Curvature-bias corrections using a pseudomass method

• Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy √s = 13 TeV during 2016, 2017 and 2018. The biases are determined using Z → μ+μ- decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10-4 GeV-1 level, improves the Z → μ+μ- mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass. © 2024 CERN.

Subject headings

NATURVETENSKAP  -- Fysik -- Subatomär fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Subatomic Physics (hsv//eng)

NATURVETENSKAP  -- Fysik -- Acceleratorfysik och instrumentering (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Accelerator Physics and Instrumentation (hsv//eng)

Keyword

Analysis and statistical methods

Detector alignment and calibration methods (lasers, sources, particle-beams)

Large detector-systems performance

Performance of High Energy Physics Detectors

Alignment

Magnetic polarity

Tellurium compounds

Alignment methods

Analyse and statistical method

Calibration method

Detector alignment and calibration method (laser, source, particle-beam)

Detector systems

High energy physics detector

Large detector-system performance

Large detectors

Laser sources

Performance

Performance of high energy physic detector

Source particles

Systems performance

Charged particles

Analysis and statistical methods

Publication and Content Type

art (subject category)

ref (subject category)