Search for Heavy Isosinglet Neutrino in e+e- Annihilation at LEP

We report on a search for the first generation heavy neutrino that is an isosinglet under the standard SU(2)_L gauge group. The data collected with the L3 detector at center-of-mass energies between 130 GeV and 208 GeV are used.The decay channel N_e --> eW is investigated and no evidence is found for a heavy neutrino, N_e, in a mass range between 80 GeV and 205 GeV. Upper limits on the mixing parameter between the heavy and light neutrino are derived

Study of Z Boson Pair Production in e^+e^- Interactions at \sqrt{s}=192 - 202 GeV

The cross section for the production of Z boson pairs is measured using the data collected by the L3 detector at LEP in 1999 in e^+e^- collisions at centre-of-mass energies ranging from 192 GeV up to 202 GeV. Events in all the visible final states are selected, measuring the cross section of this process. The special case of final states containing b quarks is also investigated. All results are in agreement with the Standard Model predictions

K0s K0s Final State in Two-Photon Collisions and Implications for Glueballs

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)

Reception Test of Petals for the End Cap TEC+ of the CMS Silicon Strip Tracker

The silicon strip tracker of the CMS experiment has been completed and was inserted into the CMS detector in late 2007. The largest sub system of the tracker are its end caps, comprising two large end caps (TEC) each containing 3200 silicon strip modules. To ease construction, the end caps feature a modular design: groups of about 20 silicon modules are placed on sub-assemblies called petals and these self-contained elements are then mounted onto the TEC support structures. Each end cap consists of 144 such petals, which were built and fully qualified by several institutes across Europe. Fro

Integration of the End Cap TEC+ of the CMS Silicon Strip Tracker

The silicon strip tracker of the CMS experiment has been completed and inserted into the CMS detector in late 2007. The largest sub-system of the tracker is its end cap system, comprising two large end caps (TEC) each containing 3200 silicon strip modules. To ease construction, the end caps feature a modular design: groups of about 20 silicon modules are placed on sub-assemblies called petals and these self-contained elements are then mounted into the TEC support structures. Each end cap consists of 144 petals, and the insertion of these petals into the end cap structure is referred to as TEC integration. The two end caps were integrated independently in Aachen (TEC+) and at CERN (TEC--). This note deals with the integration of TEC+, describing procedures for end cap integration and for quality control during testing of integrated sections of the end cap and presenting results from the testing

Measurement of the W-Pair Production Cross Section and W-Decay Branching Fractions in e+e−e^{+}e^{-} Interactions at s\sqrt{s}= 189 GeV

The data collected by the L3 experiment at LEP at a centre-of-mass energy of $188.6~\rm{Ge\kern -0.1em V}$ are used to measure the W-pair production cross section and the W-boson decay branching fractions. These data correspond to an integrated luminosity of 176.8~pb$^{-1}$. The total cross section for W-pair production, combining all final states, is measured to be $\sigma_{\rm{WW}}= 16.24 \pm 0.37~(stat.) \pm 0.22~(syst.)$~pb. Including our data collected at lower centre-of-mass energies, the hadronic branching fraction of the W-boson is determined to be $B(\rm{W} \rightarrow \rm{qq})= \left[ 68.20 \pm 0.68~(stat.) \pm 0.33~(syst.)\right]~\%$. The results agree with the Standard Model predictions.The data collected by the L3 experiment at LEP at a centre-of-mass energy of 188.6 GeV are used to measure the W-pair production cross section and the W-boson decay branching fractions. These data correspond to an integrated luminosity of 176.8pb^-1. The total cross section for W-pair production, combining all final states, is measured to be sigma_WW = 16.24 +/- 0.37(stat.) +/- 0.22(syst.) pb. Including our data collected at lower centre-of-mass energies, the hadronic branching fraction of the W-boson is determined to be B(W ->qq) = [68.20 +/- 0.68 (stat.) +/- 0.33 (syst.) ] %. The results agree with the Standard Model predictions.The data collected by the L3 experiment at LEP at a centre-of-mass energy of 188.6 GeV are used to measure the W-pair production cross section and the W-boson decay branching fractions. These data correspond to an integrated luminosity of 176.8 pb −1 . The total cross section for W-pair production, combining all final states, is measured to be σ WW =16.24±0.37 (stat.)±0.22 (syst.) pb. Including our data collected at lower centre-of-mass energies, the hadronic branching fraction of the W-boson is determined to be B (W→qq)=[68.20±0.68 (stat.)±0.33 (syst.)]%. The results agree with the Standard Model predictions

Light resonances in Ks K pi and eta pi pi final states in gamma gamma collisions at LEP

The e+e- -> e+e- Ks K+- pi-+ e+e- -> e+e- eta pi+ pi- and 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 Ks K+- pi-+ final state shows an enhancement around 1470MeV, which is identified with the pseudoscalar meson eta(1440). This state is observed in gamma gamma collisions for the first time and its two-photon width is measured to be Gamma_gamma gamma(eta(1440))x BR(eta(1440)->KK pi)= 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 eta pi+ pi- channel the f1(1285) is observed, and upper limits for the formation of eta(1440) and eta(1295) are obtained

Engineered Prototypes of the Barrel and Forward Single-Sided Silicon Modules of CMS: Milestone Report

This is intended to describe the main features of the first engineered versions of the basic single-sided detector modules for the barrel and forward silicon tracker of CMS

Petal Integration for the CMS Tracker End Caps

This note describes the assembly and testing of the 292 petals built for the CMS Tracker End Caps from the beginning of 2005 until the summer of 2006. Due to the large number of petals to be assembled and the need to reach a throughput of 10 to 15 petals per week, a distributed integration approach was chosen. This integration was carried out by the following institutes: I. and III. Physikalisches Institut - RWTH Aachen University; IIHE, ULB \& VUB Universities, Brussels; Hamburg University; IEKP, Karlsruhe University; FYNU, Louvain University; IPN, Lyon University; and IPHC, Strasbourg University. Despite the large number of petals which needed to be reworked to cope with a late-discovered module issue, the quality of the petals is excellent with less than 0.2\% bad channels