This paper presents the method and performance of primary vertex reconstruction in proton–proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of  s√=8s=8 TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed. A longitudinal vertex position resolution of about  30μm30μm is achieved for events with high multiplicity of reconstructed tracks. The transverse position resolution is better than  20μm20μm and is dominated by the precision on the size of the luminous region. An analytical model is proposed to describe the primary vertex reconstruction efficiency as a function of the number of interactions per bunch crossing and of the longitudinal size of the luminous region. Agreement between the data and the predictions of this model is better than 3% up to seventy interactions per bunch crossing.

Title

European Physical Journal C

Publisher

Springer New York LLC

Publisher Country

United States of America

Indexing

Thomson Reuters

Impact Factor

14.691

Publication Type

Prtinted only

Volume

77

Year

2017

Pages

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