9-13 July 2018
Sofia, Bulgaria
Europe/Sofia timezone

New fitting concept in ATLAS muon tracking for the LHC Run II

10 Jul 2018, 16:00
Sofia, Bulgaria

Sofia, Bulgaria

National Culture Palace, Boulevard "Bulgaria", 1463 NDK, Sofia, Bulgaria
Poster Track 6 – Machine learning and physics analysis Posters


Zachary Louis Marshall (University of California Berkeley (US))


Muons with high momentum -- above 500 GeV/c -- are an important constituent of new physics signatures in many models. Run-2 of the LHC is greatly increasing ATLAS's sensitivity to such signatures thanks to an ever-larger dataset of such particles. The ATLAS Muon Spectrometer chamber alignment contributes significantly to the uncertainty of the reconstruction of these high-momentum objects. The proper treatment of measurements during tracking and the correct propagation of the alignment effects is extremely challenging. Recently, an innovative approach that imposes Gaussian constraints on ensembles of detector hits was implemented. It provides a significant improvement to high-momentum tracking without increasing the CPU budget. Furthermore, it allows for the verification of the expected alignment quality using high-statistics collision data. A detailed discussion of the algorithmic realization is given, the expected performance gains are presented and prospects for further applications of the approach are outlined.

Primary authors

William Axel Leight (DESY) Alan Poppleton (University of Massachusetts (US)) Peter Kluit (Nikhef National institute for subatomic physics (NL)) Edward Moyse (University of Massachusetts (US)) Pierre-Francois Giraud (Université Paris-Saclay (FR)) Jochen Meyer (Technion- Israel Institute of Technology (IL)) Zachary Louis Marshall (University of California Berkeley (US))

Presentation Materials