A. Venturi

Previously published and as yet unpublished QCD results obtained with the ALEPH detector at LEP1 are presented. The unprecedented statistics allows detailed studies of both perturbative and non-perturbative aspects of strong interactions to be carried out using hadronic Z and tau decays. The studies presented include precise determinations of the strong coupling constant, tests of its flavour independence, tests of the SU(3) gauge structure of QCD, study of coherence effects, and measurements of single-particle inclusive distributions and two-particle correlations for many identified baryons and mesons.

The polarization of Λ baryons from Z decays is studied with the Aleph apparatus. Evidence of longitudinal polarization of s quarks from Z decay is observed for the first time. The measured longitudinal Λ polarization is PLΛ = −0.32 ± 0.07 for z =ppbeam> 0.3. This agrees with the prediction of −0.39 ± 0.08 from the standard model and the constituent quark model, where the error is due to uncertainties in the mechanism for Λ production. The observed Λ polarization is diluted with respect to the primary s quark polarization by Λ baryons without a primary s quark. Measurements of the Λ forward-backward asymmetry and of the correlation between back-to-back ΛΛ pairs are used to check this dilution. In addition the transverse Λ polarization is measured. An indication of transverse polarization, more than two standard deviations away from zero, is found along the normal to the plane defined by the thrust axis and the Λ direction.

Inclusive π±, K± and $$(p,\bar p)$$ differential cross-sections in hadronic decays of the Z have been measured as a function ofz=P hadron/P beam, the scaled momentum. The results are based on approximately 520 000 events measured by the ALEPH detector at LEP during 1992. Charged particles are identified by their rate of ionization energy loss in the ALEPH Time Projection Chamber. The position, ξ*, of the peak in the ln(1/z) distribution is determined, and the evolution of the peak position with centre-of-mass energy is compared with the prediction of QCD.

From a sample of 152,000 τ decays collected by the ALEPH detector at LEP an upper limit of 24 MeV at 95% CL on the τ neutrino mass has been determined. The limit is obtained using a two dimensional likelihood fit of the visible energy and the invariant mass distribution of 25 τ → 5π(π0)ντ events.

Two samples of exclusive semileptonic decays, 579 B0 →D∗+ℓ−νℓ events and 261 B0 → D+ℓ−νℓ events, are selected from approximately 3.9 million hadronic Z decays collected by the ALEPH detector at LEP. From the reconstructed differential decay rate of each sample, the product of the hadronic form factor F(ω) at zero recoil of the D(∗)+ meson and the CKM matrix element |Vcb| are measured to be FD∗+(1)|Vcb| = (31.9 ± 1.8stat ± 1.9syst) × 10−3, FD+(1)|Vcb| = (27.8 ± 6.8stat ± 6.5syst) × 10−3. The ratio of the form factors FD+(1) and FD∗+(1) is measured to be FD+(1)FD∗+(1) = 0.87 ± 0.22stat ± 0.21syst. A value of |Vcb| is extracted from the two samples, using theoretical constraints on the slope and curvature of the hadronic form factors and their normalization at zero recoil, with the result |Vcb| = (34.4 ± 1.6stat ± 2.3syst ± 1.4th) × 10−3. The branching fractions are measured from the two integrated spectra to be Br(B0 → D∗+ℓ−νℓ) = (5.53 ± 0.26stat ±0.52syst)%, Br(B0 → D∗+ℓ−νℓ) = (2.35 ± 0.20stat ± 0.44syst)%.

Using 1.45 million hadronic Z decays collected by the ALEPH experiment at LEP, the b → τ−ν-τX branching ratio is measured to be 2.75 ± 0.30 ± 0.37%. In addition an upper limit of 1.8 × 10−3 at 90% confidence level is placed upon the exclusive branching ratio of B−→ τ−ν-τ. These measurements are consistent with SM expectations, and put the constraint tan βMh±< 0.52 GeV−1 at 90% confidence level on all Type II two Higgs doublet models (such as the MSSM).

A study of scaling violations in fragmentation functions performed by the ALEPH collaboration at LEP is presented. Data samples enriched in uds, c, b and gluon jets, respectively, together with measurements of the longitudinal and transverse inclusive cross sections are used to extract the fragmentation function for the gluon and for each flavour. The measurements are compared to data from experiments at energies between 22 GeV and 91 GeV and scaling violations consistent with QCD predictions are observed. From this, a measurement of the strong coupling constant αs(Mz) = 0.126 ±0.009 is obtained.

Searches for supersymmetric particles produced in e+e− collisions at centre-of-mass energies of 130 and 136 GeV have been performed in a data sample of 5.7 pb−1 collected in the autumn of 1995 by the ALEPH detector at LEP. No candidate events were found, allowing limits to be set on the masses and production cross-sections of scalar leptons, scalar tops, charginos and neutralinos. The domains previously excluded at LEP1 are substantially extended. For instance, masses of gaugino-like charginos smaller than 67.8 GeV/c2 are excluded at the 95% C.L. for scalar neutrino masses larger than 200 GeV/c2.

In this study, we measured the stocks and pool sizes of soil organic carbon (SOC) and total soil nitrogen (TN), and their natural 13 C and 15 N abundance across a wide range of temperate European ecosystems.The objectives were to examine any distinct isotope patterns with land use or climate, and how C and N in these different ecosystems are distributed among soil organic matter (SOM) fractions to better predict soil C and N dynamics and longer term persistence.Soils were sampled to 30 cm depth at 11 sites of the Nitro Europe (NEU) network and included four forests, three grasslands and four croplands.Surface soil samples were fractionated using a combined size-density fractionation protocol separating light (LF) from heavy particulate organic matter (hPOM) by density and silt-from-clay-associated SOM by size.Down-profile natural abundance 15 N patterns pointed towards a closed N cycle in the forest sites, while 13 C patterns suggested differences in plant water use efficiency across the C3 grassland sites.The forests and grassland sites stored the majority of surface SOC and TN in the LF and hPOM pools.Sustained sequestration of C and N in these rather labile pools will rely on management practices that minimize soil disturbance and increase C input.We also found that the mineral fraction (silt and clay) in the cropland soils stored less C and N per unit of fraction mass compared to the forests and grasslands, which points towards a lower mineral-OM stabilization efficiency of cropland soils.Finally, our study revealed total POM (LF plus hPOM) as a strong predictor of SOC and TN differences, particularly among the non-cropped sites.This study shows that these sites, independent of soil type and climate, store a large fraction of C and N in POM pools that are particularly vulnerable to soil disturbance such as caused by land use change.

Measurements of the inclusive cross-sections forK 0 and Λ production in hadronic decays of the Z are presented together with measurements of two-particle correlations within pairs of Λ andK 0. The results are compared with predictions from the hadronization models Jetset, based on string fragmentation, and Herwig, based on cluster decays. TheK 0 spectrum is found to be harder than predicted by both models, while the Λ spectrum is softer than predicted. The correlation measurements are all reproduced well by Jetset, while Herwig misses some of the qualitative features and overestimates the size of the $$\Lambda \bar \Lambda $$ correlation. Finally, the possibility of Bose-Einstein correlation in theK 0 K 0 system is discussed.

Quark and gluon jets with the same energy, 24 GeV, are compared in symmetric three-jet configurations from hadronic Z decays observed by the ALEPH detector. Jets are defined using the Durham algorithm. Gluon jets are identified using an anti-tag on b jets, based on a track impact parameter method. The comparison of gluon and mixed flavour quark jets shows that gluon jets have a softer fragmentation function, a larger angular width and a higher particle multiplicity, Evidence is presented which shows that the corresponding differences between gluon and b jets are significantly smaller. In a statistically limited comparison the multiplicity in c jets was found to be comparable with that observed for the jets of mixed quark flavour.

We report on a three-step, continuous-flow synthesis of [6,6]-phenyl-C61-butyric acid tert-butyl ester (PCBtB), a promising electron-acceptor methanofullerene for solution-processed bulk-heterojunction solar cells, through the integrated use of three elements in a microstructured flow-reactor that eliminate the need of isolation steps, with a definite safety and environmental advantage.

From approximately 3 million hadronic decays of Z bosons recorded with the aleph detector at lep, a sample of 410 ± 32 B0→ D∗+ℓ−νℓ candidates is selected, where ℓ is either an electron or a muon. The differential decay rate dΓ (B0→ D∗+ℓ−νℓ)dω from this sample is fitted, yielding a value for the product of the CKM matrix element |Vcb| and the normalisation of the decay form factor at the point of zero recoil of the D∗+ meson F(ω = 1)|Vcb| = (31.4 ± 2.3stat ± 2.5syst) × 10−3. A value for |Vcb| is extracted using theoretical calculations of the form factor normalisation, with the result |Vcb| = (34.5 ± 2.5stat ± 2.7syst ± 1.5theory) × 10−3. From the integrated s the measured branching fraction is Br(B0→ D∗+ℓ−νℓ) = (5.18 ± 0.30stat± 0.62syst)%.

Using a sample of about 1.46 million hadronic Z decays collected between 1991 and 1993 with the ALEPH detector at LEP, the energy distribution of the B0 and B± mesons produced at the Z resonance is measured by reconstructing semileptonic decays B → ℓνℓD(X) or B→ ℓνℓD∗+(X). The charmed mesons are reconstructed through the decay modes D0 → K−π+, D0 → K−π+π−π+, D+ → K−π+π+ and D∗+→ D0π+. The neutrino energy is estimated from the missing energy in the lepton hemisphere. Accounting for B∗ and B∗∗ production, the shape of the scaled energy distribution xE(b) for mesons containing a b quark is compared to the predictions of different fragmentation models. The mean value of xE(b) is found to be 〈xE(b)〉 = 0.715 ± 0.007(stat) ± 0.013(syst).

The Λb polarization in hadronic Z decays is measured in semileptonic decays from the average energies of the charged lepton and the neutrino. In a data sample of approximately 3 million hadronic Z decays collected by the ALEPH detector at LEP between 1991 and 1994, 462 ± 31 Λb candidates are selected using (Λπ+)-lepton correlations. From this event sample, the Λb polarization is measured to be PΛb = −0.23−0.20+0.24(stat.)−0.07+0.08(syst.).

The reaction e+e− → HZ∗ is used to search for the standard model Higgs boson in the Hνν and the Hℓ+ℓ− channels. The data sample corresponds to about 4.5 million hadronic Z decays collected by the ALEPH experiment at LEP from 1989 to 1995 at centre-of-mass energies at and around the Z peak. Three candidate events are found in the Hμ+μ− channel, in agreement with the expected background from the electroweak process e+e− ℓ+ℓ−qq. This search results in a 95% C.L. lower limit on the Higgs boson mass of 63.9 GeV/c2.

The total cross section and the forward-backward asymmetry for the process e+e− → μ+μ−(nγ) are measured in the energy range 20–136 GeV by reconstructing the effective centre-of-mass energy after initial state radiation. The analysis is based on the data recorded with the ALEPH detector at LEP between 1990 and 1995, corresponding to a total integrated luminosity of 143.5 pb−1. Two different approaches are used: in the first one an exclusive selection of events with hard initial state radiation in the energy range 20–88 GeV is directly compared with the Standard Model predictions showing good agreement. In the second one, all events are used to obtain a precise measurement of the energy dependence of σ0 and AFB0 from a model independent fit, enabling constraints to be placed on models with extra Z bosons.

Measurements of the subjet structure of quark and gluon jets in hadronic Z decays are presented. The analysis is based on one million hadronic events recorded by the Aleph detector. Roughly symmetric three-jet events are selected with a coarse jet-resolution cut-off, y1. Gluon jets are identified with a purity of 94.6% in those events where evidence of long-lived heavy-flavour hadrons in the other two jets is found. The jets are then analyzed using a smaller cut-off y0 (< y1) so that subjets are resolved. The properties of the jets (subjet multiplicities (Nq), (Ng) and rates Rng(q) for n = 1, 2, 3, 4) are determined and are found to be in good agreement with the expectations of perturbative QCD as long as the subjet resolution parameter y0 is sufficiently large to keep non-perturbative effects small. In particular, the ratio (Ng − 1)(Nq − 1), which to leading order in QCD is given by the ratio of colour factors CACF = 94, is measured to be 1.96 ± 0.15 for y0 = 2 · 10−3, but falls to 1.29 ± 0.03 for y0 = 1.6 · 10−5.

A lower limit on the oscillation frequency of the Bs0Bs0 system is obtained from approximately four million hadronic Z decays accumulated using the ALEPH detector at LEP from 1991 to 1995. Leptons are combined with opposite sign Ds− candidates reconstructed in seven different decay modes as evidence of semileptonic Bs0 decays. Criteria designed to ensure precise proper time reconstruction select 277Ds−ℓ+ combinations. The initial state of these Bs0 candidates is determined using an algorithm optimized to efficiently utilise the tagging information available for each event. The limit at 95% confidence level on the Bs0Bs0 oscillation frequency is Δms > 6.6 ps−1. The same data is used to update the measurement of the Bs0 lifetime,τs = 1.54−0.13+0.14 (stat) ± 0.04 (syst) ps.

In a data sample of approximately four million hadronic Z decays recorded with the ALEPH detector from 1990 to 1995, a search for the strange b baryon Ξb is performed with a study of Ξ-lepton correlations. Forty-four events with same sign Ξ−ℓ− combinations are found whereas 8.4 are expected based on the rate of opposite sign Ξ−ℓ+ combinations. This significant excess is interpreted as evidence for Ξb semileptonic decays. The measured product branching ratio is Br(b → Ξb) × Br(Ξb → XcXℓ−νℓ) × Br(Xc → Ξ−X′) = (5.4±1.1(stat) ± 0.8(syst)) × 10−4 per lepton species, averaged over electrons and muons, with Xc a charmed baryon. The Ξb lifetime is measured to be τΞb = 1.35−0.28+0.37(stat)−0.17+0.15(syst) ps.

The lifetime of the Bs0 meson is measured in approximately 3 million hadronic Z decays accumulated using the ALEPH detector at LEP from 1991 to 1994. Seven different Ds− decay modes were reconstructed and combined with an opposite sign lepton as evidence of semileptonic Bs0 decays. Two hundred and eight Ds−ℓ+ candidates satisfy selection criteria designed to ensure precise proper time reconstruction and yield a measured Bs0 lifetime of τ(Bs0) = 1.59−0.15+0.17 (stat) ±0.03 (syst) ps. Using a larger, less constrained sample of events, the product branching ratio is measured to be Br(b→Bs0) ·Br(Bs0→Ds−ℓ+νX) = 0.82 ± 0.09 (stat) −0.14+0.13 (syst) %.

A lower limit is set on the Bs0 meson oscillation parameter Δms using data collected from 1991 to 1994 by the ALEPH detector. Events with a high transverse momentum lepton and a reconstructed secondary vertex are used. The high transverse momentum leptons are produced mainly by b hadron decays, and the sign of the lepton indicates the particle/antiparticle final state in decays of neutral B mesons. The initial state is determined by a jet charge technique using both sides of the event. A maximum likelihood method is used to set a lower limit of Δms. The 95% confidence level lower limit on Δms ranges between 5.2 and ̷6.5(h̷c2) ps−1 when the fraction of b quarks from Z0 decays that form Bs0 messons is varied from 8% to 16%. Assuming that the B0s fraction is 12%, the lower limit would be ̷Δms> 6.1(h̷c2) ps−1 at 95% confidence level. For xs = ΔmsτBs, this limit also gives xs > 8.8 using the B0s lifetime of τBs = 1.55 ± 0.11 ps and shifting the central value of τBs down by 1σ.

The inclusive production of D∗± mesons in photon-photon collisions has been measured by the Aleph experiment at LEP with a beam energy of 45 GeV. The D∗+ are detected in their decay to D0π+ with the D0 observed in three separate decay modes: (1) K−π+, (2) K−π+π0 and (3) K−π+π−π+, and analagously for the D∗− modes. A total of 33 events was observed from an integrated luminosity of 73 pb−1 which corresponds to a cross section for Σ(e+e−→ e+e−D∗±X) of 155 ± 33 ± 21 pb. This result is compatible with both the direct production γγ → cc in the Born approximation and with a more complete calculation which includes both radiative QCD corrections and contributions in which one of the photons is first resolved into its quark and gluon constituents. The shapes of distributions for events containing a D∗+ are found to be better described by the latter.

In a sample of 1.5 million hadronic decays of the Z collected by the ALEPH detector, a search is carried out for the decays B→ D10(2420)l−νX and B→ D2∗0(2460)l−νX. The product branching ratio for D10 production is measured to be Br(b →B) × Br(B→ D10l−νX) × Br(D10→ D∗+π−) = (2.04 ± 0.58stat± 0.34syst) × 10−3, and a 95% confidence level limit of Br(b →B) × Br(B→ D2∗0l−νX) × Br(D2∗0→ D∗+π−) ≤ 0.81 × 10−3 is obtained for D2∗0 production. A topological search sensitive to the processes above, but also to wide resonances that decay to D∗+π− and to non-resonant D∗+π− production is also carried out, yielding Br(b→B) ×Br(B→D∗+π−l−νX)= (3.7 ± 1.0stat± 0.7syst) × 10−3. Direct evidence of D∗π production inconsistent with D10 and D2∗0 in semileptonic B decay is presented.

Using about 1.5 million hadronic Z decays recorded with the aleph detector, the lifetime of the b baryons has been measured using two independent data samples. From a maximum likelihood fit to the impact parameter distribution of leptons in 519 Λℓ− combinations containing a b baryon sample of 290 decays, the measured b baryon lifetime is τb—baryon = 1.05−0.11+0.12(stat)±0.09(syst) ps. The lifetime of the Λb0 baryon from a maximum likelihood fit to the proper time distribution of 58 Λc+ℓ− candidates containing a Λb0 sample of 44 decays, is τΛb0 = 1.02−0.18+0.23(stat) ± 0.06(syst) ps.

Data collected by ALEPH in the years 1990, 1991 and 1992 have been used to update a previous search for CP violation in the decay of the Z into τ+τ−. The measurement of the weak dipole form factor of the τ lepton has been performed by studying correlations between the τ leptons. No signal of CP violation was found. The weak dipole form factor is found to be d̃τ= (+0.15 ± 0.58stat± 0.38sys)10−17e · cm, obtained with 19628 identified τ+τ− events. This gives an upper limit on the weak dipole form factor of d̃τ< 1.5 · 10−17e · cm at the 95% confidence level.

A search for the radiative decay of excited charged leptons, ℓ∗, and for radiative and weak decays of excited electron neutrinos, νe∗, is performed, using the 5.8 pb−1 of data collected by ALEPH at 130–140 GeV. No evidence for a signal is found in single or pair production. Excluded mass limits from pair production are close to 65 GeV/c2 for all excited lepton species. Limits on the couplings, λmℓ∗, of excited leptons are derived from single production. For an excited lepton mass of 130 GeV/c2, these limits are 0.04 GeV−1 for μ∗ and τ∗, and 0.0007 GeV−1 for e∗. For νe∗, the limit is at the level of 0.03 GeV−1 for a mass of 120 GeV/c2, independent of the decay branching ratios.

Hadronic and leptonic cross-sections and forward-backward asymmetries are measured using 5.7 pb−1 of data taken with the ALEPH detector at LEP at centre-of-mass energies of 130 and 136 GeV. The results agree with Standard Model expectations. The measurement of hadronic cross-sections far away from the Z resonance improves the determination of the interference between photon and Z exchange. Constraints on models with extra Z bosons are presented.

The process e+e−→, where l is a charged or a neutral lepton and f any charged fermion, is analyzed. The study uses the ALEPH data collected at LEP from 1989 to 1993 at centre-of-mass energies between 88 and 95 GeV, corresponding to almost two million hadronic Z decays and to a total integrated luminosity of 79 pb−1. For all channels, the data agree well with the standard model expectation both in shape and normalization. The indication of an excess in the $$e^ + e^ - \to \tau ^ + \tau ^ - f\bar f$$ channel, reported by ALEPH in 1991, is not confirmed.

The inclusive production of charmed particles in Z → bb decays has been measured from the yield of D0, D+, Ds+ and Λc+ decays in a sample of qq events with high b purity collected with the ALEPH detector from 1992 to 1995. From these measurements, adding the charmonia production rate and an estimate of the charmed strange baryon contribution, the average number of charm quarks per b decay is determined to be nc = 1.230 ± 0.036 ± 0.038 ± 0.053, where the uncertainties are due to statistics, systematic effects and branching ratios, respectively.

Searches for supersymmetric particles produced in e+e− interactions at the Z peak have been performed under the assumptions that R-parity is not conserved, that the dominant R-parity violating coupling involves only leptonic fields, and that the lifetime of the lightest supersymmetric particle can be neglected. In a data sample collected by the ALEPH detector at LEP up to 1993, and corresponding to almost two million hadronic Z decays, no signal was observed. As a result, supersymmetric particle masses and couplings are at least as well constrained as under the usual assumption of R-parity conservation.

The Michel parameters and the average τ-neutrino helicity are measured using correlations between the decays of the τ+ and τ− produced on the Z resonance and observed in the ALEPH detector at LEP. The Michel parameters, ϱl, ηl, ξl, (δξ)l, are determined from τ → lνlντ with l = (e, μ), and the average τ neutrino helicity, 〈h(ντ)〉, from τ → hν with h = (π, ϱ, a1). The results obtained with e−μ universality are: ϱl = 0.751±0.039±0.022, ηl = −0.04±0.15±0.11, ξl = 1.18±0.15±0.06, (δξ)l = 0.88±0.11±0.07, and the average τ neutrino helicity 〈h(ντ)〉 = −1.006±0.032±0.019. No significant deviation from the Standard Model V-A prediction is observed.

Using about 950000 hadronic events collected during 1991 and 1992 with the ALEPH detector, the ratios rb=αsbαsudsc and ruds=αsudsαscb have been measured in order to test the flavour independence of the strong coupling constant αs. The analysis is based on event-shape variables using the full hadronic sample, two b-quark samples enriched by lepton tagging and lifetime tagging, and a light-quark sample enriched by lifetime antitagging. The combined results are rb = 1.002±0.023 and ruds = 0.971 ± 0.023.

Four candidates for charmless hadronic B decay are observed in a data sample of four million hadronic Z decays recorded by the aleph detector at lep. The probability that these events come from background sources is estimated to be less than 10−6. The average branching ratio of weakly decaying B hadrons (a mixture of Bd0, Bs0 and Λb weighted by their production cross sections and lifetimes, here denoted B) into two long-lived charged hadrons (pions, kaons or protons) is measured to be Br(B → h+h−) = (1.7−0.7+1.0 ± 0.2) × 10−5. The relative branching fraction Br(Bd(s)0→ π+π−(K−))Br(Bd(s)0→ h+h−) is measured to be 1.0−0.3 −0.1+0.0 +0.0. In addition, branching ratio upper limits are obtained for a variety of exclusive charmless hadronic two-body decays of B hadrons.

A data sample of about 3.0 million hadronicZ decays collected by the ALEPH experiment at LEP in the years 1991 through 1994 is used to make an inclusive selection of B hadron events. In this event sample 4227±140±252B* mesons in the decayB*→Bγ and 1944±108±161B** u,d mesons decaying into a B meson and a charged pion are reconstructed. Here and in the followingB** u,d denotes the eightL=1(bū) and (bd) states and their charge conjugate. For the well establishedB* meson the following quantities are obtained:ΔM=M B*−MB=(45.30±0.35±0.87) MeV/c2 andN B*/(N B+N B*)=(77.1±2.6±7.0)%. The angular distribution of the photons in theB* rest frame is used to measure the relative contribution of longitudinalB* polarization states to beσ L/(σ L+σ T)=(33±6±5)%. In theM(Bπ)−M(B) mass difference resonance structure is observed at (424±4±10) MeV/c2, for which the shape and position is consistent with the expectation forB** u,d states decaying intoB(*)π ±. The relative production rate is determined to be $$\begin{gathered} \frac{{BR(Z \to b \to B_{u,d}^{ * * } )}}{{BR(Z \to b \to B_{u,d} )}} \hfill \\ = [27.9 \pm 1.6(stat) \pm 5.9(syst) {}_{ - 5.6}^{ + 3.9} (model)]\% \hfill \\ \end{gathered} $$ where the third error reflects the uncertainty due to different production and decay models for the broadB** u,d states.

A search for pair production of new heavy leptons has been performed assuming different scenarios for the mixing of the new particles with Standard Model leptons. No candidate events were found in a data sample corresponding to an integrated luminosity of 5.6 pb−1 collected by the ALEPH detector at centre-of-mass energies of 130 and 136 GeV. New limits on production cross-sections and on masses of sequential leptons were obtained which significantly extend the mass regions excluded at LEP1. For instance, charged heavy leptons with masses below 63.5 GeV/c2 are excluded at 95% C.L. for mass differences to the associated neutral lepton of more than 7 GeV/c2.

In a data sample of four million hadronic Z decays collected with the ALEPH detector at LEP, four Λb baryon candidates are exclusively reconstructed in the Λb → Λc+π− channel, with the Λc+ decaying into pK−π+, pK0, or Λπ+π+π−. The probability of the observed signal to be due to a background fluctuation is estimated to be 4.2 × 10−4. The mass of the Λb is measured to be 5614±21 (stat.) ± 4 (syst.) MeV/c2.

Earlier measurements at LEP of isolated hard photons in hadronic Z decays, attributed to radiation from primary quark pairs, have been extended in the ALEPH experiment to include hard photon productioninside hadron jets. Events are selected where all particles combine democratically to form hadron jets, one of which contains a photon with a fractional energyz≥0.7. After statistical subtraction of non-prompt photons, the quark-to-photon fragmentation function,D(z), is extracted directly from the measured 2-jet rate. By taking into account the perturbative contributions toD(z) obtained from anO(ααs) QCD calculation, the unknown non-perturbative component ofD(z) is then determined at highz. Provided due account is taken of hadronization effects nearz=1, a good description of the other event topologies is then found.

An improved measurement of the average b hadron lifetime is performed using a sample of 1.5 million hadronic Z decays, collected during the 1991–1993 runs of ALEPH, with the silicon vertex detector fully operational. This uses the three-dimensional impact parameter distribution of lepton tracks coming from semileptonic b decays and yields an average b hadron lifetime of 1.533 ± 0.013 ± 0.022 ps.

A 32-capsules spherical microphone array was employed for analyzing the spatial properties of the sound field inside a car. Both the background noise and the sound generated by the car's sound system were spatially analyzed, by superposing false-color sound pressure level maps over a panoramic 360x180 degrees image, obtained with a parabolic-mirror camera. The analysis of the noise field revealed the parts of the car body where more noise is leaking in, providing guidance for better soundproofing. The analysis of the impulse responses generated by the loudspeakers did show useful information on the reflection patterns, providing guidance for adding absorbent material in selected locations and for optimizing position and orientation of loudspeakers.

The evaluation of room acoustics characteristics in rooms has been thoroughly described in several papers since 1960s. Moreover, the ISO 3382 standard describes several acoustic parameters and their measurements. However, there are only a few information about the methods of pre-processing the impulse responses that are required before calculating those acoustic parameters. In this paper, the main processing methods (based on Luneby, Chu, and Hirata methods) are analyzed. Moreover, they are compared with the Schroeder (background integrated) methods. In a further step, these methods are applied in some acoustic measurements employed in some opera houses in Italy. Finally, after a full discussion about the uncertainties that is beyond these methods, the acoustic parameters are compared with the JND that is actually accepted in the evaluation of the mono-aural, binaural, and spatial acoustic parameters.

Phishing kits are tools that dark side experts provide to the community of criminal phishers to facilitate the construction of malicious Web sites. As these kits evolve in sophistication, providers of Web-based services need to keep pace with continuous complexity. We present an original classification of a corpus of over 2000 recent phishing kits according to their adopted evasion and obfuscation functions. We carry out an initial deterministic analysis of the source code of the kits to extract the most discriminant features and information about their principal authors. We then integrate this initial classification through supervised machine learning models. Thanks to the ground-truth achieved in the first step, we can demonstrate whether and which machine learning models are able to suitably classify even the kits adopting novel evasion and obfuscation techniques that were unseen during the training phase. We compare different algorithms and evaluate their robustness in the realistic case in which only a small number of phishing kits are available for training. This paper represents an initial but important step to support Web service providers and analysts in improving early detection mechanisms and intelligence operations for the phishing kits that might be installed on their platforms.

From 1.4 million hadronic Z decays collected by the ALEPH detector at LEP, an enriched sample of Z → cc̄ events is extracted by requiring the presence of a high momentum D∗±. The charm quark forward-backward charge asymmetry at the Z pole is measured to be AFB0.c = (8.0 ± 2.4) % corresponding to an effective electroweak mixing angle of sin2θWeff = 0.2302 ± 0.0054.

The B0 - B̄0 average mixing parameter χ and b forward-backward asymmetry AFB0(b) are measured from a sample of about 4 200 000 Z → qq̄ events recorded with the ALEPH detector at LEP in the years 1990–1995. High transverse momentum electrons and muons produced in b semileptonic decays provide the tag of the quark flavour and of its charge. The average mixing parameter and the pole b asymmetry are measured to be χ = 0.1246 ± 0.0051stat ± 0.0052syst, AFB0(b) = 0.1008 ± 0.0043stat ± 0.0028syst. The value of sin2θweff = 0.23198 ± 0.00092 is extracted from the asymmetry measurement.

A pickup coil wound around the sample is the standard method for Barkhausen noise (BN) measurements. Here we describe an apparatus where two coils are used instead of one. The relative position of the coils can be changed and this allows the experimental investigation of spatial correlation effects in BN. The signals induced in the coils are very similar when the coils are placed nearby whereas a progressive decrease of their correlation is observed by moving the coils apart. We tested our system on a ribbon of amorphous Fe63B14Si8Ni15 100 mm long. For a distance between the coils of 40 mm the signal correlation is nearly vanished.

The evaluation of room acoustics characteristics has been thoroughly described in several papers since 60-ies. Moreover, the ISO 3382 standard describes several acoustic parameters and their measurements. However, there is only a few information about the methods of pre-processing the impulse responses (background noise compensation) that are required before calculating those parameters. In this paper the main processing methods (based on Chu, Lundeby and Hirata) are analyzed. Moreover they are compared with the results obtained without any processing (original Schroeder backward integration). In a further step, these methods are applied in some acoustic measurements of some opera houses in Italy. Finally some acoustic parameters are compared with the JND that is actually accepted in the evaluation of the mono-aural, binaural and spatial acoustic parameters.

About three million hadronic decays of the Z collected by ALEPH in the years 1991 to 1994 are used to search for anomalous CP violation beyond the Standard Model in the decay Z → bbg. The study is performed by analyzing angular correlations between the two quarks and the gluon in three-jet events and by measuring the differential two-jet rate. No signal of CP violation is found. For the combinations of anomalous CP violating couplings, ĥb=ĥAbgVb−ĥVbgAb and b∗=ĥVb2+ĥAb2, limits of |ĥb| < 0.59 and hb∗< 3.02 are given at 95% CL.

Barriers employed for road traffic noise reduction can be characterized by two indices: reflection index for sound reflection and insulation index for airborne sound insulation. They can be measured following the method described in CEN/TS 1793-5 standard, based on impulse response measurements employing a pressure microphone. The method mandates for averaging results of measurements taken in different points in front of the device under test and/or for specific angles of incidence, employing the obsolete MLS signal for performing the measurements, which can cause severe artefacts due to nonlinearity and time-variance of the system. Furthermore, the CEN/TS 1793-5 standard presents some geometric problems, which could arise if the barrier does not reach a minimum height or if it has a very rough (scattering) surface. During the reflection index measurement on a barrier of limited height, the reflected sound can be contaminated by the ground reflection, compromising the fairness of the whole result. Also the insulation index can be affected by the height of the noise barrier, since the sound passing above the device under test can become mixed with the sound passing through it. It has been noticed how these practical problems, jointly with the assumption of a surface reflecting specularly in the final formula, can significantly over/under estimate the laboratory values of both the indices. Results of in situ tests based on CEN/TS 1793-5 will be shown in comparison with results obtained through a different approach, based on sound intensity measurements, and with the traditional tests performed in the lab.

Astronomische NachrichtenVolume 140, Issue 15 p. 239-240 Miscellaneous Sull' orbita definitiva della cometa 1890 IV A. Venturi, A. Venturi PalermoSearch for more papers by this author A. Venturi, A. Venturi PalermoSearch for more papers by this author First published: 1896 https://doi.org/10.1002/asna.18961401505AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume140, Issue151896Pages 239-240 RelatedInformation

Searches for charginos and neutralinos produced in e+e− collisions at centre-of-mass energies of 130 and 136 GeV have been performed under the assumptions that R-parity is not conserved, that the dominant R-parity violating coupling involves only leptonic fields, and that the lifetime of the lightest supersymmetric particle can be neglected. In the 5.7 pb−1 data sample collected by ALEPH, no candidate events were found. As a result, chargino and neutralino masses and couplings are constrained and the domains previously excluded at LEP1 are extended.

The four-jet final state is analyzed to search for hadronic decays of pair-produced heavy particles. The analysis uses the ALEPH data collected at LEP in November 1995 at centre-of-mass energies of 130 and 136 GeV, corresponding to a total integrated luminosity of 5.7 pb−1. An excess of four-jet events is observed with respect to the standard model predictions. In addition, these events exhibit an enhancement in the sum of the two di-jet masses around 105 GeV/c 2. The properties of these events are studied and compared to the expectations from standard processes and to pair production hypotheses.

Indirect limits on the mass of the lightest neutralino are derived from the results of searches for charginos, neutralinos, and sleptons performed with data taken by the ALEPH Collaboration at centre-of-mass energies near the Z peak and at 130 and 136 GeV. Within the context of the Minimal Supersymmetric Standard Model and when $M_{\tilde\nu}\ge 200$ GeV/c^2, the bound $M_\chi>12.8$ GeV/c^2 at the 95\% confidence level applies for any $\tan\beta$. The impact of lighter sneutrinos is presented in the framework of SUSY grand unified theories; a massless neutralino is allowed only for a narrow range of $\tan\beta$, $\mu$, and the scalar mass parameter $m_0$. Finally, by including Higgs mass constraints and requiring that radiative electroweak symmetry breaking occur, more stringent bounds on $M_\chi$ as a function of $\tan\beta$ are derived.

The most precise determinations of V us comes from semileptonic kaon decays.The KLOE experiment at DAΦNE the Frascati φ factory , has measured all the experimental inputs to V us for both neutral and charged kaons.Preliminary results for BR(K ± → π 0 e ± ν) and BR(K ± → π 0 µ ± ν), and for τ ± are presented, together with measurements of the K L e3 and K L µ3 decay BR, the K S e3 decay BR and the K L lifetime τ L .From our results for the 5 branching ratios and τ L we find V us =0.2258±0.0022.We have also measured the fully inclusive K + µ2 (γ) absolute branching ratio for which we obtain BR(K + → µν(γ))=0.6366±0.0017.Combining this value with recent lattice results for f K / f π gives V us =0.2223±0.0026.

The CMS all-silicon tracker was aligned using more than three millions cosmic rays particles.The positions of the modules were determined with respect to cosmic ray trajectories to a precision of 3 -4 µm RMS in the barrel and 3 -14 µm RMS in the endcap in the most sensitive coordinate.The trajectories of charged particles produced in the LHC collisions were reconstructed and their momenta were measured in the 3.8 T solenoidal magnetic field.Reconstructed tracks are used to determine the position of the primary interaction vertex in the event and to monitor the position of the colliding beams.The tracks have been used further to reconstruct the hadronic decays of several mesons, including K 0 s , Λ 0 , and φ .The performance of track reconstruction has been measured in the data and is compared to the expectation from simulation

Data on the inclusive production of the neutral vector mesonsρ 0(770),ω(782), K*0(892), andφ(1020) in hadronic Z decays recorded with the ALEPH detector at LEP are presented and compared to Monte Carlo model predictions. Bose-Einstein effects are found to be important in extracting a reliable value for theρ 0 production rate. An averageρ 0 multiplicity of 1.45±0.21 per event is obtained. Theω is detected via its three pion decay modeω→π + π − π 0 and has a total rate of 1.07±0.14 per event. The multiplicity of the K*0 is 0.83±0.09, whilst that of theφ is 0.122±0.009, both measured using their charged decay modes. The measurements provide information on the relative production rates of vector and pseudoscalar mesons, as well as on the relative probabilities for the production of hadrons containing u, d, and s quarks.

A data sample corresponding to almost two million hadronic Z decays collected by the ALEPH detector at LEP has been searched for monojet events. Three events were found, in agreement with the expectation from the process e+e−→γ*vv¯, with γ*→ff¯. Two events are hadronic, the third one being an e+e− pair. All monojet masses are in excess of 3 GeV/c2, and two of the event have large transverse momenta: 18.5 and 20.3 GeV/c. These kinematic characteristics are quite unlikely in the process e+e−→γ*vv¯. The probability of their occurence increases substantially when processes involving further Z or W exchanges are taken into account, but still remains at the 5% level.

Charged particle multiplicity distributions have been measured with the ALEPH detector in restricted rapidity intervals |Y| ≤0.5, 1.0, 1.5, 2.0 along the thrust axis and also without restriction on rapidity. The distribution for the full range can be parametrized by a log-normal distribution. For smaller windows one finds a more complicated structure, which is understood to arise from perturbative effects. The negative-binomial distribution fails to describe the data both with and without the restriction on rapidity. The JETSET model is found to describe all aspects of the data while the width predicted by HERWIG is in significant disagreement.

This note presents a combination of published and preliminary electroweak results from the four LEP collaborations and the SLD collaboration which were prepared for the 2004 summer conferences. Averages from Z resonance results are derived for hadronic and leptonic cross sections, the leptonic forward-backward asymmetries, the {tau} polarization asymmetries, the b{bar b} and c{bar c} partial widths and forward-backward asymmetries and the q{bar q} charge asymmetry. Above the Z resonance, averages are derived for di-fermion cross sections and forward-backward asymmetries, photon-pair, W-pair, Z-pair, single-W and single-Z cross sections, electroweak gauge boson couplings, W mass and width and W decay branching ratios. Also, an investigation of the interference of photon and Z-boson exchange is presented, and colour reconnection and Bose-Einstein correlation analyses in W-pair production are combined. The main changes with respect to the experimental results presented in summer 2003 are updates to the W branching fractions and four-fermion cross sections measured at LEP-2, and the SLD/LEP heavy-flavour results measured at the Z pole. The results are compared with precise electroweak measurements from other experiments, notably the final result on the electroweak mixing angle determined in neutrino-nucleon scattering by the NuTeV collaboration, the latest result in atomic parity violation in Caesium, and the measurement of the electroweak mixing angle in Moller scattering. The parameters of the Standard Model are evaluated, first using the combined LEP electroweak measurements, and then using the full set of high-Q{sup 2} electroweak results.

In the last year the CMS Silicon Tracker Inner Barrel has been tested, each shell and disk individually, assembled in the two halves, shipped to CERN, dressed with the final services and finally integrated together with the Outer Barrel and the Endcaps. These steps will be briefly described together with the results of the tests performed at each step to monitor the status of the detector and of the cosmic run of a fraction of the CMS Silicon Tracker which is, at the time of this conference, on-going.

Tracker Inner Barrel half-cylinders and Tracker Inner Disks of the CMS tracker have been integrated in three INFN sites. Integrated structures are submitted to an extensive set of tests whose main aim is to validate the functioning of the structures in CMS-like conditions. The tests have furthermore proven to be a great opportunity to study several aspects of the performance in detail. In this note the tests are described in some detail and an overview of the results is presented.

We describe the status of the analyses in progress on light meson spectroscopy in the KLOE experiment.We present the analyses of φ decays into f 0 ¡ 980¢ γ and a 0 ¡ 980¢ γ, the study of the Dalitz plot of the η £ π¤ π ¥ π 0 and η £ 3π 0 decays, the measurement of the branching ratio of η £ π 0 γγ, and the measurement of the ratio BrAll the presented results are based on a sample of about 450 pb¥ 1 of integrated luminosity collected during the 2001-2002 data taking.From the 2004-2005 data taking a factor 5 improvement in the integrated luminosity is expected.

Four-fermion events have been selected in a data sample of 5.8 pb−1 collected with the aleph detector at centre-of-mass energies of 130 and 136 GeV. The final states ℓ+ℓ−qq, ℓ+ℓ−ℓ+ℓ−, ννqq, and ννℓ+ℓ− have been examined. Five events are observed in the data, in agreement with the Standard Model predictions of 6.67±0.38 events from four-fermion processes and 0.14−0.05+0.19 from background processes.

Using 22 pb−1 of data collected at LEP in 1992 on the peak of the Z resonance, the ALEPH collaboration has measured the polarisation of the tau leptons decaying into $$ev\bar v, \mu v\bar v$$ ,πν, ρν and a1 ν from their individual decay product distributions. The measurement of the tau polarisation as a function of the production polar angle yields the two parametersN τ andN e, where, in terms of the axial and vector couplingsg Al andg Vl,N l=2g Vl gAl/(g Vl 2 +g 2 ). This analysis follows to a large extent the methods devised for the 1990 and 1991 data but with improvements which bring a better understanding of the systematic uncertainties. Combining the 1992 measurements with our previously published results yieldsN τ=0.136±0.012±0.009 andN e=0.129±0.016±0.005. Assuminge−τ universality, the measurements imply an effective weak mixing angle of sin 2 θ eff =0.2332±0.0014.

A new method for recording the spatial properties of a soundfield, or for generating a synthetic three-dimensional soundfield, is described. The spatial distribution of sound waves passing at a point in space is sampled by means of a number of virtual directive microphones, covering the surface of a sphere. This corresponds to a discretization of the spatial information, which is exactly the spatial equivalent of the PCM sampling of a waveform. The paper shows how it is possible to obtain information about the direction of early reflections in a theatre, not only by means of a 32-channels microphone, but also by means of traditional Bformat microphone (Soundfield). The method is applied to a historical Italian theatre, located in Bologna, i.e. the 1763 theatre in Villa Mazzacorati. The post processing includes the visualisation of the early reflections on a panoramic picture of the theatre, in which early reflections are reported as different circles on the figure, where the dimension and the intensity are related with the characteristics of the reflections. Moreover, the influence of the height of the microphone in the calculation of the acoustic parameters was analysed. The measurements were repeated at different height and different position on a transversal line in the theatre, and statistically analysed.

The subjective perception of 3D sound distribution in rooms is still not completely analysed and fully evaluated, even if several experiments were conducted in the last ten years in this specific field. In this paper, the subjective evaluation of room acoustics perception have been analyzed by means or virtual reconstruction of 3D characteristics of ancient theatres, Italian-styled theatres and auditorium. The virtual acoustics of real enviromnents has been obtained both by means of Ambisonics based systems and by means of Stereo Dipole based systems, in the Arlecchino listening room at University of Bologna. The realisation of the properly measured filters will be discussed, and the preliminary results obtained gathering several questionnaires about subjective perception will be shown. Afterwards, the most relevant results about the correlation between subjective evaluation and measured, physical parameters, are illustrated.

The measurement and emulation of audio systems (devices, environments and sound boxes) have been walked in these years. The most-used methods to obtain information about an audio system are those based on measuring its impulse response (IR). Once the IR has been caught it is possible to recreate, by the use of linear convolution, the output signal that the audio system will generate when it is physically driven by any input signal. This method gives great results if the system is linear and time-invariant (environments behaviour is much linear and therefore its reverberant effect can be faithfully recreated using IRs) but not satisfactory in other cases, such as the emulation of tube preamps (mainly nonlinear) and musical instruments. Since the musical instruments cannot be considered completely linear, their musical performance might be analysed properly considering also their nonlinear behaviour. By using Volterra series it is possible to represent the inputoutput relationship of nonlinear systems. This mathematical theory uses a set of impulse responses to describe the system and not only one as before. By an enhanced impulse response measurement method it is possible to obtain this set of impulses and then with Volterra series it would be possible to have the output of the audio system driven by any input. A special numerical tool has been developed to recreate the system behaviour by using this method. Satisfactory results have been obtained in comparison with the traditional linear convolution based approach.

To maintain the excellent performance of the LHC during its Run-1 also in Run-2, the Level-1 Trigger of the Compact Muon Solenoid experiment underwent a significant upgrade.One part of this upgrade was the re-organisation of the muon trigger path from a subsystem-centric view in which hits in the drift tubes, the cathode strip chambers, and the resistive plate chambers were treated separately in dedicated track-finding systems, to one in which complementary detector systems for a given region (barrel, overlap, and endcap) are merged already at the track-finding level.This also required the development of a new system to sort as well as cancel-out the muon tracks found by each system.An overview will be given of the new track-finder system for the barrel region, the Barrel Muon Track Finder (BMTF) as well as the cancel-out and sorting layer, the upgraded Global Muon Trigger (µGMT).While the BMTF improves on the proven and well-tested algorithms used in the Drift Tube Track Finder during Run-1, the µGMT is an almost complete re-development due to the re-organisation of the underlying systems from complementary track finders to regional track finders.Additionally, the µGMT can calculate a muon isolation using energy information that will be received from the calorimeter trigger in the future.This information is added to the muon objects forwarded to the Global Trigger.Finally, first results of the muon trigger performance including the barrel region are shown.Both the trigger efficiency and the rate reduction show satisfactory performance, with improvements planned for the near future.

The inner portion of the CMS microstrip Tracker consists of 3540 silicon detector modules; its construction has been under full responsibility of seven INFN (Istituto Nazionale di Fisica Nucleare) and University laboratories in Italy. In this note procedures and strategies, which were developed and perfected to qualify the Tracker Inner Barrel and Inner Disks modules for installation, are described. In particular the tests required to select highly reliable detector modules are illustrated and a summary of the results from the full Inner Tracker module test is presented. 1) INFN sez. di Catania and Universita di Catania, Italy 2) INFN sez. di Perugia and Universita di Perugia, Italy 3) INFN sez. di Pisa and Scuola Normale Superiore di Pisa, Italy 4) INFN sez. di Pisa and Universita di Pisa, Italy 5) INFN sez. di Pisa, Italy 6) INFN sez. di Torino and Universita di Torino, Italy 7) INFN sez. di Torino, Italy 8) INFN sez. di Firenze, Italy 9) INFN sez. di Bari and Dipartimento Interateneo di Fisica di Bari, Italy 10) INFN sez. di Bari, Italy 11) INFN sez. di Padova, Italy 12) INFN sez. di Firenze and Universita di Firenze, Italy 13) INFN sez. di Padova and Universita di Padova, Italy 14) INFN sez. di Perugia, Italy a) On leave from ISS, Bucharest, Romania b) On leave from IFIN-HH, Bucharest, Romania c) Corresponding Author

The ATLAS trigger will need to achieve a 10 -7 rejection factor against proton-proton collisions, and still be able to efficiently select interesting events.After a first hardware-implemented processing level, the final event selection is done by the high-level trigger (HLT), implemented on software.With more than 100 contributors and around 250 different packages, a thorough validation of the HLT software is essential.This paper describes the existing infrastructure used for validating the HLT software.

The KLOE experiment at the Frascati φ factory DAΦNE collected 450 pb -1 of data during 2001-2002 running, and is expected to have collected an additional 2 fb -1 by the end of this year.This report summarizes recently completed results on neutral kaon decays based on the 2001-2002 data, including branching ratio measurements for K S → 2π and K S → 3π decays, semileptonic K S decays, and the dominant K L decays; measurements of the K L lifetime; and measurements of the form-factor slopes for K e3 decays of the K L .Prospects for improvements and new results based on the 2004-2005 data are also described.

D + mesons produced inZ 0→bb events were separated from theZ 0→cc component using a lifetime tag. Using a sample of 1.5 million hadronicZ decays collected with theAleph detector theB 0 andD s + yields have been measured: $$\begin{gathered} \hfill B(b \to \bar B_s^0 )B(\bar B_s^0 \to D_s^ + ) = 0.088 \pm 0.020(stat.) \\ \hfill \pm 0.020(stat.) \\ \hfill B(c \to D_s^ + ) = 0.088 \pm 0.020(stat.)_{ - 0.016}^{ + 0.019} (syst.) \\ \end{gathered} $$ TheB 0 lifetime was measured in aB 0 enriched sample reconstructing the decay length from the vertex of theD + with a hadron from theB 0 decay. The result obtained is: $$\tau _{B_s } = 1.61_{ - 0.29}^{ + 0.30} (stat.)_{ - 0.016}^{ + 0.018} (syst.)$$ ps.

Accurate measurement of speed, acceleration, blocking force and torque for actuators on the micro-scale is problematic by conventional means. Forces tend to be very low and time-scales relatively short. This paper describes experimental research on a non-contact technique that can be used to measure the performance of an ultrasonic piezoelectric micro-motor. A type of sensor-less speed measurement has been achieved by studying the frequency spectrum of the real power absorbed by two different motors. This shows a characteristic spike at low frequencies corresponding to the equilibrium rotational speed. The origin of this low frequency modulation is dependent on the impedance of the motors and the applied mechanical loads.

The results of the four LEP collaborations on the fermion pair production in e+e−1 collisions at the centre-of-mass energies above the Z resonance are presented. The (preliminary) results are in good agreement with the prediction of the Standard Model and limits on new phenomena are discussed.

Indirect limits on the mass of the lightest neutralino are derived from the results of searches for charginos, neutralinos, and sleptons performed with data taken by the ALEPH Collaboration at centre-of-mass energies near the Z peak and at 130 and 136 GeV. Within the context of the Minimal Supersymmetric Standard Model and when $$M_{\tilde \nu } \geqslant 200 GeV/c^2 $$ , the boundM x > 12.8 GeV/c 2 at the 95% confidence level applies for any tanβ. The impact of lighter sneutrinos is presented in the framework of SUSY grand unified theories; a massless neutralino is allowed only for a narrow range of tanβ,μ, and the scalar mass parameterm 0. Finally, by including Higgs mass constraints and requiring that radiative electroweak symmetry breaking occur, more stringent bounds onM x as a function of tanβ are derived.

From approximately 3 million hadronic decays of Z bosons recorded with the ALEPH detector at LEP, a sample of 410 +/- 32 ($) over bar B-0 --> D*(+)l(-)nu(l) candidates is selected, where l is either an electron or a muon. The differential decay rate d Gamma(($) over bar B-0 --> D*(+)l(-)nu(l))/d omega from this sample is fitted, yielding a value for the product of the CKM matrix element \V-cb and the normalisation of the decay form factor at the point of zero recoil of the D*(+) meson F(omega = 1)\V-cb = (31.4 +/- 2.3(stat) +/- 2.5(syst)) x 10(-3). A value for \V-cb is extracted using theoretical calculations of the form factor normalisation, with the result \V-cb = (34.5 +/- 2.5(stat) +/- 2.7(syst) +/- 1.5(theory)) X 10(-3) From the integrated spectrum, the measured branching fraction is Br(($) over bar B-0 --> D*(+)l(-)nu) = (5.18 +/- 0.30(stat) +/- 0.62(syst))%.