which has a total error of 80 MeV. The LEP combined
result for the measurement of mW by direct reconstruction,
based on preliminary results available at the time of the Spring 1999
conferences [3], was
mW = 80.368
0.065 GeV.
When combined with the W mass derived from WW cross-section measurements
at and above threshold, this becomes
mW = 80.370
0.063 GeV.
The error is dominated by the systematic error.
![]() |
||||
Error source | 4q | e | ![]() |
![]() |
Statistical | 116 | 180 | 164 | 332 |
Correlated Systematics: | ||||
Fragmentation | 35![]() |
25![]() |
25![]() |
30![]() |
Calorimeter calibrations | 30 | 27 | 14 | 19 |
Tracking | - | 7 | 3 | 3 |
Jet corrections | 8 | 14 | 4 | 7 |
Initial state radiation | 10![]() |
5![]() |
5![]() |
5![]() |
LEP energy | 17 | 17 | 17 | 17 |
Uncorrelated Systematics: | ||||
Reference MC Statistics | 10 | 16 | 15 | 23 |
Background contamination | 10![]() |
8 | 1 | 25 |
Colour reconnection | 25![]() |
- | - | - |
Bose-Einstein effects | 50![]() |
- | - | - |
Total Systematics | 77 | 47 | 37 | 53 |