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Curvature-bias corrections using a pseudomass method

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Abellan Beteta, C 
Abudinen, F 


jats:titleAbstract</jats:title> jats:pMomentum 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 √(jats:italics</jats:italic>)=13 TeV during 2016, 2017 and 2018. The biases are determined using jats:italicZ</jats:italic>→jats:italicμ</jats:italic> jats:sup+</jats:sup> jats:italicμ</jats:italic> jats:sup-</jats:sup> decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10jats:sup-4</jats:sup> GeVjats:sup-1</jats:sup> level, improves the jats:italicZ</jats:italic>→jats:italicμ</jats:italic> jats:sup+</jats:sup> jats:italicμ</jats:italic> jats:sup-</jats:sup> mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass.</jats:p>



5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences

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Journal of Instrumentation

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IOP Publishing