Frederic presented the list of abstracts that the W group could send to the Osaka conference.

The rules for abstract submission are :

1. Any paper that was published after Tampere
2. Any paper in the Editorial Board pipeline
3. Any Winter 2000 conference note
4. Any new result foreseen

Submission of Aleph contributions will be centralized by Fabrizio Palla. The dead line for abstract submission is the 1^st of May, it is the 1^st of July for papers.

In total 21 abstracts could be sent to the Osaka conference.

Jorgen presented a status of the TGC (up to 189 GeV) paper. The first draft has been submitted to the collaboration on the 3^rd of March, the paper is more that 30 pages long (20 tables!!). Most of the comments (sometime very long one) refer to the editorial style, very few with physics. An effort will be made to make the paper more homogeneous and less dense (more details). Discussions with the referees (Avv and Frederic) are still going one. It is hoped (promised?) to have the second draft ready the week after Easter.

Jason announced a very soon release (next week?) of an Aleph note describing the work he did on W mass fragmentation systematic in the lvqq channel for the 189 GeV paper.

Following the success of the Crete workshop last fall, a W workshop is organized at CERN on the 18^th and 19^th of April. The Aleph contact persons are Stephane for the TGC, Avv for the W mass and cross section and Oliver for the FSI part. Each of them summarized the agenda of their session and presented the Aleph contributions.

Stephane presented the structure of the TGC group of the workshop (the conveners of the session are Robert Sekulin and Martin Grünewald). The group is subdivided in 3 subgroups : WW channels, other channels (single-W, single-gamma, quartic couplings, etc…) and tools and theory. The first two subgroups are clearly more active than the third one. The Aleph participation concentrate mostly on the WW channel, it was felt that Aleph participation to the second subgroup should be increased.

Stephane reported on the progress? made in trying to combine the TGC limits from the 4 experiments. The combined statistical error being of the same order of magnitude as the systematical one, some interest in understanding the content of the systematical error quoted by each experiment became clear. This is underway some differences have already been spotted. The second problem, is related to the method used to combine systematical errors. No obvious method has been found yet.

There will be 2 people from Aleph giving talks at the session : Tim on is log-likelihood and CP-violation TGCs study, Jorgen will give a summary of the current WW TGC analyses performed by the 4 experiments.

The conveners of this session are Avv Moutoussi and Mark Thomson. Jason is convening the sub group dealing with systematic related to W mass measurement.

Since Crete, the work has been concentrated on understanding the correlation of systematic uncertainties between experiments related to color reconnection, fragmentation and Bose-Einstein. A report will be given at the workshop.

Aleph will give quite a large number of talks at that session : Status of Aleph analysis (Frederic), Herwig tuning (Gerald), Aleph fragmentation's studies (Jason), Detector systematics (Andrea Venturi), Z-gamma (Eugeni) and higher order corrections and new generators (Andrea Valassi).

The conveners of the session are Oliver Buchmuller and Frans Verbeure. Oliver listed the Aleph contributions to that session :

• Status of 4q and qqlv particle multiplicities by Roger Jones
• Particle flow by Thomas Ziegler
• BE : comparison of results by Bolek Pietrzyk

Roger gave a status of the activities towards a combination of charged multiplicity results from the four experiments. The combination of the results could lead to a statistical error of the same order of the effect expected from several CR models. All experiments except Aleph give results corrected for PT and selections. As corrections are large and model dependent, it was suggested that the combination should not be performed on corrected numbers. Aleph will not go for it and would prefer a common acceptance to be defined. Roger also mentioned the possibility of combining the ln(xp) distributions form 0.1<P<1 GeV, this is under investigation. It was suggested to look at some other more sensitive to color reconnection variables (like particle flow or Lorentz invariant variables).

Oliver presented the Aleph studies on Particle Flow. This method originated from L3. Three similar analyses are currently being performed within Aleph (Matthew, Thomas and Roger). Thomas applied the full L3 method on Aleph data, while Matthew and Roger apply the L3 method but with some different selections. Both analyses give similar results : there is (and it is in fact the first convincing evidence) some sensitivity to color reconnection by looking at particle flow between jets. An important new information (compared to the Jamboree held on 10/04/00) is that color reconnection effect cannot be mistaken with uncertainty on the fragmentation modeling (Herwig and Jetset give similar results). Thomas will present the Aleph studies on the subject at the Workshop.

Bolek presented a comparison of the BE analyses performed by Aleph, Delphi and L3. This comparison will also be presented at the Workshop. Bolek explained that the l parameter used by the three experiments has to be different because each they are using different BE models (Aleph : BE3, Delphi : B0, L3 : B23). He then compared the mixed event method used by ADL, A and L do not favor BE between Ws while D seems to favor BE between Ws. While A and L have very uniform and small MC corrections as a function of Q2, D has corrections of the order of 10% at low Q2 (the sensitive region). It is not presently understood how Delphi handle background contamination (taken into account?, substracted?). There might be some clarification at the Workshop on this later point. Bolek then compared the Aleph and Delphi results for the so-called Aleph analysis. He reminded us about the careful tuning of the model performed at the Z by Aleph (including quark flavor dependence). The Delphi tuning when applied to semi-leptonic W decays seems to underestimate the intra-W BE effect. This might explain the contradictory conclusions between Aleph and Delphi for the BE analysis on 4q W decays. Bolek presented also the so called like-sign Delphi and L3 methods. The principle is to measure the ratio of like-sign pairs data/MC, for MC without BE. These are very difficult analyses since there are no data without BE on which to tune the MC. L3 and Delphi have contradictory conclusions on that method too (L3 does not observed inter-W effect).

Jason presented the status of MC production both for 189 and 19x GeV. The Monte-Carlo information must not be taken any more from the Web but from the new Java interfaced scanbook. Jason gave a summary of the 3 main bug found up to now, that could affect the Monte-Carlo productions. For more details look at Jacques Boucrot's Alnews and Jason's transparencies. Jason also reported on the ongoing 4f Kingal file production in view of the '99 MC production. The production has started 5 weeks ago in various labs, the total amount of events produced is to approximately 7M. Once the green light if given, those events could be passed through the simulation in 1.5 months.

Anke presented the status of the measurement of the LEP energy from the synchrotron tune (Qs) she is performing. She reminded us that the present error on the beam energy which is largely dominated by the difference between the NMR and the Flux Loop extrapolations (15 MeV out of 21). Another independent measurement is needed to reduce that error. The Qs method relies on a precise knowledge of 2 machine parameters : the momentum compaction factor (a_c) and the LEP bending radius (r). The variation of a_c with the beam energy is computed from the Mad simulation program, r is derived from a comparison of the LEP energy measured by the Qs method to the NMR one. It is expected to get less than 20 MeV precision on the beam energy from the Qs method (there will be some dedicated machine development period this year). One advantage of this method is that it allows for a measurement of the beam energy averaged over the whole LEP ring (and not a given point as for the spectrometer one). A second one is that it can be applied to data already taken in previous years.

Anne presented a review of the common Ntuple project. All Monte-Carlo and data files from 189 202 GeV have been produced. A description of the Ntuple structure can be found from a link on the W Web page. The current version (v1) of the software has been tested, for cross section and 4q mass analysis, some minor defects should be fixed in a new forthcoming release. This software will be used for the 2000 online cross section measurement and for the Osaka results.

Eugeni presented results of some checks that were asked at the Thursday meeting in January. The jet mass distribution is well reproduced by the MC, 192-202 GeV di-muon events have been looked and confirm the 4q result. ISR studies (double ISR) and the effect of parasitic HCAL energy deposits are still under investigation.

Rick reminded us about the Aleph W meeting in Heidelberg (29-30^th May) People are asked to register asap.

A new structure for the W group has been presented. There will be three main streams. Two are channel oriented : the hadronic (Avv Moutoussi) and the leptonic (Andrea Venturi) one. The last one is the TGC one (Jorgen Beck Hansen). Task groups are appointed when needed to perform specific action, like cross section measurement (Anne Ealet), BE/CR papers (Bolek Pietrzyk). In addition to the regular W meeting every Wednesday morning before a Thursday meeting, there will be on the Tuesday before a one day like W Jamboree where the three streams will have serial meetings.