On theoretical uncertainties of the W boson mass measurement at LEP2

Abstract

We discuss theoretical uncertainties of the measurement of the W boson mass at LEP2 energies, reconstructed with the help of the tandem of the Monte Carlo event generators KoralW and YFSWW3. Exploiting numerical results obtained with these programs, and the existing knowledge in the literature, we estimate that the theoretical uncertainty of the W mass due to electroweak corrections, as reconstructed at LEP2 with the help of these programs, is ∼ 5 MeV. Since we use certain idealized event selections and a simple M W -fitting procedure, our numerical exercises can be (should be) repeated for the actual "M W extraction methods" of the LEP2 measurements, using KoralW and YFSWW3 or other Monte Carlo programs.To be submitted to Physics Letters B ⋆

Predictions for ${\bar \nu} \nu \gamma$ production at LEP

“…The corresponding real pair emission then needs to be added also. This can be done by means of a separate Monte Carlo generation using any massive four-fermion MC event generator, for example KORALW [23].…”

Precision predictions for W-pair production at LEP2

“…There are two independent Monte Carlo programs for the precision predictions of Wpair production at LEP2: RacoonWW [10][11][12][13] and KoralW&YFSWW3 [7,[14][15][16][17][18][19][20][21][22]. They include the 4f -background contributions as well as all the necessary radiative corrections at the precision level required by LEP2.…”

“…The above solutions have been implemented in two MC event generators: RacoonWW [10-13] and KoralW&YFSWW3 [7,[14][15][16][17][18][19][20][21][22]. These programs are briefly described in the next two sections.…”

“…This CMC works effectively as a single MCEG and provides the description of the W -pair production process with all contributions/corrections needed for the LEP2 precision -for more details see Ref. [18].…”

Precise predictions for $e^+e^-\rightarrow 4f (+ \gamma)$ with anomalous couplings

“…In this approximation, there are factorizable corrections, which are the ones to on-shell W-pair production and on-shell W decay, and non-factorizable corrections, which originate from soft-photon exchange between the production and decay stages. Different versions of such a pole expansion have been used in the literature [7,8,9]. Although several Monte Carlo programs exist that include universal corrections, only two event generators, YFSWW3 [9,10] and RacoonWW [8,11], include non-universal corrections.…”