Related papers: The ATLAS Trigger System Commissioning and Perform…
Measurements of charged particle distributions, sensitive to the underlying event, have been performed with the ATLAS detector at the LHC. The measurements are based on data collected using a minimum-bias trigger to select proton-proton…
During the 2010 CERN Large Hadron Collider operation at $\sqrt{s}$ = 7 TeV, 35 pb$^{-1}$ of high $p_T$ triggers has been collected by the ATLAS detector. This corresponds to the production of approximately $\number 2500$ top-quark pair…
We report on performance studies of the ATLAS detector obtained with first single LHC (Large Hadron Collider) beam data in September 2008, and large samples of cosmic ray events collected in the fall of 2008. In particular, the performance…
This paper presents measurements of distributions of charged particles which are produced in proton--proton collisions at a centre-of-mass energy of $\sqrt{s} = 8$ TeV and recorded by the ATLAS detector at the LHC. A special dataset…
During the 2010 pp run of the Large Hadron Collider at \surd s = 7 TeV, a substantial data sample of high pT triggers, 35/pb, has been collected by the ATLAS detector, corresponding to about 2,500 produced top-quark pair events containing…
The ATLAS detector is capable of resolving the highest energy pp collisions at luminosities sufficient to yield 10's of simultaneous interactions within a bunch collision lasting <0.5 nsec. Already in 2011 a mean occupancy of 20 is often…
This paper describes the reconstruction of electrons and photons with the ATLAS detector, as employed for measurements and searches exploiting the complete LHC Run 2 dataset. An improved energy clustering algorithm is introduced, and its…
We study 100 images of early LHC collisions that were recorded by the ATLAS experiment and made public for outreach purposes, and extract the charged particle multiplicity as a function of momentum for proton-proton collisions at sqrt(s) =…
This paper describes the CMS trigger system and its performance during Run 1 of the LHC. The trigger system consists of two levels designed to select events of potential physics interest from a GHz (MHz) interaction rate of proton-proton…
Inclusive multi-jet production is studied using the ATLAS detector for proton-proton collisions with a center-of-mass energy of 7 TeV. The data sample corresponds to an integrated luminosity of 2.43 pb^-1, using the first proton-proton data…
At the High Luminosity LHC (HL-LHC), the CMS experiment will face a harsh environment with a high instantaneous luminosity up to 7x10$^{34}$/cm$^2$/s corresponding to an average of 140-200 multiple proton-proton collisions per bunch…
The Large Hadron Collider (LHC) is expected to provide proton-proton collisions at a centre-of-mass energy of 14 TeV, yielding millions of of top quark events. The top-physics potential of the two general purpose experiments, ATLAS and CMS,…
After the successful LHC operation at the center-of-mass energies of 7 and 8 TeV in 2010-2012, plans are actively advancing for a series of upgrades of the accelerator, culminating roughly ten years from now in the high-luminosity LHC…
The most recent QCD measurements performed in ATLAS are reviewed; the results summarized here are based on data collected with the ATLAS detector during the 2010 and 2011 data taking in proton-proton collisions at center of mass energy sqrt…
The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data- taking with…
The first level trigger of the CMS experiment is comprised of custom electronics that process data from the electromagnetic and hadron calorimeters and three technologies of muon detectors in order to select the most interesting events from…
An overview of the analyses that led to the observation of the Higgs boson production in association with a top quark pair ($t\bar t H$) with the ATLAS experiment is given. Up to 80 fb$^{-1}$ of proton-proton collision data recorded by the…
After nearly two decades of design, construction and commissioning, the CMS detector was operated with colliding LHC proton beams for the first time in November 2009. Collision data were recorded at centre-of-mass energies of 0.9 and 2.36…
This thesis consists of three closely related parts. An analysis of data recorded by the ATLAS detector in 2010 in proton-proton collisions at a center-of-mass energy of 7 TeV with an integrated luminosity of 33.4/pb is performed, searching…
The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking…