A lower limit on the oscillation frequency of the B0s Bs 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 D s candidates reconstructed in seven di erent decay modes as evidence of semileptonic Bs decays. Criteria designed to ensure precise proper time reconstruction select 277 D s ` + combinations. The initial state of these Bs candidates is determined using an algorithm optimized to e ciently utilise the tagging information available for each event. The limit at 95% con dence level on the Bs B0s oscillation frequency is ms > 6:6 ps . The same data is used to update the measurement of the B0s lifetime, s = 1:54 +0:14 0:13 (stat) 0:04 (syst) ps. (Submitted to Physics Letters B) The ALEPH Collaboration D. Buskulic, I. De Bonis, D. Decamp, P. Ghez, C. Goy, J.-P. Lees, A. Lucotte, M.-N. Minard, P. Odier, B. Pietrzyk Laboratoire de Physique des Particules (LAPP), INP-CNRS, 74019 Annecy-le-Vieux Cedex, France M.P. Casado, M. Chmeissani, J.M. Crespo, M. Del no, 12 I. Efthymiopoulos, 1 E. Fernandez, M. Fernandez-Bosman, Ll. Garrido, 15 A. Juste, M. Martinez, S. Orteu, A. Pacheco, C. Padilla, A. Pascual, J.A. Perlas, I. Riu, F. Sanchez, F. Teubert Institut de Fisica d'Altes Energies, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona), Spain A. Colaleo, D. Creanza, M. de Palma, G. Gelao, M. Girone, G. Iaselli, G. Maggi, 3 M. Maggi, N. Marinelli, S. Nuzzo, A. Ranieri, G. Raso, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, G. Zito Dipartimento di Fisica, INFN Sezione di Bari, 70126 Bari, Italy X. Huang, J. Lin, Q. Ouyang, T. Wang, Y. Xie, R. Xu, S. Xue, J. Zhang, L. Zhang, W. Zhao Institute of High-Energy Physics, Academia Sinica, Beijing, The People's Republic of China R. Alemany, A.O. Bazarko, G. Bonvicini, 23 M. Cattaneo, P. Comas, P. Coyle, H. Drevermann, R.W. Forty, M. Frank, R. Hagelberg, J. Harvey, P. Janot, B. Jost, E. Kneringer, J. Knobloch, I. Lehraus, G. Lutters, E.B. Martin, P. Mato, A. Minten, R. Miquel, Ll.M. Mir, 2 L. Moneta, T. Oest, 20 J.R. Pater, 27 J.-F. Pusztaszeri, F. Ranjard, P. Rensing, 34 L. Rolandi, D. Schlatter, M. Schmelling, 24 O. Schneider, W. Tejessy, I.R. Tomalin, A. Venturi, H. Wachsmuth, A.Wagner, T. Wildish European Laboratory for Particle Physics (CERN), 1211 Geneva 23, Switzerland Z. Ajaltouni, A. Barr es, C. Boyer, A. Falvard, P. Gay, C . Guicheney, P. Henrard, J. Jousset, B. Michel, S. Monteil, J-C. Montret, D. Pallin, P. Perret, F. Podlyski, J. Proriol, J.-M. Rossignol Laboratoire de Physique Corpusculaire, Universit e Blaise Pascal, INP-CNRS, Clermont-Ferrand, 63177 Aubi ere, France T. Fearnley, J.B. Hansen, J.D. Hansen, J.R. Hansen, P.H. Hansen, B.S. Nilsson, A. Waananen Niels Bohr Institute, 2100 Copenhagen, Denmark A. Kyriakis, C. Markou, E. Simopoulou, I. Siotis, A. Vayaki, K. Zachariadou Nuclear Research Center Demokritos (NRCD), Athens, Greece A. Blondel, G. Bonneaud, J.C. Brient, P. Bourdon, A. Roug e, M. Rumpf, A. Valassi, 6 M. Verderi, H. Videau 21 Laboratoire de Physique Nucl eaire et des Hautes Energies, Ecole Polytechnique, INP-CNRS, 91128 Palaiseau Cedex, France D.J. Candlin, M.I. Parsons Department of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom E. Focardi, 21 G. Parrini Dipartimento di Fisica, Universit a di Firenze, INFN Sezione di Firenze, 50125 Firenze, Italy M. Corden, C. Georgiopoulos, D.E. Ja e Supercomputer Computations Research Institute, Florida State University, Tallahassee, FL 32306-4052, USA A. Antonelli, G. Bencivenni, G. Bologna, 4 F. Bossi, P. Campana, G. Capon, D. Casper, V. Chiarella, G. Felici, P. Laurelli, G. Mannocchi, 5 F. Murtas, G.P. Murtas, L. Passalacqua, M. Pepe-Altarelli Laboratori Nazionali dell'INFN (LNF-INFN), 00044 Frascati, Italy L. Curtis, S.J. Dorris, A.W. Halley, I.G. Knowles, J.G. Lynch, V. O'Shea, C. Raine, P. Reeves, J.M. Scarr, K. Smith, A.S. Thompson, F. Thomson, S. Thorn, R.M. Turnbull Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ,United Kingdom U. Becker, C. Geweniger, G. Graefe, P. Hanke, G. Hansper, V. Hepp, E.E. Kluge, A. Putzer, B. Rensch, M. Schmidt, J. Sommer, H. Stenzel, K. Tittel, S. Werner, M. Wunsch Institut f ur Hochenergiephysik, Universit at Heidelberg, 69120 Heidelberg, Fed. Rep. of Germany D. Abbaneo, R. Beuselinck, D.M. Binnie, W. Cameron, P.J. Dornan, A. Moutoussi, J. Nash, J.K. Sedgbeer, A.M. Stacey, M.D. Williams Department of Physics, Imperial College, London SW7 2BZ, United Kingdom G. Dissertori, P. Girtler, D. Kuhn, G. Rudolph Institut f ur Experimentalphysik, Universit at Innsbruck, 6020 Innsbruck, Austria A.P. Betteridge, C.K. Bowdery, P. Colrain, G. Crawford, A.J. Finch, F. Foster, G. Hughes, T. Sloan, M.I. Williams Department of Physics, University of Lancaster, Lancaster LA1 4YB, United Kingdom A. Galla, A.M. Greene, K. Kleinknecht, G. Quast, B. Renk, E. Rohne, H.-G. Sander, P. van Gemmeren C. Zeitnitz Institut f ur Physik, Universitat Mainz, 55099 Mainz, Fed. Rep. of Germany J.J. Aubert, 21 A.M. Bencheikh, C. Benchouk, A. Bonissent, 21 G. Bujosa, D. Calvet, J. Carr, C. Diaconu, F. Etienne, N. Konstantinidis, P. Payre, D. Rousseau, M. Talby, A. Sadouki, M. Thulasidas, K. Trabelsi Centre de Physique des Particules, Facult e des Sciences de Luminy, INP-CNRS, 13288 Marseille, France M. Aleppo, F. Ragusa 21 Dipartimento di Fisica, Universit a di Milano e INFN Sezione di Milano, 20133 Milano, Italy I. Abt, R. Assmann, C. Bauer, W. Blum, H. Dietl, F. Dydak, 21 G. Ganis, C. Gotzhein, K. Jakobs, H. Kroha, G. L utjens, G. Lutz, W. Manner, H.-G. Moser, R. Richter, A. Rosado-Schlosser, S. Schael, R. Settles, H. Seywerd, R. St. Denis, W. Wiedenmann, G. Wolf Max-Planck-Institut f ur Physik, Werner-Heisenberg-Institut, 80805 M unchen, Fed. Rep. of Germany J. Boucrot, O. Callot, A. Cordier, M. Davier, L. Du ot, J.-F. Grivaz, Ph. Heusse, M. Jacquet, D.W. Kim, 19 F. Le Diberder, J. Lefran cois, A.-M. Lutz, I. Nikolic, H.J. Park, 19 I.C. Park, 19 M.-H. Schune, S. Simion, J.-J. Veillet, I. Videau Laboratoire de l'Acc el erateur Lin eaire, Universit e de Paris-Sud, INP-CNRS, 91405 Orsay Cedex, France P. Azzurri, G. Bagliesi, G. Batignani, S. Bettarini, C. Bozzi, G. Calderini, M. Carpinelli, M.A. Ciocci, V. Ciulli, R. Dell'Orso, R. Fantechi, I. Ferrante, L. Fo a, 1 F. Forti, A. Giassi, M.A. Giorgi, A. Gregorio, F. Ligabue, A. Lusiani, P.S. Marrocchesi, A. Messineo, F. Palla, G. Rizzo, G. Sanguinetti, A. Sciab a, P. Spagnolo, J. Steinberger, R. Tenchini, G. Tonelli, 26 C. Vannini, P.G. Verdini, J. Walsh Dipartimento di Fisica dell'Universit a, INFN Sezione di Pisa, e Scuola Normale Superiore, 56010 Pisa, Italy G.A. Blair, L.M. Bryant, F. Cerutti, J.T. Chambers, Y. Gao, M.G. Green, T. Medcalf, P. Perrodo, J.A. Strong, J.H. von Wimmersperg-Toeller Department of Physics, Royal Holloway & Bedford New College, University of London, Surrey TW20 OEX, United Kingdom D.R. Botterill, R.W. Cli t, T.R. Edgecock, S. Haywood, P. Maley, P.R. Norton, J.C. Thompson, A.E. Wright Particle Physics Dept., Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 OQX, United Kingdom B. Bloch-Devaux, P. Colas, S. Emery, W. Kozanecki, E. Lan con, M.C. Lemaire, E. Locci, B. Marx, P. Perez, J. Rander, J.-F. Renardy, A. Roussarie, J.-P. Schuller, J. Schwindling, A. Trabelsi, B. Vallage CEA, DAPNIA/Service de Physique des Particules, CE-Saclay, 91191 Gif-sur-Yvette Cedex, France S.N. Black, J.H. Dann, R.P. Johnson, H.Y. Kim, A.M. Litke, M.A. McNeil, G. Taylor Institute for Particle Physics, University of California at Santa Cruz, Santa Cruz, CA 95064, USA C.N. Booth, R. Boswell, C.A.J. Brew, S. Cartwright, F. Combley, A. Koksal, M. Letho, W.M. Newton, J. Reeve, L.F. Thompson Department of Physics, University of She eld, She eld S3 7RH, United Kingdom A. Bohrer, S. Brandt, V. B uscher, G. Cowan, C. Grupen, J. Minguet-Rodriguez, F. Rivera, 25 P. Saraiva, L. Smolik,

Inclusive differential cross sections dσpA/dxF and dσpA/dpt 2 for the production of Ks 0, Λ, and Λ̄ particles are measured at HERA in proton-induced reactions on C, Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to √s = 41.6 GeV in the proton-nucleon system. The ratios of differential cross sections dσpA(Ks 0)/dσpA(Λ) and dσpA(Λ̄)/dσpA(Λ) are measured to be 6.2 ± 0.5 and 0.66 ± 0.07, respectively, for xF ≈ -0.06. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions dσpA/dpt 2 also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections σpA on the atomic mass A of the target material is discussed, and the deduced cross sections per nucleon σPN are compared with results obtained at other energies.

Using data collected by the HERA-B experiment, we have measured the fraction of J/psi's produced via radiative chi(c) decays in interactions of 920 GeV protons with carbon and titanium targets. We obtained R-chic = 0.32 +/- 0.06(stat) +/- 0.04(sys) for the fraction of J/psi from chi(c) decays averaged over proton-carbon and proton-titanium collisions. This result is in agreement with previous measurements and is compared with theoretical predictions. (C) 2003 Published by Elsevier Science B.V.

Using the ARGUS detector at the e+e storage ring DORIS II at DESY, we have studied lepton energy spectra in ~decays. We present a "pseudo-rest-frame" technique in which the second r in the event, decaying into a heavy hadronic system, is used as reference. This method allows for the first measurement of the Michel Parameter 7/ in ~decays. We also determine the Michel Parameter p in 7" --~ e~u decays with a precision comparable to the present world average. The measured values of the parameters p = 0.735 40.036 40.020 and r 1 = 0.03 40.18 40.12 are in good agreement with standard V-A coupling at the ~--~,-W vertex. 0370-2693/95/$09.50 Q 1995 Elsevier Science B.V. All rights reserved S S D I 0 3 7 0 2 6 9 3 ( 9 4 ) 0 1 3 8 6 1 442 ARGUS Collaboration/Physics Letters B 341 (1995) 441-447 Michel parameters [ 1-3 ] describing the space-time structure of the weak leptonic decays have been determined with high accuracy [4]. All values are in perfect agreement with the Standard Model predictions. The 7lepton discovered in 1975 [5], with its two leptonic decays 7" ~ e~ , and 7" --~/x~u, offers a unique opportunity to study the universality of the charged weak interaction. Describing the leptonic 7" decay by the most general four-fermion Hamiltonian we get the following matrix element [6]:

Using the HERA B detector, the bb production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The bb production was tagged via inclusive bottom quark decays into J/ψ by exploiting the longitudinal separation of J/ψ → l + l − decay vertices from the primary proton-nucleus interaction. Both e + e − and µ + µ − channels have been reconstructed and the combined analysis yields the cross section σ ( bb ) = 32 +14 − 12 (stat) +6 − 7 (sys) nb / nucleon.

An analysis of the reaction yy ~ r/c was l~erformed in five different decay channels of the r/c: /~sK+~r ~, K+K-Tr+~ ", 27r+21r , ~b~b and 2K+2K . A value Fry(r/c) = ( 11.3 + 4.2) keV was obtained for the radiative decay width by combining the results from the first four channels. Using our result on the two-photon width we also determined the branching ratio for the decay r/c --~ 2K+2K . 0370-2693/94/$07.00 (~) 1994 Elsevier Science B.V. All rights reserved SSDI 0 3 7 0 2 6 9 3 ( 9 4 ) 0 1 1 1 6-8 ARGUS Collaboration / Physics Letters B 338 (1994) 390-396 391 The measurements of the radiative decay widths of hadrons have proved to be one of the most important tools to study the composition and the properties of the bound states of strong interactions. While for light quarks the understanding of the binding forces is still on a more phenomenological level, in heavy quark systems, such as charmonium, fundamental tests of QCD dynamics can be made. One of the important quantities in the charmonium system is the relation between the leptonic decay width of the J/qt and the two-photon width of the r/c which is to the lowest order given by (see for example [ 1 ] ) Frr (r&) = 3e~( Ms/¢ )2. r,+e_ ( J l Cs ) " --~< QCD corrections have been calculated to order as by Barbieri et al. [2] resulting in the relation Frr(~7~) = Fete ( J / O ) " (1 ~a+O.OT~ which, together . . . . _0.05.1, with Fe+ e(J/~b) = (5.36:t:0.29) keV [31, yields the prediction Frr(r/c) = (8.6 + 0.6) keV. Furthermore, with the assumption that the hadronic r/c decays can be described by the lowest order two-gluon diagram one obtains the ratio of the hadronic to two-photon partial width Fhadrons(~'lc)/Fyr(rlc) proportional to ( a s / a ) 2. This relation could in principle be used to determine as. However, in this case the QCD radiative corrections seem to be too large to provide a reliable prediction. The radiative decay width Frt(r/~) has been measured by two different methods: in photon-photon collision experiments [4-7] and by the measurement of the process p/~ --* ~ [ 8 ]. The most significant results I DESY, IfH Zeuthen 2 Supported by the German Bundesministerium for Forschung und Technologic, under contract number 05413051P. 3 Supported by the German Bundesministerium for Forschung und Technologie, under contract number 056DDI 1P. 4 Supported by the German Bundesministerium ?dr Forschung und Technologie, under contract number 054ERI2R 5 Supported by the German Bundesministerium ?dr Forschung und Technologie, under contract number 055HD21P. 6 University of Toronto, Toronto, Ontario, Canada. 7 McGill University, Montreal, Quebec, Canada. 8 Supported by the Natural Sciences and Eagineering Research Council, Canada. 9 Supported by the German Bundesministerium ?dr Forschung und Technologie, under contract number 055KA l 1R l0 Supported by the Ministry of Science and Technology of the Republic of SIovenia and the Intemationales Bilro KfA, Jiilich. were obtained from the analysis of the decay channel r/¢ --* K~sK+cr :F, where a good identification of the/~s was achieved by determining its decay vertex. The results range from 4 to 27 keV and have large errors because of the small number of collected r& events and uncertainties in the knowledge of r/c branching ratios. The present analysis aims at improving the precision of the Fr~ (r/c) measurement by using several decay channels of the r/c meson. The data used in this analysis were collected using the ARGUS detector at the e+e storage ring DORIS II at DESY, and correspond to an integrated luminosity of 473 pb t . The beam energies varied between 4.7 and 5.3 GeV. The ARGUS detector and details about its trigger and its particle identification capabilities were described elsewhere [9]. In what follows, we describe the main features of the analysis, while details can be found in Refs. [10,11]. The two-photon production of the r/c was studied in e+e interactions via the reaction

Using the ARGUS detector at the e+e- storage ring DORIS II, we have searched for the real and imaginary part of the electric dipole formfactor d_tau of the tau lepton in the production of tau pairs at q^2=100 GeV^2. This is the first direct measurement of this CP violating formfactor. We applied the method of optimised observables which takes into account all available information on the observed tau decay products. No evidence for CP violation was found, and we derive the following results: Re(d_tau)=(1.6+-.9)*10^(-16) ecm and Im(d_tau)=(-0.2+-0.8)*10^(-16) ecm, where statistical and systematic errors have been combined.

Using the ARGUS detector at the e(+)e(-) storage ring DORIS II, we have measured the Michel parameters rho,xi, and xi delta for tau(+/-) --> l (+/-) v (v) under bar decays in tau-pair events produced at center of mass energies in the region of the tau resonances. Using tau(-/+) --> rho(-/+) v as spin analyzing tags, we find rho(e) = 0.68 +/- 0.04 +/- 0.08, xi(e) = 1.12 +/- 0.20 +/- 0.09, xi delta(e) = 0.57 +/- 0.14 +/- 0.07, rho(mu)= 0.69 +/- 0.06 +/- 0.08, xi(mu) = 1.25 +/- 0.27 +/- 0.14 and xi delta(mu) = 0.72 +/- 0.18 +/- 0.10. In addition, we report the combined ARGUS results on rho, xi, and xi delta using this work and previous measurements. (C) 1998 Elsevier Science B.V. All rights reserved.

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.

Using the ARGUS detector at the e+e− storage ring DORIS II at DESY, we have found evidence for the production of the excited charmed baryon state Λc(2593)+ in the channel Λc+π+π−. Its mass was determined to be (2594.6±0.9±0.4) MeV/c2, and the natural width measured to be Γ = (2.9−2.1−1.4+2.9+1.8) MeV. The production cross section times the branching ratios of σ(e+e− → Λc(2593)+X) × Br(Λc(2593)+ → Λc+π+π−) × Br(Λc+ → pK−π+) was measured to be (0.25−0.13+0.24 ±0.13) pb. The fractions of Λc(2593)+ decays proceeding through the Σc0π+ and Σc++π− channels were determined to be 0.29±0.10±0.11 and 0.37±0.12±0.13, respectively.

An analysis of the properties of hadronic final states produced in electron-positron annihilation at centre-of-mass energies of 130 and 136 GeV is presented. The measurements are based on a data sample of 5.7 pb(-1) collected in November 1995 with the ALEPH detector at LEP. Inclusive charged particle distributions, jet rates and event-shape distributions are measured and the results are compared with the predictions of QCD-based models. From the measured distributions quantities are determined for which the dependence on the centre-of-mass energy can be predicted by QCD, including the mean multiplicity of charged particles, the peak position of the inclusive distribution of xi = - 1nx(p) (x(p) = p/p(beam)), and the strong coupling constant alpha(s). The QCD predictions are tested by comparing with corresponding measurements at E(cm) = 91.2 GeV and at lower energies.

The 132 pbt - 1 of data collected by ALEPH from 1991 to 1994 have been used to analyze η and ω production in τ decays. The following branching fractions have been measured: \(B\left( {{\tau ^ - } \to {\nu _\tau }\omega {h^ - }} \right) = \left( {1.91 \pm 0.07 \pm 0.06} \right) \times {10^{ - 2}},\) \(B\left( {{\tau ^ - } \to {\nu _\tau }\omega {h^ - }{\pi ^0}} \right) = \left( {4.3 \pm 0.6 \pm 0.5} \right) \times {10^{ - 3}},\) \(B\left( {{\tau ^ - } \to {\nu _\tau }\eta {K^ - }} \right) = \left( {2.9_{ - 1.2}^{ + 1.3} \pm 0.7} \right) \times {10^{ - 4}},\) \(B\left( {{\tau ^ - } \to {\nu _\tau }\eta {h^ - }{\pi ^0}} \right) = \left( {1.8 \pm 0.4 \pm 0.2} \right) \times {10^{ - 3}}\) and the 95% C.L. limit B(τ− → ντηπt -) < 6.2 × 10t - 4 has been obtained. The ωπt- and ηπt -π0 rates and dynamics are found in agreement with the predictions made from e+e∼ - annihilation data with the help of isospin invariance (CVC).

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)%.