34,747 research outputs found
Search for a Heavy Particle Decaying into an Electron and a Muon with the ATLAS Detector in âs = 7 TeV pp collisions at the LHC
This Letter presents the first search for a heavy particle decaying into an e^±Ό^â final state in âs=7ââTeV pp collisions at the LHC. The data were recorded by the ATLAS detector during 2010 and correspond to a total integrated luminosity of 35ââpb^(-1). No excess above the standard model background expectation is observed. Exclusions at 95% confidence level are placed on two representative models. In an R-parity violating supersymmetric model, tau sneutrinos with a mass below 0.75 TeV are excluded, assuming all R-parity violating couplings are zero except λ'_(311)=0.11 and λ_(312)=0.07. In a lepton flavor violating model, a ZâČ-like vector boson with masses of 0.70â1.00 TeV and corresponding cross sections times branching ratios of 0.175â0.183 pb is excluded. These results extend to higher mass R-parity violating sneutrinos and lepton flavor violating Zâs than previous constraints from the Tevatron
Autonomous spacecraft maintenance study group
A plan to incorporate autonomous spacecraft maintenance (ASM) capabilities into Air Force spacecraft by 1989 is outlined. It includes the successful operation of the spacecraft without ground operator intervention for extended periods of time. Mechanisms, along with a fault tolerant data processing system (including a nonvolatile backup memory) and an autonomous navigation capability, are needed to replace the routine servicing that is presently performed by the ground system. The state of the art fault handling capabilities of various spacecraft and computers are described, and a set conceptual design requirements needed to achieve ASM is established. Implementations for near term technology development needed for an ASM proof of concept demonstration by 1985, and a research agenda addressing long range academic research for an advanced ASM system for 1990s are established
Resummed thermodynamic perturbation theory for bond cooperativity in associating fluids with small bond angles: Effects of steric hindrance and ring formation
In this paper we develop a thermodynamic perturbation theory for two site
associating fluids which exhibit bond cooperativity. We include both steric
hindrance and ring formation such that the equation of state is bond angle
dependent. Here the bond angle is the angle separating the centers of the two
association sites. As a test, new Monte Carlo simulations are performed, and
the theory is found to accurately predict the internal energy as well as the
distribution of associated clusters as a function of bond angle and bond
cooperativity.Comment: To appear in The Journal of Chemical Physic
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
The use of ERTS-1 to more fully utilize and apply marine station data to the study and productivity along the eastern shelf waters of the United States
The author has identified the following significant results. Sea truth data were obtained during two ERTS overpasses in waters near the entrance of the Chesapeake Bay. Correlations were made between total phytoplankton and chlorophyll values in these waters to radiance detected by ERTS in an effort to map areas of similar productivity levels. Band 4 radiance had the highest correlation to all parameters with bands 5 and 6 showing decreasing correlations in each case. The radiance values were apparently influenced by one or more factors, most likely including the sediment content of the water. Data have shown that ERTS MSS is not suitable for monitoring chlorophyll in near-shore waters where sediment loads are high. It is suggested that in more seaward or pelagic locations, that ERTS MSS would be more efficient in monitoring surface chlorophyll values and establishing direct relationships to phytoplankton concentrations
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
Differential-geometric approach to the integrability of hydrodynamic chains: the Haantjes tensor
The integrability of an m-component system of hydrodynamic type, u_t=V(u)u_x,
by the generalized hodograph method requires the diagonalizability of the mxm
matrix V(u). This condition is known to be equivalent to the vanishing of the
corresponding Haantjes tensor. We generalize this approach to hydrodynamic
chains -- infinite-component systems of hydrodynamic type for which the
infinite matrix V(u) is `sufficiently sparse'. For such systems the Haantjes
tensor is well-defined, and the calculation of its components involves finite
summations only. We illustrate our approach by classifying broad classes of
conservative and Hamiltonian hydrodynamic chains with the zero Haantjes tensor.
We prove that the vanishing of the Haantjes tensor is a necessary condition for
a hydrodynamic chain to possess an infinity of semi-Hamiltonian hydrodynamic
reductions, thus providing an easy-to-verify necessary condition for the
integrability.Comment: 36 pages, the classification results and proofs are refined. A
section on generating functions is adde
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