James G Branson

We report the analysis of the spatial energy distribution of data for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadrons}$ obtained with the MARK-J detector at PETRA. We define the quantity "oblateness" to describe the flat shape of the energy configuration and the three-jet structure which is unambiguously observed for the first time. Our data can be explained by quantum chromodynamic predictions for the production of quark-antiquark pairs accompanied by hard noncollinear gluons.

We report the measurements of the inclusive $\ensuremath{\mu}$-pair production by 150-GeV protons and ${\ensuremath{\pi}}^{+}$ mesons on beryllium. Absolute cross sections as well as the Feynman-$x$ and ${P}_{T}$ dependence are presented in the mass region between 0.211 and 3.5 ${\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c}}^{2}$. Upper limits are also given for the inclusive production of $\ensuremath{\eta}$ and ${\ensuremath{\rho}}^{\ensuremath{'}}(1600)$ mesons.

A search for exotic unstable neutral and charged heavy leptons as well as for stable charged heavy leptons is performed with the L3 detector at LEP. Sequential, vector and mirror natures of heavy leptons are considered. No evidence for their existence is found and lower limits on their masses are set.

Data from a study of muon pairs produced in hadron-nucleus collisions are compared with the Drell-Yan model. Comparison of dimuon production by ${\ensuremath{\pi}}^{+}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$ mesons on an isoscalar target shows evidence for a charge asymmetry characteristic of an isospin-nonconserving electromagnetic process. The average transverse momentum of the pairs increases smoothly with pair mass. Data taken on carbon and tin targets are used to extract the dependence on target atomic weight.

We have measured the cross section for ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ production in the reactions $({\ensuremath{\pi}}^{+}, p)+\mathrm{Be}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}+{\ensuremath{\mu}}^{\ensuremath{-}}+X$, at an incident momentum of 150 GeV/c. This Letter covers the pairs with masses above 2 GeV/${\mathit{c}}^{2}$, in which region the signal is dominated by production of the $J(3.1)$. No events with $\ensuremath{\mu}$-pair mass >4.1 GeV/${\mathit{c}}^{2}$ were seen, although the experiment is sensitive up to \ensuremath{\ge}12 GeV/${\mathit{c}}^{2}$.

We present results of a large-acceptance experiment in which muon pairs were observed in the mass range 0.6 to 6.0 GeV/${\mathit{c}}^{2}$. Emphasis is given to features of the production of $\frac{J}{\ensuremath{\psi}}$ and ${\ensuremath{\psi}}^{\ensuremath{'}}(3.7)$ particles. We find $\frac{{[B\ensuremath{\sigma}]}_{{\ensuremath{\psi}}^{\ensuremath{'}}(3.7)}}{{[B\ensuremath{\sigma}]}_{\frac{J}{\ensuremath{\psi}}}}$ to be 0.007\ifmmode\pm\else\textpm\fi{}0.004 for $p$-C and 0.018\ifmmode\pm\else\textpm\fi{}0.007 for ${\ensuremath{\pi}}^{+}$-C interactions. Comparison with results from ${e}^{+}{e}^{\ensuremath{-}}$ storage rings indicates that both the $\frac{J}{\ensuremath{\psi}}$ and the ${\ensuremath{\psi}}^{\ensuremath{'}}(3.7)$ are produced strongly rather than electromagnetically in our experiment.

The two-loop massive operator matrix elements for the fermionic local twist-2 operators with external massive fermion lines in Quantum Electrodynamics (QED) are calculated up to the constant terms in the dimensional parameter ε=D−4. We investigate the hypothesis of Berends et al. (1988) [1] that the 2-loop QED initial state corrections to e+e− annihilation into a virtual neutral gauge boson, except power corrections of O((mf2/s)k), k⩾1, can be represented in terms of these matrix elements and the massless 2-loop Wilson coefficients of the Drell–Yan process.

Measurements of the reactions ${e}^{+}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}+{e}^{\ensuremath{-}}$, ${\ensuremath{\mu}}^{+}+{\ensuremath{\mu}}^{\ensuremath{-}}$, and ${\ensuremath{\tau}}^{+}+{\ensuremath{\tau}}^{\ensuremath{-}}$ at PETRA energies (${s}^{\frac{1}{2}}=13,17,27.4,30 \mathrm{and} 31.6$ GeV) are reported. The results show that these reactions agree well with the predictions of quantum electrodynamics thus determining that all the known charged leptons are pointlike particles to a distance \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}16}$ cm.

We have made a precise measurement of the cross section for e+e−→Z0→hadrons with the L3 detector at LEP, covering the s range from 88.28 to 95.04 GeV. From a fit to the Z0 mass, total width, and the hadronic cross section to be MZ0=91.160 ± 0.024 (experiment) ±0.030(LEP) GeV, ΓZ0=2.539±0.054 GeV, and σh(MZ0)=29.5±0.7 nb. We also used the fit to the Z0 peak cross section and the width todetermine Γinvisible=0.548±0.029 GeV, which corresponds to 3.29±0.17 species of light neutrinos. The possibility of four or more neutrino flavors is thus ruled out at the 4σ confidence level.

We have searched for scalar muons μ, scalar electrons ẽ, and winos W̃ from the reactions e+e− →ẽ+ẽ−, μ+μ−, W̃+W̃− at √s ∼ 91 GeV with an integrated luminosity of 157 nb −1. We have searched for μ+μ−, e+e−, or e−μ final states with missing transverse momentum PT > 6 GeV. These final states are signatures for the production of ẽ, μ, and W̃. We found no events. Our results are Mμ > 41 GeV, Mẽ > 41 GeV, and MW̃ > 44 GeV at the 95% confidence level.

Single top production in e+e- annihilations is searched for in data collected by the L3 detector at centre-of-mass energies from 189 to 209 GeV, corresponding to a total integrated luminosity of 634 pb-1. Investigating hadronic and semileptonic top decays, no evidence of single top production at LEP is obtained and upper limits on the single top cross section as a function of the centre-of-mass energy are derived. Limits on possible anomalous couplings, as well as on the scale of contact interactions responsible for single top production are determined.

PETRA, the e+e− collider, has operated at a maximum CM energy of 46.78 GeV. We update our previous results on new particle searches and set significantly better mass limits on some.

We report the measurement of the reaction e+ + e− → hadronic jets at a center-of-mass energy √s=30 GeV using the MARK-J detector at PETRA. By measuring the energy and angular distribution of both neutrals and charged particles we were able to isolate unambiguously the three-jet events in a kinematic region where the backgrounds from qq and phase space contributions and other processes are small. Various comparisons of the data with quantum chromodynamics were made. The relative yield of three-jet events and the shape distribution of the events enable us to determine αs = 0.23 ± 0.02 (statistical error) with a systematic error of ± 0.04.

The results of a high-statistics study of inclusive muon spectra at PETRA are reported.Improved mass limits have been obtained for heavy quarks, heavy leptons, and charged Higgs particles.It is shown that the fragmentation properties of b quarks and c quarks

Measurements of $\mathrm{pp}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}+X$ at $\sqrt{s}=44 \mathrm{and} 62$ GeV are compared. The data are taken under identical conditions utilizing clean proton-proton collisions from the CERN intersecting storage rings and confirm scaling to 5%. The observed ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ yield is a factor of 1.6\ifmmode\pm\else\textpm\fi{}0.2 larger than estimated from a simple parton model but is consistent with QCD. The ${p}_{T}$ dependence of the muon pairs agrees well with expectations from QCD.

This report reviews the experimental investigation of high energy e+e− interactions by the MARK J collaboration at PETRA, the electron-positron colliding beam accelerator at DESY in Hamburg, Germany. The physics objectives include studies of several purely electromagnetic processes and hadronic final states, which further our knowledge of the nature of the fundamental constituents and of their strong, electromagnetic and weak interactions. Before discussing the physics results, the main features and the principal components of the MARK J detector are discussed in terms of design, function, and performance. Several aspects of the on-line data collection and the off-line analysis are also outlined. Results are presented on tests of quantum electrodynamics using e+e− → e+e−, μ+μ− and τ+τ−, on the measurement of R, the ratio of the hadronic to the point-like muon pair cross section, on the search for new quark flavors, on the discovery of three jet events arising from the radiation of hard noncollinear gluons as predicted by quantum chromodynamics, and on the determination of the strong coupling constant αs.

The ηπ+π− final state in two-photon collisions is studied with the L3 detector at LEP, at centre-of-mass energies from 183 to 209 GeV with an integrated luminosity of 664.6 pb−1. The f1(1285) meson is observed and the Q2 dependence of its production is compared to different form factor models. The γγ-coupling parameter Γγγ is found to be 3.5±0.6(stat.)±0.5(sys.) keV. The branching fraction Γ(f1(1285)→a0π)/Γ(f1(1285)→ηππ) is also measured.

With use of the MARK-J detector at $\sqrt{s}=34.7$ GeV 21 000 ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadron}$ events have been collected. By measurement of the asymmetry in angular energy correlations the strong coupling constant ${\ensuremath{\alpha}}_{s}=0.13\ifmmode\pm\else\textpm\fi{}0.01 (\mathrm{statistical})\ifmmode\pm\else\textpm\fi{}0.02 (\mathrm{systematic})$ is determined, in complete second order, and independent of the fragmentation models and QCD cutoff values used.

With a PETRA energy scan in \ensuremath{\le}30-MeV steps, the continuum production of open top quark up to 38.54 GeV is excluded. Over regions of energy scan from 29.90 to 38.63 GeV limits are set on the product of hadronic branching ratio and electronic width ${B}_{h}{\ensuremath{\Gamma}}_{\mathrm{ee}}$ for toponium to be less than 2.0 keV at the 95% confidence level. By a search for flavor-changing neutral currents in $b$ decay, models without a top quark are excluded.

We report the results of a study of the mechanism of inclusive dimuon production from the reaction $p+p\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}+X$ at the CERN intersecting storage rings. The present experiment was done at the center-of-mass energies $\sqrt{s}=62 \mathrm{and} 44$ GeV and in the dimuon pair invariant-mass region $m=3\ensuremath{-}25$ GeV. The dependence on the Feynman variable $x$ has been measured. The average transverse momentum is found to increase with $\sqrt{s}$ and with mass and reaches $〈{p}_{T}〉\ensuremath{\simeq}1.9$ GeV, compatible with predictions from quantum-chromodynamic gluon processes.

Using a data sample of 1 475 000 Z → qq̄(γ) events collected during 1994 with the L3 detector at LEP, we have studied the purely leptonic decays of heavy flavour mesons, Ds− → τ−ντ and B− → τ−ντ. A signal is observed in the invariant mass distribution M(γDs−) corresponding to the decay sequence D∗− → γDs−, Ds− → τ−ντ, τ− → l−νlντ. The branching fraction for Ds− → τ−ντ decays is measured to be β(Ds− → τ−ντ) = 0.074 ± 0.028(stat) ± 0.016(syst) ± 0.018(norm). No signal of B− → τ−ντ decays is observed in the data, corresponding to an upper limit on the branching franction β(B− → τ−ντ) < 5.7 × 10−4 at 90% CL.

We report the result of a search for charginos and neutralinos, in e+e− collisions at 189 GeV centre-of-mass energy at LEP. No evidence for such particles is found in a data sample of 176 pb−1. Improved upper limits for these particles are set on the production cross sections. New exclusion contours in the parameter space of the Minimal Supersymmetric Standard Model are derived, as well as new lower limits on the masses of these supersymmetric particles. Under the assumptions of common gaugino and scalar masses at the GUT scale, we set an absolute lower limit on the mass of the lightest neutralino of 32.5 GeV, and a limit on the mass of the lightest chargino of 67.7 GeV for M2<2TeV.

We present a study of the inclusive production of π0, η, Ks0 and Λ based on 929,000 hadronic Z decays recorded with the L3 detector at LEP. The measured inclusive momentum distributions have been compared with predictions from parton shower models as well as an analytical Quantum Chromodynamics calculation. Comparing to low energy e+e- data, we find that QCD describes the energy evolution of the hadron spectrum.

We have performed a high-statistics measurement of Bhabha scattering and of the production of hadrons in electron-positron annihilation at PETRA energies ($12 \mathrm{GeV}&lt;~\sqrt{s}&lt;~36.7 \mathrm{GeV}$). Combining the results with measurements of ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ and ${\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ production enables us to compare our results with electroweak theory. We find ${{sin}^{2}\ensuremath{\theta}}_{w}=0.27\ifmmode\pm\else\textpm\fi{}0.08$. This is in good agreement with the value obtained from neutrino experiments which were carried out in entirely different kinematic regions.

Prompt dimuon production has been measured. Events with mass up to 25 ${\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c}}^{2}$ are observed, as well as the $J$ and $\ensuremath{\Upsilon}$ resonances. Cross sections are given for $J$ and $\ensuremath{\Upsilon}$ production. For the continuum, the scaling function $F(\ensuremath{\tau})$ is measured at very small values of $\sqrt{\ensuremath{\tau}}=\frac{m}{\sqrt{s}}$ covering the range $0.05&lt;\sqrt{\ensuremath{\tau}}&lt;0.20$.

By combining results from the MARK-J at PETRA on Bhabha scattering, μ+μ- and τ+τ- production with recent world data from neutrino-electron scattering experiments, we determine unique values for the leptonic weak neutral current coupling constants gV and gA in the framework of electroweak models containing a single Z0. In contrast to previous analyses, we only use data from purely leptonic interactions, and therefore avoid the inherent uncertainties resulting from the use of hadronic targets. From the MARK-J data alone in the context of the standard SU(2) ⊗ U (1) model of Glashow, Weinberg and Salam, we find sin2θW=0.24±0.11.

The production of c and b quarks in gamma-gamma collisions is studied with the L3 detector at LEP with 410 pb^-1 of data, collected at centre-of-mass energies from 189 GeV to 202 GeV. Hadronic final states containing c and b quarks are identified by detecting electrons or muons from their semileptonic decays. The cross sections sigma(e+e- -> e+e- c c~ X) and sigma(e+e- -> e+e- b b~ X) are measured and compared to next-to-leading order perturbative QCD calculations. The cross section of b production is measured in gamma-gamma collisions for the first time. It is in excess of the QCD prediction by a factor of three.

We have searched for neutralinos produced via the reactions e+e− → χχ′ and e+e−→ χ′χ′, where the next-to lightest neutralino, χ′, decays into the lightest neutralino, χ, and either a photon or a fermion pair. Based on 1.8 × 106 hadronic Z decays collected with the L3 detector at LEP, no signal has been observed. We present upper limits of a few times 10−5 on the branching ratios Z → χχ′ and Z → χ′χ′. In the framework of the Minimial Supersymmetric Standard Model, we exclude a lightest χ with mχ less than 18 GeV, if either tan β > 2 or the gluino mass m≈g > 100 GeV.

The e+e−→e+e−KS0K±π∓ and e+e−→e+e−ηπ+π− final states are studied with the L3 detector at LEP using data collected at centre-of-mass energies from 183 GeV up to 202 GeV. The mass spectrum of the K0SK±π∓ final state shows an enhancement around 1470 MeV, which is identified with the pseudoscalar meson η(1440). This state is observed in γγ collisions for the first time and its two-photon width is measured to be Γγγ(η(1440))×BR(η(1440)→KK̄π)=212±50 (stat.)±23 (sys.) eV. Clear evidence is also obtained for the formation of the axial vector mesons f1(1420) and f1(1285). In the ηπ+π− channel the f1(1285) is observed, and upper limits for the formation of η(1440) and η(1295) are obtained.

We have searched for the neutral Higgs boson produced in the decays of the Z0 through the processes Z0→H0μ+μ−, Z0→H0e+e− and Z0→H0νν. The data sample analysed corresponds to about 50 200 Z0→hadrons. Combining the results of all three processes we exclude a minimal standard model Higgs boson in the mass range 2<MH0<32 GeV at the 95% confidence level.

We have measured the partial widths of the Z0 into lepton pairs, and the forward-backward charge asymmetry for the process e+e−→μ+μ− using the L3 detector at LEP. We obtain an average Γℓℓ of 83.0±2.1±1.1 MeV.From this result and the asymmetry measurement, we extract the values of the vector and axial vector couplings of the Z0 to leptons: grmv=−0.066−0.027+0.046 and grmA= −0.495−0.007+0.007.

This paper reports the results of a study of hadron production in e+e− collisions at c.m. system energies of 33, 35, and 35.8 GeV. Production of a new quark flavor has been sought. The measured values of the total cross section, the thrust distributions, and the study of inclusive muon production show no evidence for the production of a new charge-23e quark near threshold. In addition, during an energy scan in the region 29.9<~√s<~31.6 GeV, no hadron resonance indicating the existence of a bound state composed of charge-23e quarks has been found.Received 1 April 1980DOI:https://doi.org/10.1103/PhysRevLett.44.1722©1980 American Physical Society

We report on the measurement of the reaction ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$ with a large---solid-angle electromagnetic shower detector at center-of-mass energies $\sqrt{s}=13 \mathrm{and} 17$ GeV. Comparison of our results with predictions of quantum electrodynamics shows excellent agreement in both the angular distribution and energy dependence. Values of cutoff parameters are also given.

We report the first measurement of the ratio R=(σe+e−→hadrons)(σe+e−→μ+μ−) (with negligible τ-lepton contribution) at a center-of-mass energy s=13 GeV and s=17 GeV, from the just finished electron-positron colliding-beam facility PETRA. The detector, MARK-J, has an approximately 4π solid angle and measures γ, e, μ, and charged and neutral hadrons simultaneously. Our results yield R(s=17 GeV)=4.9±0.6 (statistical) ±0.7 (systematic error), and R(s=13 GeV)=4.6±0.5 (statistical) ±0.7 (systematic error). The ratio R(s=17 GeV)R(s=13 GeV) is 1.08±0.18.Received 6 February 1979DOI:https://doi.org/10.1103/PhysRevLett.42.1113©1979 American Physical Society

The K0s K0s final state in two-photon collisions is studied with the L3 detector at LEP. The mass spectrum is dominated by the formation of the f_2'(1525) tensor meson in the helicity-two state with a two-photon width times the branching ratio into K Kbar of 76 +- 6 +- 11 eV. A clear signal for the formation of the f_J(1710) is observed and it is found to be dominated by the spin-two helicity-two state. No resonance is observed in the mass region around 2.2 GeV and an upper limit of 1.4 eV at 95% C.L. is derived for the two-photon width times the branching ratio into K0s K0s for the glueball candidate xi(2230).

The reaction e+e− → e+e−γ∗γ∗ → e+e− hadrons is analysed using data collected by the L3 detector during the LEP runs at s = 130−140 GeV and s = 161 GeV. The cross sections σ(e+e− → e+e− hadrons) and σ(γγ → hadrons) are measured in the interval 5 ≤ Wγγ ≤ 75 GeV. The energy dependence of the σ(γγ → hadrons) cross section is consistent with the universal Regge behaviour of total hadronic cross sections.

A search, in e^+e^- collisions, for chargino, neutralino, scalar lepton and scalar quark pair-production is performed, without assuming R-parity conservation in decays, in the case that only one of the coupling constants lambda_ijk or lambda''_ijk is non-negligible. No signal is found in data up to a centre-of-mass energy of 208GeV. Limits on the production cross sections and on the masses of supersymmetric particles are derived.

The results are reported of a search for excited muons (${\ensuremath{\mu}}^{*}$) and electrons (${e}^{*}$) and for a stable charged heavy lepton by measurements of the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}\ensuremath{\gamma}$, ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}\ensuremath{\gamma}$, ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}\ensuremath{\gamma}\ensuremath{\gamma}$, and $\ensuremath{\gamma}\ensuremath{\gamma}$ final states. Excluded are large regions of the $\ensuremath{\lambda}$ (coupling constant), $M$ (mass) planes for spin-\textonehalf{} ${\ensuremath{\mu}}^{*}$ and ${e}^{*}$, and a new stable charged heavy lepton with mass 14 GeV.

We have measured both the rates and the forward-backward asymmetry of ℓ+ℓ− from Z0→ℓ+ℓ− (where ℓ=μ, τ) with the L3 detector. We obtained Γℓℓ=88±4±3 MeV and the vector neutral current coupling constant, gv=0.00±0.07 and the axial vector neutral current coupling constant, gA=−0.515±0.015.

We use the reaction e+ e p, + p, , in the Mark J detector at the DESY high-energy e+ e col- lider PETRA, to test the standard electroweak theory and find good agreement.We also set limits on the parameters of several extended gauge theories.

We report mass limits on the ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{Z}}^{0}$ and ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}}^{\ifmmode\pm\else\textpm\fi{}}$, supersymmetric partners of the ${Z}^{0}$ and ${W}^{\ifmmode\pm\else\textpm\fi{}}$, respectively, using the MARK-J detector at PETRA. The experimental signatures in both cases are acoplanar lepton pairs with missing energy. For the ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}}^{\ifmmode\pm\else\textpm\fi{}}$, an additional signature is a single energetic lepton. No evidence is found for either the ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{Z}}^{0}({M}_{{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{Z}}^{0}}&lt;35\mathrm{GeV})$ or the ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}}^{\ifmmode\pm\else\textpm\fi{}}({M}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}}&lt;25\mathrm{GeV})$.

We have used our measurements of final states from e+e− containing an isolated muon and a hadronic or electron shower to search for new spin 0 charged particles. We exclude (95% CL) a supersymmetric partner of the τ with a mass less than 14 GeV/c2. We obtain upper limits on the branching ratio to τvτ for charged Higgs particles or technipions with masses up to 14 GeV/c2. This disagrees with some technicolor model predictions.

We have searched for resonances in the reaction ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadrons}, \ensuremath{\gamma}\ensuremath{\gamma}, \ensuremath{\mu}\ensuremath{\mu}, \mathrm{and} \mathrm{ee}$, in the energy range $39.79&lt;\sqrt{s}&lt;45.52$ GeV, using the Mark J detector at PETRA. We obtain stringent upper limits on the production of toponium and particles postulated to explain ${Z}^{0}\ensuremath{\rightarrow}\mathrm{lepton}\mathrm{pair}+\ensuremath{\gamma}$ events observed at the CERN $\stackrel{-}{p}p$ collider. We also set limits on the mass and coupling constant of excited electrons.

The CMS data acquisition system is made of two major subsystems: event building and event filter. The presented paper describes the architecture and design of the software that processes the data flow in the currently operating experiment. The central DAQ system relies on industry standard networks and processing equipment. Adopting a single software infrastructure in all subsystems of the experiment imposes, however, a number of different requirements. High efficiency and configuration flexibility are among the most important ones. The XDAQ software infrastructure has matured over an eight years development and testing period and has shown to be able to cope well with the requirements of the CMS experiment.

The CMS data acquisition (DAQ) is implemented as a service-oriented architecture where DAQ applications, as well as general applications such as monitoring and error reporting, are run as self-contained services. The task of deployment and operation of services is achieved by using several heterogeneous facilities, custom configuration data and scripts in several languages. In this work, we restructure the existing system into a homogeneous, scalable cloud architecture adopting a uniform paradigm, where all applications are orchestrated in a uniform environment with standardized facilities. In this new paradigm DAQ applications are organized as groups of containers and the required software is packaged into container images. Automation of all aspects of coordinating and managing containers is provided by the Kubernetes environment, where a set of physical and virtual machines is unified in a single pool of compute resources. We demonstrate that a container-based cloud architecture provides an acrossthe-board solution that can be applied for DAQ in CMS. We show strengths and advantages of running DAQ applications in a container infrastructure as compared to a traditional application model.

The Online Monitoring System (OMS) at the Compact Muon Solenoid experiment (CMS) at CERN aggregates and integrates different sources of information into a central place and allows users to view, compare and correlate information. It displays real-time and historical information. The tool is heavily used by run coordinators, trigger experts and shift crews, to ensure the quality and efficiency of data taking. It provides aggregated information for many use cases including data certification. OMS is the successor of Web Based Monitoring (WBM), which was in use during Run 1 and Run 2 of the LHC. WBM started as a small tool and grew substantially over the years so that maintenance became challenging. OMS was developed from scratch following several design ideas: to strictly separate the presentation layer from the data aggregation layer, to use a well-defined standard for the communication between presentation layer and aggregation layer, and to employ widely used frameworks from outside the HEP community. A report on the experience from the operation of OMS for the first year of data taking of Run 3 in 2022 is presented.

The data acquisition (DAQ) of the Compact Muon Solenoid (CMS) experiment at CERN, collects data for events accepted by the Level-1 Trigger from the different detector systems and assembles them in an event builder prior to making them available for further selection in the High Level Trigger, and finally storing the selected events for offline analysis. In addition to the central DAQ providing global acquisition functionality, several separate, so-called “MiniDAQ” setups allow operating independent data acquisition runs using an arbitrary subset of the CMS subdetectors. During Run 2 of the LHC, MiniDAQ setups were running their event builder and High Level Trigger applications on dedicated resources, separate from those used for the central DAQ. This cleanly separated MiniDAQ setups from the central DAQ system, but also meant limited throughput and a fixed number of possible MiniDAQ setups. In Run 3, MiniDAQ-3 setups share production resources with the new central DAQ system, allowing each setup to operate at the maximum Level-1 rate thanks to the reuse of the resources and network bandwidth. Configuration management tools had to be significantly extended to support the synchronization of the DAQ configurations needed for the various setups. We report on the new configuration management features and on the first year of operational experience with the new MiniDAQ-3 system.

The reaction e+e−→e+e−γ∗γ∗→e+e−hadrons for quasi-real photons is studied using data from s=183 GeV up to 202 GeV. Results on the total cross sections σ(e+e−→e+e−hadrons) and σ(γγ→hadrons) are given for the two-photon centre-of-mass energies 5 GeV⩽Wγγ⩽185 GeV. The total cross section of two real photons is described by a Regge parametrisation. We observe a steeper rise with the two-photon centre-of-mass energy as compared to the hadron–hadron and the photon–proton cross sections. The data are also compared to the expectations of different theoretical models.

We report on the measurement of W-boson pair-production with the L3 detector at LEP at a centre-of-mass energy of 161.34 GeV. In a data sample corresponding to a total luminosity of 11 pb−1, we select four-fermion events with high invariant masses of pairs of hadronic jets or leptons. Combining all final states, the measured total cross section for W-pair production is: sigmaWW = 2.89−0.70+0.81(stat.) ± 0.14 (syst.) pb. Within the Standard Model, this corresponds to a mass of the W boson of: MW = 80.80−0.42+0.48 (exp.) ± 0.03 (LEP) GeV. Limits on anomalous triple-vector-boson couplings are derived.

The search for an additional heavy gauge boson Z′ is described. The models considered are based on either a superstring-motivated E6 or on a left-right symmetry and assume a minimal Higgs sector. Cross sections and asymmetries measured with the L3 detector in the vicinity of the Z resonance during the 1990 and 1991 running periods are used to determine limits on the Z-Z′ gauge boson mixing angle and on the Z′ mass. For Z′ masses above the direct limits, we obtain the following allowed ranges of the mixing angle, θM at the 95% confidence level: −0.004 ⪕ θM⪕ 0.015 for the χ model, −0.003 ⪕ θM⪕ 0.020 for the ψ model, −0.029 ⪕ θM⪕ 0.010 for the η model, −0.002 ⪕ θM⪕ 0.020 for the LR model,

We have searched for direct leptoquark production in Z0 decays from a scan of the Z0 resonance, in the energy range 88.2 ⩽ √s ⩽ 94.2 GeV, using 5.2 pb−1 of data. We exclude the existence of scalar leptoquarks with masses less than 41 to 44 GeV, depending on the charge assignments, at the 95% confidence level.

We use the reaction e+e−→hadrons, in the Mark J detector at the DESY electron-positron collider PETRA, to determine the hadronic cross section up to 46.78 GeV. The production of a top quark with a charge equal to (2/3) is excluded up to 46.6 GeV with 95% C.L. The observed rise in the cross section at higher energies is consistent with the electroweak prediction for a Z0 mass of 93 GeV. We describe some unusual muon inclusive events.Received 27 January 1986DOI:https://doi.org/10.1103/PhysRevD.34.681©1986 American Physical Society

We have measured the forward-backward asymmetry in Z0→bb decays using hadronic events containing muons and electrons. The data sample corresponds to 118 200 hadronic events at √s≈Mz. From a fit to the single and dilepton p and P⊥ spectra, we determine Abb=0.130−0.042+0.044 including the correction for B0−B0 mixing.

Using data from our recent experiment on inclusive $\ensuremath{\mu}$-pair production by 150-GeV/c protons on beryllium, we have calculated the contribution of muon pairs to the yield of single prompt muons. We find, both at 90\ifmmode^\circ\else\textdegree\fi{} in the center-of-mass system and in the forward direction, that the resulting single-muon cross sections are in reasonable agreement with the existing measurements for which only one muon is detected.

This paper reports on the first results of the study of e+e collisions at 4's =27.4 GeV and vs = 27.7 GeV at PETRA, using the 47'-sr electromagnetic and calorimetric detector MARK-J.We obtain an average A=a(e+e hadrons)/o(e+e p+p ) = 8.8+0.3 (statis- tical) + 0.6 (systematic) and a relative R = 1.0+ 0.2 between the two energies.The R values, the measured thrust distribution, and average spherocity show no evidence for the production of new quark flavors.

We report on the results of the study of e+e− collisions at the highest PETRA energy of √s = 31.57 GeV, using the 4π sr, electromagnetic and calorimetric detector Mark J. Based on 88 hadron events, and an integrated luminosity of 243 nb−1 we obtain R = σ(e+e− → hadrons)/σ(e+e− → μ+μ−) = 4.0 ± 0.5 (statistical) ± 6 (systematic). The R value, the measured thrust distribution and average spherocity show no evidence for the production of new quark flavors.

The K0SK±π∓ final state in two-photon collisions is studied with the L3 detector at LEP at e+e− centre-of-mass energies from 183 to 209 GeV with an integrated luminosity of 664.6 pb−1. The η(1475) and f1(1420) mesons are observed and their contribution is separated by measuring the formation rates as a function of the photon virtuality Q2. The η(1475) is found to be dominant for Q2 ⩽ 0.01GeV2 and its two-photon width is measured to be 0.23±0.05 (stat.) ±0.05 (sys.) keV. At higher Q2, the f1(1420) is formed and decays to K*(892)K. The γγ coupling and form factor parameters of this state are measured to be Γγγ = 3.2±0.6 (stat.) ±0.7 (sys.) keV and Λ1 = 926±72 (stat.) ±32 (sys.) MeV, respectively.

With a data sample of 86 000 Z → τ+τ−(γ) events collected in 1990 through 1993 we have measured the polarization of τ-leptons as a function of the production polar angle using the following 1-prong τ decay modes: τ−→e−vevτ, τ−→π−(K−)vτ, τ−→ϱ−vτandτ−→a1−vτ. We obtain for the ratio vector to axial-vector weak neutral couplings for electrons gVe/gAe=0.0791±0.0099(stat)±0.0025 (syst) and taus gVτ/gAτ=0.0752±0.0063 (stat)±0.0045 (syst) consistent with the hypothesis of e - τ universality. Assuming universality of the e - τ neutral current we determine the effective electroweak mixing angle to be sin2 θeffw = 0.2309 ± 0.0016.

We have measured the ratio of the strong coupling constants αs for bottom quarks and light quarks at the Z0 resonance, in order to test the flavour independence of the strong interaction. The coupling strength αs has been determined from the fraction of events with three jets, measured for a sample of all hardronic events, and for inclusive muon and electron events. The b purity is evaluated to be 22% for the first data set and 87% for the inclusive lepton sample. We find αs(b)αs(udsc)=1.00± 0.05 (stat.)±0.06 (syst.).

We have measured the forward-backward asymmetry in e+e−→bband e+e−→cc processes using hadronic events containing muons or electrons. The data sample corresponds to 4100000 hadronic decays of the Z0. From a fit to the single lepton and dilepton p and pT spectra, we determine Abb=0.086±0.015±0.007andAcc=0.083±0.038±0.027 at the effective center-of-mass energy √s=91.24 GeV. These measurements yield a value of the electroweak mixing angle sin2θw=0.2336±0.0029.

In a large-acceptance spectrometer at Fermilab, we have searched for multimuon events produced in collisions of 225-GeV/c protons and ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ mesons with nuclei. In particular, additional muons accompanying the $\frac{J}{\ensuremath{\psi}}\ensuremath{\rightarrow}\ensuremath{\mu}\ensuremath{\mu}$ decay could signal charmed-particle production. For all data combined, the 90%-confidence limit on charmed-particle production in association with the $\frac{J}{\ensuremath{\psi}}$ is $\frac{{\ensuremath{\sigma}}_{\mathrm{JC}\overline{C}}}{{\ensuremath{\sigma}}_{J}}&lt;0.01$; the limit on production of $\frac{J}{\ensuremath{\psi}}$ pairs is $\frac{{\ensuremath{\sigma}}_{\mathrm{JJ}}}{{\ensuremath{\sigma}}_{J}}&lt;0.021$. Limits are also given for each beam particle separately.

We trigger a large-acceptance spectrometer by single muons and observe any additional muons with good efficiency. The effect of $\ensuremath{\pi}$ and $K$ decays is subtracted to obtain the prompt muon signal in the kinematic region $0.1&lt;x&lt;0.4$ and ${p}_{T}&lt;1.0$ GeV/c. We find 0.7 \ifmmode\pm\else\textpm\fi{} 0.2 of all prompt $\ensuremath{\mu}'\mathrm{s}$ are produced in pairs; the $\frac{\ensuremath{\mu}}{\ensuremath{\pi}}$ ratio decreases with $x$ but increases with ${p}_{T}$, averaging 3 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}5}$.

We report on measurements of the triple-gauge-boson couplings of the W boson in e+e− collisions with the L3 detector at LEP. W-pair, single-W and single-photon events are analysed in a data sample corresponding to a total luminosity of 76.7 pb−1 collected at centre-of-mass energies between 161GeV and 183GeV. CP-conserving as well as both C- and P-conserving triple-gauge-boson couplings are determined. The results, in good agreement with the Standard-Model expectations, confirm the existence of the self coupling among the electroweak gauge bosons and constrain its structure.

We describe the sample of energetic single-photon events (Eγ > 15 GeV) collected by L3 in the 1991–1993 LEP runs. The event distributions agree with expectations from the Standard Model. The data are used to constrain the ZZγ coupling and to set an upper limit of 4.1 × 10−6, μB (90% C.L.) on the the magnetic moment of the τ neutrino.

Bose-Einstein correlations in W-pair production at LEP are investigated in a data sample of 629 pb^-1 collected by the L3 detector at centre-of-mass energies of 189-209 GeV. Bose-Einstein correlations between pions within a W decay are observed and found to be in good agreement with those in light-quark Z decay. No evidence is found for Bose-Einstein correlations between hadrons coming from different W's in the same event.

We have searched for the excited electron neutrino produced from Z0 decays in the channel e+e−→νν∗ using the L3 detector at LEP. The decays ν∗→eW and ν∗→νγ have been investigated. We have determined an upper limit on the Zνν∗ coupling as a function of mν∗ up to the Z0 mass.

We have searched for the neutral Higgs boson produced in the decays of the Z0 through the process Z0 → H0l+l− in the mass range MH0 <2 GeV. From the analysis of a data sample corresponding to about 70 000 Z0→ hadrons we exclude a minimal standard model Higgs boson in the mass range 0<MH0<2 GeV at the 99% confidence level independent of the Higgs decay channels.

We have measured the partial width and forward-backward charge asymmetry for the reaction e+e-→Z0→μ+μ-(γ). We obtain a partial width Γμμ of 83.3±1.3(stat)±0.9(sys) MeV and the following values for the vector and axial vector couplings: gv=−0.062−0.015+0.020 and gA=−0.497−0.005+0.005. From our measurement of the partial width and the mass of the Z0 boson we determine the effective electroweak mixing angle, sin2θw=0.232±0.005, and the neutral current coupling strength parameter, ϱ=0.998±0.016.

Using the Mark-J detector at the high-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider PETRA, we compare the data from hadron production with the complete second-order QCD calculation over the energy region 22 to 46.78 GeV. We determine the QCD parameter $\ensuremath{\Lambda}=100\ifmmode\pm\else\textpm\fi{}{30}_{\ensuremath{-}45}^{+60}$ MeV which yields the strong-coupling constant ${\ensuremath{\alpha}}_{s}=0.12\ifmmode\pm\else\textpm\fi{}0.02$ for $\sqrt{s}=44$ GeV.

The data-acquisition system of the CMS experiment at the LHC performs the read-out and assembly of events accepted by the first level hardware trigger. Assembled events are made available to the high-level trigger which selects interesting events for offline storage and analysis. The system is designed to handle a maximum input rate of 100 kHz and an aggregated throughput of 100GB/s originating from approximately 500 sources. An overview of the architecture and design of the hardware and software of the DAQ system is given. We discuss the performance and operational experience from the first months of LHC physics data taking.

The data acquisition (DAQ) system of the CMS experiment at the CERN Large Hadron Collider assembles events at a rate of 100 kHz, transporting event data at an aggregate throughput of 100 GB/s to the high level trigger (HLT) farm. The HLT farm selects interesting events for storage and offline analysis at a rate of around 1 kHz. The DAQ system has been redesigned during the accelerator shutdown in 2013/14. The motivation is twofold: Firstly, the current compute nodes, networking, and storage infrastructure will have reached the end of their lifetime by the time the LHC restarts. Secondly, in order to handle higher LHC luminosities and event pileup, a number of sub-detectors will be upgraded, increasing the number of readout channels and replacing the off-detector readout electronics with a <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu {\hbox {TCA}}$</tex></formula> implementation. The new DAQ architecture will take advantage of the latest developments in the computing industry. For data concentration, 10/40 Gb/s Ethernet technologies will be used, as well as an implementation of a reduced TCP/IP in FPGA for a reliable transport between custom electronics and commercial computing hardware. A Clos network based on 56 Gb/s FDR Infiniband has been chosen for the event builder with a throughput of <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\sim 4~\hbox{Tb/s}$</tex> </formula> . The HLT processing is entirely file based. This allows the DAQ and HLT systems to be independent, and to use the HLT software in the same way as for the offline processing. The fully built events are sent to the HLT with 1/10/40 Gb/s Ethernet via network file systems. Hierarchical collection of HLT accepted events and monitoring meta-data are stored into a global file system. This paper presents the requirements, technical choices, and performance of the new system.

A search for rare charmless decays of Bd0 and Bs0 mesons has been performed in the exclusive channels Bd(s)0 →ηη, Bd(s)0 →ηπ0 and Bd(s)0 →π0π0. The data sample consisted of three million hadronic Z decays collected by the L3 experiment at LEP from 1991 through 1994. No candidate event has been observed and the following upper limits at 90% confidence level on the branching ratios have been set: Br(B()d→ηη) <4.1 x 10−4, Br(B()s→ηη) < 1.5 x 10−3, Br(B()d→ηφ()) < 2.5 x 10−4, Br(B()s→ηphi;()) < 1.0 x 10−3, Br(B()d→phi;()phi;()) < 6.0 x 10−5, Br(B()s→phi;()phi;()) < 2.1 x 10−4. These are the first experimental limits on Bd0→ηη and on the Bs0 neutral charmless modes.

The structure functions of real and virtual photons are derived from cross section measurements of the reaction e+e−→e+e−+ hadrons at LEP. The reaction is studied at s≃91GeV with the L3 detector. One of the final state electrons is detected at a large angle relative to the beam direction, leading to Q2 values between 40 GeV2 and 500 GeV2. The other final state electron is either undetected or it is detected at a four-momentum transfer squared P2 between 1 GeV2 and 8 GeV2. These measurements are compared with predictions of the Quark Parton Model and other QCD based models.

We have measured the partial widths for the three reactions e+e− → Z0 → e+e−, μ+μ−, τ+τ−. The results are Γee = 84.3±1.3 MeV, √ΓeeΓμμ=83.9±1.4 MeV, and √ΓeeΓττ=83.9±1.4 MeV, where the errors are statistical. The systematic errors are estimated to be 1.0 MeV, 0.9 MeV, and 1.4 MeV, respectively. We perform a simultaneous fit to the cross sections for the e+e−→e+e−, μ+μ−, and τ+τ− data, the differential cross section as a function of polar angle for the electron data, and the forward- backward asymmetry for the muon data. We obtain the leptonic partial with Γℓℓ=84.0±0.9 (stat.) MeV. The systematic error is estimated to be 0.8 MeV. Also, we obtain the axial-vector and vector weak coupling constants of charged leptons, gA=−0.500±0.003 and gν=−0.064−0.013+0.017.

The CMS data acquisition system is designed to build and filter events originating from 476 detector data sources at a maximum trigger rate of 100 kHz. Different architectures and switch technologies have been evaluated to accomplish this purpose. Events will be built in two stages: the first stage will be a set of event builders called front-end driver (FED) builders. These will be based on Myrinet technology and will pre-assemble groups of about eight data sources. The second stage will be a set of event builders called readout builders. These will perform the building of full events. A single readout builder will build events from about 60 sources of 16 kB fragments at a rate of 12.5 kHz. In this paper, we present the design of a readout builder based on TCP/IP over Gigabit Ethernet and the refinement that was required to achieve the design throughput. This refinement includes architecture of the readout builder, the setup of TCP/IP, and hardware selection.

The DAQ system of the CMS experiment at CERN collects data from more than 600 custom detector Front-End Drivers (FEDs). During 2013 and 2014 the CMS DAQ system will undergo a major upgrade to address the obsolescence of current hardware and the requirements posed by the upgrade of the LHC accelerator and various detector components. For a loss-less data collection from the FEDs a new FPGA based card implementing the TCP/IP protocol suite over 10Gbps Ethernet has been developed. To limit the TCP hardware implementation complexity the DAQ group developed a simplified and unidirectional but RFC 793 compliant version of the TCP protocol. This allows to use a PC with the standard Linux TCP/IP stack as a receiver. We present the challenges and protocol modifications made to TCP in order to simplify its FPGA implementation. We also describe the interaction between the simplified TCP and Linux TCP/IP stack including the performance measurements.

For the upgrade of the DAQ of the CMS experiment in 2013/2014 an interface between the custom detector Front End Drivers (FEDs) and the new DAQ eventbuilder network has to be designed. For a loss-less data collection from more then 600 FEDs a new FPGA based card implementing the TCP/IP protocol suite over 10Gbps Ethernet has been developed. We present the hardware challenges and protocol modifications made to TCP in order to simplify its FPGA implementation together with a set of performance measurements which were carried out with the current prototype.

A search for single and multi-photon events with missing energy is performed using data collected at centre-of-mass energies between 161 GeV and 172 GeV for a total of 20.9 pb−1 of integrated luminosity. The results obtained are used to derive the value for the ννγ(γ) cross section as well as upper limits on new physics processes.

The pair production of Z bosons is studied using the data collected by the L3 detector at LEP in 1998 in e+e- collisions at a centre-of-mass energy of 189 GeV. All the visible final states are considered and the cross section of this process is measured to be 0.74 +0.15 -0.14 (stat.) +/- 0.04 (syst.) pb. Final states containing b quarks are enhanced by a dedicated selection and their production cross section is found to be 0.18 +0.09 -0.07 (stat.) +/- 0.02 (syst.) pb. Both results are in agreement with the Standard Model predictions. Limits on anomalous couplings between neutral gauge bosons are derived from these measurements.

A study of resonance formation is presented in the π+π−π0 final state in two-photon collisions at LEP. The a2(1320) radiative width is measured to be Λγγ = 0.98 ± 0.05 ± 0.09 keV. The helicity 2 production is dominant. Exclusive π+π−π0 production has also been studied in the mass region above the a2 in the ϱπ and f2π channels. This region is dominated by a JP = 2+ helicity 2 wave.

Using the data collected by the L3 experiment at LEP from 1991 to 1995 at energies around the Z mass, a measurement of the weak anomalous magnetic dipole moment, awτ, and of the weak electric dipole moment, dwτ, of the τ lepton is performed. These quantities are obtained from angular distributions in e+e−→τ+τ−→h+ν̄τh−ντ, where h is a π or a ρ. The results are: Re(awτ)=(0.0±1.6±2.3)×10−3, Im(awτ)=(−1.0±3.6±4.3)×10−3 and Re(dwτ)=(−0.44±0.88±1.33)×10−17e·cm. This is the first direct measurement of awτ.

A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at centre-of-mass energies between 192 and 202 GeV, corresponding to an integrated luminosity of 233.2 pb−1. Decays into a charm and a strange quark or into a tau lepton and its neutrino are considered. The observed events are consistent with the expectations from Standard Model background processes. Including data taken at lower centre-of-mass energies, lower limits on the charged Higgs mass are derived at the 95% confidence level. They vary from 67.4 to 79.9 GeV as a function of the H±→τν branching ratio.

We present a study of the inclusive η production based on 300 000 hadronic Z0 decays. The measured inclusive momentum distribution can be reproduced by parton shower Monte Carlo programs and also by an analytical QCD calculation. Comparing our results with low energy e+e− data, we find that QCD describes both the shape and the energy evolution of the η spectrum. The comparison of η production rates in quark- and gluon-enriched jet samples does not show statistically significant evidence for more abundant production of η mesons in gluon fragmentation.

We have searched for the neutral Higgs boson produced in decays of the Z0 through the process e+e−→Z0→H0Z0∗. The data sample analyzed corresponds to 111 200 hadronic decays of the Z0. Combining the results of this analysis with previous L3 results we exclude a minimal standard model Higgs boson in the mass range 0<MH0 < 41.8 GeV at the 95% confidence level.

Bose-Einstein correlations of both neutral and like-sign charged pion pairs are measured in a sample of 2 million hadronic Z decays collected with the L3 detector at LEP. The analysis is performed in the four-momentum difference range 300 MeV < Q < 2 GeV. The radius of the neutral pion source is found to be smaller than that of charged pions. This result is in qualitative agreement with the string fragmentation model.

A study of τ-lepton production in the CMS energy region from 14 to 46.8 GeV at PETRA is reported. The cross section, the decay branching ratio into μνν, and the electroweak parameters are determined with a total integrated luminosity of 115 pb−1.

We have performed a high statistics measurement of the production rate and the energy flow pattern of hadron events between √s=33 and 36.7 GeV. The data show no evidence for the production of a new quark with charge 23e. Planar events in e+e−→hadrons are shown to have three well separated jets. The production rate and the shape of three-jet events are compared with many models and we find that only the QCD model can explain the data.

The Compact Muon Solenoid (CMS) experiment operating at the CERN (European Laboratory for Nuclear Physics) Large Hadron Collider (LHC) is in the process of upgrading several of its detector systems. Adding more individual detector components brings the need to test and commission those components separately from existing ones so as not to compromise physics data-taking. The CMS Trigger, Timing and Control (TTC) system had reached its limits in terms of the number of separate elements (partitions) that could be supported. A new Timing and Control Distribution System (TCDS) has been designed, built and commissioned in order to overcome this limit. It also brings additional functionality to facilitate parallel commissioning of new detector elements. The new TCDS system and its components will be described and results from the first operational experience with the TCDS in CMS will be shown.

The S matrix ansatz is a rigorously model independent approach to describe the cross-sections and asymetries in e+e− annihilation. Using the cross-sections and asymetries measured with the L3 detector during the 1990 and 1991 running period, we determine the mass and the width of the Z boson, the contributions of the Z exchange and the γZ interference. Including the polarization of the τ lepton in the analysis, the leptonic helicity amplitudes of the scattering process are determined assuming lepton universality. The results are compared with other model independent ansatzes as realized in ZFITTER. A systematic bias of the Z mass due to the γZ interference term is detected, which leads to an underestimation of the error on mZ for model independent determinations.

From a fit to the impact parameter distribution of lepton tracks from semileptonic b decay, the lifetime of B-hadrons produced in e+e− collisions at the Z0 is measured to be 1.32±0.08 (stat.)±0.09(syst.) ps. Combined with an earlier measurement of the branching ratio Br(B→ℓνX), the CKM matrix element |Vcb| is determined to be 0.046±0.002 (exp.)−0.003+0.004 (theory).

We report on the observation of single W boson production in a data sample collected by the L3 detector at LEP2. The signal consists of large missing energy final states with a single energetic lepton or two hadronic jets. The cross-section is measured to be 0.61−0.33+0.43 ± 0.05 pb at the centre of mass energy s = 172 GeV, consistent with the Standard Model expectation. From this measurement the following limits on the anomalo γWW gauge couplingsare derived at 95% CL: −3.6 < Δκγ < 1.5 and −3.6 < λγ < 3.6.

We report on the measurement of W-boson pair-production with the L3 detector at LEP. In a data sample corresponding to a total luminosity of 55.47 pb−1 collected at an average centre-of-mass energy of 182.68GeV, we select 824 four-fermion events with pairs of hadronic jets or pairs of leptons with high invariant masses. Branching fractions of W decays into different fermion-antifermion pairs are determined. Assuming charged-current lepton universality, the branching fraction for hadronic W decays is measured to be: B(W→hadrons)=70.1±1.3(stat.)±0.4(syst.)%. Combining all final states the total cross section for W-pair production is measured to be: σWW=16.53±0.67(stat.)±0.26(syst.) pb.

Single W boson production in electron–positron collisions is studied with the L3 detector at centre-of-mass energies between 192 GeV and 209 GeV. Events with two acoplanar hadronic jets or a single energetic lepton are selected, and the single W cross section is measured. Combining the results with measurements at lower centre-of-mass energies, the ratio of the measured cross section to the Standard Model expectation is found to be 1.12+0.11−0.10±0.03. From all single W data, the WWγ gauge coupling parameter κγ is measured to be 1.116+0.082−0.086±0.068.

Inclusive charged hadron production, e+e- -> e+e- h+- X, is studied using 414 pb-1 of data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 202 GeV. Single particle inclusive differential cross sections are measured as a function of the particle transverse momentum, pt, and pseudo-rapidity, eta. For p_t < 1.5 GeV, the data are well described by an exponential, typical of soft hadronic processes. For higher pt, the onset of perturbative QCD processes is observed. The pi+- production cross section for pt > 5 GeV is much higher than the NLO QCD predictions.

A direct test is presented of higher-order QED (${\ensuremath{\alpha}}^{4}$) at large momentum transfers (up to \ensuremath{\sim}100 Ge${\mathrm{V}}^{2}$). These tests were carried out with the MARK-J detector at PETRA by comparing the measured cross section for the process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ with the prediction of QED for $12 \mathrm{GeV}&lt;~\sqrt{s}&lt;~36.7 \mathrm{GeV}$. The cross sections and the various kinematic distributions agree with QED.

The cross section for open-beauty production in photon–photon collisions is measured using the whole high-energy and high-luminosity data sample collected by the L3 detector at LEP. This corresponds to 627 pb−1 of integrated luminosity for electron–positron centre-of-mass energies from 189 to 209 GeV. Events containing b quarks are identified through their semi-leptonic decay into electrons or muons. The e+e−→e+e−bb¯X cross section is measured within our fiducial volume and then extrapolated to the full phase space. These results are found to be in significant excess with respect to Monte Carlo predictions and next-to-leading order QCD calculations.

The QED processes e+e−→e+e−μ+μ− and e+e−→e+e−τ+τ− are studied with the L3 detector at LEP using an untagged data sample collected at centre-of-mass energies 161 GeV⩽s⩽209 GeV. The τ-pairs are observed through the associated decay of one τ into eνν and the other into ππν. The cross sections are measured as a function of s. For muon pairs, the cross section of the γγ→μ+μ− process is also measured as a function of the two-photon centre-of-mass energy for 3 GeV⩽Wγγ⩽40 GeV. Good agreement is found between these measurements and the O(α4) QED expectations. In addition, limits on the anomalous magnetic and electric dipole moments of the τ lepton are extracted.

The average lifetime of b hadrons has been measured using the L3 detector at LEP, running at √s ≈ MZ. A b-enriched sample was obtained from 432538 hadronic Z events collected in 1990 and 1991 by tagging electrons and muons from semileptonic b hadron decays. From maximum likelihood fits to the electron and muon impact parameter distributions, the average b hadron lifetime was measured to be τb = (1535 ± 35 ± 28) fs, where the first error is statistical and the second includes both the experimental and the theoretical systematic uncertainties.

We have analyzed one-prong τ decays with neutral kaons using the information from a fine-grained hadron calorimeter. The data sample consists of 43 500 Z → τ+τ−(γ) events collected by the L3 detector at LEP in 1991, 1992 and 1993. The following branching fractions are measured: B(τ− → ντπ−K0) = 0.0095 ± 0.0015(stat) ± 0.0006(syst); B(τ− → ντπ− π0K0) = 0.0041 ± 0.0012(stat) ± 0.0003(syst) and B(τ− → ντπ−K0K0) = 0.0031 ± 0.0012(stat) ± 0.0004(syst).

The reaction e+e− → e+e−γ∗γ∗ → e+e−KS0KS0 is studied with the L3 detector at LEP and the formation of the f2′(1525) resonance is observed. For an integrated luminosity of 114 pb−1, 31±6 f2′ events are found. Their angular distribution is consistent with a pure helicity two. The radiative width times the branching ratio is measured to be Γγγ(f2′)×Br(f2′ → KK)=(0.093±0.018±0.022) keV. Only three events are found in the f2(1270)−a2(1320) mass region, consistent with destructive f2−a2 interference in the KS0KS0 final state. The mixing angle of the tensor meson nonet is determined to the θ = (29.4−1.6+1.4)°.