Speaker
Kyungeon CHOI,
(ATLAS)
Description
Run-2 of the LHC has provided new challenges to track and vertex reconstruction with higher centre-of-mass
energies and luminosity leading to increasingly high-multiplicity environments, boosted, and highly-collimated
physics objects. To achieve this goal, ATLAS is equipped with the Inner Detector tracking system built using
different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a
2T solenoidal magnetic field. In addition, the Insertable B-layer (IBL) is a fourth pixel layer, which was inserted
at the centre of ATLAS during the first long shutdown of the LHC. An overview of the use of each of these
subdetectors in track and vertex reconstruction, as well as the algorithmic approaches taken to the specific tasks
of pattern recognition and track fitting, is given. The performance of the Inner Detector tracking and vertexing
will be summarised. These include a factor of three reduction in the reconstruction time, optimisation for the
expected conditions, novel techniques to enhance the performance in dense jet cores, time-dependent alignment of
sub-detectors and special reconstruction of charged particle produced at large distance from interaction points.
Moreover, data-driven methods to evaluate vertex resolution, fake rates, track reconstruction inefficiencies in
dense environments, and track parameter resolution and biases will be shown. Luminosity increases in 2017 and beyond
will also provide challenges for the detector systems and offline reconstruction, and strategies for mitigating the
effects of increasing occupancy will be discussed.
Primary author
Kyungeon CHOI,
(ATLAS)
