extracted and, in combination with a previous CMS result at $ \sqrt{s} $ = 7 TeV, a value |V$_{tb}$| = 0.998 ± 0.038 (exp.) ± 0.016 (theo.) is obtained.

The double-differential cross sections of promptly produced J/psi and psi(2S) mesons are measured in pp collisions at sqrt(s) = 7 TeV, as a function of transverse momentum pt and absolute rapidity abs(y). The analysis uses J/psi and psi(2S) dimuon samples collected by CMS, corresponding to integrated luminosities of 4.55 and 4.90 inverse femtobarns, respectively. The results are based on a two-dimensional analysis of the dimuon invariant mass and decay length, and extend to pt = 120 and 100 GeV for the J/psi and psi(2S), respectively, when integrated over the interval abs(y) < 1.2. The ratio of the psi(2S) to J/psi cross sections is also reported for abs(y) < 1.2, over the range 10 < pt < 100 GeV. These are the highest pt values for which the cross sections and ratio have been measured.

A search for baryon number violation (BNV) in top-quark decays is performed using pp collisions produced by the LHC at sqrt(s) = 8 TeV. The top-quark decay considered in this search results in one light lepton (muon or electron), two jets, but no neutrino in the final state. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.5 inverse femtobarns. The event selection is optimized for top quarks produced in pairs, with one undergoing the BNV decay and the other the standard model hadronic decay to three jets. No significant excess of events over the expected yield from standard model processes is observed. The upper limits at 95% confidence level on the branching fraction of the BNV top-quark decay are calculated to be 0.0016 and 0.0017 for the muon and the electron channels, respectively. Assuming lepton universality, an upper limit of 0.0015 results from the combination of the two channels. These limits are the first that have been obtained on a BNV process involving the top quark.

Searches for anomalous top quark-antiquark production are presented, based on pp collisions at sqrt(s) = 8 TeV. The data, corresponding to an integrated luminosity of 19.7 inverse femtobarns, were collected with the CMS detector at the LHC. The observed ttbar invariant mass spectrum is found to be compatible with the standard model prediction. Limits on the production cross section times branching fraction probe, for the first time, a region of parameter space for certain models of new physics not yet constrained by precision measurements.

A search is performed for pair-produced spin-3/2 excited top quarks t ∗ t ¯ ∗ , each decaying to a top quark and a gluon. The search uses data collected with the CMS detector from pp collisions at a center-of-mass energy of s = 8 TeV, selecting events that have a single isolated muon or electron, an imbalance in transverse momentum, and at least six jets, of which one must be compatible with originating from the fragmentation of a b quark. The data, corresponding to an integrated luminosity of 19.5 fb(−1), show no significant excess over standard model predictions, and provide a lower limit of 803 GeV at 95% confidence on the mass of the spin-3/2 t(*) quark in an extension of the Randall-Sundrum model, assuming a 100% branching fraction of its decay into a top quark and a gluon. This is the first search for a spin-3/2 excited top quark performed at the LHC.

<p>The ratio between the prompt <inline-formula><mml:math display="inline"><mml:mi>ψ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>2</mml:mn><mml:mi>S</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:math></inline-formula> and <inline-formula><mml:math display="inline"><mml:mi>J</mml:mi><mml:mo stretchy="false">/</mml:mo><mml:mi>ψ</mml:mi></mml:math></inline-formula> yields, reconstructed via their decays into <inline-formula><mml:math display="inline"><mml:msup><mml:mi>μ</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>μ</mml:mi><mml:mo>-</mml:mo></mml:msup></mml:math></inline-formula>, is measured in Pb-Pb and <inline-formula><mml:math display="inline"><mml:mi>p</mml:mi></mml:math></inline-formula>-<inline-formula><mml:math display="inline"><mml:mi>p</mml:mi></mml:math></inline-formula> collisions at <inline-formula><mml:math display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:msub><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mi>N</mml:mi><mml:mi>N</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>2.76</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:mrow></mml:math></inline-formula>. The analysis is based on Pb-Pb and <inline-formula><mml:math display="inline"><mml:mi>p</mml:mi></mml:math></inline-formula>-<inline-formula><mml:math display="inline"><mml:mi>p</mml:mi></mml:math></inline-formula> data samples collected by CMS at the Large Hadron Collider, corresponding to integrated luminosities of <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>150</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>μ</mml:mi><mml:msup><mml:mrow><mml:mi mathvariant="normal">b</mml:mi></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula> and <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>5.4</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msup><mml:mrow><mml:mi>pb</mml:mi></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula>, respectively. The double ratio of measured yields <inline-formula><mml:math display="inline"><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>ψ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>2</mml:mn><mml:mi>S</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:msub><mml:mo stretchy="false">/</mml:mo><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>J</mml:mi><mml:mo stretchy="false">/</mml:mo><mml:mi>ψ</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mo stretchy="false">)</mml:mo></mml:mrow><mml:mrow><mml:mi>Pb</mml:mi><mml:mtext>-</mml:mtext><mml:mi>Pb</mml:mi></mml:mrow></mml:msub><mml:mo stretchy="false">/</mml:mo><mml:mspace linebreak="goodbreak"/><mml:mo stretchy="false">(</mml:mo><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>ψ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>2</mml:mn><mml:mi>S</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:msub><mml:mo stretchy="false">/</mml:mo><mml:msub><mml:mrow><mml:mi>N</mml:mi></mml:mrow><mml:mrow><mml:mi>J</mml:mi><mml:mo stretchy="false">/</mml:mo><mml:mi>ψ</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mo stretchy="false">)</mml:mo></mml:mrow><mml:mrow><mml:mi>p</mml:mi><mml:mtext/><mml:mtext>-</mml:mtext><mml:mi>p</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> is computed in three Pb-Pb collision centrality bins and two kinematic ranges: one at midrapidity, <inline-formula><mml:math display="inline"><mml:mrow><mml:mo stretchy="false">|</mml:mo><mml:mi>y</mml:mi><mml:mo stretchy="false">|</mml:mo></mml:mrow><mml:mo>&lt;</mml:mo><mml:mn>1.6</mml:mn></mml:math></inline-formula>, covering the transverse momentum range <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>6.5</mml:mn><mml:mo>&lt;</mml:mo><mml:msub><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>T</mml:mi></mml:mrow></mml:msub><mml:mo>&lt;</mml:mo><mml:mn>30</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>GeV</mml:mi><mml:mo>/</mml:mo><mml:mi>c</mml:mi></mml:mrow></mml:math></inline-formula>, and the other at forward rapidity, <inline-formula><mml:math display="inline"><mml:mn>1.6</mml:mn><mml:mo>&lt;</mml:mo><mml:mrow><mml:mo stretchy="false">|</mml:mo><mml:mi>y</mml:mi><mml:mo stretchy="false">|</mml:mo></mml:mrow><mml:mo>&lt;</mml:mo><mml:mn>2.4</mml:mn></mml:math></inline-formula>, extending to lower <inline-formula><mml:math display="inline"><mml:msub><mml:mi>p</mml:mi><mml:mi>T</mml:mi></mml:msub></mml:math></inline-formula> values, <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>3</mml:mn><mml:mo>&lt;</mml:mo><mml:msub><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>T</mml:mi></mml:mrow></mml:msub><mml:mo>&lt;</mml:mo><mml:mn>30</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>GeV</mml:mi><mml:mo>/</mml:mo><mml:mi>c</mml:mi></mml:mrow></mml:math></inline-formula>. The centrality-integrated double ratio changes from <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>0.45</mml:mn><mml:mo>±</mml:mo><mml:mn>0.13</mml:mn><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mtext>stat</mml:mtext><mml:mo stretchy="false">)</mml:mo></mml:mrow><mml:mo>±</mml:mo><mml:mn>0.07</mml:mn><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mtext>syst</mml:mtext><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> in the first range to <inline-formula><mml:math display="inline"><mml:mn>1.67</mml:mn><mml:mo>±</mml:mo><mml:mn>0.34</mml:mn><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mtext>stat</mml:mtext><mml:mo stretchy="false">)</mml:mo></mml:mrow><mml:mo>±</mml:mo><mml:mn>0.27</mml:mn><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mtext>syst</mml:mtext><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math></inline-formula> in the second. This difference is most pronounced in the most central collisions.</p>

A search is presented for particle dark matter produced in association with a pair of top quarks in pp collisions at a centre-of-mass energy of $ \sqrt{s}=8 $ TeV. The data were collected with the CMS detector at the LHC and correspond to an integrated luminosity of 19.7 fb$^{−1}$. This search requires the presence of one lepton, multiple jets, and large missing transverse energy. No excess of events is found above the SM expectation, and upper limits are derived on the production cross section. Interpreting the findings in the context of a scalar contact interaction between fermionic dark matter particles and top quarks, lower limits on the interaction scale are set. These limits are also interpreted in terms of the dark matter-nucleon scattering cross sections for the spin-independent scalar operator and they complement direct searches for dark matter particles in the low mass region.

A search for neutral Higgs bosons decaying into a $ \mathrm{b}\overline{\mathrm{b}} $ quark pair and produced in association with at least one additional b quark is presented. This signature is sensitive to the Higgs sector of the minimal supersymmetric standard model (MSSM) with large values of the parameter tan β. The analysis is based on data from proton-proton collisions at a center-of-mass energy of 8 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.7 fb$^{−1}$. The results are combined with a previous analysis based on 7 TeV data. No signal is observed. Stringent upper limits on the cross section times branching fraction are derived for Higgs bosons with masses up to 900 GeV, and the results are interpreted within different MSSM benchmark scenarios, m$_{h}^{max}$ , m$_{h}^{mod +}$ , m$_{h}^{mod −}$ , light-stau and light-stop. Observed 95% confidence level upper limits on tan β, ranging from 14 to 50, are obtained in the m$_{h}^{mod +}$ benchmark scenario.

A search for neutral Higgs bosons predicted in the minimal supersymmetric standard model (MSSM) for μ+μ− decay channels is presented. The analysis uses data collected by the CMS experiment at the LHC in proton–proton collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.3 fb −1 , respectively. The search is sensitive to Higgs bosons produced either through the gluon fusion process or in association with a bb‾ quark pair. No statistically significant excess is observed in the μ+μ− mass spectrum. Results are interpreted in the framework of several benchmark scenarios, and the data are used to set an upper limit on the MSSM parameter tan⁡β as a function of the mass of the pseudoscalar A boson in the range from 115 to 300 GeV. Model independent upper limits are given for the product of the cross section and branching fraction for gluon fusion and b quark associated production at s=8 TeV . They are the most stringent limits obtained to date in this channel.

A comparison of the differential cross sections for the processes Z/γ$^{*}$ + jets and photon (γ)+jets is presented. The measurements are based on data collected with the CMS detector at $ \sqrt{s}=8 $ TeV corresponding to an integrated luminosity of 19.7 fb$^{−1}$. The differential cross sections and their ratios are presented as functions of p$_{T}$. The measurements are also shown as functions of the jet multiplicity. Differential cross sections are obtained as functions of the ratio of the Z/γ$^{*}$ p$_{T}$ to the sum of all jet transverse momenta and of the ratio of the Z/γ$^{*}$ p$_{T}$ to the leading jet transverse momentum. The data are corrected for detector effects and are compared to simulations based on several QCD calculations.

A search is described for a Higgs boson decaying into two photons, one of which has an internal conversion to a muon or an electron pair ( ℓℓγ ). The analysis is performed using proton–proton collision data recorded with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb −1 . The events selected have an opposite-sign muon or electron pair and a high transverse momentum photon. No excess above background has been found in the three-body invariant mass range 120<mℓℓγ<150 GeV , and limits have been derived for the Higgs boson production cross section times branching fraction for the decay H→γ⁎γ→ℓℓγ , where the dilepton invariant mass is less than 20 GeV. For a Higgs boson with mH=125 GeV , a 95% confidence level (CL) exclusion observed (expected) limit is 6.7 ( 5.9−1.8+2.8 ) times the standard model prediction. Additionally, an upper limit at 95% CL on the branching fraction of H→(J/ψ)γ for the 125 GeV Higgs boson is set at 1.5×10−3 .

A search for new resonances decaying to WW, ZZ, or WZ is presented. Final states are considered in which one of the vector bosons decays leptonically and the other hadronically. Results are based on data corresponding to an integrated luminosity of 19.7 inverse femtobarns recorded in proton-proton collisions at $\sqrt{s}$ = 8 TeV with the CMS detector at the CERN LHC. Techniques aiming at identifying jet substructures are used to analyze signal events in which the hadronization products from the decay of highly boosted W or Z bosons are contained within a single reconstructed jet. Upper limits on the production of generic WW, ZZ, or WZ resonances are set as a function of the resonance mass and width. We increase the sensitivity of the analysis by statistically combining the results of this search with a complementary study of the all-hadronic final state. Upper limits at 95% confidence level are set on the bulk graviton production cross section in the range from 700 to 10 femtobarns for resonance masses between 600 and 2500 GeV, respectively. These limits on the bulk graviton model are the most stringent to date in the diboson final state.