10811384
Measurement of associated W + charm production in pp collisions at $ \sqrt{s} $ = 7 TeV
A bstractMeasurements are presented of the associated production of a W boson and a charm-quark jet (W + c) in pp collisions at a center-of-mass energy of 7 TeV. The analysis is conducted with a data sample corresponding to a total integrated luminosity of 5 fb−1, collected by the CMS detector at the LHC. W boson candidates are identified by their decay into a charged lepton (muon or electron) and a neutrino. The W + c measurements are performed for charm-quark jets in the kinematic region $ p_{\mathrm{T}}^{\mathrm{jet}} $> 25 GeV, |ηjet| < 2.5, for two different thresholds for the transverse momentum of the lepton from the W-boson decay, and in the pseudorapidity range |ηℓ| < 2.1. Hadronic and inclusive semileptonic decays of charm hadrons are used to measure the following total cross sections: σ(pp → W + c + X) × $ \mathcal{B} $(W → ℓν) = 107.7 ± 3.3 (stat.) ± 6.9 (syst.) pb ($ p_{\mathrm{T}}^{\ell } $> 25 GeV) and σ(pp → W + c + X)×$ \mathcal{B} $(W → ℓν) = 84.1 ± 2.0 (stat.) ± 4.9 (syst.) pb ($ p_{\mathrm{T}}^{\ell } $> 35 GeV), and the cross section ratios σ(pp → W+ + $ \overline{c} $ + X)/σ(pp → W− + c + X) = 0.954 ± 0.025 (stat.) ± 0.004 (syst.) ($ p_{\mathrm{T}}^{\ell } $> 25 GeV) and σ(pp → W+ + $ \overline{\mathrm{c}} $ + X)/σ(pp → W− + c + X) = 0.938 ± 0.019 (stat.) ± 0.006 (syst.) ($ p_{\mathrm{T}}^{\ell } $> 35 GeV). Cross sections and cross section ratios are also measured differentially with respect to the absolute value of the pseudorapidity of the lepton from the W-boson decay. These are the first measurements from the LHC directly sensitive to the strange quark and antiquark content of the proton. Results are compared with theoretical predictions and are consistent with the predictions based on global fits of parton distribution functions.

86624438
Search for massive resonances decaying into pairs of boosted bosons in semi-leptonic final states at s$$ \sqrt{s} $$ = 8 TeV
A bstractA 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 fb−1 recorded in proton-proton collisions at s$$ \sqrt{s} $$ = 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 fb 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.

841502
Observation of the diphoton decay of the Higgs boson and measurement of its properties
Observation of the diphoton decay mode of the recently discovered Higgs boson and measurement of some of its properties are reported. The analysis uses the entire dataset collected by the CMS experiment in proton-proton collisions during the 2011 and 2012 LHC running periods. The data samples correspond to integrated luminosities of 5.1$$\,\text {fb}^\text {-1}$$fb-1at $$\sqrt{s}=7\,\text {TeV}\,$$s=7TeV and 19.7$$\,\text {fb}^\text {-1}$$fb-1at 8$$\,\text {TeV}$$TeV . A clear signal is observed in the diphoton channel at a mass close to 125$$\,\text {GeV}$$GeV with a local significance of $$5.7\,\sigma $$5.7σ, where a significance of $$5.2\,\sigma $$5.2σ is expected for the standard model Higgs boson. The mass is measured to be $$124.70\pm 0.34\,\text {GeV} \,=124.70\pm 0.31\,\text {(stat)}\,\pm 0.15\,\text {(syst)}\,\,\text {GeV} \,$$124.70±0.34GeV=124.70±0.31(stat)±0.15(syst)GeV , and the best-fit signal strength relative to the standard model prediction is $$1.14^\mathrm{+0.26}_{-0.23}=1.14\pm 0.21\,\text {(stat)}\,$$1.14-0.23+0.26=1.14±0.21(stat)$$^\mathrm{+0.09}_{-0.05}\,\text {(syst)}\,$$-0.05+0.09(syst)$$^\mathrm{+0.13}_{-0.09}\,\text {(theo)}\,$$-0.09+0.13(theo). Additional measurements include the signal strength modifiers associated with different production mechanisms, and hypothesis tests between spin-0 and spin-2 models.
32172622
Measurement of WZ and ZZ production in pp collisions at $$\sqrt{s} = 8\,\text {TeV} $$s=8TeV in final states with b-tagged jets
Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at $$\sqrt{s} = 8$$s=8$$\,\text {TeV}$$TeV in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either $$\mathrm {W}\rightarrow \mathrm {e}\nu $$W→eν, $$\mathrm {\mu }\nu $$μν or $$\mathrm {Z}\rightarrow \mathrm {e}^+\mathrm {e}^-$$Z→e+e-, $$\mathrm {\mu ^+}\mathrm {\mu ^-}$$μ+μ-, or $${\nu }\overline{\nu }$$νν¯). The results are based on data corresponding to an integrated luminosity of 18.9 fb$$^{-1}$$-1 collected with the CMS detector at the Large Hadron Collider. The measured cross sections, $$\sigma (\mathrm {p}\mathrm {p}\rightarrow \mathrm {W}\mathrm {Z}) = 30.7 \pm 9.3\,\text {(stat.)} \pm 7.1\,\text {(syst.)} \pm 4.1\,\text {(th.)} \pm 1.0\,\text {(lum.)} \,\text {pb} $$σ(pp→WZ)=30.7±9.3(stat.)±7.1(syst.)±4.1(th.)±1.0(lum.)pb and $$\sigma (\mathrm {p}\mathrm {p}\rightarrow \mathrm {Z}\mathrm {Z}) = 6.5 \pm 1.7\,\text {(stat.)} \pm 1.0\,\text {(syst.)} \pm 0.9\,\text {(th.)} \pm 0.2\,\text {(lum.)} \,\text {pb} $$σ(pp→ZZ)=6.5±1.7(stat.)±1.0(syst.)±0.9(th.)±0.2(lum.)pb, are consistent with next-to-leading order quantum chromodynamics calculations.
119204233
Search for new physics in events with same-sign dileptons and b-tagged jets in pp collisions at $ \sqrt {s} = 7 $ TeV
A bstractA search for new physics is performed using isolated same-sign dileptons with at least two b-quark jets in the final state. Results are based on a 4.98 fb−1 sample of proton-proton collisions at a centre-of-mass energy of 7 TeV collected by the CMS detector. No excess above the standard model background is observed. Upper limits at 95% confidence level are set on the number of events from non-standard-model sources. These limits are used to set constraints on a number of new physics models. Information on acceptance and efficiencies are also provided so that the results can be used to confront additional models in an approximate way.
37672579
Search for heavy neutrinos and $$\mathrm {W}$$W bosons with right-handed couplings in proton–proton collisions at $$\sqrt{s} = 8\,\text {TeV} $$s=8TeV
A search for heavy, right-handed neutrinos, $$\mathrm {N}_{\ell }$$Nℓ ($$\ell = \mathrm {e}, \mu $$ℓ=e,μ), and right-handed $$\mathrm {W}_{\mathrm {R}}$$WR bosons, which arise in the left-right symmetric extensions of the standard model, has been performed by the CMS experiment. The search was based on a sample of two lepton plus two jet events collected in proton–proton collisions at a center-of-mass energy of 8$$\,\text {TeV}$$TeV corresponding to an integrated luminosity of 19.7 $$\mathrm{fb}^{-1}$$fb-1. For models with strict left-right symmetry, and assuming only one $$\mathrm {N}_{\ell }$$Nℓ flavor contributes significantly to the $$\mathrm {W}_{\mathrm {R}}$$WR decay width, the region in the two-dimensional $$(M_{\mathrm {W}_{\mathrm {R}}}, M_{\mathrm {N}_{\ell }})$$(MWR,MNℓ) mass plane excluded at a 95 % confidence level extends to approximately $$M_{\mathrm {W}_{\mathrm {R}}} = 3.0\,\text {TeV} $$MWR=3.0TeV and covers a large range of neutrino masses below the $$\mathrm {W}_{\mathrm {R}}$$WR boson mass, depending on the value of $$M_{\mathrm {W}_{\mathrm {R}}}$$MWR. This search significantly extends the $$(M_{\mathrm {W}_{\mathrm {R}}}, M_{\mathrm {N}_{\ell }})$$(MWR,MNℓ) exclusion region beyond previous results.
118924562
The leptophilic dark matter with $Z'$ interaction: from indirect searches to future $e^+ e^-$ collider searches
We investigate the scenario where the dark matter only interacts with the charged leptons in the standard model via a neutral vector mediator $Z'$. Such a scenario with a 430 GeV dark matter can fit the recent positron fluxes observed by the AMS-02 Collaborations, with the reasonable boost factors. We study the possibility of searching such leptophilic $Z'$ via its lepton final states and invisible decay modes at the future electron-positron colliders, such as the International Linear Collider (ILC) and the Compact Linear Collider (CLIC). We find that for the benchmark models with $Z'$ mass from 1.0 TeV to 1.5 TeV, the searches for the invisible decays of $Z'\to \bar \chi \chi$ is easily achieved at the CLIC 1.5 TeV runs via the mono-photon process. However, lighter $Z'$ with mass from 0.5 TeV to 0.8 TeV are challenging to see. The di-lepton plus single photon channel can reveal the $Z'$ mass at the ILC and CLIC with moderate luminosities.
109931424
Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H --> gamma-gamma, H --> ZZ* --> 4 leptons and H --> WW --> 2 leptons + 2 neutrinos. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of 7 TeV and 8 TeV, corresponding to an integrated luminosity of about 25/fb. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson.
119439946
$B$ physics at the Tevatron: Run II and beyond
Starting in September 1999, a series of workshops was carried out to study the prospects for B physics at the Tevatron. There were four working groups covering CP Violation, Rare and Semileptonic Decays, Mixing and Lifetimes, as well as Production, Fragmentation and Spectroscopy. Upon the completion of a comprehensive written report summarizing the results of this workshop, we will review the highlights of B Physics at the Tevatron in Run II and beyond. On our way to this goal, we will pass by questions such as ‘Why are there so many B factories these days?’ or ‘Why do we also want to do B Physics at Fermilab?’
6924797
Design of the detuned accelerator structure
This is a summary of the design procedure for the detuned accelerator structure for SLAC's Next Linear Collider program. The 11.424 GHz accelerating mode of each cavity must be synchronous with the beam. The distribution of the disk thicknesses and lowest synchronous dipole mode frequencies of the cavities in the structure is Gaussian in order to reduce the effect of wake fields. The finite element field solver YAP calculated the accelerating mode frequency and the lowest synchronous dipole mode frequency for various cavity diameters, aperture diameters and disk thicknesses. Polynomial 3-parameter fits are used to calculate the dimensions for a 1.8 m detuned structure. The program SUPERFISH was used to calculate the shunt impedances, quality factors and group velocities. The RF parameters of the section like filling time, attenuation factor, accelerating gradient and maximum surface field along the section are evaluated. Error estimates are discussed and comparisons with conventional constant gradient and constant impedance structures are be presented.<<ETX>>
201238536
Measurements of spin correlation in top-antitop quark events from proton-proton collisions at √s =7 TeV using the ATLAS detector
Measurements of spin correlation in top quark pair production are presented using data collected with the ATLAS detector at the LHC with proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 4.6 fb(-1). Events are selected in final states with two charged leptons and at least two jets and in final states with one charged lepton and at least four jets. Four different observables sensitive to different properties of the top quark pair production mechanism are used to extract the correlation between the top and antitop quark spins. Some of these observables are measured for the first time. The measurements are in good agreement with the Standard Model prediction at next-to-leading-order accuracy.