Determination of the Jet Energy Scale

The uncertainty in jet energy scale is one of the dominating systematic errors for many measurements at hadron colliders - most notably for the measurement of the top-quark-mass, inclusive jet cross section measurements and last but not least for events with large missing transverse energy as expected in searches beyond the standard model. This talk will review the approaches taken at Tevatron towards controlling the jet energy scale and discuss prospects for the LHC experiments

Digitization of LAr calorimeter for CSC simulations

This note describes the digitization of the LAr signals, which is the step creating RDO from Geant4 Hits, as used during the production of the CSC simulated samples with athena release 12

Phytoremediation of Alberta oil sand tailings using native plants and a fungal endophyte species

Non-Peer ReviewedThe Athabasca Oil Sands produce a high volume byproduct called tailing sands (TS). Typically, TS are remediated by planting young trees in large quantities of mulch (from elsewhere) plus mineral fertilizer. This is costly and labour intensive. Fungal endophytes colonize host plants without causing disease. Some endophytes confer plant tolerance to harsh environments. Trichoderma harzianum strain TSTh20-1 was isolated from a plant growing on Athabasca oil tailings sand (TS). TS are a high volume waste product from oil sand extraction that the industry is required to remediate. TS are low in organic carbon and mineral nutrients, and are hydrophobic due to residual hydrocarbons. In greenhouse trials, TSTh20-1 supports growth of tomato seedlings on TS without fertilizer. TSTh20-1 is a promising candidate for economical TS remediation. We tested 23 plant species for seed germination and growth on TS in the presence of TSTh20-1. The four best candidates are currently being used in microcosm-scale growth trials, and for outdoor mesocosm trials this summer. Potential mechanisms that contribute to endophyte-induced plant growth promotion are also being assessed. TSTh20-1 is nutritionally frugal, which may be characteristic of other plant fungal endophytes. We are also tagging TSTh20-1 with GFP to follow it in the plant and in the environment

Calorimeter Clustering Algorithms: Description and Performance

This note describes the performance of the calorimeter clustering algorithms used for ATLAS, and which provide inputs for particle identification. ATLAS uses two principal algorithms. The first is the ``sliding-window'' algorithm, which clusters calorimeter cells within fixed-size rectangles; results from this are used for electron, photon, and tau lepton identification. The second is the ``topological'' algorithm, which clusters together neighboring cells, as long as the signal in the cells is significant compared to noise. The results of this second algorithm are further used for jet and missing transverse energy reconstruction. This note first summarizes the steps of the calorimeter reconstruction software. A detailed description of the two clustering algorithms is then given. A last section summarizes their performance. The results presented in this note are obtained with the ATLAS athena software releases 12 and 13

Issues in determining alpha_s from hadronic tau decay and electroproduction data

We discuss some key issues associated with duality-violating and non-perturbative OPE contributions to the theoretical representations of light quark current-current two-point functions and relevant to precision determinations of alpha_s from hadronic tau decay and electroproduction cross-section data. We demonstrate that analyses with an explicit representation of duality-violating effects are required to bring theoretical errors in such extractions under control, motivating the accompanying paper in these proceedings, which presents the results of such an analysis.Comment: 5 pages, 4 figures. Prepared for the Proceedings of the International Workshop on e+e- collisions from Phi to Psi (PHIPSI11), Sep. 19-22, 2011, BINP, Novosibirsk, Russi

Status of the Lattice and Tau Decay Determinations of alpha_s

The two highest precision determinations of alpha_s(M_Z^2), that based on the analysis of short-distance-sensitive lattice observables, and that based on an analysis of hadronic tau decay data, have, until very recently, given results which are not in good agreement. I review new versions of these analyses which bring the two determinations into excellent agreement, and discuss prospects for additional future improvements.Comment: Prepared for the Proceedings of the 5th International Conference on Quarks and Nuclear Physics, Beijing, China, Sept. 21-26, 200