results

The measurements of The measurements of mW and GW in the following subsections are determined using the standard DURHAM-PE algorithm to cluster all selected particle flow objects.

Combinations are made weighted by statistical errors only at the moment, systematics are preliminary where quoted. Also, 27 MeV is not yet added to the mass values quoted

The individual measurements of mW and GW are combined at each CM energy weighted by their statistical errors and systematic uncertainties (shown for example in Tables  and ). Correlations in these uncertainties with CM energy are taken into account. The mass found from the one-parameter maximum likelihood fit to the data is

m4qW
=   80.465 ±0.052 (stat.) ±0.026 (syst.)±0.0? (FSI) GeV/c2.
The FSI error is taken from the Bose-Einstein and colour reconnection systematic uncertainties in quadrature. The quoted systematic error includes the LEP energy uncertainty. The expected statistical error is ±0.053 GeV/c2. Fig. (a) shows the mass distribution from the 5C kinematic fits to the data before the window cuts between 70 and 90 GeV/c2  compared with the Monte Carlo prediction reweighted to the fitted W mass.

The W total width found from the two-parameter fit to the hadronic data is

G4qW
=
  2.31 ±0.12 (stat.) ±0.06 (syst.)±0.0? (FSI) GeV/c2,
with a measured correlation of +?% between the fitted mass and width, to be compared to an expectation of ? ±?%. The corresponding expected statistical error is 0.? GeV/c2.

Figure Figure


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Figure Figure

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Mass distributions for the 4q, enq[`q], mnq[`q] and tnq[`q] channels for data (points with error bars), non-WW background (shaded area) and signal+background Monte Carlo with mW values set to those fitted from each individual channel (solid line histogram). The distribution in the 4q channel is restricted to the window defined by the pairing algorithm, 60 < MW < 86 GeV/c2, as the pair of jets whose invariant mass should be plotted is uniquely defined only for these events.

The results from the one-parameter fit to the data, with the statistical and systematic errors including the LEP energy, are

menq[`q]W
=
80.526±0.087 (stat.) ±0.042 (syst.) GeV/c2,
mmnq[`q]W
=
80.327±0.082 (stat.) ±0.039 (syst.) GeV/c2,
mtnq[`q]W
=
80.376±0.123 (stat.) ±0.032 (syst.) GeV/c2.
The expected errors are ±0.087, ±0.082 and ±0.123 GeV/c2 for the e, m and t semileptonic channels, respectively. Figs. (b), (c) and (d) display the mass distributions resulting from the 2C kinematic fit to semileptonic final states for data. For comparison the mass distribution predicted from Monte Carlo, reweighted to the fitted W mass in data, is superimposed on each figure. The individual measurements of mW and GW are combined by minimising a c2 built from the full covariance matrix, taking into account all systematic uncertainties derived at each CM energy (shown for example in Tables  and ) with the appropriate correlation and the statistical error from each channel. The systematic uncertainties listed in part (a) of the tables are taken as 100% correlated between channels. The resulting combined mass for the semileptonic channels from the one-parameter fits is
mlnq[`q]W
=
80.412 ±0.054 (stat.) ±0.0? (syst.) GeV/c2,
with a c2/dof of 0.14/2.

A two-parameter fit to the data gives the following results for the W total width:

Genq[`q]W
=
1.84 ±0.20 (stat.) ±0.10 (syst.) GeV/c2,
Gmnq[`q]W
=
2.17±0.20 (stat.) ±0.08 (syst.) GeV/c2,
Gtnq[`q]W
=
2.23±0.30 (stat.) ±0.? (syst.) GeV/c2,
where the expected errors are determined to be ±0.?, ±0.? and ±0.? GeV/c2\ for the e, m and t channels respectively. The measured correlation from the fit to the data between mW and GW is ?%, ?% and ?% for the enq[`q], mnq[`q] and tnq[`q] channels respectively.

The combined total width from the two-parameter fits in all lnq[`q] channels is

Glnq[`q]W
=
2.05±0.13 (stat.) ±0.? (syst.) GeV/c2,
with a c2/dof of 0.?/1.

The combined mass and width from all channels are

mW
=
80.439 ±0.037 (stat.) ±0.0? (syst.)±0.0? (FSI) GeV/c2,
GW
=
2.189 ±0.088 (stat.) ±0.? (syst.) GeV/c2.
The combinations are performed in the same way as described in section . The LEP energy uncertainty has been added in quadrature to the mass and width systematic errors. The c2/dof is ?/1 and ?/1 for the mass and width combinations, respectively.

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On 10 Nov 2004, 16:45.