Four-fermion production near the W pair-production threshold

M. Beneke, P. Falgari, C. Schwinn, A. Signer, G. Zanderighi

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43 Scopus citations

Abstract

We perform a dedicated study of the four-fermion production process e- e+ → μ- over(ν, ̄)μ u over(d, ̄) X near the W pair-production threshold in view of the importance of this process for a precise measurement of the W boson mass. Accurate theoretical predictions for this process require a systematic treatment of finite-width effects. We use unstable-particle effective field theory (EFT) to perform an expansion in the coupling constants, ΓW / MW, and the non-relativistic velocity v of the W boson up to next-to-leading order in ΓW / MW ∼ αew ∼ v2. We find that the dominant theoretical uncertainty in MW is currently due to an incomplete treatment of initial-state radiation. The remaining uncertainty of the NLO EFT calculation translates into δ MW ≈ 10 - 15   MeV, and to about 5 MeV with additional input from the NLO four-fermion calculation in the full theory.

Original languageEnglish
Pages (from-to)89-135
Number of pages47
JournalNuclear Physics, Section B
Volume792
Issue number1-2
DOIs
StatePublished - 21 Mar 2008
Externally publishedYes

Keywords

  • Effective Lagrangian
  • Electroweak interaction
  • Radiative corrections
  • W bosons

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