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

Track E Implementation Science, Health Systems and Economics

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138412/1/jia218443.pd

Nuclear quadrupole double resonance

The basic theories of Nuclear Quadrupole Resonance are outlined, together with some basic NMR theory and its application to double resonance techniques. An improved design of spectrometer using double resonance is presented, including a description of a new flow cryostat which can operate down to 4.2°K with low (250 cc/hour) consumption of liquid He. The whole apparatus may be used to detect NQR signals in solids over the frequency range 100 kHz-5 MHz. The theory of double resonance with spin mixing by continuous coupling (D R CC) is developed and illustrated by experiments performed on HCOOD, HDO and several nitrogen-containing compounds, including Imidazole. Further experiments were then carried out on samples dilute in deuterium, including the detection of NQR in formic acid (HCOOH) due to naturally abundant deuterium. Other experiments on proton-deuteron interactions in amide groups and in water molecules are also described and compared with results previously published on fully-deuterated amides and D20 as a water of crystallisation in L-serine hydrate. The NQR spectrum of Lanthanum Nicotinate Dihydrate is obtained using F.M. techniques and related to its structure. The theory of Zeeman NQR in spin 3/2 nuclei is developed with reference to the double resonance technique, and the measured quadrupole coupling constants of 23Na and 2D in NaOH and some of its hydrates are discussed. Finally, some standard theories concerning proton relaxation times in solids at low temperatures (4°K-300°K) are outlined and related to some, measured relaxation times, illustrating their significance to the double resonance technique. The concluding chapter outlines a speculative proposal for a new spectrometer design.</p