Performance of CMS muon reconstruction in cosmic-ray events

The performance of muon reconstruction in CMS is evaluated using a large data sample of cosmic-ray muons recorded in 2008. Efficiencies of various high-level trigger, identification, and reconstruction algorithms have been measured for a broad range of muon momenta, and were found to be in good agreement with expectations from Monte Carlo simulation. The relative momentum resolution for muons crossing the barrel part of the detector is better than 1% at 10 GeV/c and is about 8% at 500 GeV/c, the latter being only a factor of two worse than expected with ideal alignment conditions. Muon charge misassignment ranges from less than 0.01% at 10GeV/c to about 1% at 500 GeV/c. © 2010 IOP Publishing Ltd and SISSA.

First measurement of the underlying event activity at the LHC with √ = 0.9 TeV

A measurement of the underlying activity in scattering processes with pT scale in the GeV region is performed in proton-proton collisions at √ = 0.9 TeV, using data collected by the CMS experiment at the LHC. Charged particle production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD-inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production of charged particles with pseudorapidity {pipe}η{pipe} < 2, pT > 0.5 GeV/c, and azimuthal direction transverse to that of the leading object. © 2010 CERN for benefit of the CMS collaboration.

Concentration of Cu(II) and Cd(II) from natural river water by Adsorption on a Modified Silica Surface

A high surface area silica gel (737 ± m2 g-1) was synthesized modified through a two-step reaction with a 4-amino-2-mercaptopyrimidine ligand and applied to Cu(II) and Cd(II) adsorption from an aqueous medium. The modified material was characterized by FTIR, which showed that attachment of the molecule occurred via thiol groups at 2547 and 2600 cm-1, and by elemental analysis that indicated the presence of 0.0102 mmol of ligand. The data from adsorption experiments were adjusted to a modified Langmuir equation and the maximum adsorption capacity was 6.6 and 3.8 μmol g-1 for Cu(II) and Cd(II), respectively. After adjusting several parameters, the material was applied in the preconcentration of natural river water using a continuous flow system before and after sample mineralization, and the results showed a 10-fold enrichment factor. The proposed method was validated through preconcentration and analysis of certified standard reference material (1643e), whose results were in agreement with the values provided by the manufacturer.

Prompt and non-prompt J/ψ production in pp collisions at √s =7 TeV

The production of J/ψ mesons is studied in pp collisions at √s = 7 TeV with the CMS experiment at the LHC. The measurement is based on a dimuon sample corresponding to an integrated luminosity of 314 nb-1. The J/ψ differential cross section is determined, as a function of the J/ψ transverse momentum, in three rapidity ranges. A fit to the decay length distribution is used to separate the prompt from the non-prompt (b hadron to J/ψ) component. Integrated over J/ψ transverse momentum from 6.5 to 30 GeV/c and over rapidity in the range {pipe}y{pipe} < 2.4, the measured cross sections, times the dimuon decay branching fraction, are 70.9 ± 2.1(stat.) ± 3.0(syst.) ± 7.8(luminosity) nb for prompt J/ψ mesons assuming unpolarized production and 26.0 ± 1.4(stat.) ± 1.6(syst.) ± 2.9(luminosity) nb for J/ψ mesons from b-hadron decays. © CERN for the benefit of the CMS collaboration 2011.

Long-range and short-range dihadron angular correlations in central PbPb collisions at psNN = 2:76 TeV

First measurements of dihadron correlations for charged particles are presented for central PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76TeV over a broad range in relative pseudorapidity (Δν) and the full range of relative azimuthal angle (Δø). The data were collected with the CMS detector, at the LHC. A broadening of the away-side (Δø y≈ π) azimuthal correlation is observed at all Δν, as compared to the measurements in pp collisions. Furthermore, long-range dihadron correlations in Δν are observed for particles with similar ø values. This phenomenon, also known as the \ridge, persists up to at least jΔνj = 4. For particles with transverse momenta (pT) of 2-4 GeV/c, the ridge is found to be most prominent when these particles are correlated with particles of pT = 2-6 GeV/c, and to be much reduced when paired with particles of pT = 10-12 GeV/c. Copyright CERN.

Measurements of inclusive W and Z cross sections in pp collisions at √s = 7 TeV The CMS collaboration

Measurements of inclusive W and Z boson production cross sections in pp collisions at √s = 7 TeV are presented, based on 2.9 pb-1 of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give σ(pp → WX) × B(W → l?) = 9.95 ± 0.07 (stat.) ± 0.28 (syst.) ± 1.09 (lumi.) nb and σ(pp → ZX) × B(Z → l +l-) = 0.931 ± 0.026 (stat.) ± 0.023 (syst.) ± 0.102 (lumi.) nb, where l stands for either e or μ. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported.

Further characterization of the subunits of the giant extracellular hemoglobin of Glossoscolex paulistus (HbGp) by SDS-PAGE electrophoresis and MALDI-TOF-MS

Further characterization of hemoglobin of Glossoscolex paulistus (HbGp) subunits was performed based on SDS-PAGE, size exclusion chromatography (SEC) and MALDI-TOF-MS analysis. SDS-PAGE has shown a total of four linker chains, two quite intense and two of lower intensity. HbGp fractions (I-VI), obtained by size exclusion chromatography (SEC), from oligomeric dissociation at alkaline pH 9.6, were monitored. Fraction I is identical to the whole protein. The monomeric chains c, obtained from the trimer abc reduction, present four isoforms with MM 17,336 Da, 17,414 Da, 17,546 Da and 17,620 Da. Furthermore, the trimer subunit presents two isoforms, T 1 and T 2, with MM 51,200 ± 60 and 51,985 ± 50 Da, respectively. Based on SDS-PAGE, the linker chains seem to be distributed along the different fractions of the SEC chromatogram, appearing along the peaks corresponding to fractions I-V. The fraction IV contains, predominantly, trimers with some linkers contamination. The strong interaction of linker chains L with the trimers abc, makes it difficult to obtain these subunits in pure form. The monomer d in fraction VI appears to be quite pure, in agreement with previous studies. © 2011 Elsevier Ltd. All rights reserved.

Measurement of the Drell-Yan cross section in pp collisions at √ s = 7 TeV

The Drell-Yan differential cross section is measured in pp collisions at √ s = 7TeV, from a data sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 36 pb-1. The cross section measurement, normalized to the measured cross section in the Z region, is reported for both the dimuon and dielectron channels in the dilepton invariant mass range 15{600 GeV. The normalized cross section values are quoted both in the full phase space and within the detector acceptance. The effect of final state radiation is also identified. The results are found to agree with theoretical predictions. Copyright CERN.

Charged particle transverse momentum spectra in pp collisions at √s = 0:9 and 7 TeV

The charged particle transverse momentum (pT) spectra are presented for pp collisions at √s = 0:9 and 7TeV. The data samples were collected with the CMS detector at the LHC and correspond to integrated luminosities of 231 μb-1 and 2.96 pb-1, respectively. Calorimeter-based high-transverse-energy triggers are employed to enhance the statistical reach of the high-pT measurements. The results are compared with leading and next-toleading order QCD and with an empirical scaling of measurements at different collision energies using the scaling variable xT - 2pT=ps over the pT range up to 136 GeV/c. Using a combination of xT scaling and direct interpolation at fixed pT, a reference transverse momentum spectrum at √s = 2:76TeV is constructed, which can be used for studying high-pT particle suppression in the dense QCD medium produced in heavy-ion collisions at that centre-of-mass energy. Copyright CERN.

Search for supersymmetry in pp collisions at √s = 7 TeV in events with a single lepton, jets, and missing transverse momentum

Results are reported from a search for physics beyond the standard model in proton-proton collisions at a center-of-mass energy of 7TeV, focusing on the signature with a single, isolated, high-transverse-momentum lepton (electron or muon), energetic jets, and large missing transverse momentum. The data sample comprises an integrated luminosity of 36 pb-1, recorded by the CMS experiment at the LHC. The search is motivated by models of new physics, including supersymmetry. The observed event yields are consistent with standard model backgrounds predicted using control samples obtained from the data. The characteristics of the event sample are consistent with those expected for the production of tt̄ and W+jets events. The results are interpreted in terms of limits on the parameter space for the constrained minimal supersymmetric extension of the standard model.

Measurement of the lepton charge asymmetry in inclusive W production in pp collisions at √s = 7 TeV

A measurement of the lepton charge asymmetry in inclusive pp → WX production at √s = 7TeV is presented based on data recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 36 pb -1. This high precision measurement of the lepton charge asymmetry, performed in both the W → eν and W → μν channels, provides new insights into parton distribution functions. Copyright CERN.

Measurement of the underlying event activity at the LHC with √s = 7 TeV and comparison with √s = 0:9 TeV

A measurement of the underlying activity in events with a jet of transverse momentum in the several GeV region is performed in proton-proton collisions at √ s = 0:9 and 7TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity |η|<2 and transverse momentum pT >0:5 GeV/c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. A significant growth of the average multiplicity and scalar-pT sum of the particles in the transverse region is observed with increasing pT of the leading trackjet, followed by a much slower rise above a few GeV/c. For track-jet pT larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centreof- mass energy increase from 0:9 to 7TeV. Predictions of several QCD-inspired models as implemented in pythia are compared to the data.

Morphological changes in the fast vs slow fiber profiles of the urethras of diabetic pregnant rats

Background: This study was undertaken to test the hypothesis that diabetes and pregnancy detrimentally affect the normal function of urethral striated muscles in rats, providing a model for additional studies related to urinary incontinence. The aim of this study was to evaluate morphological alterations in the urethral striated muscles of diabetic pregnant rats. Materials and Methods: Twenty female Wistar rats were distributed into four experimental groups of five rats as follows: virgin, pregnant, diabetic virgin, and diabetic pregnant. Diabetes was induced using streptozotocin administration (40 mg/kg i.v.). The rats were lethally anesthetized, and the urethra and vagina were extracted as a unit. Cryostat sections (6 μm thick) were cut and stained with hematoxylin-eosin, and immunohistochemical procedures were performed and subjected to morphological and semi quantitative analysis. Results: The urethral striated muscle from the diabetic pregnant rats presented with the following variations: thinning and atrophy, disorganization and disruption associated with the colocalization of fast and slow fibers and a steady decrease in the proportion of fast vs slow fibers. Conclusion: Diabetes and pregnancy impair the urethral striated muscle and alter its fiber type distribution. © Copyright G. Marini et al., 2011.

J/ψ and ψ (2S) production in pp collisions at √s = 7 TeV

A measurement of the J/ ψ and ψ (2S) production cross sections in pp collisions at √s = 7TeV with the CMS experiment at the LHC is presented. The data sample corresponds to an integrated luminosity of 37 pb -1. Using a fit to the invariant mass and decay length distributions, production cross sections have been measured separately for prompt and non-prompt charmonium states, as a function of the meson transverse momentum in several rapidity ranges and integrated in the kinematical regions considered in this study. In addition, cross sections restricted to the acceptance of the CMS detector are given, which are not affected by the polarization of the charmonium states. The ratio of the differential production cross sections of the two states, where systematic uncertainties largely cancel, is also determined. The branching fraction of the inclusive B → ψ (2S)X decay is extracted from the ratio of the non-prompt cross sections to be: B(B → ψ (2S)X) = (3:08 ± 0:12 (stat.+syst.) ± 0:13 (theor.) ± 0:42 (BPDG)) × 10 -3: B(B → ψ(2S)X) = (3.08 ± 0.12 (stat.+syst.) ± 0.13 (theor.) ± 0.42 (B PDG)) × 10 -3.

Search for microscopic black holes in pp collisions at √ s = 7 TeV

A search for microscopic black holes in pp collisions at a center-of-mass energy of 7TeV is presented. The data sample corresponds to an integrated luminosity of 4.7 fb1 recorded by the CMS experiment at the LHC in 2011. Events with large total transverse energy have been analyzed for the presence of multiple energetic jets, leptons, and photons, which are typical signals of evaporating semiclassical and quantum black holes, and string balls. Agreement with the expected standard model backgrounds, which are dominated by QCD multijet production, has been observed for various combined multiplicities of jets and other reconstructed objects in the final state. Model-independent limits are set on new physics processes producing high-multiplicity, energetic final states. In addition, new model-specific indicative limits are set excluding semiclassical and quantum black holes with masses below 3.8 to 5.3TeV and string balls with masses below 4.6 to 4.8TeV . The analysis has a substantially increased sensitivity compared to previous searches.