Abstract
Abstract:
Knowledge of the material in the ATLAS inner tracking detector is crucial in understand-
ing the reconstruction of charged-particle tracks, the performance of algorithms that identify jets
containing b-hadrons and is also essential to reduce background in searches for exotic particles
that can decay within the inner detector volume. Interactions of primary hadrons produced in pp
collisions with the material in the inner detector are used to map the loca- tion and amount of
this material. The hadronic interactions of primary particles may result in secondary vertices,
which in this analysis are reconstructed by an inclusive vertex-finding al- gorithm. Data were
collected using minimum-bias triggers by the ATLAS detector operating
at the LHC during 2010 at centre-of-mass energy √s = 7 TeV, and correspond to an integ-
rated luminosity of 19 nb−1. Kinematic properties of these secondary vertices are used to study the
validity of the modelling of hadronic interactions in simulation. Secondary-vertex yields are
compared between data and simulation over a volume of about 0.7 m3 around the
interaction point, and agreement is found within overall uncertainties.