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Measurement of the e+ e- ---> W+ W- cross section and W decay branching fractions at LEP

The OPAL collaboration
Eur.Phys.J. C52 (2007) 767-785, 2007.
Inspire Record 757918 DOI 10.17182/hepdata.48533

From a total data sample of 701.1 pb^-1 recorded with e+e- centre-of-mass energies of sqrt = 161-209 GeV with the OPAL detector at LEP, 11693 W-pair candidate events are selected. These data are used to obtain measurements of the W-pair production cross sections at 10 different centre-of-mass energies. The ratio of the measured cross sections to the Standard Model expectation is found to be: data/SM = 1.002 +- 0.011(stat.) +- 0.007(syst.) +- 0.005(theory), where the uncertainties are statistical, experimental systematics and theory systematics respectively. The data are used to determine the W boson branching fractions, which are found to be consistent with lepton universality of the charged current interaction. Assuming lepton universality, the branching ratio to hadrons is determined to be 67.41 +- 0.37(stat.) +- 0.23(syst.)%, from which the CKM matrix element Vcs is determined to be 0.96+-0.017(stat.)+-0.012(syst.). The differential cross section as a function of the W^- production angle is measured for the qqev and qqmv final states. The results described in this paper are consistent with the expectations from the Standard Model.

5 data tables

Measured cross section for the (lepton nu lepton nu) decay mode.

Measured cross section for the (quark quark lepton nu) decay mode.

Measured cross section for the (quark quark quark quark) decay mode.

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Measurement of W-pair production in e+ e- collisions at centre-of-mass energies from 183-GeV to 209-GeV

The ALEPH collaboration Heister, A. ; Schael, S. ; Barate, R. ; et al.
Eur.Phys.J. C38 (2004) 147-160, 2004.
Inspire Record 653296 DOI 10.17182/hepdata.48582
13 data tables

The measured cross section for the E NU E NU final state. The DSYS error is the typical systematic error.

The measured cross section for the E NU MU NU final state. The DSYS error is the typical systematic error.

The measured cross section for the E NU TAU NU final state. The DSYS error is the typical systematic error.

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Measurement of the cross section of W-boson pair production at LEP

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett. B600 (2004) 22-40, 2004.
Inspire Record 658254 DOI 10.17182/hepdata.48792

The cross section of W-boson pair-production is measured with the L3 detector at LEP. In a data sample corresponding to a total luminosity of 629.4/pb, collected at centre-of-mass energies ranging from 189 to 209 GeV, 9834 four-fermion events with W bosons decaying into hadrons or leptons are selected. The total cross section is measured with a precision of 1.4 % and agrees with the Standard Model expectation. Assuming charged-lepton universality, the branching fraction for hadronic W-boson decays is measured to be: Br(W-->hadrons) = 67.50 +- 0.42 (stat.) +- 0.30(syst.) %, in agreement with the Standard Model. Differential cross sections as a function of the W- production angle are also measured for the semi-leptonic channels qqev and qqmv.

11 data tables

Measured cross section for the process E+ E- --> LEPTON NU LEPTON NU.

Measured cross section for the process E+ E- --> QUARK QUARKBAR ELECTRON NEUTRINO.

Measured cross section for the process E+ E- --> QUARK QUARKBAR MUON NEUTRINO.

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W boson polarization at LEP2

The OPAL collaboration
Phys.Lett. B585 (2004) 223-236, 2004.
Inspire Record 635790 DOI 10.17182/hepdata.49660

Elements of the spin density matrix for W bosons in e+e- -> W+W- -> qqln events are measured from data recorded by the OPAL detector at LEP. This information is used calculate polarised differential cross-sections and to search for CP-violating effects. Results are presented for W bosons produced in e+e- collisions with centre-of-mass energies between 183 GeV and 209 GeV. The average fraction of W bosons that are longitudinally polarised is found to be (23.9 +- 2.1 +- 1.1)% compared to a Standard Model prediction of (23.9 +- 0.1)%. All results are consistent with CP conservation.

7 data tables

The fraction of longitudinal polarization for leptonically and hadronically decaying W bosons. The average values for all the centre of mass energies and for both lepton and hadron decay combined are also given.

The luminosity weighted average over all the centre of mass energies of the diagonal elements of the RHO++ and RHO-- SDM as a function of the cosine of the angle of the W- boson for the leptonic decay channel.

The luminosity weighted average over all the centre of mass energies of the diagonal element of the RHO00 SDM as a function of the cosine of the angle of the W- boson for both leptonic and hadronic decay channels, and combined.

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Measurement of the W pair production cross-section and W branching ratios in e+ e- collisions at s**(1/2) = 161-GeV to 209-GeV

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J. C34 (2004) 127-144, 2004.
Inspire Record 635851 DOI 10.17182/hepdata.48832

These final results on e+e- -> W+W- production cross-section measurements at LEP2 use data collected by the DELPHI detector at centre-of-mass energies up to 209 GeV. Measurements of total cross-sections, W angular differential distributions and decay branching fractions, and the value of the CKM element |V_{cs}| are compared to the expectations of the Standard Model. These results supersede all values previously published by DELPHI.

5 data tables

W pair production cross section for the fully hadronic channel.

W pair production cross section for the semi-leptonic decay channel.

W pair production cross section for the fully leptonic decay channel.

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Charged and identified particles in the hadronic decay of W bosons and in e+ e- ---> q anti-q from 130-GeV to 200-GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Eur.Phys.J. C18 (2000) 203-228, 2000.
Inspire Record 526164 DOI 10.17182/hepdata.43294

Inclusive distributions of charged particles in hadronic W decays are experimentally investigated using the statistics collected by the DELPHI experiment at LEP during 1997, 1998 and 1999, at centre-of-mass energies from 183 to around 200 GeV. The possible effects of interconnection between the hadronic decays of two Ws are not observed. Measurements of the average multiplicity for charged and identified particles in q qbar and WW events at centre-of-mass energies from 130 to 200 GeV and in W decays are presented. The results on the average multiplicity of identified particles and on the position xi^* of the maximum of the xi_p = -log(2p/sqrt(s)) distribution are compared with predictions of JETSET and MLLA calculations.

16 data tables

Corrected multiplicites and dispersions of charged particles produced in hadronic decays from QQBAR events. The 200 GeV results are a weighted average fromthe 192, 196 and 200 GeV data.

Average multiplicities of identified hadrons produced in hadronic decays from QQBAR events.

Corrected multiplicites and dispersions of charged particles produced in fully hadronic W decays from two W 4Q and 2Q events.

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W+ W- production cross-section and W branching fractions in e+ e- collisions at 189-GeV

The OPAL collaboration
Phys.Lett. B493 (2000) 249-265, 2000.
Inspire Record 533110 DOI 10.17182/hepdata.49910

From a data sample of 183 pb^-1 recorded at a center-of-mass energy of roots = 189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are selected. Assuming Standard Model W boson decay branching fractions, the W-pair production cross section is measured to be sigmaWW = 16.30 +- 0.34(stat.) +- 0.18(syst.) pb. When combined with previous OPAL measurements, the W boson branching fraction to hadrons is determined to be 68.32 +- 0.61(stat.) +- 0.28(syst.) % assuming lepton universality. These results are consistent with Standard Model expectations.

2 data tables

Total W+ W- pair production cross section.

Cross sections for the individual decay modes of the W+ W-.


W pair production cross-section and W branching fractions in e+ e- interactions at 189-GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett. B479 (2000) 89-100, 2000.
Inspire Record 526222 DOI 10.17182/hepdata.49983

The cross-section for the process e+e- -> W+W- has been measured with the data sample collected by DELPHI at an average centre-of-mass energy of 189 GeV and corresponding to an integrated luminosity of 155 pb^{-1}. Based on the 2392 events selected as WW candidates, the cross-section for the doubly resonant process e+e- -> W+W- has been measured to be 15.83 +- 0.38 (stat) +- 0.20 (syst) pb. The branching fractions of the W decay were also measured and found to be in good agreement with the Standard Model expectation. From these a value of the CKM mixing matrix element |V_{cs}| = 1.001 +- 0.040 (stat) +- 0.020 (syst) was derived.

2 data tables

Total W+ W- production cross section.

Cross section for the different decay channels.


Measurement of W pair production in e+ e- collisions at 189-GeV

The ALEPH collaboration Barate, R. ; Decamp, D. ; Ghez, Philippe ; et al.
Phys.Lett. B484 (2000) 205-217, 2000.
Inspire Record 527492 DOI 10.17182/hepdata.49968

The production of W-pairs is analysed in a data sample collected by ALEPH at a mean centre-of-mass energy of 188.6 GeV, corresponding to an integrated luminosity of 174.2 pb^-1. Cross sections are given for different topologies of W decays into leptons or hadrons. Combining all final states and assuming Standard Model branching fractions, the total W-pair cross section is measured to be 15.71 +- 0.34 (stat) +- 0.18 (syst) pb. Using also the W-pair data samples collected by ALEPH at lower centre-of-mass energies, the decay branching fraction of the W boson into hadrons is measured to be BR (W > hadrons) = 66.97 +- 0.65 (stat) +- 0.32 (syst) %, allowing a determination of the CKM matrix element |V(cs)|= 0.951 +- 0.030 (stat) +- 0.015 (syst).

3 data tables

Total W+ W- production cross section.

Cross section for the fully leptonic decay channels.

Results of cross sections for decays into the different topological decay channels.


Measurement of the W pair cross-section and of the W mass in e+ e- interactions at 172-GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Eur.Phys.J. C2 (1998) 581-595, 1998.
Inspire Record 453267 DOI 10.17182/hepdata.47359
2 data tables

Overall total cross section.

Cross sections for different decay topologies.


Measurement of the W pair cross-section in e+ e- collisions at 172-GeV

The ALEPH collaboration Barate, R. ; Buskulic, D. ; Decamp, D. ; et al.
Phys.Lett. B415 (1997) 435-444, 1997.
Inspire Record 446940 DOI 10.17182/hepdata.47408
2 data tables

Cross sections for the different topologies.

Combined W+ W- cross section.


$W^{+} W^{-}$ production and triple gauge boson couplings at LEP energies up to 183-GeV

The OPAL collaboration Abbiendi, G. ; Ackerstaff, K. ; Alexander, G. ; et al.
Eur.Phys.J. C8 (1999) 191-215, 1999.
Inspire Record 479051 DOI 10.17182/hepdata.49338

A study of W-pair production in e+e- annihilations at Lep2 is presented, based on 877 W+W- candidates corresponding to an integrated luminosity of 57 pb-1 at sqrt(s) = 183 GeV. Assuming that the angular distributions of the W-pair production and decay, as well as their branching fractions, are described by the Standard Model, the W-pair production cross-section is measured to be 15.43 +- 0.61 (stat.) +- 0.26 (syst.) pb. Assuming lepton universality and combining with our results from lower centre-of-mass energies, the W branching fraction to hadrons is determined to be 67.9 +- 1.2 (stat.) +- 0.5 (syst.)%. The number of W-pair candidates and the angular distributions for each final state (qqlnu,qqqq,lnulnu) are used to determine the triple gauge boson couplings. After combining these values with our results from lower centre-of-mass energies we obtain D(kappa_g)=0.11+0.52-0.37, D(g^z_1)=0.01+0.13-0.12 and lambda=-0.10+0.13-0.12, where the errors include both statistical and systematic uncertainties and each coupling is determined setting the other two couplings to the Standard Model value. The fraction of W bosons produced with a longitudinal polarisation is measured to be 0.242+-0.091(stat.)+-0.023(syst.). All these measurements are consistent with the Standard Model expectations.

2 data tables

Total W+ W- cross section measurement. The DSYS error corresponds to the total systematic error.

Cross section for W+ W- production in different decay channels. The DSYS error corresponds to the total systematic error.


Measurement of W pair production in e+ e- collisions at 183-GeV

The ALEPH collaboration Barate, R. ; Decamp, D. ; Ghez, Philippe ; et al.
Phys.Lett. B453 (1999) 107-120, 1999.
Inspire Record 497105 DOI 10.17182/hepdata.49130

The production of W+W- pairs is analysed in a data sample collected by ALEPH at a mean centre-of-mass energy of 182.7 GeV, corresponding to an integrated luminosity of 57 pb-1. Cross sections are given for different topologies of W decays into leptons or hadrons. Under Standard Model assumptions for the W-pair production and decay, the W-pair cross section is measured to be 15.57+-0.62(stat.)+-0.29(syst.) pb. Using also the W-pair data samples collected by ALEPH at lower centre-of-mass energies, the decay branching ratio of the W boson into hadrons is measured to be B(W->hadrons)= 68.93+-1.21(stat.)+-0.51(syst.)%, allowing a determination of the CKM matrix element |Vcs|= 1.043 +- 0.058(stat.) +- 0.026(syst.). The agreement of the cross sections with the Standard Model prediction allows a limit to be set on the W decay rate to undetectable final states.

3 data tables

The overal total cross section.

Cross sections for the fully leptonic decay channels.

Cross sections for the parial leptonic and hadronic decay channels.


Measurement of $W$ pair cross-sections in $e^{+} e^{-}$ interactions at $S^{(1/2)}$ = 183-GeV and $W$ decay branching fractions

The L3 collaboration Acciarri, M. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett. B436 (1998) 437-452, 1998.
Inspire Record 474663 DOI 10.17182/hepdata.49387
2 data tables

Cross section with LEPTON is evaluated under lepton universality assumption.

No description provided.


Measurement of $W$ pair cross-sections in $e^{+} e^{-}$ interactions at $\sqrt{s}$ = 172-GeV and $W$ decay branching fractions

The L3 collaboration Acciarri, M. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett. B407 (1997) 419-431, 1997.
Inspire Record 445324 DOI 10.17182/hepdata.47464
1 data table

No description provided.


Charged particle multiplicity in e+ e- ---> q anti-q events at 161-GeV and 172-GeV and from the decay of the W boson

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett. B416 (1998) 233-246, 1998.
Inspire Record 449290 DOI 10.17182/hepdata.47398
3 data tables

No description provided.

No description provided.

No description provided.


Measurement of the $W$ boson mass and $W^{+} W^{-}$ production and decay properties in $e^{+} e^{-}$ collisions at $\sqrt{s}$ = 172-GeV

The OPAL collaboration Ackerstaff, K. ; Alexander, G. ; Allison, John ; et al.
Eur.Phys.J. C1 (1998) 395-424, 1998.
Inspire Record 448093 DOI 10.17182/hepdata.47403

This paper describes the measurement of the W boson mass, M_W, and decay width, Gamma_W, from the direct reconstruction of the invariant mass of its decay products in W pair events collected at a mean centre-of-mass energy of sqrt{s} = 172.12 GeV with the OPAL detector at LEP. Measurements of the W pair production cross-section, the W decay branching fractions and properties of the W decay final states are also described. A total of 120 candidate W^+W^- events has been selected for an integrated luminosity of 10.36 pb^-1. The W^+W^- production cross-section is measured to be sigma_WW = 12.3 +/- 1.3(stat.) +/- 0.3(syst.) pb, consistent with the Standard Model expectation. The W^+W^- -> qq(bar) l nu and W^+W^- -> qq(bar)qq(bar) final states are used to obtain a direct measurement of Gamma_W = 1.30^{+0.62}_{-0.55}(stat.) +/- 0.18(syst.) GeV. Assuming the Standard Model relation between M_W and Gamma_W, the W boson mass is measured to be M_W = 80.32 +/- 0.30(stat.) +/- 0.09(syst.) GeV. The event properties of the fully-hadronic decays of W^+W^- events are compared to those of the semi-leptonic decays. At the current level of precision there is no evidence for effects of colour reconnection in the observables studied. Combining data recorded by OPAL at sqrt{s} ~ 161-172 GeV, the W boson branching fraction to hadrons is determined to be 69.8^{+3.0}_{-3.2}(stat.) +/- 0.7(syst.)%, consistent with the prediction of the Standard Model. The combined mass measurement from direct reconstruction and from the W^+W^- production cross-sections measured at sqrt{s} ~ 161 and sqrt{s} ~ 172 GeV is M_W = 80.35 +/- 0.24(stat.) +/- 0.07(syst.) GeV.

1 data table

The fit assumptions are as follows: fitting branching ratios (C=BR-FIT), lepton universality is assumed (C=LEPT-UNIVERSALITY), and SM Br (C=BR-SM).


Pair production of $W$ bosons in $e^{+} e^{-}$ interactions at $\sqrt{s}$ = 161-GeV

The L3 collaboration Acciarri, M. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett. B398 (1997) 223-238, 1997.
Inspire Record 440408 DOI 10.17182/hepdata.47356
2 data tables

No description provided.

No description provided.


Measurement and interpretation of the $W$ pair cross-section in $e^{+} e^{-}$ interactions at 161-GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett. B397 (1997) 158-170, 1997.
Inspire Record 440217 DOI 10.17182/hepdata.47441
1 data table

No description provided.


Measurement of the $W$ mass in $e^{+} e^{-}$ collisions at production threshold

The ALEPH collaboration Barate, R. ; Buskulic, D. ; Decamp, D. ; et al.
Phys.Lett. B401 (1997) 347-362, 1997.
Inspire Record 441188 DOI 10.17182/hepdata.47488
1 data table

No description provided.


Measurement of the mass of the $W$ boson in $e^{+} e^{-}$ collisions at $S^{(1/2)}$ = 161-GeV

The OPAL collaboration Ackerstaff, K. ; Alexander, G. ; Allison, John ; et al.
Phys.Lett. B389 (1996) 416-428, 1996.
Inspire Record 425320 DOI 10.17182/hepdata.47712
1 data table

No description provided.