53 research outputs found

    First measurement of the BSB_S meson mass

    Get PDF
    If simplified, every information retrieval problem can be solved when the information need implied by its expression has been identified. We are interested in the criteria used in realising a good information retrieval problem expression. We have listed these criteria through some principles and maxims which first characterized the communication between two persons are applied. We choose to use the gricean maxims because they are the most favoured for this type of situation. Secondly, we have tried to identify some others principles that can be used to realise a good information retrieval problem expression. The principles by Grice can not resolve all forms of error associated with this particular form of communication. In our work, we defined three other principles namely: adhesion principle, reformulation principle, memorization principle. We give some examples of situations where the principles we have formulated are not applicable and the consequences. We present the possible applications of our new model: MIRABEL, which can help in the description of information retrieval problem from. It also compels its user to use essential good expression principle implicitly

    Search for particles with unexpected mass and charge in Z decays

    Get PDF

    Update of electroweak parameters from Z decays

    Get PDF

    Persistence of Pyridine Bases in Polluted Water

    No full text

    Measurement of the Mass of the Z-Boson and the Energy Calibration of Lep

    Get PDF
    Contains fulltext : 26847___.PDF (publisher's version ) (Open Access

    Measurement of the b ---> tau- anti-tau-neutrino X branching ratio

    No full text
    Using a missing energy tag, evidence is presented for the decay b ---> tau- anti-tau-neutrino X, and its branching ratio is measured to be (4.08 ± 0.76 ± 0.62)%

    A Precise measurement of the tau lepton lifetime

    No full text
    Three different techniques are used to measure the mean decay length of the τ lepton with a high precision vertex detector in a sample of 11 800 τ pairs coming from Z decays, collected in1991 by ALEPH at LEP. Events in which both τ's decay into one charged track are analyzed using two largely independent methods. Displaced vertices in three-prong decays yield another independent measurement. The derived lifetime is 295.5 ± 5.9 ± 3.1 fs, using mτ = 1777.1 ± 0.5 MeV/c2. Including previous (1989–1990) ALEPH measurements, the combined τ lifetime is 294.7 ± 5.4 ± 3.0 fs

    Measurement of the b→τ−Μ‟τXb \rightarrow \tau^- \overline{\nu}_{\tau}X branching ratio

    No full text
    The definitions of “anthropology” found in various dictionaries cover a whole range of terms and in this section we provide an overview of all its connotations. In this way a variety of reflections about the essence of man become possible, for instance as : summit of creation; source of his own values; specific biological reality; intelligence (but what is this, really?); knowing subject or object of knowledge; social being and product of a culture. Following these lines of thought one realises that all these preoccupations have already been taken up, or at least touched upon, by communication theory

    Observation of the time dependence of Bd0_{d}^{0} - B‟d0\overline{B}_{d}^{0} mixing

    No full text

    Search for CP violation in Z ---> tau tau

    No full text
    Using the 18.8 pb−1 of data accumulated at LEP in 1990 and 1991 with the ALEPH detector, a direct test of neutral current CP-invariance is performed by a search for CP-odd correlations in Z decays to τ pairs where both τ decay modes are identified. No evidence for CP-violation is observed. The weak dipole moment of the τ has been measured to be dτ(mZ) = (1.3 ± 1.4 ± 0.1) × 10−17e·cm which results in an upper limit on the weak dipole moment of |dτ(mZ)| â©œ 3.7 × 10−17e·cm with 95% confidence level
    • 

    corecore