A study of B meson decays intoDl X final states is presented. In these events, neutral and chargedD mesons originate predominantly fromB + andB 0 decays, respectively. The dilution of this correlation due toD ** production has been taken into account. From 263 700 hadronicZ 0 decays collected in 1991 with the DELPHI detector at the LEP collider, 92D 0→K -π+, 35D +→K -π+π+ and 61D *0→D 0π+ followed byD 0→K -π+ orD 0→K -π+π+π-, are found with an associated lepton of the same charge as the kaon. From theD 0 l - andD *+ l -, the probabilityf d that ab quark hadronizes into aB − (or Bˉ0 ) meson is found to be 0.44 ±0.08±0.09, corresponding to a total (B s+Λ b ) hadronization fraction of 0.12 −0.12 +0.24 . By reconstructing the energy of eachB meson, theb quark fragmentation is directly measured for the first time. The mean value of theB meson energy fraction is: ⟨XE(B)⟨=0.695±0.015(stat.)±0.029(syst.) Reconstructing D-lepton vertices, the followingB lifetimes are measured: τ(B)=1.27+0.22−0.18(stat.)±0.15(syst.)ps,hfillwhereBˉ→D0ℓ −X,hfillτ(B)=1.18+0.39−0.27(stat.)±0.15(syst.)ps,hfillwhereBˉ→D+ℓ−X,hfillτ(B)=1.19+0.25−0.19(stat.)±0.15(syst.)pshfillwhereBˉ→D∗+ℓ−X,hfill

During 1993 and 1995 LEP was run at 3 energies near the Z peak in order to give improved measurements of the mass and width of the resonance. During 1994, LEP operated only at the Z peak. In total DELPHI accumulated data corresponding to an integrated luminosity of approximately 116 pb . Analyses of the hadronic cross-sections and of the cross-sections and forward-backward asymmetries in the leptonic channels used the most precise evaluations of the LEP energies. In the dimuon channel, events with a photon radiated from the initial state have been used to probe the cross-sections and asymmetries down to PETRA energies. Model independent ts to all DELPHI lineshape and asymmetry data from 1990 to 1995 have been carried out giving values of the resonance parameters: MZ = 91:1863 0:0028 GeV Z = 2:4876 0:0041 GeV 0 = 41:578 0:069 nb Rl = 20:730 0:060 A FB = 0:0187 0:0019: These values are signi cantly more precise than those previously published. The results are interpreted in terms of the Standard Model. (Accepted by E. Phys. J. C)

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)

F rom the analysis of a data sample corresponding to an integrated luminosity of 4.63 pb -1 taken during the 1990 run of LEP at centre of mass energies between 88.2GeV an 94.2GeV, the tau decays r ~ e g e v T , r -* ,u-~ .v~ , r ~ z c ( K ) v T , r r p v ~ and their charge conjugates have been studied. The following branching ratios have been measured; B R ( r ~ e aTeVT) = 18.6 + 0.8 (stat.) _ 0.6 (sys.)%, BR (z---+ /~17u vT) = 17.4 • 0.7 + 0.6%, B R ( r ~ z c ( K ) v T ) = 11.9_+0.7_ 0.7%, BR ( r > p vT) = 22.4 + 0.8 + 1.3%, in good agreement with world averages. The measured electronic and muonic branching ratios lead to a measurement of the strong coupling constant, es (mT) = 0.26 + 0.09 Extrapolating the c L value from -0 .12" m T to m z yields cL(mz)=0 .109 +0.012 0.028" The average polarization P~ of taus produced in Z---, r + r decays has also been measured using the above decay modes. The weighted mean of the polarizations obtained from the four decay modes is PT = 0.24 _+ 0.07. This value of PT gives, in the improved Born approximation, a ratio between the axial and vector coupling constants of the tau of vT/aT=0.12+__O.04, and hence a value of the effective electroweak mixing parameter sin 2 0 w(m~) = 0.220 _ 0.009.

This paper summarises the mechanical construction and installation of the Tile Calorimeter for the ATLAS experiment at the Large Hadron Collider in CERN, Switzerland. The Tile Calorimeter is a sampling calorimeter using scintillator as the sensitive detector and steel as the absorber and covers the central region of the ATLAS experiment up to pseudorapidities ±1.7. The mechanical construction of the Tile Calorimeter occurred over a period of about 10 years beginning in 1995 with the completion of the Technical Design Report and ending in 2006 with the installation of the final module in the ATLAS cavern. During this period approximately 2600 metric tons of steel were transformed into a laminated structure to form the absorber of the sampling calorimeter. Following instrumentation and testing, which is described elsewhere, the modules were installed in the ATLAS cavern with a remarkable accuracy for a structure of this size and weight.

The Tile Calorimeter, covering the central region of the ATLAS experiment up to pseudorapidities of ±1.7, is a sampling device built with scintillating tiles that alternate with iron plates. The light is collected in wave-length shifting (WLS) fibers and is read out with photomultipliers. In the characteristic geometry of this calorimeter the tiles lie in planes perpendicular to the beams, resulting in a very simple and modular mechanical and optical layout. This paper focuses on the procedures applied in the optical instrumentation of the calorimeter, which involved the assembly of about 460,000 scintillator tiles and 550,000 WLS fibers. The outcome is a hadronic calorimeter that meets the ATLAS performance requirements, as shown in this paper.

This paper summarises the mechanical construction and installation of the Tile Calorimeter for the ATLAS experiment at the Large Hadron Collider in CERN, Switzerland. The Tile Calorimeter is a sampling calorimeter using scintillator as the sensitive detector and steel as the absorber and covers the central region of the ATLAS experiment up to pseudorapidities +/- 1.7. The mechanical construction of the Tile Calorimeter occurred over a period of about 10 years beginning in 1995 with the completion of the Technical Design Report and ending in 2006 with the installation of the final module in the ATLAS cavern. During this period approximately 2600 metric tons of steel were transformed into a laminated structure to form the absorber of the sampling calorimeter. Following instrumentation and testing, which is described elsewhere, the modules were installed in the ATLAS cavern with a remarkable accuracy for a structure of this size and weight.

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)

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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This paper discusses hadron energy reconstruction for the ATLAS barrel prototype combined calorimeter (consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part) in the framework of the non-parametrical method. The non-parametrical method utilizes only the known e/h ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique. Thus, this technique lends itself to an easy use in a first level trigger. The reconstructed mean values of the hadron energies are within ±1% of the true values and the fractional energy resolution is [(58±3)%/E+(2.5±0.3)%]⊕(1.7±0.2)/E. The value of the e/h ratio obtained for the electromagnetic compartment of the combined calorimeter is 1.74±0.04 and agrees with the prediction that e/h>1.66 for this electromagnetic calorimeter. Results of a study of the longitudinal hadronic shower development are also presented. The data have been taken in the H8 beam line of the CERN SPS using pions of energies from 10 to 300GeV.

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.

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.

The DELPHI detector at LEP has collected 54 pb^{-1} of data at a centre-of-mass energy around 183 GeV during 1997, 158 pb^{-1} around 189 GeV during 1998, and 187 pb^{-1} between 192 and 200 GeV during 1999. These data were used to measure the average charged particle multiplicity in e+e- -> b bbar events, _{bb}, and the difference delta_{bl} between _{bb} and the multiplicity, _{ll}, in generic light quark (u,d,s) events: delta_{bl}(183 GeV) = 4.55 +/- 1.31 (stat) +/- 0.73 (syst) delta_{bl}(189 GeV) = 4.43 +/- 0.85 (stat) +/- 0.61 (syst) delta_{bl}(200 GeV) = 3.39 +/- 0.89 (stat) +/- 1.01 (syst). This result is consistent with QCD predictions, while it is inconsistent with calculations assuming that the multiplicity accompanying the decay of a heavy quark is independent of the mass of the quark itself.