J. Mnich

A comprehensive review of physics at an e+e- Linear Collider in the energy range of sqrt{s}=92 GeV--3 TeV is presented in view of recent and expected LHC results, experiments from low energy as well as astroparticle physics.The report focuses in particular on Higgs boson, Top quark and electroweak precision physics, but also discusses several models of beyond the Standard Model physics such as Supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analyzed as well.

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.

Transition metal dihalide structures forming layered van der Waals materials exhibit often nontrivial magnetic order. Here studied 1T-NiI2 belongs to the family of multiferroic dihalides with the helical magnetic ground state order. The helical state in monolayer 1T-NiI2 differs from the cycloidal state in the bulk. Here we report that the ground state of 1T-NiI2 monolayer is the proper helix, which is uniquely given by the propagation vector of the helix. The calculated in-plane ferroelectric polarization points perpendicularly to the helical propagation vector. The microscopic mechanism for the polarization is the p-d hybridization of the iodine p-orbitals and nickel d-orbitals.

Measurements and numerical simulations on the charge transfer in Gas Electron Multiplier (GEM) foils are presented and their implications for the usage of GEM foils in Time Projection Chambers are discussed. A small test chamber has been constructed and operated with up to three GEM foils. The charge transfer parameters derived from the electrical currents monitored during the irradiation with an Fe-55 source are compared with numerical simulations. The performance in magnetic fields up to 2 T is also investigated.

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 ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{Z}}^{0}({M}_{{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{Z}}^{0}}<35\mathrm{GeV})$ or the ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}}^{\ifmmode\pm\else\textpm\fi{}}({M}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{W}}<25\mathrm{GeV})$.

FTIR spectroscopy holds significant untapped potential for materials analysis and laser characterization, but new developments are limited by the availability of simple, universal, and scalable components. Addressing this challenge, pyroelectric receivers PR No1 IR and PR No2 IR, and detectors ALUT3151 with sub-pixel binning and Diff ALUT3151 with additional true differential output have been developed. All models are based on thin LiTaO₃, cover a wide wavelength range, do not require cooling, and operate at high Detectivity (D*) in the kHz range while being rugged and linear over four orders of IR flux magnitude. In this paper, we will focus on recent results towards a people´s-FTIR with reduced TTWS (Time Towards Working Setup). Besides the detector, the thermal source and the beamsplitter have been identified as critical components.

We report on the measurements of charge transfer in Gas Electron Multipliers (GEM) structures in high magnetic fields. These were performed in the framework of the R&D work for a Time Projection Chamber at a future Linear Collider. A small test chamber has been installed in the aperture of a superconducting magnet with the GEM structures mounted perpendicular to the B-field direction. The charge transfer is derived from the electrical currents monitored during irradiation with an 55Fe source. No significant loss of primary ionisation charge is observed, and an improved ion feedback suppression is achieved for high magnetic fields. Additionally, the width of the charge cloud released by individual 55Fe photons is measured using a finely segmented strip readout after the triple GEM structure. Charge widths between 0.3 and 0.5mm RMS are observed, which originate from the charge broadening inside the GEM amplification. This charge broadening is only partly suppressed at high magnetic fields.

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

A bstract A search for new top quark interactions is performed within the framework of an effective field theory using the associated production of either one or two top quarks with a Z boson in multilepton final states. The data sample corresponds to an integrated luminosity of 138 fb − 1 of proton-proton collisions at $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 13 TeV collected by the CMS experiment at the LHC. Five dimension-six operators modifying the electroweak interactions of the top quark are considered. Novel machine-learning techniques are used to enhance the sensitivity to effects arising from these operators. Distributions used for the signal extraction are parameterized in terms of Wilson coefficients describing the interaction strengths of the operators. All five Wilson coefficients are simultaneously fit to data and 95% confidence level intervals are computed. All results are consistent with the SM expectations.

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.

We report on measurements of mass and total decay width of the W boson and of triple-gauge-boson couplings, γWW and ZWW, with the L3 detector at LEP. W-pair events produced in e+e− interactions between 161 GeV and 172GeV centre-of-mass energy are selected in a data sample corresponding to a total luminosity of 21.2 pb−1. The mass and total decay width of the W boson are determined to be MW = 80.75−0.27+0.26(exp.) ± 0.03 (LEP) GeV and ΓW = 1.74−0.78+0.88(stat.) ± 0.25(syst.)GeV, respectively. Limits on anomalous triple-gauge-boson couplings, γWW and ZWW, are determined, in particular −1.5 < δZ < 1.9 (95% CL), excluding vanishing ZWW coupling at more than 95% confidence level.

The Mark J Collaboration at the DESY e+e− collider PETRA presents results on the electroweak reactions e+e−→μ+μ−τ+τ−,μ+μ−γ, and e+e−μ+μ−. The c.m. energy range is 12 to 46.78 GeV. In the μ+μ− and τ+τ− channels the total cross sections and the forward-backward asymmetries are reported and compared with other experiments. The results are in excellent agreement with the standard model. The weak-neutral-current vector and axial-vector coupling constants are determined. The values for muons and τ’s are compatible with universality and with the predictions of the standard model. In the μ+μ−γ channel, all measured distributions, including the forward-backward muon asymmetry, are in excellent agreement with the electroweak theory. Our data on the two-photon process, e+e−μ+μ−, agrees with QED to order α4 over the entire energy range and the Q2 range from 0.7 to 166 GeV2.Received 29 April 1988DOI:https://doi.org/10.1103/PhysRevD.38.2665©1988 American Physical Society

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.

Proceedings of ISMD08

The L3 central tracking detector has been in operation since the start-up of LEP (Large Electron Positron collider) in 1989. This detector consists of a Time Expansion Chamber (TEC), a layer of Plastic Scintillating Fibers and a Z-chamber. The TEC gives a high spatial resolution and an excellent multi-track reconstruction capability. The fibers are designed to calibrate the drift velocity with high precision. The Z-Chamber provides TEC with accurate information about the z-coordinates of the tracks. A description of the design and the infrastructure of these three detectors, including the readout and data acquisition system, is given. The performance of the detectors during the 1990 and 1991 LEP running periods is presented.

The CMS and TOTEM experiments intend to carry out a joint diffractive/forward physics program with an unprecedented rapidity coverage. The present document outlines some aspects of such a physics program, which spans from the investigation of the low-x structure of the proton to the diffractive production of a SM or MSSM Higgs boson.

We report on measurements of a triple GEM (Gas Electron Multiplier) structure in high magnetic fields up to 5 T which were performed in the framework of the R&D work for a Time Projection Chamber at a future Linear Collider. The determination of charge transfer is performed using a triple GEM structure installed into a small test chamber which is irraditated with a 55Fe source. The measurements are parametrised using a functional depen- dence on the electric setup which was motivated by detailed numerical simulations of a GEM using the programs MAXWELL and GARFIELD. This parametrisation of a single GEM foil is extended to a model which describes the performance of the triple GEM structure and allows to predict the parameter setup leading to minimum ion backdrift. Applying this setup, ion backdrift of only 2.5 permille is achieved. Also the use of MHSPs (Micro Hole Strip Plates) for ion backdrift reduction is investigated. Setting an optimised negative strip voltage, a suppression factor of approximately 4 is reached at 4 T magnetic field. Additionally, the width of the charge cloud of individual 55Fe photons is measured using a fine segmented strip readout after the triple GEM structure. Charge widths between 0.2 and 0.3 mm RMS are observed, which appear to be dominated by the diffusion in the space between the individual GEMs. This charge broadening is partly suppressed at high magnetic fields.

The physics goals and the expected environment at the ILC requires the development of a detector with unprecedented tracking capabilities. A high-resolution TPC with gas amplification based on micro-pattern gas detectors is a promising candidate for the main tracker at the ILC detector. Significant progress has been achieved in the development of a TPC concept with Gas Electron Multipliers (GEM [F. Sauli, Nucl. Instr. and Meth. A 386 (1997) 531]) used for gas amplification. Significant ion backdrift reduction was obtained using special settings of the GEM structures. To further study the spatial resolution of a GEM-based TPC, a prototype with low-mass fieldcages was constructed. It was operated within a high-resolution silicon hodoscope. Additionally, extensive effort is spent on the development of an accurate numerical simulation of the TPC properties, such as drift, diffusion and gas amplification.

During the first six years of operation in the vicinity of the Z pole the four LEP experiments ALEPH, DELPHI, L3 and OPAL have collected approximately 14 million decays of the Z into hadrons and charged leptons. These data allow the precise determination of many parameters and stringent tests of the Standard Model of electroweak interactions. Among the outstanding results are the precise determination of the Z mass, mZ = 91 188.4 ± 2.2 MeV, the measurement of its total and partial decay widths to per mille accuracy and the definite conclusion that there are three different types of light neutrinos in the universe. From the measured asymmetries at LEP and SLC the effective weak mixing angle is derived to be sin2 ḡJw = 0.2314 ± 0.0003. The data support the concept of lepton universality and the axial-vector and vector coupling constants of charged leptons are determined to ḡAℓ = −0.5011 ± 0.0004 and ḡVℓ = −0.0380 ± 0.0007. Electroweak observables studied at the Z resonance are found to be in agreement with the Standard Model and from a common fit the mass of the top quark can be derived to be mt = 181−9 −20+8 +17(mH) GeV. This Standard Model prediction is now confirmed by the recent direct observation and mass measurement of the top quark in pp̄ experiments.

The strong interaction coupling constant αs has been measured with a new method, the planar triple energy correlation in the reaction e+e- → hadrons at center-of-mass energies ranging from 14 GeV to 46.78 GeV. A complete second-order perturbative QCD calculation was used. ΛMS = 110 ± 30 −55+70 MeV is found.

The vertex drift chamber of the L3 Experiment at LEP, based on the time expansion principle, was in operation from the start-up of LEP in 1989 until the shutdown of LEP in 2000. The gas mixture used was 80% CO2 and 20% i-C4H10 at a pressure of 1200mbar. We present the design of the chamber, the infrastructure and the performance during the 11 years of operation. The total radiation received on the anode wires was ∼10−4C/cm. No degradation of the anode pulse amplitude, wire efficiencies and resolution was observed for the whole running period.

A readout system for plastic scintillating fibers has been developed using a multi-anode microchannel photomultiplier tube operated in a 5 kG magnetic field and the CMOS MX4 microplexer chip. The microchannel photomultiplier tube with an anode array of 10×10 is coupled to an array of fibers using a precise alignment procedure. Each readout unit is capable of sampling signals from 100 fibers simultaneously and multiplexing the analog signals serially with rates of up to 5 MHz. The analog signals are subsequently digitized and subtracted from the pedestals previously stored using a specially designed analog to digital VME module. Such a readout system has many applications in high energy physics, solid state physics, and other fields where a large number of fibers must be read out in short times and at relatively high rates.

A large volume Time Projection Chamber (TPC) has been proposed as the main tracking device for one of the experiments at the International Linear Collider (ILC). Gas Electron Multipliers (GEMs) are being studied as potential replacements for the conventional wire-based gas amplification system of TPCs. In this paper, recent results are presented from R&D activities with small GEM–TPC prototypes ongoing at DESY.

The CMS Silicon Strip Tracker will be equipped with 16000 silicon microstrip detector modules covering a surface of approximately 200m2. The APV Readout Controller system was developed at RWTH Aachen, III. Physikalisches Institut in order to perform full readout tests of hybrids and modules at each production step. From the experience derived from initial module production, an automated fault finding algorithm has been developed which uses the full correlations between different electrical tests. The results of a recent production of over 250 Tracker Outer Barrel and 25 Tracker End Cap modules at UCSB demonstrate that the testing protocols are sufficient to find all known faults and that electrical module components produced have a high quality. The results are typical of all CMS tracker assembly and bonding sites.

The International Linear Collider (ILC) is now under consideration as the next global project in particle physics. In this report, we review of all aspects of the ILC program: the physics motivation, the accelerator design, the run plan, the proposed detectors, the experimental measurements on the Higgs boson, the top quark, the couplings of the W and Z bosons, and searches for new particles. We review the important role that polarized beams play in the ILC program. The first stage of the ILC is planned to be a Higgs factory at 250 GeV in the centre of mass. Energy upgrades can naturally be implemented based on the concept of a linear collider. We discuss in detail the ILC program of Higgs boson measurements and the expected precision in the determination of Higgs couplings. We compare the ILC capabilities to those of the HL-LHC and to those of other proposed e+e- Higgs factories. We emphasize throughout that the readiness of the accelerator and the estimates of ILC performance are based on detailed simulations backed by extensive RandD and, for the accelerator technology, operational experience.

We study the production of single γ, e and μ at high πt using the high energy data of the Mark-J detector at PETRA. We find good agreement with QED. We give mass limits of the SUSY particles γ̃, ṽ, ẽ and W̃ studying the associated production of W̃ and ẽ and radiative production of pairs of γ̃ or ṽ in three-body reactions.

Abstract The CMS tracker will be equipped with 16,000 silicon microstrip detector modules covering a surface of approximately 220 m 2 . For quality control, a compact and inexpensive DAQ system is needed to monitor the mass production in industry and in the CMS production centres. To meet these requirements a set-up called APV Readout Controller (ARC) system was developed and distributed among all collaborating institutes to perform full readout tests of hybrids and modules at each production step. The system consists of all necessary hardware components, C++ based readout software using LabVIEW 1 as graphical user interface and provides full database connection to track every single module component during the production phase. Two preseries of Tracker End Cap (TEC) silicon detector modules have been produced by the TEC community and tested with the ARC system at Aachen. The results of the second series are presented.

EUDET is an initiative supported by the European Union to improve infrastructures for detector R&D, in particular for the International Linear Collider (ILC). The project is focused on providing support for larger scale prototype experiments as well as on facilitating collaborative efforts. It encompasses developments for vertex detectors, gaseous and silicon tracking, and highly granular electromagnetic and hadron calorimeters. In total 32 European institutes participate in the project. 27 other institutes in Europe and abroad are associated members and linked to the progress and later exploitation of the infrastructures. EUDET is closely linked to the international R&D collaborations for a future ILC detector. The R&D infrastructure programme is described and some results of the R&D efforts are presented

The International Linear Collider (ILC) is the next large project in high energy physics and currently being designed in a global effort. The main scientific goal is to complement the anticipated discoveries at the LHC by precision measurements at the TeV scale. This has challenging implications on the ILC detector design and performance requiring unprecedented precision in vertexing, tracking and calorimetry. Design studies on four detector concepts are ongoing which are complemented by international R&D programmes to develop detectors suitable for the conditions at the collider and matching the required performances. A survey will be given on the detector concepts and technologies under investigation together with the current status of the R&D programmes and future plans.

The L3 vertex detector is comprised of the time expansion chamber (TEC), the Z-chamber and a layer of plastic scintillating fibers. The TEC has shown a high spatial resolution and an excellent multi-track reconstruction capability at LEP luminosity. The Z-chamber provides information about the z-coordinates of the tracks and the fibers are used for calibrating the drift velocity with a high precision. A description of the L3 vertex detector, its readout and data acquisition and its performance during the 1990 LEP running period is presented in this paper.

The performance of a readout system for the Synchrotron Radiation Detector (SRD) is studied. The detector is proposed as part of the Alpha Magnetic Spectrometer experiment, an experiment to fly on the International Space Station (ISS) beginning of 2005. The SRD is designed to detect the synchrotron radiation from electrons and positrons (TeV energy range) produced in the earth's magnetic field. For the planned array of scintillators and photomultipliers a readout system is chosen, which is compact, space qualified and has a low-power consumption. The low-power chip APV, originally designed for the CMS experiment at LHC (CERN), is foreseen for the readout. To overcome the diffuse background from photons and charged particles the SRD readout must have a time resolution better than 10 ns. The intrinsic time resolution (sigma from Gauss fit) of the APV25-S0 was found to be 0.46±0.01 and 0.68±0.02ns for the APVM, whereas the time resolution of the photomultiplier-APV readout system was measured to be 2.73±0.10ns for the APV25-S0 and 2.90±0.21ns for the APVM. The investigated timing capabilities of the photomultiplier-APV readout system show that the APV chip is suitable for the SRD readout.

In addition to the large discovery potential for Higgs bosons and new physics phenomena, like for instance Supersymmetry, experiments at the LHC will also be able to perform precise measurements of many Standard Model processes. The huge cross sections and the high collision energy will allow the exploration of less well tested areas of the Standard Model and to improve significantly on the precision of many parameters. Therefore the detailed experimental study of known Standard Model processes at the LHC will not only prepare the anticipated discoveries but also complement their interpretation. This article describes some selected items on the perspectives of the two general purpose detectors ATLAS and CMS on the determination of parton distribution functions, tests of QCD and electroweak physics at the highest energies and the physics of the top quark.

The Compact Muon Solenoid (CMS) is one of two general purpose detectors which are foreseen to operate at the Large Hadron Collider (LHC), which is presently being built at the European laboratory for particle physics (CERN) in Switzerland. The Central Tracker of CMS consists of a Pixel System, which is located close to the interaction point and a Silicon Strip Tracker (SST) which instruments the intermediate and outer region. The SST is composed of 15148 Silicon Microstrip Detector Modules which contain the readout electronics (hybrids) and sensors. These modules will be assembled into substructures with control electronics and optics for transmitting data. The substructures will be integrated into the subsystems of the SST. The SST will be operated for up to ten years in the harsh radiation environment of the LHC. The lifetime of the SST will be extended by operating the detector at lowered temperature. The sensors, which are very delicate with respect to radiation damage, will be operated at a maximum temperature of -10/spl deg/C. Since the assembly of the modules as well as the mounting on substructures is done at room temperature, tests in a CMS-like environment are necessary to prove the mechanical and electrical stability.

The proposals under discussion for a new e+e− Linear Collider with centre-of-mass energies around 1 TeV include designs for large detectors with unprecedented performances in energy, momentum and position resolution. These very stringent requirements are dictated by the precision measurements aimed at this collider to complement the exploratory experiments at the Large Hadron Collider. Here a status report on detector R&D projects for the Liner Collider is given focused on the technologies under study for the vertex detector, the large tracking chamber and the calorimeters.

The innermost region of the CMS detector will consist of silicon pixel and silicon microstrip detectors. One microstrip detector module is essentially composed of three elements: a set of silicon sensors, a mechanical support structure and the Front End Electronics (FE hybrid). During the production phase of the CMS tracking device, various quality and functionality tests of each detector component have to be performed to assure a stable tracker performance for a time scale of about 10 years of LHC running. This demands a chain of testing procedures beginning at the Hybrid component level and ending at the assembled module level. Each production and assembly step needs a specific testing environment and procedure (e.g. long- or short-term tests and temperature cyclings). A compact, cost efficient test and diagnostic tool which is suited for the operation and characterization of hybrids and silicon detector modules will be presented. The test setup is mainly composed of two printed circuit boards, one interface to the PC and the graphical user interface.

The Large Hadron Collider (LHC) at CERN started end of 2009 to provide first proton-proton collisions. The full scientific exploitation of the LHC commenced in spring 2010 with first collisions at the new record energy of 7 TeV in the proton-proton system. This article reviews first results and the status of the accelerator and experiments in April 2010 together with prospects for the coming years. The rapid progress made since then is not reflected here.

The goal of the EUDET project is the development and construction of infrastructure to permit detector R&D for the international linear collider (ILC) with larger scale prototypes. It encompasses major detector components: the vertex detector, the tracker and the calorimeters. We describe here the status and plans of the project with emphasis on issues related to data acquisition for future test beam experiments.

This document is motivated by the need of clarification of possible interference between the operation of PETRA III and the DESY test beam. The document is intended to describe shortly the DESY test beam performance and the expected conditions after the start-up of PETRA III. We evaluate the possible impact of PETRA III on the availability, the intensity, and the energy of the electrons/positrons provided to the test beam lines at DESY II. In the interest of a very large community of test beam users we intend to identify, and eventually resolve, possible conflicts between the two main programs of the DESY II machine, namely the filling of PETRA III and DORIS and the beam delivery to test beam facilities.

The case for the International Linear Collider and the prospects for its realisation as well as possible timelines are discussed.

The International Linear Collider (ILC) being proposed in Japan is an electron-positron linear collider with an initial energy of 250 GeV. The ILC accelerator is based on the technology of superconducting radio-frequency cavities. This technology has reached a mature stage in the European XFEL project and is now widely used. The ILC will start by measuring the Higgs properties, providing high-precision and model-independent determinations of its parameters. The ILC at 250 GeV will also search for direct new physics in exotic Higgs decays and in pair-production of weakly interacting particles. The use of polarised electron and positron beams opens new capabilities and scenarios that add to the physics reach. The ILC can be upgraded to higher energy, enabling precision studies of the top quark and measurement of the top Yukawa coupling and the Higgs self-coupling. The international -- including European -- interest for the project is very strong. Europe has participated in the ILC project since its early conception and plays a major role in its present development covering most of its scientific and technological aspects: physics studies, accelerator and detectors. The potential for a wide participation of European groups and laboratories is thus high, including important opportunities for European industry. Following decades of technical development, R&amp;D, and design optimisation, the project is ready for construction and the European particle physics community, technological centers and industry are prepared to participate in this challenging endeavour.

The case for the International Linear Collider and the prospects for its realisation as well as possible timelines are discussed.

We report on R&D work for a time projection chamber (TPC) at the International Linear Collider (ILC). A high resolution TPC with gas amplification based on micropattern gas detectors is one of the options for the main tracking system at the ILC detector. The physics to be studied and the environment at the ILC pose new challenges to the performance of all detector components. For instance the momentum resolution of the tracker should be improved by an order of magnitude with respect to LEP detectors. Significant progress towards this goal has been achieved recently and we report here on results of our groups which are studying a TPC concept with triple gas electron multiplier (GEM) structures for gas amplification. The required spatial resolution of 100 /spl mu/m has been achieved in measurements with a prototype TPC in high magnetic fields. The problem of ion backdrift has been studied and found to be significantly reduced in such GEM structures. In addition, a low mass TPC field cage has been designed and constructed demonstrating a way to minimise the total radiation length of the ILC tracker. A detailed simulation for a TPC has been developed. Simulations concerning the background at the ILC are ongoing.

Abstract This article summarises recent results obtained by the four experiments ALEPH, DELPHI, L3 and OPAL at the LEP e+e− collider. The experimental results discussed here comprise a summary of the measurements of electroweak observables at the Z resonance, the measurement of W-pair production from the threshold up to √s = 189 GeV and results from the searches for Higgs bosons and Supersymmetric particles at these highest energies attained in e+e− collisions.