A study of the role of the PDF uncertainty on the LHC W-boson mass measurement

摘要

The determination of the W-boson mass through an analysis of the decay charged-lepton transverse momentum distribution has a sizable uncertainty due to the imperfect knowledge of the relevant parton distribution functions (PDFs). In this paper, a quantitative assessment of the W-boson mass uncertainty at the LHC resulting from the PDF uncertainty is examined. We use the CT14 NNLO PDFs with a NNLL + NNLO calculation (ResBos) to simulate the W-boson production and decay kinematics. The uncertainty of the W-boson mass determination is then determined as a function of the boson and lepton kinematics. For W+ production using P-T(W) < 15 GeV and 35 < P-T(l) (GeV) < 45, PDF uncertainties lead (at the 68% CL) to a mass uncertainty for the M(W)(+)of (+16.0-17.5) MeV, (+13.9-14.8) MeV, and (+12.2-19.2) MeV, are determined at 7 TeV, 8 TeV and 13 TeV, respectively. The uncertainties of M-(W) over bar for the same cuts are found to be +15.9-15.6 MeV,(+15.0)(-12.7) MeV and (+14.8-15.3) MeV, at 7 TeV, 8 TeV and 13 TeV, respectively.