Data taken by the DELPHI experiment at centre-of-mass energies of 183 GeV and 189 GeV with a total integrated luminosity of 212 pb^{-1} have been used to search for the supersymmetric partners of the electrons, muons, and taus in the context of the Minimal Supersymmetric Standard Model (MSSM). The decay topologies searched for were the direct decay ({\tilde \ell} -> \ell {\tilde \chi_1^0}), producing acoplanar lepton pairs plus missing energy, and the cascade decay ({\tilde \ell} -> \ell {\tilde \chi_2^0} > \ell \gamma {\tilde \chi_1^0}), producing acoplanar lepton and photon pairs plus missing energy. The observed number of events is in agreement with Standard Model predictions. The 95% CL excluded mass limits for selectrons, smuons and staus are m_{\tilde {e}} \leq 87 GeV/c^2, m_{\tilde {\mu}} \leq 80 GeV/c^2 and m_{\tilde {\tau}} \leq 75 GeV/c^2, respectively, for values of \mu=-200 GeV/c^2 and tan(beta)=1.5.

DELPHI results are presented on the inclusive production of the neutral mesons , f0(980), f2(1270), K 0 2 (1430) and f 0 2(1525) in hadronic Z 0 decays. They are based on about 2 million multihadronic events collected in 1994 and 1995, using the particle identi cation capabilities of the DELPHI Ring Imaging Cherenkov detectors and measured ionization losses in the Time Projection Chamber. The total production rates per hadronic Z decay have been determined to be: 1:19 0:10 for ; 0:164 0:021 for f0(980); 0:214 0:038 for f2(1270); 0:073 0:023 for K 0 2 (1430); and 0:012 0:006 for f 0 2(1525). The total production rates for all mesons and di erential cross-sections for the , f0(980) and f2(1270) are compared with the results of other LEP experiments and with models. (Accepted by Physics Letters B)

A new precise measurement of |Vcb| and of the branching ratio BR(B̄0 → Dlν̄l) has been performed using a sample of about 5000 semileptonic decays B̄0 → Dlν̄l, selected by the DELPHI detector at LEP I by tagging the soft pion from D → Dπ. The results are: Vcb = (39.0 ± 1.5 (stat.) +2.5 −2.6 (syst. exp.) ± 1.3 (syst. th.)) × 10 BR(B̄0 → Dlν̄l) = (4.70 ± 0.13 (stat.) +0.36 −0.31 (syst. exp.))% The analytic dependences of the differential cross-section and of the Isgur Wise form factor as functions of the variable w = vB0 · vD∗ have also been obtained by unfolding the experimental resolution. (Accepted by Phys.Lett.B)

Distributions of event shape variables obtained from 120600 hadronic Z decays measured with the DELPHI detector are compared to the predictions of QCD based event generators. Values of the strong coupling constant c~ s are derived as a function of the renormalization scale from a quantitative analysis of eight hadronic distributions. The final result, c% (Mz) = 0.113 +_ 0.007, is based on second order perturbation theory and uses two hadronization corrections, one computed with a pat ton shower model and the other with a QCD matrix element model.

A study of inclusive production of the meson resonances r!°, [{•o(892), f 0 (975) and f 2 (1270) in hadronic decays of the zo is presented. The measured mean meson multiplicity per hadronic event is 0.83 ± 0.14 for the (Jo, 0.64 ± 0.24 for the [{• (892), 0.10 ± 0.04 for the fo(975) in the momentum range p > 0.05Pbeam (xp > 0.05) and 0.11 ±0.05 for the fz(l270) for Xp > 0.1. These values and the corresponding differential cross sections 1/ O'hadr · dO' / dxp for the vector mesons are in good agreement with the predictions of the JETSET 7.3 PS and HERWIG 5.4 models. The fz(1270) production is overestimated by HER\VIG but its Xpshape is correctly reproduced. The measured ratios of the production cross sections 0'(!2(1270))/0'((Jo) = 0.22 ± 0.08 and 0'(!2(1270))/0'(!0 (975)) = 3~i for Xp > 0.1 are consistent with the results obtained in hadronic reactions. (Submitted to Physics Letters B)

An analysis of inclusive production of K ~ and the meson resonances K*+(892), p~ f0(975) and f2(1270) in hadronic decays of the Z ~ is presented, based on about 973,000 multihadronic events collected by the DELPHI detector at LEP during 1991 and 1992. Overall multiplicities have been determined as 1.962 -40.060 K ~ mesons, 0.712 • 0.067 K*• and 1.21 + 0.15 p~ per hadronic Z ~ decay. The average multiplicities of f0(975) for scaled momentum, xp = P/Pb~a,~, in the range 0.05 _< xp _<0.6 and of f2(1270) for 0.05 _< zp _<1.0 are 0.098 + 0.016 and 0.170 • 0.043 respectively. The fo(975) and p~ zp-spectra have similar shapes. The fz(1270)/p~ ratio increases with zp. The average multiplicities and the differential cross sections are compared with the JETSET Parton Shower model. The model with default parameters fails to reproduce the experimental K ~ momentum spectrum at low momentum, describes the K*• and p~ zp-spectrum shapes, but significantly overestimates their production rates.

sion 7.2, giving: e (b) = (8 + ~ ___ 2)10 -3. The corresponding value of the mean fraction of the beam energy taken by a B hadron in the fragmentation of a b quark is: + 0 02 X~=0.69 0"03-t-0.01. If the values of F~ and F n are taken from the Standard Model, the following value is obtained for the mean semi-leptonic braching fraction of B hadrons" BR~I=(10.1 +0.7)%. Taking the value of Fb~/F n from an independent analysis of DELPHI data based on the use of the boosted sphericity product, a value: BRs~ =(10.1 -+ 1.3)% is obtained. 1 I n t r o d u c t i o n In the Standard Model the Z ~ boson couples with different strengths to up and down type quarks. Experimentally jets produced by heavy quarks are the easiest to isolate because of the use of characteristic properties of heavy hadron production and decay. In the present paper, semi-leptonic decays of B hadrons are used to isolate the Z ~ decays into bb pairs. Studying the distributions of the lepton energy and transverse momentum relative to the jet axis allows one to select this channel. This measurement provides a value for the coupling of the Z ~ to b quarks weighted by the mean semi-leptonic branching fraction of B hadrons. DELPHI has measured previously the fraction of b quarks produced in hadronic events using the distribution of an event shape variable, the boosted sphericity product [1], and also by studying the impact parameter distribution of charged tracks at the level of the beam interaction point [2]. Combining these measurements allows one to give a value for the mean semi-leptonic branching fraction of B hadrons produced in Z ~ decays. The lepton energy distribution is sensitive to the energy distribution of heavy hadrons and a comparison between data and Monte Carlo simulations allows the fragmentation distributions of the b quark to be studied. Leptons coming from the decays of charm particles do not have such distinctive features as leptons from direct B decays and with the present statistics only very crude measurements could be extracted on c g production. For this reason, in the following analysis, it was assumed that the production of c quarks is given by the Standard Model. After a description of the event selection and of the aspects of the apparatus that are relevant for this analysis, measurements obtained with selected data samples enriched in muons and in electrons are presented separately and then combined to get the final results. 2 D a t a a n d d e t e c t o r 2.1 Event selection and apparatus For this analysis, the sample of 120 K hadronic events recorded in DELPHI in 1990, were required to fulfill the following selection criteria: at least 7 reconstructed charged particles with momentum greater than 100 MeV/c; a total charged energy greater than 14% of the centre of mass energy; the thrust axis of the event at more than 32 ~ from the beam axis; the muon chambers had to be operational for the muon analysis; the barrel electromagnetic calorimeter (the HPC) had to be operational for the electron analysis. The resulting samples of about 100 K events were analyzed for the presence of electron and muon candidates. To define the solid angle covered by the detectors the following conventions were used. The z axis was taken along the electron beam direction and the y axis was vertical. Polar coordinates of a point in the transverse (x, y) plane were labeled R and ~. The 0 angle was used to define a direction relative to the z axis. The muon identification relied mainly on the muon chambers, a set of drift chambers providing three dimensional information. In the barrel part of the detector (52~ 0 < 128 ~ there are 3 sets of chambers (see Fig. 1). One set of chambers is located just inside the hadron calorimeter and two sets are just beyond it, with 2 layers I X ' ~ DELPHI InteraCtive Analysis i

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A search for fully reconstructed A): beauty baryons is performed using about 3 million Z decays collected with the DELPHI detector at LEE The analysis relies on the combined use of the accurate tracking and of the hadron identification capabilities of DELPHI. A total of four events has been found, three in the A:Y channel and one in the &!a; channel over a small background. The ill: beauty baryon mass is measured to be (5668 rt 16 (stat.) f 8 (syst.) ) MeV/c*.

P. Abreu t, W. Adam g, T. Adye ak, E. Agasi ad, I. Ajinenko aq, R. Aleksan am, G.D. Alekseev n, A. Algeri m, p. Allport u, S. Almehed w, S.J. Alvsvaag d, U. Amaldi g, A. Andreazza aa, P. Antilogus x, W-D. Apel o, R.J. Apsimon ak, y . Arnoud am, B. ~,sman as J-E. Augustin r, A. Augustinus ad, p. Baillon g, P. Bambade r, F. Barao t, R. Barate e, G. Barbiellini au, D.Y. Bardin n, G.J. Barker ah, A. Baroncelli ao, O. Barring g, J.A. Barrio Y, W. Bartl ay, M.J. Bates ak, M. Battaglia m, M. Baubillier v, K-H. Becks ha, M. Begalli aj, p. Beilliere f, Yu. Belokopytov aq, p. Beltran i, A.C. Benvenuti e, M. Berggren r, D. Bertrand b, F. Bianchi at, M. Bigi at, M.S. Bilenky n, P. Billoir v, J. Bjarne w, D. Bloch h, J. Blocki az, S. Blyth ah, V. Bocci ae, P.N. Bogolubov n, T. Bolognese am, M. Bonesini aa, W. Bonivento aa, P.S.L. Booth u, G. Borisov aq, H. Bornerg, C. Bosio ao, B. Bostjancic ar, S. Bosworth ah, O. Botner av, B. Bouquet r, C. Bourdarios r, T.J.V. Bowcock u, M. Bozzo k, S. Braibant b, p. Branchini ao, K.D. Brand ai, R.A. Brenner g, H. Briand v, C. Bricman b, L. Brillault v, R.C.A. Brown g, P. Bruckman P, J-M. Brunet f, A. Budziak P, L. Bugge af, T. Buran af, H. Burmeister g, A. Buys g, J.A.M.A. Buytaert g, M. Caccia aa, M. Calvi aa, A.J. Camacho Rozas ap, R. Campion u, T. Camporesi g, V. Canale ae, K. Cankocak as, F. Cao b, F. Carena g, L. Carroll u, C. Caso k, M.V. Castillo Gimenez aw, A. Cattai g, F.R. Cavallo e, L. Cerrito ae V. Chabaud g, A. Chan a, M. Chapkin aq, Ph. Charpentier g, J. Chauveau v, p. Checchia ai, G.A. Chelkov n, L. Chevalier am, P. Chliapnikov aq, V. Chorowicz v, J.T.M. Chrin aw, V. Cindro ar, p. Collins an, J.L. Contreras r, R. Contri k, E. Cortina aw, G. Cosme r, F. Couchot r, H.B. Crawley a, D. Crennell ak, G. Crosetti k, J. Cuevas Maestro ag, S. Czellar m, E. Dahl-Jensen ab, j. Dahm ha, B. Dalmagne r, M. Dam af, G. Damgaard ah, E. Daubie h, A. Daum o, P.D. Daunceyg, M. Davenport g, J. Davies u, W. Da Silva v, C. Defoix f, P. Delpierre z, N. Demaria at, A. De Angelis g, H. De Boeck b, W. De Boer °, S. De Brabandere h, C. De Clercq b, M.D.M. De Fez Laso aw, C. De La Vaissiere v, B. De Lotto au, A. De Min aa, H. Dijkstrag, L. Di Ciaccio ae , F. Djama h, J. Dolbeau f, M. Donszelmann g, K. Doroba az, M. Dracos ~, J. Drees ba, M. Dris ae, y . Dufour g, F. Dupont i, D. Edsall a, L-O. Eek a~, P.A.-M. Eerola g, R. Ehret °, T. Ekelof av, G. Ekspong as, A. Elliot Peisert g, M. Elsing ba, j_p. Engel h, N. Ershaidat ~, M. Espirito Santo t, D. Fassouliotis ae, M. Feindt g, A. Ferrer aw, T.A. Filippas ae, A. Firestone a, H. Foeth 8, E. Fokitis ae, F. Fontanelli k, K.A.J. Forbes u, J-L. Fousset z, S. Francon x, B. Franek ak, p. Frenkiel f, D.C. Fries o, A.G. Frodesen d, R. Fruhwirth ay, F. Fulda-Quenzer r, H. Furstenau o, j. Fuster 8, D. Gamba at, M. Gandelman q, C. Garcia aw, j. Garcia ap, C. Gaspar g, U. Gasparini ai, Ph. Gavillet g, E.N. Gazis ae, j_p. Gerber h, p. Giacomelli g, D. Gillespie g, R. Gokieli az, B. Golob ar, V.M. Golovatyuk n, j . j . Gomez Y Cadenas g, G. Gopal ak, L. Gorn a, M. Gorski az, V. Gracco k, A. Grant g, F. Grard b, E. Graziani ao, G. Grosdidier r, E. Gross 8, B. Grossetete v, p. Gunnarsson as, J. Guy ak, U. Haedinger °, F. Hahn ha, M. Hahn as, S. Hahn ba, S. Haider ad, Z. Hajduk p, A. Hakansson w, A. Hallgren av, K. Hamacher ha, G. Hamel De Monchenault am, W. Hao ad, F.J. Harris an, V. Hedberg w T. Henkes 8, R. Henriques t, j . j . Hernandez aw, j.A. Hernando aw, P. Herquet b, H. Herr g, T.L. Hessing u, I. Hietanen m, C.O. Higgins u, E. Higon aw, H.J. Hilke g,

Searches for spontaneous R-parity-violating signals at roots = 183 GeV and roots = 189 GeV have been performed using the 1997 and 1998 DELPHI data, under the assumption of R-parity breaking in the third lepton family. The expected topology for the decay of a pair of charginos into two acoplanar taus plus missing energy was investigated and no evidence for a signal was found. The results were used to derive a limit on the chargino mass and to constrain the allowed domains of the MSSM parameter space. (C) 2001 Elsevier Science B.V. All rights reserved.

Higgs bosons predicted by the fermiophobic scenario within Two Higgs Doublets Models were searched for in the data collected by the DELPHI detector at centre-of-mass energies between 189 GeV and 202 GeV, corresponding to a total integrated luminosity of 380 pb^-1. No signal was found and confidence limits were derived in the framework of possible extensions of the Standard Model Higgs sector.

Measurements of the trilinear gauge boson couplings WWgamma and WWZ are presented using the data taken by DELPHI in 1998 at a centre-of-mass energy of 189 GeV and combined with DELPHI data at 183 GeV. Values are determined for Delta(g_1^Z) and Delta(kappa_gamma), the differences of the WWZ charge coupling and of the WWgamma dipole coupling from their Standard Model values, and for lambda_gamma, the WWgamma quadrupole coupling. A measurement of the magnetic dipole and electric quadrupole moment of the W is extracted from the results for Delta(kappa_gamma) and lambda_gamma. The study uses data from the final states jjlv, jjjj, lX, jjX and gammaX, where j represents a quark jet, l an identified lepton and X missing four-momentum. The observations are consistent with the predictions of the Standard Model.

Searches for the Standard Model Higgs boson have been performed in the data collected by the. DELPHI experiment at LEP in the year 2000 at centre-of-mass energies between 200 and 209 GeV corresponding to a total integrated luminosity of 224 pb(-1). No evidence for a Higgs signal is observed in the kinematically accessible mass range, and a 95% CL lower mass limit of 114.3 GeV/c(2) is set, to be compared with an expected median limit of 113.5 GeV/c(2) for these data. (C) 2001 Elsevier Science B.V. All rights reserved.

The search for sleptons, neutralinos, charginos and sgoldstinos in the context of scenarios where the lightest supersymmetric particle is the gravitino, and the search for heavy stable charged particles in light gravitino scenarios and minimal supersymmetric standard models, is presented. Data collected during 2000 with the DELPHI detector at centre-of-mass energies from around 204 to 208 GeV were analysed and combined with all the data collected from 1995 to 1999 at lower energies. No evidence for the production of these particles was found, therefore preliminary new mass limits for the supersymmetric and the heavy stable charged particles searched for are set.

A new precise measurement of \V-cb\ and of the branching ratio BR(<(Bover bar>(0)--> D(+*)l(-)<()over bar>(l)) has been performed using a sample of about 5000 semileptonic decays (B) over bar (0) --> D(*+)l(-)<()over bar>(l), selected by the DELPHI detector at LEP 1 by tagging the soft pion from D*+ --> D(0)pi (+). The results are: V-cb = (39.0 +/- 1.5 (stat.)(-2.6)(+2.5) (syst. exp.) +/- 1.3(ayst. th.)) x 10(-3). BR((B) over bar0 --> D(*+)l(-)<()over bar>(l)) = (4.70 +/- 0.13(stat.)(-0.31)(+0.36) (syst. exp.))%. The analytic dependencies of the differential cross-section and of the Isgur-Wise form factor as functions of the variable w = v(B)0 . v(D)* have also been obtained by unfolding the experimental resolution. (C) 2001 Published by Elsevier Science B.V.

Measurements of on-shell ZZ production are described, using data collected by DELPHI in 1997 and 1998, at centre-of-mass energies roots = 182.6 GeV and 188.6 GeV, respectively. Results obtained in each of the final states q (q) over barq (q) over bar, mu (+)mu (-) q (q) over bar e(+)e(-)q (q) over bar, nu<()over bar>q (q) over bar, l(+)l(-)l(+)l(-), and nu<()over bar>l(+)l(-) are presented. The measured cross-sections for on-shell ZZ production via the tree-level doubly-resonant graphs (NC02) are: sigma (NC02) (182.6 GeV) = 0.38 +/- 0.18 (stat) +/- 0.04 (syst) pb, sigma (NC02) (188.6 GeV) = 0.60+/-0.13 (stat) +/- 0.07 (syst) pb. They are consistent with the Standard Model expectations of 0.25 and 0.65 pb at each energy. (C) 2001 Published by Elsevier Science B.V.

The cross sections for the production of single charged and neutral intermediate vector bosons were measured using integrated luminosities of 52 pb(-1) and 154 pb(-1) collected by the experiment at centre-of-mass energies of 182.6 GeV and 188.6 GeV, respectively. The cross sections for the reactions were determined in limited kinematic regions. The results found are in agreement with the Standard Model predictions for these channels. (C) 2001 Published by Elsevier Science B.V.

A new precise measurement of |Vcb| and of the branching ratio BR(B̄0→D∗+ℓ−ν̄ℓ) has been performed using a sample of about 5000 semileptonic decays B̄0→D∗+ℓ−ν̄ℓ, selected by the DELPHI detector at LEP I by tagging the soft pion from D∗+→D0π+. The results are: Vcb=(39.0±1.5(stat.)+2.5−2.6(syst. exp.)±1.3(syst. th.))×10−3, BR(B̄0→D∗+ℓ−ν̄ℓ)=(4.70±0.13(stat.)+0.36−0.31(syst. exp.))%. The analytic dependencies of the differential cross-section and of the Isgur–Wise form factor as functions of the variable w=vB0·vD∗ have also been obtained by unfolding the experimental resolution.

Searches for pair production of gauginos and squarks in e(+)e(-) collisions at a centre-of-mass energy of 189 GeV have been performed on data corresponding to an integrated luminosity of 158 pb(-1) collected by the DELPHI detector at LEP. The data were analyzed under the assumption of non-conservation of R-parity through a single dominant (U) over bar(D) over bar(D) over bar coupling between squarks and quarks. Typical final states contain between 4 and 10 jets with or without additional leptons. No excess of data above Standard Model expectations was observed. The results were used to constrain domains of the MSSM parameter space and derive limits on the masses of supersymmetric particles. The following mass limits at 95% CL were obtained from these searches: neutralino mass: m(<()over tilde>1)(0) greater than or equal to 32 GeV; chargino mass: m(<()over tilde>1)(+) greater than or equal to 94 GeV; stop and sboctom mass (indirect decay) with DeltaM > 5 GeV: m((t) over tilde1) greater than or equal to 74 GeV for Phi (mix) = 0 rad, m((t) over tilde1) greater than or equal to 59 GeV for Phi (mix) = 0.98 rad, m((b) over tilde1) greater than or equal to 72 GeV for Phi (mix) = 0 rad. The angle phi (mix) is the mixing angle between left and right handed quarks. (C) 2001 Elsevier Science B.V. All rights reserved.