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ATLAS jet trigger performance during run1 and preparation for run2

During run 1 the Large Hadron Collider collided proton beams at the centre-of-mass energy of 7 and 8 TeV, as well as heavy ions at the centre-of-mass energy of 2.76 TeV. The ATLAS trigger is designed to reduce the rate of events from the nominal maximum bunch-crossing rate of 20 MHz to approximately...

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Detalles Bibliográficos
Autor principal: Cheatham, S
Lenguaje:eng
Publicado: 2014
Materias:
Acceso en línea:https://dx.doi.org/10.1016/j.nuclphysbps.2015.09.145
http://cds.cern.ch/record/1952311
Descripción
Sumario:During run 1 the Large Hadron Collider collided proton beams at the centre-of-mass energy of 7 and 8 TeV, as well as heavy ions at the centre-of-mass energy of 2.76 TeV. The ATLAS trigger is designed to reduce the rate of events from the nominal maximum bunch-crossing rate of 20 MHz to approximately 400 Hz, which is then written on disk offline. The online selection of events containing jets uses a dedicated jet trigger. The rate from jet events is very high, with a steeply falling spectrum in the distribution of the transverse energy. The jet trigger has been designed to keep an approximately constant jet rate of 0.5 Hz in various transverse momentum intervals and accounts for around 10 % of the total ATLAS trigger rate. During run 1 the jet trigger was fully efficient at Level 1 for jets with transverse energies above 25 GeV, whilst at Event Filter full efficiency was reached for jets with transverse energies above 60 GeV. The overall performance of the jet trigger during the 2011 data taking will be summarised, together with important updates made during 2012. In addition, the expected performance of the jet trigger in run 2, to start in 2015, will be described.