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From her early photographs of the ruinous aftermath of the Lebanon War in Beirut(1982) to her more recent images of bomb craters in Eleven Blowups(2006), the French artist Sophie Ristelhueber has been intent to maintain, in her own metaphor, ‘the analytical distance of an anatomy lesson’. Exhibiting the evidence of warfare but withholding their explanation, Ristelhueber’s provocative gesture of making art of war, removing human conflicts from their political contexts to render them as still-lifes, ready-mades, earthworks, or surrealist poems, is patently anti-journalistic. In keeping with the artist’s surgical analogy, this article explores Ristelhueber’s aesthetic mode of address as one that shares its fundamental operation with that of photography – namely, to make a cut. Retracing the morphology of recurring imprints and injuries that appear across the terrestrial and corporeal expanses traversed in her work, the article considers the ways in which these cuts pertain to the transformative power of violence and images alike. [ABSTRACT FROM PUBLISHER]

This document presents a brief overview of some of the experimental techniques employed by the ATLAS experiment at the CERN Large Hadron Collider (LHC) in the search for the Higgs boson predicted by the standard model (SM) of particle physics. The data and the statistical analyses that allowed in July 2012, only few days before this presentation at the Marcel Grossman Meeting, to firmly establish the observation of a new particle are described. The additional studies needed to check the consistency between the newly discovered particle and the Higgs boson are also discussed. [ABSTRACT FROM AUTHOR]

Abstract: The ATLAS Transition Radiation Tracker (TRT) is a large straw tube tracking system that is the outermost of the three subsystems of the ATLAS Inner Detector (ID). With over 350,000 readout channels, the TRT provides both excellent particle identification capabilities and electron-pion separation, as well as contributing significantly to the resolution for high-pt tracks in the ID. As the instantaneous luminosity of the LHC increases, the occupancy of the TRT will increase as well. The low-occupancy tracking resolution and efficiency will be presented, as will be studies of resolution and PID at higher occupancies. [Copyright &y& Elsevier]

Abstract: The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as B-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy is sufficiently low and hit efficiency exceed the design specification. [Copyright &y& Elsevier]

Abstract: The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The SCT was installed and commissioned within ATLAS in 2007, and has been used to exploit fully the physics potential of the LHC since the first proton–proton collisions at 7TeV were delivered in 2009. In this paper, its operational status throughout data taking up to the end of 2011 is presented, and its tracking performance is reviewed. [Copyright &y& Elsevier]

Abstract: A new type of n-in-p planar pixel sensors have been developed at KEK/HPK in order to cope with the maximum particle fluence of 1–3×1016 1MeV equivalent neutrons per square centimeter in the upcoming LHC upgrades. Four n-in-p devices were connected by bump-bonding to the new ATLAS Pixel front-end chip (FE-I4A) and characterized before and after the irradiation to 2×1015 . These planar sensors are thick, using biasing structures made out of polysilicon or punch-through dot and isolation structures of common or individual p-stop. Results of measurements with radioactive 90Sr source and with a 120GeV/c momentum pion beam at the CERN Super Proton Synchrotron (SPS) are presented. The common p-stop isolation structure shows a better performance than the individual p-stop design, after the irradiation. The flat distribution of the collected charge in the depth direction after the irradiation implies that the effect of charge trapping is small, at the fluence, with the bias voltage well above the full depletion voltage. [Copyright &y& Elsevier]

Abstract: The ALFA (Absolute Luminosity For ATLAS) project aims at measuring luminosity of the LHC with high precision using pp elastic scattering under small angles. This will be done by moving an upper and a lower tracking detector inside Roman Pots very close to the beam. To align the upper and lower tracking detector a dedicated part overlaps and the alignment will be done with particles passing both the upper and the lower detector. The tracking detectors are made of scintillating square fibers read out by MultiAnode PhotoMutiplier Tubes, MAPMTs, with custom made electronics. The gain of the MAPMT channels has been equalized and the average light yield of scintillating fibers determined before installation in the LHC. Also reflections on the Roman Pot windows have been observed and the window has been blackened to reduce the effect. The ALFA detectors are currently being commissioned at ATLAS/LHC and the first particles have been observed in the detectors. [Copyright &y& Elsevier]

Abstract: A search for the Standard Model Higgs boson has been performed in the channel using 4.7 fb−1 of pp collision data recorded at a centre-of-mass energy of with the ATLAS detector at the Large Hadron Collider. Higgs boson candidates produced in association with zero, one or two jets are included in the analysis to maximize the acceptance for both gluon fusion and weak boson fusion Higgs boson production processes. No significant excess of events is observed over the expected background and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range . The best sensitivity is reached for , where the observed (expected) 95% confidence level upper bound on the cross section for produced in association with zero or one jet is 2.2 pb (1.9 pb), corresponding to 1.9 (1.6) times the Standard Model prediction. In the Higgs boson plus two jets channel, which is more sensitive to the weak boson fusion process, the observed (expected) 95% confidence level upper bound on the cross section for production with is 0.7 pb (0.6 pb), corresponding to 7.9 (6.5) times the Standard Model prediction. [Copyright &y& Elsevier]

Abstract: This Letter presents the results of a direct search with the ATLAS detector at the LHC for a Standard Model Higgs boson of mass produced in association with a W or Z boson and decaying to . Three decay channels are considered: , and , where ℓ corresponds to an electron or a muon. No evidence for Higgs boson production is observed in a dataset of pp collisions corresponding to of integrated luminosity collected by ATLAS in 2011. Exclusion limits on Higgs boson production, at the confidence level, of 2.5 to 5.5 times the Standard Model cross section are obtained in the mass range . The expected exclusion limits range between 2.5 and 4.9 for the same mass interval. [Copyright &y& Elsevier]

Results of searches for supersymmetry in events with significant missing transverse energy and two isolated leptons with the ATLAS experiment at the LHC are presented. Three analyses are presented here, the first two are analyses with leptons of opposite charge and same charge, respectively. The third one is an analysis that searches for an excess of same-flavour opposite-charge lepton pairs over those of different-flavour. Data corresponding to an integrated luminosity of 1 fb are analysed. [ABSTRACT FROM AUTHOR]

Tau leptons play a central role in the LHC physics programme, in particular as an important signature in many Higgs boson and supersymmetry searches. They are further used in Standard Model electroweak measurements, as well as detector-related studies like the determination of the missing transverse energy scale. Copious backgrounds from QCD processes call for both efficient identification of hadronically decaying tau leptons, as well as large suppression of fake candidates. A solid understanding of the combined performance of the calorimeter and tracking detectors is also required. We present the current status of the tau reconstruction, energy calibration and identification with the ATLAS detector at the LHC. Identification efficiencies are measured in W → τν events in data and compared with predictions from Monte Carlo simulations, whereas the misidentification probabilities of QCD jets and electrons are determined from various jet-enriched data samples and from Z → ee events, respectively. The tau energy scale calibration is described and systematic uncertainties on both energy scale and identification efficiencies discussed. [ABSTRACT FROM AUTHOR]

Abstract: A search for a heavy Standard Model Higgs boson decaying via , where or μ, is presented. The search uses a data set of pp collisions at , corresponding to an integrated luminosity of collected in 2011 by the ATLAS detector at the CERN LHC. No significant excess of events above the estimated background is found. Upper limits at 95% confidence level on the production cross section of a Higgs boson with a mass in the range between 200 and are derived. A Standard Model Higgs boson with a mass in the range or is excluded at 95% CL. The corresponding expected exclusion range is at 95% CL. [Copyright &y& Elsevier]

This is a review of searches for supersymmetry (SUSY) with the ATLAS detector in proton-proton collisions at a center-of-mass energy of 7 TeV at the Large Hadron Collider (LHC) at CERN. The review covers results that have been published, or submitted for publication, up to September 2012, many of which cover the full 7 TeV data-taking period. No evidence for SUSY has been seen; some possibilities for future directions are discussed. [ABSTRACT FROM AUTHOR]

The investigation of the mechanism responsible for electroweak symmetry breaking is one of the most important tasks of the scientific program of the Large Hadron Collider. The experimental results on the search of the Standard Model Higgs boson with 1 to 2 fb of proton-proton collision data at $\sqrt s=7$ TeV recorded by the ATLAS detector are presented and discussed. No significant excess of events is found with respect to the expectations from Standard Model processes, and the production of a Higgs boson is excluded at 95% Confidence Level for the mass regions 144-232, 256-282 and 296-466 GeV. [ABSTRACT FROM AUTHOR]

The LHC has delivered several fb of data in spring and summer 2011, opening new windows of opportunity for discovering phenomena beyond the Standard Model. A summary of the searches conducted by the ATLAS and CMS experiments based on about 1 fb of data is presented. [ABSTRACT FROM AUTHOR]

We present the measurements of the differential cross-sections for inclusive electron and muon production in proton-proton collisions at a centre-of-mass energy of $\sqrt{s} = $ 7 TeV, using ∼1.4 pb of data collected by the ATLAS detector at the Large Hadron Collider. The muon cross-section is measured as a function of muon transverse momentum p in the range 4 < p < 100 GeV and within pseudorapidity | η| < 2.5. In addition, the electron and muon cross-sections are measured in the range 7 < p < 26 GeV and within | η| < 2.0, excluding 1.37 < | η| < 1.52. After subtraction of the W/ Z/ γ contribution, the differential cross-sections are found to be in good agreement with theoretical predictions for heavy-flavour production obtained from fixed order NLO calculations with NLL high- p resummation, and to be sensitive to the effects of NLL resummation. [ABSTRACT FROM AUTHOR]

We present a search for physics beyond the Standard Model in proton-proton collisions at a centre-of-mass energy of $\sqrt{s} = {7}\;{\rm{TeV}}$, performed with the ATLAS detector at the Large Hadron Collider (LHC). No evidence for new physics is found in dijet mass and angular distributions and stringent limits are set on a variety of models of new physics, including excited quarks, quark contact interactions, axigluons, and quantum black holes. [ABSTRACT FROM AUTHOR]

A search for a Higgs boson has been performed in the H→ WW→ℓ νjj channel using 1.04 fb of pp collision data at $\sqrt{s} = 7~{\rm TeV}$ recorded with the ATLAS detector at the Large Hadron Collider. No significant excess of events is observed over the expected Standard Model (SM) background and limits on the Higgs boson production cross-section are derived for a Higgs boson mass in the range 240 GeV < m < 600 GeV. The best sensitivity is obtained for m = 400 GeV, where the 95% confidence level upper bound on the cross-section for H→ WW production is 3.1 pb, or 2.7 times the Standard Model prediction. [ABSTRACT FROM AUTHOR]

Abstract: This Letter presents evidence for the associated production of a W boson and a top quark using of pp collision data at accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the cross-section. The result is incompatible with the background-only hypothesis at the 3.3σ level, the expected sensitivity assuming the Standard Model production rate being 3.4σ. The corresponding cross-section is determined and found to be , in good agreement with the Standard Model expectation. From this result the CKM matrix element is derived assuming that the Wt production through and is small. [Copyright &y& Elsevier]

Abstract: A search for the Standard Model Higgs boson in the () decay mode is presented. The search is performed using proton–proton collision data corresponding to an integrated luminosity of at a centre-of-mass energy of 7 TeV collected during 2011 with the ATLAS detector at the Large Hadron Collider. No significant excess of events over the expected background is observed. An upper bound is placed on the Higgs boson production cross section as a function of its mass. A Standard Model Higgs boson with mass in the range between and is excluded at 95% confidence level, while the expected exclusion range is from to . [Copyright &y& Elsevier]

Abstract: The ATLAS Muon Spectrometer is designed to measure the momentum of muons with a resolution of dp/p=3% at 100GeV and 10% at 1TeV. For this task, the spectrometer employs 355,000 Monitored Drift Tubes (MDTs) arrayed in 1200 chambers. Calibration (RT) functions convert drift time measurements into tube-centered impact parameters for track segment reconstruction. RT functions depend on MDT environmental parameters and so must be appropriately calibrated for local chamber conditions. We report on the creation and application of a gas monitor system based calibration program for muon track reconstruction in the LHC startup phase. [Copyright &y& Elsevier]

Abstract: Tracking systems in large multipurpose particle physics detectors are comprised of a large number of active elements designed, for precision measurement of particle trajectories. If detectors are to perform as designed a precise knowledge of the location of the different elements, with precision similar to the intrinsic detector resolution, is required. We will describe the design criteria and design considerations for optical alignment systems that achieve these goals. Issues discussed will include resolution discussions, integrating alignment with tracking detectors, geometric considerations, test beam activities, optical devices, calibration, and software analysis and validation procedures. We will describe the implementation of these ideas mainly in the CMS and ATLAS detectors operating at LHC. [Copyright &y& Elsevier]

Abstract: In this review paper the present state-of-the-art of muon detection systems using gaseous detectors at the Large Hadron collider (LHC) is described. Beginning with a discussion of the concepts of muon detection systems, a comparison of the various technologies used is made with respect to the challenges at present experiments, and developments for future upgrades are discussed. Starting from wire chambers, micropattern detectors are described and their readiness for upgrades is highlighted. Aging, long-term sustained operation and factors affecting gas choice are discussed. Finally some applications outside particle physics are also presented. [Copyright &y& Elsevier]

Abstract: This Letter describes the measurement of elliptic flow of charged particles in lead–lead collisions at using the ATLAS detector at the Large Hadron Collider (LHC). The results are based on an integrated luminosity of approximately 7 μb−1. Elliptic flow is measured over a wide region in pseudorapidity, , and over a broad range in transverse momentum, . The elliptic flow parameter is obtained by correlating individual tracks with the event plane measured using energy deposited in the forward calorimeters. As a function of transverse momentum, reaches a maximum at of about 3 GeV, then decreases and becomes weakly dependent on above 7–8 GeV. Over the measured pseudorapidity region, is found to be only weakly dependent on η, with less variation than observed at lower beam energies. The results are discussed in the context of previous measurements at lower collision energies, as well as recent results from the LHC. [Copyright &y& Elsevier]

Abstract: A search for a heavy Standard Model Higgs boson decaying via , where , is presented. The search is performed using a data set of pp collisions at , corresponding to an integrated luminosity of 1.04 fb−1 collected in 2011 by the ATLAS detector at the CERN LHC collider. No significant excess of events above the estimated background is found. Upper limits at 95% confidence level on the production cross section (relative to that expected from the Standard Model) of a Higgs boson with a mass in the range between 200 and are derived. Within this mass range, there is at present insufficient sensitivity to exclude a Standard Model Higgs boson. For a Higgs boson with a mass of , where the sensitivity is maximal, the observed and expected cross section upper limits are factors of 1.7 and 2.7, respectively, larger than the Standard Model prediction. [Copyright &y& Elsevier]

Abstract: The existing ATLAS tracker will be at its functional limit for particle fluences of 1015 (LHC). Thus for the upgrades at smaller radii like in the case of the planned Insertable B-Layer (IBL) and for increased LHC luminosities (super LHC) the development of new structures and materials which can cope with the resulting particle fluences is needed. n-in-p silicon devices are a promising candidate for tracking detectors to achieve these goals, since they are radiation hard, cost efficient and are not type inverted after irradiation. A n-in-p pixel production based on a MPP/HLL design and performed by CiS (Erfurt, Germany) on thick Float-Zone material is characterised and the electrical properties of sensors and single chip modules (SCM) are presented, including noise, charge collection efficiencies, and measurements with MIPs as well as an 241Am source. The SCMs are built with sensors connected to the current ATLAS read-out chip FE-I3. The characterisation has been performed with the ATLAS pixel read-out systems, before and after irradiation with 24GeV/c protons. In addition preliminary testbeam results for the tracking efficiency and charge collection, obtained with a SCM, are discussed. [Copyright &y& Elsevier]

Abstract: The ATLAS Pixel Detector is the innermost detector of the ATLAS Experiment at the Large Hadron Collider at CERN. It consists of 1744 silicon sensors equipped with approximately 80 million electronic channels, providing typically three measurement points with high resolution for particles emerging from the beam-interaction region, thus allowing to measure particle tracks and secondary vertices with very high precision. In the following, the performance reached by the Pixel Detector with LHC collision data will be presented, with particular attention to its spatial resolution, efficiency, particle identification properties and the Lorentz angle measurement. Offline calibration procedures and optimization techniques will be discussed in detail. [Copyright &y& Elsevier]

Abstract: ATLAS is a multipurpose experiment that records the products of the LHC collisions. In order to reconstruct the trajectories of the charged particles produced in these collisions, ATLAS has an internal tracking system made of silicon planar sensors (pixels and micro-strips) and drift-tube based detectors; both together, they constitute the ATLAS Inner Detector. The alignment of the ATLAS tracking system requires the determination of their almost 36,000 degrees-of-freedom (DOF) with high accuracy. Thus, the demanded precision for the alignment of the pixel and micro-strip sensors is below . As alignment algorithms are based on the minimization of the track-hit residuals, a linear system with a large number of DOF has to be solved. The alignment results of the ATLAS tracker using data recorded during cosmic commissioning phases in 2008 and 2009 and the LHC start up run in 2009 will be presented. Moreover recent 7TeV data collected during 2010 run have been used to study the detector performance. These studies reveal that the detector is aligned with a precision high enough to cope with the requirements. [Copyright &y& Elsevier]

Abstract: A new pixel module concept is presented, where thin sensors and a novel vertical integration technique are combined. This R&D activity is carried out in view of the ATLAS pixel detector upgrades. A first set of n-in-p pixel sensors with active thicknesses of and has been produced using a thinning technique developed at the Max-Planck-Institut Halbleiterlabor (HLL). Charge Collection Efficiency measurements have been performed, yielding a higher CCE than expected from the present radiation damage models. The interconnection of thin n-in-p pixels to the FE-I3 ATLAS electronics is under way, exploiting the Solid Liquid Interdiffusion (SLID) technique developed by the Fraunhofer Institut EMFT. In addition, preliminary studies aimed at Inter-Chip-Vias (ICV) etching into the FE-I3 electronics are reported. ICVs will be used to route the signals vertically through the read-out chip, to newly created pads on the backside. This should serve as a proof of principle for future four-side tileable pixel assemblies, avoiding the cantilever presently needed in the chip for the wire bonding. [Copyright &y& Elsevier]

Abstract: The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN. It consists of 1744 silicon sensors equipped with approximately 80 million electronic channels, providing typically three measurement points with high resolution for charged particles emerging from the beam-interaction region, thus allowing the reconstruction of particle tracks and secondary vertices with very high precision. Before the start of LHC operations, the completed Pixel Detector was operated for many months under nominal conditions in the ATLAS experimental hall. This allowed for the optimization of the operating parameters of the system, and to qualify the detector with physics data from cosmic muons. After the commissioning phase was complete, the Pixel Detector was 97.5% operational during the first LHC pp collisions run. Noise occupancy and hit efficiency exceed the design specifications. The alignment is close enough to the ideal to allow good track reconstruction and invariant mass determination. A review of the commissioning and first operational experience with the Pixel Detector will be presented. This will include detector calibration procedures, online data quality monitoring, module timing optimization and the status of the Pixel Detector during the first year of LHC operations. [Copyright &y& Elsevier]

Abstract: The Inner Detector of the ATLAS experiment at the Large Hadron Collider at CERN contains three tracking systems: The silicon Pixel Detector, the Silicon Microstrip Tracker and the Transition Radiation Tracker. In combination these detectors provide excellent track and vertex reconstruction efficiencies and resolutions. This paper describes studies which show the performance of track and vertex reconstruction on data collected at 7TeV center-of-mass energy. [Copyright &y& Elsevier]

Abstract: Results are presented of a search for supersymmetric particles in events with large missing transverse momentum and at least one heavy flavour jet candidate in proton–proton collisions. In a data sample corresponding to an integrated luminosity of 35 pb−1 recorded by the ATLAS experiment at the Large Hadron Collider, no significant excess is observed with respect to the prediction for Standard Model processes. For R-parity conserving models in which sbottoms (stops) are the only squarks to appear in the gluino decay cascade, gluino masses below 590 GeV (520 GeV) are excluded at the 95% C.L. The results are also interpreted in an MSUGRA/CMSSM supersymmetry breaking scenario with and in an SO(10) model framework. [Copyright &y& Elsevier]

Constraints on dark matter from the first CMS and ATLAS SUSY searches are investigated. It is shown that within the minimal supergravity model, the early search for supersymmetry at the LHC has depleted a large portion of the signature space in dark matter direct detection experiments. In particular, the prospects for detecting signals of dark matter in the XENON and CDMS experiments are significantly affected in the low neutralino mass region. Here the relic density of dark matter typically arises from slepton coannihilations in the early universe. In contrast, it is found that the CMS and ATLAS analyses leave untouched the Higgs pole and the Hyperbolic Branch/Focus Point regions, which are now being probed by the most recent XENON results. Analysis is also done for supergravity models with non-universal soft breaking where one finds that a part of the dark matter signature space depleted by the CMS and ATLAS cuts in the minimal SUGRA case is repopulated. Thus, observation of dark matter in the LHC depleted region of minimal supergravity may indicate non-universalities in soft breaking. [ABSTRACT FROM AUTHOR]

Abstract: A search for squarks and gluinos in final states containing jets, missing transverse momentum and no electrons or muons is presented. The data were recorded by the ATLAS experiment in proton–proton collisions at the Large Hadron Collider. No excess above the Standard Model background expectation was observed in of analysed data. Gluino masses below 500 GeV are excluded at the 95% confidence level in simplified models containing only squarks of the first two generations, a gluino octet and a massless neutralino. The exclusion increases to 870 GeV for equal mass squarks and gluinos. In MSUGRA/CMSSM models with , and , squarks and gluinos of equal mass are excluded below 775 GeV. These are the most stringent limits to date. [Copyright &y& Elsevier]

Abstract: The CMS and the ATLAS Collaborations have recently reported on the search for supersymmetry with 35 pb−1 of data and have put independent limits on the parameter space of the supergravity unified model with universal boundary conditions at the GUT scale for soft breaking, i.e., the mSUGRA model. We extend this study by examining other regions of the mSUGRA parameter space in and . Further, we contrast the reach of CMS and ATLAS with 35 pb−1 of data with the indirect constraints, i.e., the constraints from the Higgs boson mass limits, from flavor physics and from the dark matter limits from WMAP. Specifically it is found that a significant part of the parameter space excluded by CMS and ATLAS is essentially already excluded by the indirect constraints and the fertile region of parameter space has yet to be explored. We also emphasize that gluino masses as low as 400 GeV but for squark masses much larger than the gluino mass remain unconstrained and further that much of the hyperbolic branch of radiative electroweak symmetry breaking, with low values of the Higgs mixing parameter μ, is essentially untouched by the recent LHC analysis. [Copyright &y& Elsevier]

Abstract: The LHC will begin colliding lead nuclei at a nucleon-nucleon center of mass energy of 2.76 TeV in November, 2010. The luminosity during this first LHC heavy ion run is expected to be roughly one hundredth of the Pb+Pb “design” luminosity. The ATLAS experiment is prepared to carry out measurements during this first Pb+Pb run of bulk observables such as charged particle multiplicity, charged particle spectra and elliptic flow and to make first measurements of jet spectra and jet fragment spectra. The prospects for these measurements are briefly described. [Copyright &y& Elsevier]

Abstract: In this document the results of the ATLAS J/Ψ studies on very early LHC proton-proton data are shown. The double differential cross-section is measured with respect to the transverse momentum and rapidity of the J/Ψ on 9.5 nb− 1 of integrated luminosity. The non-prompt to prompt cross-section ratio using 17.5 nb−1 as a function of the J/Ψ transverse momentum has been estimated. [Copyright &y& Elsevier]

Abstract: Jet cross sections have been measured in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector. The measurement uses an integrated luminosity of 17 nb−1 recorded at the Large Hadron Collider. The anti- algorithm is used to identify jets with a jet resolution parameter . The dominant uncertainty comes from the jet energy scale, which is determined to within 7% for central jets above 60 GeV transverse momentum. Inclusive single-jet differential cross sections are presented as functions of jet transverse momentum and rapidity. The results are compared to expectations based on next-to-leading-order QCD, which agree with the data, providing a validation of the theory in a new kinematic regime. [Copyright &y& Elsevier]

Abstract: The ATLAS detector has collected more than 11 pb−1 of data on pp collisions at , at the LHC. The detector status and performance on reconstruction of the different probes of the interaction, jets, leptons and vector bosons, will be described, with some highlights of the earliest experimental results. [Copyright &y& Elsevier]

Abstract: The ATLAS experiment has extensive charged particle tracking over full azimuth and within . The performance of this system is illustrated and some of the first results for pp collisions are presented. The prospects for tracking in the expected high-multiplicity heavy ion environment are shortly commented. The tracking performance within jets, which is essential for the measurement of jet fragmentation functions, will also be shortly presented. [Copyright &y& Elsevier]

Abstract: Upgrades to the inner tracking detectors at the Super Large Hadron Collider (SLHC) will require more efficient methods of power delivery. Serial power is one architecture that delivers power efficiently by powering a chain of front-end circuits (hybrids) with a common current. A major concern with serial power is the loss of the full hybrid chain due to an open circuit failure of a single hybrid. We propose a method to protect a serial chain of hybrids with emphasis on application to the ATLAS silicon strip upgrade. A prototype protection circuit and its discrete component implementation are described. Results from tests of the protection circuit used with individual “dummy” hybrids and in a system test with a collection of dummy hybrids are given. Finally, a path towards a radiation-hard ASIC implementation is discussed. This work demonstrates that the protection of a serial chain is viable and is not an obstacle to the implementation of serial power. [Copyright &y& Elsevier]

Abstract: Using the ATLAS detector, a centrality-dependent suppression has been observed in the yield of mesons produced in the collisions of lead ions at the Large Hadron Collider. In a sample of minimum-bias lead–lead collisions at a nucleon–nucleon centre of mass energy , corresponding to an integrated luminosity of about , mesons are reconstructed via their decays to pairs. The measured yield, normalized to the number of binary nucleon–nucleon collisions, is found to significantly decrease from peripheral to central collisions. The centrality dependence is found to be qualitatively similar to the trends observed at previous, lower energy experiments. The same sample is used to reconstruct Z bosons in the final state, and a total of 38 candidates are selected in the mass window of 66 to 116 GeV. The relative Z yields as a function of centrality are also presented, although no conclusion can be inferred about their scaling with the number of binary collisions, because of limited statistics. This analysis provides the first results on and Z production in lead–lead collisions at the LHC. [Copyright &y& Elsevier]

Abstract: The restart of the Large Hadron Collider (LHC) at CERN, foreseen in November 2009 after the incident of 2008, will finally open a new window on the physics at the TeV scale and will allow the discovery of the Standard Model Higgs boson, if it exists, or of possible alternative schemes for the spontaneous symmetry-breaking mechanism. Moreover the LHC Collider will hopefully provide an answer to one of the most compelling questions of today coming from astronomical observations, astrophysics and cosmic ray experiments: which is the particle physics candidate for the Dark Matter component of the Universe? Supersymmetry (SUSY) is a theoretically attractive scenario for physics beyond the Standard Model which can provide a suitable Dark Matter candidate in case R-parity is conserved. If SUSY is manifesting at the TeV scale, as favored by several arguments, it will be accessible at the LHC Collider within the first few years of data taking. In this paper search strategies for a generic SUSY models with R-parity conservation with the ATLAS detector are described. These inclusive search strategies are based on signatures with missing transverse momentum from undetected neutralinos, in addition to multiple hard jets and leptons. The corresponding discovery reach for the first fb −1 of integrated luminosity of ATLAS data will be presented together with a discussion of possible measurements needed to extract the masses of SUSY particles including the Lightest Supersymmetric Particle (LSP), which in various supersymmetric (SUSY) symmetry breaking scenarios, is the lightest neutralino . [Copyright &y& Elsevier]

Abstract: The ATLAS Tile Calorimeter is a sampling detector composed by cells made of iron-scintillator tiles. The calorimeter cell signals are digitized in the front-end electronics and transmitted to the Read-Out Drivers (RODs) at the first level trigger rate. The ROD receives triggered data from up to 9856 channels and provides the energy, phase and quality factor of the signals to the second level trigger. The back-end electronics is divided into four partitions containing eight RODs each. Therefore, a total of 32 RODs are used to process and transmit the data of the TileCal detector. In order to emulate the detector signals in the production and commissioning of ROD modules a board called ROD Injector and Multiplexer Board (RIMBO) was designed. In this paper, the RIMBO main functional blocks, PCB design and the different operation modes are described. It is described the crucial role of the board within the TileCal ROD test-bench in order to emulate the front-end electronics during the validation of ROD boards as well as during the evaluation of the ROD signal reconstruction algorithms. Finally, qualification and performance results for the injection operation mode obtained during the Tile Calorimeter ROD production tests are presented. [ABSTRACT FROM AUTHOR]