5,387 research outputs found
Test report for 8-inch Check Valve Mission Valve and Pump Company part number 15 CPF-311 NASA drawing number 75M17763 HCV-9
Functional and environment testing of 8-inch valve used in vaporizer units and umbilical tower hydrogen ven
Charged particle multiplicities in pp interactions at √s = 0.9, 2.36, and 7 TeV
Measurements of primary charged hadron multiplicity distributions are presented for non-single-diractive events in proton-proton collisions at centre-of-mass energies
of √s = 0.9, 2.36, and 7 TeV, in five pseudorapidity ranges from |η| < 0.5 to |η| < 2.4. The data were collected with the minimum-bias trigger of the CMS experiment during the LHC commissioning runs in 2009 and the 7 TeV run in 2010. The multiplicity distribution at √s = 0.9 TeV is in agreement with previous measurements. At higher energies the increase of the mean multiplicity with √s is underestimated by most event generators. The average transverse momentum as a function of the multiplicity is also presented. The measurement of higher-order moments of the multiplicity distribution confirms the violation of
Koba-Nielsen-Olesen scaling that has been observed at lower energies
Measurements of inclusive W and Z cross sections in pp collisions at √s=7 TeV
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) x B (W → lv) = 9.95 ± 0.07 (stat.) ± 0.28 (syst.) ± 1.09 (lumi.) nb and σ(pp → ZX) x 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
First measurement of hadronic event shapes in pp collisions at √s = 7 TeV
Hadronic event shapes have been measured in proton–proton collisions at √s = 7 TeV source, with a data sample collected with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 3.2 pb^(−1). Event-shape distributions, corrected for detector response, are compared with five models of QCD multijet production
Prevalence and co-infection of Toxoplasma gondii and Neospora caninum in Apodemus sylvaticus in an area relatively free of cats
The protozoan parasite Toxoplasma gondii is prevalent worldwide and can infect a remarkably wide range of hosts despite
felids being the only definitive host. As cats play a major role in transmission to secondary mammalian hosts, the interaction
between cats and these hosts should be a major factor determining final prevalence in the secondary host. This study
investigates the prevalence of T. gondii in a natural population of Apodemus sylvaticus collected from an area with low cat
density (<2·5 cats/km2). A surprisingly high prevalence of 40·78% (95% CI: 34·07%–47·79%) was observed despite this.
A comparable level of prevalence was observed in a previously published study using the same approaches where a
prevalence of 59% (95% CI: 50·13%–67·87%) was observed in a natural population of Mus domesticus from an area with high
cat density (>500 cats/km2). Detection of infected foetuses frompregnant dams in both populations suggests that congenital
transmission may enable persistence of infection in the absence of cats. The prevalences of the related parasite, Neospora
caninum were found to be low in both populations (A. sylvaticus: 3·39% (95% CI: 0·12%–6·66%); M. domesticus: 3·08%
(95% CI: 0·11%–6·05%)). These results suggest that cat density may have a lower than expected effect on final prevalence in
these ecosystems
Strange particle production in pp collisions at √s = 0.9 and 7 TeV
The spectra of strange hadrons are measured in proton-proton collisions, recorded by the CMS experiment at the CERN LHC, at centre-of-mass energies of 0.9 and 7 TeV. The K^(0)_(S), Λ, and Ξ ͞ particles and their antiparticles are reconstructed from their decay topologies and the production rates are measured as functions of rapidity and
transverse momentum, pT. The results are compared to other experiments and to predictions of the Pythia Monte Carlo program. The p_T distributions are found to differ
substantially from the Pythia results and the production rates exceed the predictions by up to a factor of three
Measurement of BB angular correlations based on secondary vertex reconstruction at √s = 7 TeV
A measurement of the angular correlations between beauty and anti-beauty hadrons (BB) produced in pp collisions at a centre-of-mass energy of 7 TeV at the CERN LHC is presented, probing for the first time the region of small angular separation. The B hadrons are identified by the presence of displaced secondary vertices from their decays. The B hadron angular separation is reconstructed from the decay vertices and the primary-interaction vertex. The differential BB production cross section, measured from a data sample collected by CMS and corresponding to an integrated luminosity of 3.1 pb^(−1), shows that a sizable fraction of the BB pairs are produced with small opening angles. These studies provide a test of QCD and further insight into the dynamics of bb production
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