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 t t ¯ H (tt¯H) 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 t t ¯ H tt¯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

Measurements of the t(t)Overbar charge asymmetry using the dilepton decay channel in pp collisions at root s=7 TeV

The tt¯ charge asymmetry in proton-proton collisions at s√ = 7 TeV is measured using the dilepton decay channel (ee, e μ , or μμ ). The data correspond to a total integrated luminosity of 5.0 fb −1 , collected by the CMS experiment at the LHC. The tt and lepton charge asymmetries, defined as the differences in absolute values of the rapidities between the reconstructed top quarks and antiquarks and of the pseudorapidities between the positive and negative leptons, respectively, are measured to be A C = −0 . 010 ± 0 . 017 (stat . ) ± 0 . 008 (syst . ) and AlepC = 0 . 009 ± 0 . 010 (stat . ) ± 0 . 006 (syst . ). The lepton charge asymmetry is also measured as a function of the invariant mass, rapidity, and transverse momentum of the tt¯ system. All measurements are consistent with the expectations of the standard model

Measurement of prompt Jψ\psi pair production in pp collisions at \sqrt s = 7 Tev

Production of prompt J/ ψ meson pairs in proton-proton collisions at s s√ = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb −1 . The two J/ ψ mesons are fully reconstructed via their decays into μ + μ − pairs. This observation provides for the first time access to the high-transverse-momentum region of J/ ψ pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/ ψ transverse momentum ( p T J/ ψ ) and rapidity (| y J/ ψ |): | y J/ ψ | 6.5 GeV/ c ; 1.2 4.5 GeV/ c . The total cross section, assuming unpolarized prompt J/ ψ pair production is 1.49 ± 0.07 (stat) ±0.13 (syst) nb. Different assumptions about the J/ ψ polarization imply modifications to the cross section ranging from −31% to +27%

A century of trends in adult human height

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5-22.7) and 16.5 cm (13.3-19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8-144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries

Influence of Plant Available Water at Seeding on Spring Wheat and Sunflower Production in North Dakota

The article presents the findings of a study to learn the effects of water available at planting time. Having access to up to date information on the water content available at seeding time for crops is necessary in order to make correct decisions concerning fallow or re-crop, range carrying capacity, hay production, saline seep control and participation in farm programs

Progress on yttria-stabilized zirconia sensors for hydrothermal pH measurements

Electrochemical cells are reviewed and a new design is evaluated for potentiometric pH measurements to above 300 °C. The new design system minimizes the effects of metal corrosion on measured pH. In addition, a recently developed [Zhou, X.Y., Lvov, S.N., Ulyanov, S.M., 2003. Yttria-Stabilized Zirconia Membrane Electrode, US Patent #6, S17, 694] flow-through, yttria-stabilized zirconia (YSZ) pH sensor has been further tested. The Nernstian behavior and precision of the YSZ electrode were evaluated by measuring the potentials vs. H 2–Pt electrode at 320 and 350 °C. Also, using the YSZ electrode, the association constants of HCl(aq) at 320 and 350 °C have been determined from the potentials of a HCl(aq) solutions at 0.01 to 0.001 mol kg −1. The results, p K 320=−1.46±0.46 and p K 350=−2.35±0.25, in good agreement with literature data, both demonstrate the effective use of the cell and YSZ electrode for pH measurements to about ±0.05 pH units, and confirm the Nernstian behavior of the YSZ electrode in acidic HCl solutions up to 350 °C. Commercial YSZ tubes available for high-temperature pH sensing are, however, far from ideal because of irregular compositions, phase structures, and interstitial materials. A consequence is the premature structural decay of YSZ tubes in acidic solutions at elevated temperatures. In spite of the long-term decay, YSZ sensors respond rapidly to changes in pH, apparently limited only by the rate of mixing of solutions within the cell. This system makes the measurement feasible above 300 °C of mineral hydrolysis equilibrium constants and their free energy changes within uncertainties of about ±1.0 kJ