Transient global amnesia: an atypical presentation of acute aortic dissection

Aortic dissection (AD) is a cardiovascular emergency whose most frequent symptom is chest pain. However, clinical presentation can also be varied and atypical. In the present study we report a case of painless AD, which resulted in a sudden memory loss at presentation. Physical examination and laboratory tests regarding the patient did not show any abnormal findings and a benign transient global amnesia was diagnosed. The day after being discharged, the patient came back to the emergency department because a recurrent episode of severe memory impairment occurred. This time, additional clinical and laboratory signs suggested clinical suspicion of AD. A chest computed tomography angiogram was performed and an extensive AD type A involving carotid and iliac arteries was found. Our case report shows that acute aortic dissection diagnosis can be difficult if clinical presentation is atypical and must be assessed in the light of various clinical signs and laboratory data

Searches for heavy Higgs bosons in two-Higgs-doublet models and for t→cht→ch decay using multilepton and diphoton final states in pppp collisions at 8 TeV

Searches are presented for heavy scalar ($\mathrm{H}$) and pseudoscalar ($\mathrm{A}$) Higgs bosons posited in the two doublet model (2HDM) extensions of the standard model (SM). These searches are based on a data sample of $\mathrm{p}\mathrm{p}$ collisions collected with the CMS experiment at the LHC at a center-of-mass energy of $\sqrt{s} = 8~\mathrm{TeV}$ and corresponding to an integrated luminosity of $19.5~\mathrm{fb}^{-1}$. The decays $\mathrm{H} \rightarrow \mathrm{h} \mathrm{h}$ and $\mathrm{A} \rightarrow \mathrm{Z} \mathrm{h}$, where $\mathrm{h}$ denotes an SM-like Higgs boson, lead to events with three or more isolated charged leptons or with a photon pair accompanied by one or more isolated leptons. The search results are presented in terms of the $\mathrm{H}$ and $\mathrm{A}$ production cross sections times branching fractions and are further interpreted in terms of 2HDM parameters. We place 95% CL cross section upper limits of approximately $7~\mathrm{pb}$ on $\sigma \mathcal{B}$ for $\mathrm{H} \rightarrow \mathrm{h} \mathrm{h}$ and $2~\mathrm{pb}$ for $\mathrm{A} \rightarrow \mathrm{Z} \mathrm{h}$. Also presented are the results of a search for the rare decay of the top quark that results in a charm quark and an SM Higgs boson, $\mathrm{t} \rightarrow \mathrm{c} \mathrm{h}$, the existence of which would indicate a nonzero flavor-changing Yukawa coupling of the top quark to the Higgs boson. We place a 95% CL upper limit of 0.56% on $\mathcal{B}(\mathrm{t} \rightarrow \mathrm{c} \mathrm{h})$.Peer Reviewe

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

A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at s=8  TeV. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7  fb-1. Events are selected with an electron and muon with opposite charges that both have transverse impact parameter values between 0.02 and 2 cm. The search has been designed to be sensitive to a wide range of models with nonprompt e-μ final states. Limits are set on the “displaced supersymmetry” model, with pair production of top squarks decaying into an e-μ 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 cτ=2  cm, excluding masses below 790 GeV at 95% confidence level.Peer Reviewe

Performance of Photon Reconstruction and Identification with the CMS Detector in Proton-Proton Collisions at sqrt(s) = 8 TeV

A description is provided of the performance of the CMS detector for photon reconstruction and identification in proton-proton collisions at a centre-of-mass energy of 8 TeV at the CERN LHC. Details are given on the reconstruction of photons from energy deposits in the electromagnetic calorimeter (ECAL) and the extraction of photon energy estimates. The reconstruction of electron tracks from photons that convert to electrons in the CMS tracker is also described, as is the optimization of the photon energy reconstruction and its accurate modelling in simulation, in the analysis of the Higgs boson decay into two photons. In the barrel section of the ECAL, an energy resolution of about 1% is achieved for unconverted or late-converting photons from H→γγ decays. Different photon identification methods are discussed and their corresponding selection efficiencies in data are compared with those found in simulated events.Peer Reviewe

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at s=7\sqrt s=7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta ( pT ) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta ( HT ), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb −1 . The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa , and to next-to-leading-order calculations from BlackHat + sherpa . The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high- HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.Peer Reviewe

Measurements of jet multiplicity and differential production cross sections of Z+Z + jets events in proton-proton collisions at s=\sqrt{s} = 7 TeV

Measurements of differential cross sections are presented for the production of a Z boson and at least one hadronic jet in proton-proton collisions at s=7  TeV, recorded by the CMS detector, using a data sample corresponding to an integrated luminosity of 4.9  fb−1. The jet multiplicity distribution is measured for up to six jets. The differential cross sections are measured as a function of jet transverse momentum and pseudorapidity for the four highest transverse momentum jets. The distribution of the scalar sum of jet transverse momenta is also measured as a function of the jet multiplicity. The measurements are compared with theoretical predictions at leading and next-to-leading order in perturbative QCD.Peer Reviewe

Constraints on the Higgs boson width from off-shell production and decay to Z-boson pairs

Constraints are presented on the total width of the recently discovered Higgs boson, Gamma[H], using its relative on-shell and off-shell production and decay rates to a pair of Z bosons, where one Z boson decays to an electron or muon pair, and the other to an electron, muon, or neutrino pair. The analysis is based on the data collected by the CMS experiment at the LHC in 2011 and 2012, corresponding to integrated luminosities of 5.1 inverse femtobarns at a centre-of-mass energy sqrt(s) = 7 TeV and 19.7 inverse femtobarns at sqrt(s) = 8 TeV. A simultaneous maximum likelihood fit to the measured kinematic distributions near the resonance peak and above the Z-boson pair production threshold leads to an upper limit on the Higgs boson width of Gamma[H] < 22 MeV at a 95% confidence level, which is 5.4 times the expected value in the standard model at the measured mass.Peer Reviewe

Search for the associated production of the Higgs boson with a top-quark pair

A search for the standard model Higgs boson produced in association with a top-quark pair $\left(\mathrm{t}\overline{\mathrm{t}}\mathrm{H}\right)$ is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb$^{−1}$ and 19.7 fb$^{−1}$ collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H → hadrons, H → photons, and H → leptons. The results are characterized by an observed $\mathrm{t}\overline{\mathrm{t}}\mathrm{H}$ signal strength relative to the standard model cross section, μ=σ/σ$_{SM}$,under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is μ = 2.8 ± 1.0 for a Higgs boson mass of 125.6 GeV.Peer Reviewe

Measurement of the pp→ZZpp \to ZZ production cross section and constraints on anomalous triple gauge couplings in four-lepton final states at s=\sqrt s=8 TeV

A measurement of the inclusive ZZ production cross section and constraints on anomalous triple gauge couplings in proton–proton collisions at s=8 TeV are presented. The analysis is based on a data sample, corresponding to an integrated luminosity of 19.6 fb−1 , collected with the CMS experiment at the LHC. The measurements are performed in the leptonic decay modes ZZ→ℓℓℓ′ℓ′ , where ℓ=e,μ and ℓ′=e,μ,τ . The measured total cross section σ(pp→ZZ)=7.7±0.5 (stat)−0.4+0.5 (syst)±0.4(theo)±0.2 (lumi) pb , for both Z bosons produced in the mass range 60<mZ<120 GeV , is consistent with standard model predictions. Differential cross sections are measured and well described by the theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous ZZZ and ZZγ couplings at the 95% confidence level: −0.004<f4Z<0.004 , −0.004<f5Z<0.004 , −0.005<f4γ<0.005 , and −0.005<f5γ<0.005 .Peer Reviewe