Ann reported on recent studies on fragmentation issues in the 4q channel. She compared mass differences between Jetset and Herwig for different jet algorithms, both at kingal level and after full reconstruction. The standard jet algorithm is the so called Durham PE one. She tried the Ptclus algorithm which leads to worth energy and angular resolutions. Luclus leads to similar resolutions and to similar mass shifts JT-HW wrt to Durham :

Similar studies at reconstruction level can be found in Matthew's thesis(p. 70-76), Ima's thesis (p. 53-54) and Adel thesis (p. 160-171). Those studies were performed in view of getting the best W mass reconstruction but not the smallest Systematical error from fragmentation effects.

Ann presented a study shifts of the W mass wrt to changes of the L Jetset parameter value (PARJ(81)). Aleph default value is 0.291 GeV, the Jetset one 0.290. Two MC data set (independent 4f events) have been generated by Jason, with L values of 0.1 and 0.5 GeV (no retuning of other Jetset parameters. The observed mass shifts compared to the standard Aleph parameter value are : +36+/-12 MeV and -76+/-12 MeV for L values of 100 and 500 MeV respectively. Ann showed also some inclusive distributions demonstrating that those very extreme L are clearly incompatible with our data.

Ann presented an overview of her talk on fragmentation issues in aleph for the W workshop in Lisbon. She has 45' to explain all our fragmentation studies and Herwig tests.

Jorgen presented some studies performed by Stephane on systematic error evaluations for TGC. Results of these study will be presented at the workshop. The problem with the current LEP averaging procedure is to correctly evaluate systematic errors in nD fits. Stephane showed for example that the current LEPTGC average does not properly treat the 2% uncertainty on the WW cross section. He also showed that for infinite statistic, the current LEP procedure will not converge to the estimated from OO method systematic uncertainty. This combination procedure will be discussed at the workshop and Aleph has clearly some points to make. Jorgen will present an alternative proposal based on OO.

Jorgen also presented the update of the work from David and Jacques on neutral TGCs from ZZ cross section. Compared to Aix, changes are that 183 GeV data are now included (marginal change on limits) and that the naïve QCD correction (1+alphas/pi factor) is now taking into account, resulting in somewhat worst limits. The work will be presented by David at the workshop.

Benjamin presented an update of the analysis. 500K events at 189 GeV have been generated with Galeph 309. When this data set is fitted against a reference produced with Galeph 308, a shift of -60+/-27 MeV is observed. On data, switching from a Galeph 308 to a Galeph 309 reference, shifted the fitted LEP energy by +74 MeV.

Benjamin, then gave an overview of his talk for the workshop. He reminded us that a shift of 600 MeV on the LEP energy corresponds to a shift of 5 mrad on the jet-jet angle. He has looked again at Roberto's angular corrections and found an energy shift of 130 MeV, which is larger to the value quoted for the conference note : 40 MeV. Some checks have still to be done, it was suggested to provide a range of value 40-100 MeV for the angular bias systematic mentioning that it is under study.

Guillaume uses the same selection (and ntuples) as Benjamin but instead of fitting the LEP energy assuming the Z mass, he fits the Z mass assuming the knowledge of the beam energy. This is somewhat different to what Benjamin is doing because it is the Z mass distribution which is reweighted. Several fits have been tested, Galeph 308 against 309. Similar results as Benjamin are obtained : the fitted Z mass is 2.6 s too high.

Andrea presented the difference he found between MC data set generated with Galeph 308/Julia 309 and Galeph 309/Julia 312. There are two main differences. The famous Geisha bug has been corrected for Galeph 309. This bug induced a 10mrad shift in phi of HCAL deposits. The net effect is a 2mrad change of phi on jets. This cannot explain the 70 MeV difference reported by Benjamin at Aix (which is in fact a 2sigma effect). Another bug was corrected in Julia. VDET bounding map correction haven wrongly been applied to MC. Resulting in a momentum shift (opposite for negative and positive tracks) in a particular theta interval on side A. Again this effect cannot explain the 70 MeV from Aix.

Djamel presented some systematic studies of the W mass measurement from the semileptonic tau channel for his tau reconstruction algorithm. Detector systematics were not checked, fragmentation systematic error was found to be of the same size as for the published 189 GeV data. Djamel will present this new analysis at the workshop.

Andrea will present at the workshop the Bose Einstein Correlation studies on single ratios presented by Bolek at the last W meeting. A common set of luboi parameters (l,s) is being to investigated between the four experiments.

Scott presented the work on bin to bin correlation (see previous W meeting) on the particle flow distribution and the influence of correlations on the upper Ki value. This work will also be presented in Lisbon.