Conveners
01 - Early Experience and Results from LHC
- Guenther Dissertori (Institut fur Teilchenphysik)
01 - Early Experience and Results from LHC
- Thomas Ruf (CERN)
01 - Early Experience and Results from LHC
- Guenther Dissertori (Institut fur Teilchenphysik)
01 - Early Experience and Results from LHC
- Thomas Ruf (CERN)
01 - Early Experience and Results from LHC
- Andreas Hoecker (CERN)
01 - Early Experience and Results from LHC
- Andreas Hoecker (CERN)
Dr
Helmut Burkhardt
(CERN)
7/22/10, 9:00โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
We report on the monitoring and optimization of the beam conditions in early LHC operation :
luminosity monitoring, optimization and calibration, beam-spot size and position and machine induced backgrounds
Massimiliano Ferro-Luzzi
(CERN)
7/22/10, 9:25โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
The high resolution of the LHCb vertex detector allows for precise measurements of vertex positions of beam-gas and beam-beam interactions. From these measurements beam parameters such as width and position can be inferred. A novel method will be presented for determining the absolute luminosity at the LHC using these directly measured beam parameters, in combination with beam intensity...
John Baines
(Particle Physics-Rutherford Appleton Laboratory-STFC - Science &)
7/22/10, 9:45โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
The ATLAS trigger has been used very successfully to collect collision data during 2009 and 2010 LHC running at centre of mass energies of 900 GeV, 2.36 TeV, and 7 TeV. The trigger system reduces the event rate, from the design bunchโcrossing rate of 40 MHz, to an average recording rate of 200Hz. The ATLAS trigger is composed of three levels. The first (Level 1) uses custom electronics to...
Edgar Fernando Carrera Jarrin
(Boston University-Unknown-Unknown)
7/22/10, 10:00โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
The CMS trigger system has been designed to cope with unprecedented luminosities and accelerator bunch-crossing rates of up to 40 MHz at LHC. The High-Level-Trigger (HLT) combines in a novel way the traditional L2 and L3 trigger components which are implemented in a commercial Filter Farm with thousands of CPUs. The flexibility of a contiguous software environment allows the coherent tuning of...
Eric Van Herwijnen
(CERN)
7/22/10, 10:15โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
The Large Hadron Collider beauty experiment (LHCb) is a dedicated heavy flavour physics experiment at the LHC. The trigger system employs the finite lifetime and relative large mass of charm and beauty hadrons to distinguish heavy flavour and background from inelastic pp-scattering. The LHCb trigger is a two level system. The first level is implemented in hardware, it reduces the visible...
Steven Lowette
(UCSB)
7/22/10, 11:00โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
The CMS tracker is the largest silicon detector ever built, covering an area close to 200 m2 and consisting of 15 148 silicon strip and 1440 silicon pixel modules. The use of tracker data in physics analysis requires fine-grained monitoring and calibration procedures. Results from timing studies, threshold optimization, calibration of gains and Lorentz angle determination are shown and the...
Dr
Antonio Limosani
(University of Melbourne)
7/22/10, 11:18โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
ATLAS is a multipurpose experiment which records the products of the LHC collisions. To reconstruct trajectories of charged particles produced in these collisions, the experiment is equipped with large-scale tracking systems built of silicon planar sensors (pixel and strip-based), as well as a driftโtube based detector system. This talk will cover the first experience gained with these...
Silvia Borghi
(University of Glasgow)
7/22/10, 11:36โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
The LHCb detector is a forward spectrometer. Its tracking system consists of silicon strip detectors and straw tube drift chambers. The LHCb experiment is dedicated to the reconstruction of B decays into many particle final states. For a high B reconstruction efficiency a high efficient track reconstruction is crucial. We will report on the performance of the individual tracking subdetectors...
Johanna Fleckner
(CERN / University of Mainz)
7/22/10, 11:54โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
First 7 TeV proton-proton collisions produced by the Large Hadron Collider at CERN have been recorded by the ATLAS experiments in 2010. The ability to accurately and efficiently reconstruct the trajectories of charged particles produced in these collisions is a critical component in the measurements that will be presented at this conference. This talk will present results on the performance of...
Boris Mangano
(UCSD)
7/22/10, 12:12โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
First 7 TeV proton-proton collisions produced by the Large Hadron Collider at CERN have been recorded by the CMS experiment in 2010. The ability to accurately and efficiently reconstruct the trajectories of charged particles produced in these collisions is a critical component for most measurements at the LHC. We present several methods for determining the efficiency and measuring the...
Andrew Powell
(University of Oxford)
7/22/10, 2:00โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
Particle identification (PID) is a fundamental requirement for LHCb and is provided by CALO, MUON and RICH sub-detectors. The Calorimeters provide identification of electrons, photons and hadrons in addition to the measurement of their energies and positions. As well as being part of the LHCb trigger, the MUON system provides identification of muons to a very high level of purity, essential...
Philippe Gras
(DAPNIA)
7/22/10, 2:20โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
We present results on the commissioning and performance of the CMS electromagnetic and hadron calorimeters in pp collisions at a centre of mass energy of 7 TeV at the LHC. The first LHC beams have been used to finalize the commissioning of the readouts and triggers. The calibrations and synchronisations of the calorimeters using cosmic muons, beam splash events (where the LHC beam is targeted...
Pascal Pralavorio
(Faculte des Sciences de Luminy-Centre de Physique des Particules)
7/22/10, 2:40โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
The commissioning, operation and general performance of the electromagnetic and hadronic calorimeters of ATLAS will be presented, as achieved using random triggers, calibration data, cosmic muons, and LHC proton-proton collisions. Methods will be presented for verifying the precision of inter-channel synchronization and calibration, and their improvement with in-situ data.
Scott Snyder
(Brookhaven National Laboratory (BNL))
7/22/10, 3:00โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
The understanding of the reconstruction of electrons in the ATLAS experiment at LHC is one of the key issues for the 2010 run at a center of mass energy of 7 TeV. Two aspects are of interest: the energy calibration and the reconstruction efficiency. The energy measurement of electrons is based on the electromagnetic calorimeter over most of the relevant energy range (5 GeV to a few TeV). The...
Salerno Roberto
(LLR-Ecole Polytechnique)
7/22/10, 3:20โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
The performance of electron and photon reconstruction and identification has been studied at โs = 7 TeV. Reconstruction and identification variables as well as isolation and photon conversion rejection variables, in the case of electrons, have been compared between data and Monte Carlo for signal and background. Electron and photon identification efficiency, electron fake rate and photon...
Anthony Morley
(CERN)
7/22/10, 4:15โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
With the start of the LHC operations at at center of mass energy of 7 TeV a large sample of low energy photons, mostly coming from the decay of neutral mesons, have been collected with the ATLAS detector. Due to the large amount of material upstream the electromagnetic (EM) calorimeter, about 50% of these photons will convert before reaching it. The converted photons are used as a tool to map...
Ariel Schwartzman
(SLAC National Accelerator Laboratory)
7/22/10, 4:35โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
This talk presents the first results on jet, missing transverse energy (MET) and tau reconstruction performance, as obtained with the ATLAS detector in 7 TeV proton-proton collisions at the LHC. Jets are reconstructed with the anti-kt jet algorithm using calorimeter clusters, or as so called 'track jets' using the Inner Detector only. The performance of the jet reconstruction will be compared...
Joanna Weng
(CERN)
7/22/10, 4:55โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
Data from pp collisions have been used to study jets and missing transverse energy (MET) in the CMS experiment at the Large Hadron Collider. Results are presented for four different approaches to reconstruct jets and three different approaches to reconstruct MET in The CMS detector: calorimeter-only based jet and MET reconstruction; an algorithm which improves the measurement of calorimeter...
Dr
Florian Beaudette
(CERN)
7/22/10, 5:15โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
The aim of the CMS particle flow event-reconstruction algorithm is to identify and reconstruct individually each particle arising from the LHC proton-proton collision, by combining the information from all subdetectors. The resulting particle-flow event reconstruction leads to an improved performance for the reconstruction of jets and MET, and for the identification of electrons, muons, and...
Giovanni Petrucciani
(Univ. of California, San Diego)
7/22/10, 5:35โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
The performance of muon reconstruction in CMS has been studied on a sample of muons collected in pp collisions at โs = 7 TeV at the LHC. Measured distributions of basic muon-track quantities are well reproduced by the Monte Carlo simulation. Efficiencies of various high-level trigger, identification, and reconstruction algorithms have been measured and compared with the expectations from Monte...
Martin Woudstra
(University of Massachusetts)
7/22/10, 5:55โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
The large cosmic data samples collected in fall 2009 by the ATLAS experiment have been used to study the performance of the Muon Spectrometer. Detailed studies of the basic Muon spectrometer performance in terms of sagitta resolution, tracking efficiency and momentum resolution are presented and provide an update with respect to the results recently published. The results are also compared...
Francesco Cafagna
(Univ. + INFN)
7/23/10, 9:00โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
Totem is the only LHC experiment that will explore the forward region at pseudorapidity larger than 3.1. The main goal is the measurement of the total and elastic cross-section at 14 TeV and the study of diffractive physics in the forward region. The experiment approved and funded in the 2006, was build, largely commissioned and started his data taking in December 2009. The total cross...
Alessia Tricomi
(Dipartimento di Fisica)
7/23/10, 9:15โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
The LHCf detector is the smallest of the six experiments which are taking data at the CERN LHC accelerator. The whole detector has been installed at the beginning of 2008 on both sides of LHC collision point 1 (IP1). LHCf has been designed to measure with high accuracy energy and transverse momentum spectra of neutral particles in the very forward region (ฮท > 8.4) of LHC collisions by means of...
Iouri BELIKOV
(IPHC, CNRS-IN2P3)
7/23/10, 9:30โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
ALICE is the LHC experiment dedicated to the study of heavy-ion collisions. The main purpose of ALICE is to investigate the properties of a state of deconfined nuclear matter, the Quark Gluon Plasma. Heavy flavour measurements will play a crucial role in this investigation. The physics programme of ALICE has started by studying proton-proton collisions at unprecedented high energies. We will...
Sheldon STONE
(Syracuse)
7/23/10, 10:00โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
The LHCb experiment is primarily designed to study charm and bottom hadron decays at the LHC. The first exclusively reconstructed charm and bottom hadrons signals have been observed shortly after the start of the first LHC physics run at โs = 7 TeV, in events collected with a minimum bias trigger. Charm cross-sections for D0, D+, Ds and Lambda_c are measured in the forward region covered by...
Julie Kirk
(RAL)
7/23/10, 11:00โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
This talk will give an overview on first results on QCD, quarkonia, and heavy-flavour physics in proton-proton collisions at โs=7 TeV, recorded with the ATLAS experiment at the LHC. The QCD measurements address properties of both soft and hard collisions, such as the underlying event, particle production in minimum bias events and jet production. First results from quarkonia and heavy flavour...
Sara Bolognesi
(CERN)
7/23/10, 11:25โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
This talk will give an overview on first results on QCD, quarkonia, and heavy-flavour physics in proton-proton collisions at โs=7 TeV, recorded with the CMS experiment at the LHC. The QCD measurements address properties of both soft and hard collisions, such as the underlying event, particle production in minimum bias events and jet production. First results from quarkonia and heavy flavour...
Maria Cepeda
(CIEMAT (Madrid))
7/23/10, 11:50โฏAM
01 - Early Experience and Results from LHC
Parallel Session Talk
The production of W and Z bosons has been observed in pp collisions at a center-of-mass energy of 7 TeV using data collected in the CMS experiment. W events were selected containing an isolated, energetic electron or muon. The presence of an energetic neutrino is demonstrated using the distribution of missing transverse energy (MET), which is calculated from calorimetric and tracking...
1057.
First Results from ATLAS on W and Z Boson Production in proton-proton Collisions at โs=7 TeV
Dr
Jan Kretzschmar
(University of Liverpool)
7/23/10, 12:10โฏPM
01 - Early Experience and Results from LHC
Parallel Session Talk
This talk will give an overview on first results on W and Z production in proton-proton collisions at โs=7 TeV, recorded with the ATLAS experiment at the LHC. The selection of W and Z events will be described, together with data-driven methods used to estimate the trigger and reconstruction efficiencies, as well as the main backgrounds. The W and Z signal yields and the extracted cross...
