30,439 research outputs found
Use of ordination and classification procedures to evaluate phytoplankton communities during Superflux II
Cluster analysis and an ordination procedure were performed on two data matrices to investigate real and environmental spatial relationships. Multiple regression analysis was used to relate the measured environmental variables to the phytoplankton community changes. Qualitative type phytoplankton data proved to be less structured in both of these spaces, relative to the biomass data. The salinity gradients of the northern transects covaried significantly with the phytoplankton association changes. In the southern transects the light variable was most important in explaining the variance in the ordination axes. These data suggest the close relationships between phytoplankton community changes and the physical hydrology of the area
Resolving an Individual One-Proton Spin Flip to Determine a Proton Spin State
Previous measurements with a single trapped proton or antiproton detected
spin resonance from the increased scatter of frequency measurements caused by
many spin flips. Here a measured correlation confirms that individual spin
transitions and states are detected instead. The high fidelity suggests that it
may be possible to use quantum jump spectroscopy to measure the p and \pbar
magnetic moments much more precisely.Comment: 4 pages, 7 figure
Measurement of the differential cross-sections of inclusive, prompt and non-prompt J/Ï production in protonâproton collisions at âs = 7 TeV
The inclusive J/Ï production cross-section and fraction of J/Ï mesons produced in B-hadron decays are measured in protonâproton collisions at âs = 7 TeV with the ATLAS detector at the LHC, as a function of the transverse momentum and rapidity of the J/Ï, using 2.3 pb^(â1) of integrated luminosity. The cross-section is measured from a minimum pT of 1 GeV to a maximum of 70 GeV and for rapidities within |y|<2.4 giving the widest reach of any measurement of J/Ï production to date. The differential production cross-sections of prompt and non-prompt J/Ï are separately determined and are compared to Colour Singlet NNLO^â
, filled, Colour Evaporation Model, and FONLL predictions
Search for Diphoton Events with Large Missing Transverse Energy in 7 TeV Proton-Proton Collisions with the ATLAS Detector
A search for diphoton events with large missing transverse energy is presented. The data were collected with the ATLAS detector in proton-proton collisions at âs = 7ââTeV at the CERN Large Hadron Collider and correspond to an integrated luminosity of 3.1ââpb^(-1). No excess of such events is observed above the standard model background prediction. In the context of a specific model with one universal extra dimension with compactification radius R and gravity-induced decays, values of 1/R < 729ââGeV are excluded at 95% C.L., providing the most sensitive limit on this model to date
Search for Supersymmetry Using Final States with One Lepton, Jets, and Missing Transverse Momentum with the ATLAS Detector in âs = 7 TeV pp Collisions
This Letter presents the first search for supersymmetry in final states containing one isolated electron or
muon, jets, and missing transverse momentum from
âs = 7 TeV proton-proton collisions at the LHC.
The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated
luminosity of 35 pb^(-1). No excess above the standard model background expectation is observed. Limits
are set on the parameters of the minimal supergravity framework, extending previous limits. Within this
framework, for A_0 = GeV, tanÎČ = 3, and ” > 0 and for equal squark and gluino masses, gluino masses
below 700 GeV are excluded at 95% confidence level
A search for new physics in dijet mass and angular distributions in pp collisions at âs = 7 TeV measured with the ATLAS detector
A search for new interactions and resonances produced in LHC protonâproton (pp) collisions at a centre-of-mass energy âs = 7 TeV was performed with the ATLAS detector. Using a dataset with an integrated luminosity of 36 pb^(â1), dijet mass and angular distributions were measured up to dijet masses of ~3.5 TeV and were found to be in good agreement with Standard Model predictions. This analysis sets limits at 95% CL on various models for new physics: an excited quark is excluded for mass between 0.60 and 2.64 TeV, an axigluon hypothesis is excluded for axigluon masses between 0.60 and 2.10 TeV and quantum black holes are excluded in models with six extra spaceâtime dimensions for quantum gravity scales between 0.75 and 3.67 TeV. Production cross section limits as a function of dijet mass are set using a simplified Gaussian signal model to facilitate comparisons with other hypotheses. Analysis of the dijet angular distribution using a novel technique simultaneously employing the dijet mass excludes quark contact interactions with a compositeness scale Î below 9.5 TeV
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Attachment styles as predictors of Facebook-related jealousy and surveillance in romantic relationships
This is the post-print of the Article. The official published version can be accessed from the link below - Copyright @ 2012 John Wiley & SonsFacebook has become ubiquitous over the past five years, yet few studies have examined its role within romantic relationships. In two studies, we tested attachment anxiety and avoidance as predictors of Facebook-related jealousy and surveillance (i.e., checking a romantic partnerâs Facebook page). Study 1 found that anxiety was positively associated, and avoidance negatively associated, with Facebook jealousy and surveillance. The association of anxiety with Facebook jealousy was mediated in part by lower trust. Study 2 replicated this finding, and daily diary results further showed that over a one-week period, anxiety was positively associated, and avoidance negatively associated, with Facebook surveillance. The association of anxiety with greater surveillance was mediated in part by daily experiences of jealousy
Measurement of the W charge asymmetry in the WâΌΜ decay mode in pp collisions at âs = 7 TeV with the ATLAS detector
This Letter reports a measurement of the muon charge asymmetry from W bosons produced in protonâproton collisions at a centre-of-mass energy of 7 TeV with the ATLAS experiment at the LHC. The asymmetry is measured in the WâΌΜ decay mode as a function of the muon pseudorapidity using a data sample corresponding to a total integrated luminosity of 31 pb^(â1). The results are compared to predictions based on next-to-leading order calculations with various parton distribution functions. This measurement provides information on the u and d quark momentum fractions in the proton
Search for high-mass states with one lepton plus missing transverse momentum in protonâproton collisions at âs = 7 TeV with the ATLAS detector
The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (WâČ,W_*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb^(â1). No excess beyond standard model expectations is observed. A WâČ with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a Wlow asterisk (charged chiral boson) for masses below 1.35 TeV
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