Wieslaw presented the status of YFSWW3 MC (v1.14). In contrast to KORALW 4f generator, YFSWW only generates CC03 events, but includes full O(alpha) EW radiative corrections, (absolutely needed given the experimental accuracy on the WW cross-section measurements).

The initial comparisons between YFSWW (v1.13) and RACOONWW gave an agreement at the level of 0.7%, predicting a lower value of the WW cross-section by ~2.5%, while both programs were expected to agree better than 0.5%. Both programs include O(alpha^3) LL ISR, Coulomb Corrections and non-diagonal CKM matrix elements. Detailed comparisons of the implementation of radiative corrections show that the splitting between QED corrections and NON-QED corrections in YFSWW could be improved and in fact, the prescription used in RACOONWW is supposed to be more accurate. YFSWW3 (v1.14) split these corrections in a similar way than RACOONWW and the agreement between both programs is now better than 0.4% at LEP2 energies.

YFSWW3 has also been compared with KORALW. The CC03 processes at Born level agree better than 0.02% (technical precision), and the comparison between KORALW 4f and KORALW CC03 gives negligible 4f corrections, when a simplified version of the selection cuts is used ( d 4f < 0.08% at LEP2 energies).

The effect of the O(alpha) EW radiative corrections depends on cos(theta_W) and goes from ~1% at cos(theta_W) = 1 to ~4% at cos(theta_W) = -1. The effect of this dependence on the different WW analysis needs to be evaluated.

Benjamin presented his initial studies on the extraction of the neutral ZZ(gamma/Z) couplings using qqgamma radiative events. Following the notation from Hagiwara there are 8 possible anomalous couplings (4 of them violate CP): h1,h2,h3,h4 for gamma and for Z. They can be determined from the total cross-section measurement and are predicted to be zero in the SM. Additional information can be used from the photon angular distribution and the photon energy distribution.

A first attempt to extract these couplings from Benjamin includes the cross-section measurement and the photon angular distribution with an extended likelihood. The code to predict the dependence with anomalous couplings was provided by DELPHI and it is used to compute the weights to re-weight the SM MC prediction (KORALZ).

First results fitting one parameter each time (1D) were shown combining 1998 and 1999 data. All couplings are compatible with the SM prediction of zero. The comparisons with the other LEP experiments need to be understood. The results are slightly worse than DELPHI (probably due to the nunugamma channel not used by Benjamin) but much worse than L3 and OPAL.

David presented his initial studies on the extraction of the neutral ZZ(gamma/Z) couplings using ZZ events. After requiring on-shell ZZ production and Bose-symmetry only 4 anomalous couplings remain, denoted by f4 and f5 for gamma and for Z. They are predicted to be zero in the SM.

David used YFSZZ to predict the parabolic dependence of the total cross-section with the anomalous couplings, and used 1998 and part of the 1999 data to extract the anomalous couplings. The results are compatible with the SM predictions and have a better sensitivity than expected probably due to the low ZZ cross-section measured.

Gunter gave a brief summary of the status of the W mass combination software. Everybody can used it and give feedback. It can be found in afs at:

Aafke has been working with Ann and Oliver on the possible optimization of the W mass extraction in the 4q channel. The first idea she tried was to categorize the events using Y45 in order to separate the 4-jet topology from the 5-jet topology. Using Y45 as a third dimension added to the two 4C-rescaled masses, slightly improves the expected error from 101 to 99 MeV.

She performed a systematic study of all the possible combinations using 2D and 3D W mass fits and using: 4C mass, 4C rescaled mass, 5C mass and Y45. The expected statistical error ranges from 101 GeV (default analysis) down to 95 MeV . The best expected statistical error (95 MeV) is obtained using M5C Ä M4CÄ log(Y45).

In all cases the W mass fitted with Data is consistent with the published value: 80.524 +- 0.108 GeV. For instance using the last combination that gives the best expected statistical error (95 MeV) gives: 80.535 +- 0.100 GeV.

DELPHI show in the last LEP-W Mass systematic group meeting a quite different dependence on the CR probability using the CRETE files (ALEPH CC03 KORALW) or using their own implementation in EXCALIBUR 4f. In particular the differences were striking for the W width. John has had a preliminary look comparing our standard CC03 KORALW samples, and some 4f EXCALIBUR samples and found similar behaviour than what DELPHI claims.

We do not expect any difference using EXCALIBUR or KORALW as EW generators, as both of them use JETSET for the fragmentation process. Something to be understood…

Oliver gave a brief summary of the discussions going on at the LEP-FSI Working Group.

The comparisons of the different BE analysis between experiments have revealed that the choice of Lambda and sigma (BE parameters in the MC) using Z data depend on the variable used to tune this parameters. Therefore the ALEPH tunning using double ratio does not reproduce the single ratio used by DELPHI. DELPHI has repeated the double ratio analysis a la ALEPH, and found consistent results with ALEPH (preference for no BE correlations between different W's)!!!

The main focus on the CR studies is on the possibility to combine the four LEP experiments results on interjet particle flow. The results shown by ALEPH in Osaka on the implications for the W mass systematic error has encouraged the other LEP collaborations to follow a similar strategy.

Jason reported on the work going on at the LEP-W Mass Systematics Group. The main emphasis of the group is on Fragmentation , Z/gamma studies and other systematics such as O(alpha) corrections. More information can be found at:

Next meeting is foreseen earlier October before the meeting in Lisbon 1-4 November.

Jorgen reported on the work going on at the LEP-TGC Working Group.

On the charged TGCs the main topics of discussion are common systematics and LEP combination. The LEP experiments use very different ways to asses systematic errors. Need to establish a common procedure. Several combination methods have been compared with the most rigorous method used by ALEPH, and found significative differences in the combined value, especially in the case of multidimensional fits. The objective is to establish a procedure by Lisbon meeting.

The theoretical framework used on neutral anomalous couplings, and quartic gauge boson couplings is being discussed extensively on these meetings. The ALEPH representation on the LEP-TGC group is very short, and people involved on Couplings analysis is strongly encouraged to participate.