7 research outputs found

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

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    The e+e- --> W+W- cross section is measured in a data sample collected by ALEPH at a mean centre--of--mass energy of 172.09 GEV, corresponding to an integrated luminosity of 10.65 pb-1. Cross sections are given for the three topologies, fully leptonic, semi-leptonic and hadronic of a W-pair decay. Under the assumption that no other decay modes are present, the W-pair cross section is measured to be 11.7 +- 1.2 (stat.) +- 0.3 (syst.) pb. The existence of the triple gauge boson vertex of the Standard Model is clearly preferred by the data. The decay branching ratio of the W boson into hadrons is measured to be B(W --> hadrons) = 67.7 +- 3.1 (stat.) +- 0.7 (syst.)%, allowing a determination of the CKM matrix element |Vcs|= 0.98 +- 0.14 (stat.) +- 0.03 (syst.)

    Measurement of the b baryon lifetime and branching fractions in Z decays

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    Measurements of ∣Vcb∣\mid V_{cb} \mid form factors and branching fractions in the decays Bˉ0→D⋆+l−Μˉl\bar B^0 \rightarrow D^{\star+}l^-\bar{\nu}_l and Bˉ0→D+l−Μˉl\bar B^0 \rightarrow D^+l^-\bar{\nu}_l

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    Measurements of ∣Vcb∣\mid V_{cb} \mid form factors and branching fractions in the decays Bˉ0→D⋆+l−Μˉl\bar B^0 \rightarrow D^{\star+}l^-\bar{\nu}_l and Bˉ0→D+l−Μˉl\bar B^0 \rightarrow D^+l^-\bar{\nu}_l

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    Search for the neutral Higgs bosons of the MSSM in e+e−e^+ e^- collisions at s\sqrt{s} from 130 to 172 GeV

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    The process e+e- --> h A is used to search for the Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM), in the bbbb and tautaubb final states. The search is performed in the data collected by the ALEPH experiment at LEP, at centre-of-mass energies between 130 and 172 GeV and with a total luminosity of 27.2 pb-1. No candidate events are found in either of the final states, in agreement with the expected background of 0.91 events from all Standard Model processes. Combined with searches for e+e- --> hZ, this results in a 95% C.L. lower limit on the masses of both h and A of 62.5 GeV/c2, for tan(beta) 1

    Search for the neutral Higgs bosons of the MSSM in e+e−e^+ e^- collisions at s\sqrt{s} from 130 to 172 GeV

    No full text
    The process e+e- --> h A is used to search for the Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM), in the bbbb and tautaubb final states. The search is performed in the data collected by the ALEPH experiment at LEP, at centre-of-mass energies between 130 and 172 GeV and with a total luminosity of 27.2 pb-1. No candidate events are found in either of the final states, in agreement with the expected background of 0.91 events from all Standard Model processes. Combined with searches for e+e- --> hZ, this results in a 95% C.L. lower limit on the masses of both h and A of 62.5 GeV/c2, for tan(beta) 1

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

    No full text
    The e+e- --> W+W- cross section is measured in a data sample collected by ALEPH at a mean centre--of--mass energy of 172.09 GEV, corresponding to an integrated luminosity of 10.65 pb-1. Cross sections are given for the three topologies, fully leptonic, semi-leptonic and hadronic of a W-pair decay. Under the assumption that no other decay modes are present, the W-pair cross section is measured to be 11.7 +- 1.2 (stat.) +- 0.3 (syst.) pb. The existence of the triple gauge boson vertex of the Standard Model is clearly preferred by the data. The decay branching ratio of the W boson into hadrons is measured to be B(W --> hadrons) = 67.7 +- 3.1 (stat.) +- 0.7 (syst.)%, allowing a determination of the CKM matrix element |Vcs|= 0.98 +- 0.14 (stat.) +- 0.03 (syst.)
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