Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Evaluation of the reproductive performance of rabbits does fed a half-simplified diet based on cassava byproducts

A total of 70 five-month-old female New Zealand White rabbits were assigned in a completely randomized design, over three reproductive cycles, with two treatments: a reference diet and a half-simplified diet containing 79.83% cassava byproduct. The study evaluated body weight and feed intake of does, feed cost, number and total body weight of kits at kindling and weaning per female during three cycles, number and percentage of mortality/female/cycle, and weight gain of kits from birth to weaning. No interaction was observed between the diets and among the reproductive cycles for any evaluated characteristics. The body weight of does at the moment of weaning was similar in both groups for all three reproductive cycles. However, does fed the half-simplified diet had lower feed intake during the three reproductive cycles and, consequently, more reproductive flaws. The number of kits at weaning, body weight of kits at kindling and weaning, weight gain of kits from birth to weaning, and total body weight of kits at weaning were lower for the group of does fed the half-simplified diet and, consequently, there was a higher number and percentage of dead kits in this group. The total numbers of kits at kindling and weaning and total body weight of kits at birth during all three reproductive cycles were similar between the groups; however, total body weight of weaning rabbits was higher for the animals receiving the reference diet. It is possible to conclude that although the use of the half-simplified diet decreases the reproductive performance of does, it reduces feed cost per kg of body weight by 23.63% compared with the reference diet, proving to be a viable nutritional option for rabbit production

Evidence for the associated production of a W boson and a top quark in ATLAS at √s = 7 TeV

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