arXiv subjects

Dominik Dannheim

Publications and source records attributed to Dominik Dannheim.

40 records · Page 3Linked to original sources

arXiv2008

Commissioning and Performance of the ATLAS Liquid Argon Calorimeters

The ATLAS liquid argon (LAr) calorimeter system consists of an electromagnetic barrel calorimeter and two end-caps with electromagnetic, hadronic and forward calorimeters. The construction of the full calorimeter system is completed since mid-2004. The detector has been operated with LAr at nominal high voltage and fully equipped with readout electronics. Online software, monitoring tools and offline signal reconstruction have been developed for data collection and processing. Extensive tests with calibration pulses have been carried out, and the electronics calibration scheme for all 182468 channels has been exercised. Since Augst 2006, cosmic muon data have been collected together with the rest of the ATLAS detector system as part of the ATLAS commissioning program. The reconstructed LAr signals from energy deposited by cosmic rays are compared to the prediction derived from measured detector parameters and calibration pulses. The uniformity of the detector response within regions that have sufficient cosmic muons are examined. The expected performance of the LAr calorimeter for ATLAS physics, based on previous beam tests and Monte Carlo simulation, is also summarised.

physics.ins-det↗

arXiv2006

Probing Extra Dimensions with ATLAS

In the late nineties several authors suggested that the extra dimensions predicted by string theory might lead to observable effects at high energy colliders. The ATLAS experiment which will start taking data at the LHC in 2007 will be an excellent place to search for such effects. The sensitivity of ATLAS to signatures of Extra Dimensions will be presented.

hep-ex↗

arXiv2004

Events with Isolated Charged Leptons and Large Missing Transverse Momentum at HERA

Striking events with isolated charged leptons, large missing transverse momentum and large transverse momentum of the hadronic final state were observed at the electron proton collider HERA in a data sample corresponding to a luminosity of about 130 pb-1. The H1 collaboration observed 11 events with isolated electrons or muons and with transverse momentum above 25 GeV. Only 3.4+-0.6 events were expected from Standard Model (SM) processes. Six of these events have a transverse momentum of greater than 40 GeV, while 1.3+-0.3 events were expected. The ZEUS collaboration observed good agreement with the SM. However, ZEUS found two events with a similar event topology, but tau leptons instead of electrons or muons in the final state. Only 0.2+-0.05 events were expected from SM processes. For various hypotheses the compatibility of the experimental results was investigated with respect to the SM and with respect to possible explanations beyond the SM. Prospects for the high-luminosity HERA-II data taking period are given.

hep-ph↗

arXiv2003

Search for single-top production with the ZEUS detector at HERA

A search for anomalous single-top production, ep -> etX, t -> Wb, has been made with the ZEUS detector at HERA using an integrated luminosity of 130 pb^-1. No evidence for top-quark production was found in either the leptonic or the hadronic decay channel of the W boson. The resulting constraints on single-top production via quark-flavour changing neutral current (FCNC) transitions exclude a substantial region in the FCNC t-u-gamma coupling not ruled out by other experiments.

hep-ex↗