[en] This contribution concerns three contributed papers that share the common feature of analysing fully- (or almost fully-) reconstructed B decays coming from a sample of four million hadronic Z decays collected with the ALEPH detector at LEP. In the first paper, 404 charged and neutral B mesons decaying in standard modes are fully reconstructed and used to look for resonant structure in the Bπ^± system. In the framework of Heavy Quark Symmetry (HQS), the mass of the B₂^* state and the relative production rate of the B^** system are measured. In the same sample of B mesons, significant Bπ^± charge-flavour correlations are observed. In the second paper, a search for doubly-charmed B decays with both charmed mesons reconstructed is performed. A clear signal is observed in the channels b → D_SD-bar(X) and b → DD-bar(X) providing the first direct evidence for doubly-charmed b decays involving no D_S production. Evidence for associated K_S⁰ and K^± production in the decays B → DD-bar(X) is also presented and some candidates for completely reconstructed B meson decays B → D_SD-bar(nπ), B → DD-bar K_S⁰ and B → DD-bar K^± are observed. Furthermore, candidates for the two-body Cabibbo suppressed decays B⁰ → D^*-D^*+ and B^- → D^(*)0D^(*)- are also observed. One B_S⁰ → D_S⁺D_S^- event is reconstructed, which can be only the short-lived CP even eigenstate. In the third paper, the B_S decay to D_S^(*)+D_S^(*)- (X) is observed, tagging the final state with two φ in the same hemisphere. It corresponds mostly to the short-lived CP even eigenstate. A preliminary value of the B_S short lifetime is obtained. (author)

[en] The production of heavy flavours by photons can be considered as a good test of a simple process; the photon-gluon fusion, where the high mass of the produced quark allows perturbative calculations. Experiments have been done to measure hidden charm (J/Psi...) photoproduction with virtual and real photons; but for inelastic J/Psi photoproduction (color conservation implies an extra gluon in the final state), experimental results differ in the two cases. The contribution of NA14 to this point is the principal subject of this paper. For open beauty photoproduction, limits have been obtained so far by virtual photon experiments; the status of the analysis of the NA14 real photon beam-dump is briefly described

[en] Heavy flavour decays is the ideal place to measure weak couplings and mixing angles of heavy quarks; moreover, at these very short distances, the interplay between weak and strong interactions can be studied. Due to the unexpected experimental difference of lifetime between D/sup o/ and D/sup +/, the effect of the remaining light quark has also to be taken into account; the situation is evolving fast with measurements of new decay modes for charm and beauty. The production of heavy flavours by photons can be considered as a good test of a simple QCD process: the photon-gluon fusion, where the high mass of the produced quark allows perturbative calculations. It can be compared with the Vector Dominance Model (VDM) predictions. With inelastic Psi photoproduction, second order QCD processes can be measured. These lectures were divided in four almost equal parts: charms, decays, beauty decays, photoproduction mechanisms and experimental methods. Due to lack of space the author mainly gives the references used to prepare the lectures, and develops only the production mechanism with real photons, for which a recent review doesn't exist

[en] Charginos and neutralinos are searched for in the data collected by the ALEPH experiment at LEP for centre-of-mass energies up to 209 GeV. The negative result of these searches is combined with those from searches for sleptons and Higgs bosons to derive an absolute lower limit of 43.1 GeV/c² on the mass of the lightest supersymmetric particle (LSP), assumed to be the lightest neutralino. This limit is obtained in the framework of the MSSM with R-parity conservation and with gaugino and sfermion mass unification at the GUT scale and assuming no mixing in the stau sector. The LSP limit degrades only slightly to 42.4 GeV/c² if stau mixing is considered. Within the more constrained framework of minimal supergravity, the limit is 50 GeV/c²

[en] Searches for the production of supersymmetric particles under the assumption that R-parity is violated via a single dominant LL anti E, LQ anti D or anti U anti D anti D coupling were performed. These use the data collected by the ALEPH detector at LEP at centre-of-mass energies from 188.6 to 201.6 GeV. The numbers of candidate events observed in the data are consistent with Standard Model expectations. Upper limits on the production cross sections and lower limits on the masses of charginos, sleptons, squarks and sneutrinos are derived. (orig.)

[en] Inclusive branching ratios involving b →τ transitions are measured in approximately four million hadronic Z decays collected by the ALEPH detector at LEP. The fully-inclusive branching ratio BR(b→τ^- anti ν_τX) and the semi-inclusive branching ratio BR(b→τ^- anti ν_τD^*±X) are measured to be (2.43 ±0.20 ±0.25)% and (0.88±0.31±0.28)%, in agreement with the standard model predictions. Upper limits on the branching fractions BR(B^-→τ^- anti ν_τ) and BR(b→νanti ν) are set to 8.3 x 10^-4 and 6.4 x 10^-4 at the 90% C.L. These results allow a 90% C.L. lower limit of 0.40 (GeV/c²)^-1 to be set on the tan β/m_H^± ratio, in the framework of type-II two-Higgs-doublet models. (orig.)

[en] Exclusive production of π and K meson pairs in two photon collisions is measured with ALEPH data collected between 1992 and 2000. Cross-sections are presented as a function of cosθ* and invariant mass, for vertical bar cosθ* vertical bar <0.6 and invariant masses between 2.0 and 6.0 GeV/c² (2.25 and 4.0 GeV/c²) for pions (kaons). The shape of the distributions are found to be well described by QCD predictions but the data have a significantly higher normalization

[en] Indications of the production of chi(3515)→J/psiγ have been observed in the Goliath spectrometer leading to the ratio (chi→J/psiγ)/Jpsi = 0.11+-0.04 (statistical errors only)

[en] Charm photoproduction has been studied at photon energies around 90 GeV at CERN, with a silicon vertex detector. From the high statistics of reconstructed D mesons (> 1500 D), results are given on P_T dependence and cross-section testing the γ-g fusion mechanism and on the percentages of the different D and D_s mesons testing the string-fragmentation mechanism; a possible D^** signal is also presented

[en] We report on π^-N events observed at 150 and 175 GeV/c in a large-acceptance spectrometer triggered by J/psi→μμ. We observe with high mass-resolution the particles psi', K⁰ and Λ. We present evidence for a new resonance at 5.3 GeV/c², whose possible interpretation is a meson containing a b-quark