476. Measurement of isolated direct photons in lead-lead collisions at 2.76 TeV with the ATLAS detector
Iwona Grabowska-Bold (AGH Univesity of Science and Technology (PL))
Direct photons are a powerful tool to study heavy ion collisions. Their production rates provide access to the initial state PDFs, which are expected to be modified by nuclear effects. They also provide a means to calibrate the expected energy of jets that are produced in the medium, and thus are a tool to probe the physics of jet quenching more precisely both through jet rates and...
George Stephans (Massachusetts Inst. of Technology (US))
Final data on isolated photon production will be presented, measured in both pp and PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV with the CMS detector at the LHC. The isolated photon transverse energy (ET) spectra, covering the pseudorapidity range |eta| < 1.44 and transverse energy ET > 20 GeV, are found to be in good agreement with next-to-leading-order perturbative...
474. Measurements of W and Z boson production in Pb+Pb collisions at 2.76 TeV with the ATLAS detector.
Jiri Dolejsi (Charles University (CZ))
Collisions of lead nuclei at the LHC allow study of the deconfined phase of QCD matter at unparalleled temperatures and energy densities. The use of leptonic observables is particularly appealing as a consequence of their electroweak nature, allowing them to traverse the strongly-coupled medium essentially unaffected. W and Z bosons, observed through their semi-leptonic decay channels, may...
Lamia Benhabib (Ecole Polytechnique (FR))
The Compact Muon Solenoid (CMS) is fully equipped to measure leptonic decays of electroweak probes in the high multiplicity environment of nucleus-nucleus collisions. Electroweak boson production is an important benchmark process at hadron colliders. Precise measurements of W and Z production in heavy-ion collisions can help to constrain nuclear PDFs as well as serve as a standard candle of...