Р. Тенчини

The pion form factor has been measured in the space-like q2 region 0.014 to 0.26 (GeV/c)2 by scattering 300 GeV pions from the electrons of a liquid hydrogen target. A detailed description is given of the apparatus, data analysis and corrections to the data. The mean square charge radius extracted from the data is model-dependent. We find that a form which includes a realistic description of the form factor phase gives a similar results to the naive pole form, and conclude 〈r2π〉 = 0.438±0.008 fm2.

We propose a new experiment to measure the running of the electromagnetic coupling constant in the space-like region by scattering high-energy muons on atomic electrons of a low-Z target through the elastic process $$\mu \, e \rightarrow \mu \, e$$ . The differential cross section of this process, measured as a function of the squared momentum transfer $$t=q^2<0$$ , provides direct sensitivity to the leading-order hadronic contribution to the muon anomaly $$a^\mathrm{{HLO}}_{\mu }$$ . By using a muon beam of 150 GeV, with an average rate of $$\sim $$ 1.3 $$\times 10^7$$ muon/s, currently available at the CERN North Area, a statistical uncertainty of $$\sim $$ 0.3% can be achieved on $$a^\mathrm{{HLO}}_{\mu }$$ after two years of data taking. The direct measurement of $$a^\mathrm{{HLO}}_{\mu }$$ via $$\mu e$$ scattering will provide an independent determination, competitive with the time-like dispersive approach, and consolidate the theoretical prediction for the muon g-2 in the Standard Model. It will allow therefore a firmer interpretation of the measurements of the future muon g-2 experiments at Fermilab and J-PARC.

The negative kaon electromagnetic form factor has been measured in the space-like q2 range 0.015–0.10 (GeV/c)2 by the direct scattering of 250 GeV kaons from electrons at the CERN SPS. It is found that the kaon mean square charge radius 〈r2K〉 = 0.34 ± 0.05 fm2. From data collected simultaneously for πe scattering, the difference between the charged pion and kaon mean square radii (which is less sensitive to systematic errors) is found to be 〈r2π〉 − 〈r2K = 0.1 0 ± 0.045 fm2.

We report a measurement of the negative pion electromagnetic form factor in the range of space-like four-momentum transfer 0.014 < q2 < 0.122 (GeV/c)2. The measurement was made by the NA7 collaboration at the CERN SPS, by observing the interaction of 300 GeV pions with the electrons of a liquid hydrogen target. The form factor is fitted by a pole form with a pion radius of 〈r2〈12 = 0.657 ± 0.012 fm.

The EM form factor of the pion has been studied in the time-like region by measuring σ(e+e− → π+π−) normalized to σ(e+e− → μ+μ−). Results have been obtained for q2 down to the physical threshold.

The ϱ− radiative decay width has been measured by studying the production of ϱ− via the Primakoff effect by 200 GeV incident π− on Cu and Pb targets. This width was obtained by fitting the measured dσ/dt for ϱ production with the theoretical coherent differential cross section including both the electromagnetic and strong contributions. The measured radiative width value is 81 ± 4 ± 4 keV: it is consistent with the ratio Γ(ϱ → πγ)/Γ(ω → πγ) ∼ case:19 as expected from the vector dominance and the quark model.

Multiple scattering effects of 12 and 20 GeV electrons on 8 and 20 mm thickness carbon targets have been studied with high-resolution silicon microstrip detectors of the UA9 apparatus at the H8 line at CERN . Comparison of the scattering angle between data and GEANT4 simulation shows excellent agreement in the core of the distributions leaving some residual disagreement in the tails.

In 2018, a test run with muons in the North Area at CERN was performed, running parasitically downstream of the COMPASS spectrometer. The aim of the test was to investigate the elastic interactions of muons on atomic electrons, in an experimental configuration similar to the one proposed by the project MUonE, which plans to perform a very precise measurement of the differential cross-section of the elastic interactions. COMPASS was taking data with a 190 GeV pion beam, stopped in a tungsten beam dump: the muons from these pions decays passed through a setup including a graphite target followed by 10 planes of Si tracker and a BGO crystal electromagnetic calorimeter placed at the end of the tracker. The elastic scattering events were analysed, and compared to expectations from MonteCarlo simulation.

This review summarizes the results of the activities which have taken place in 2014 within the Standard Model Working Group of the “What Next” Workshop organized by INFN, Italy. We present a framework, general questions, and some indications of possible answers on the main issue for Standard Model physics in the LHC era and in view of possible future accelerators.

This document answers in simple terms many FAQs about FCC-ee, including comparisons with other colliders. It complements the FCC-ee CDR and the FCC Physics CDR by addressing many questions from non-experts and clarifying issues raised during the European Strategy symposium in Granada, with a view to informing discussions in the period between now and the final endorsement by the CERN Council in 2020 of the European Strategy Group recommendations. This document will be regularly updated as more questions appear or new information becomes available.

The first observation of neutral pion production in πe inelastic scattering is presented. The cross section at 300 GeV for |t‖>62;10−3 (GeV / c)2 is 2.11 ± 0.47 nb, in good agreement with the theory of PCAC anomalies with 3 quark colours.

The first stage of the FCC (Future Circular Collider) is a high-luminosity electron-positron collider (FCC-ee) with centre-of-mass energy ranging from 88 to 365 GeV, to study with high precision the Z, W, Higgs and top particles, with samples of $5 \times 10^{12}$ Z bosons, $10^8$ W pairs, $10^6$ Higgs bosons and $10^6$ top quark pairs. A cornerstone of the physics program lays in the precise (ppm) measurements of the W and Z masses and widths, as well as forward-backward asymmetries. To this effect the centre-of-mass energy distribution should be determined with the high precision. This document describes the capacity offered by FCC-ee, starting with transverse polarization of the beams around the Z pole and the W pair threshold. A running scheme based on regular measurements of the beam energy by resonant depolarization of pilot bunches, during physics data taking, is proposed. The design for polarization wigglers, polarimeter and depolarizer is outlined. The $e^\pm$ beam energies will be monitored with a relative precision of $10^{-6}$. The centre-of-mass energy is derived subject to further corrections, related to the beam acceleration, synchrotron radiation and beamstrahlung; these effects are identified and evaluated. Dimuon events $e^+e^- \to \mu^+ \mu^-$, recorded in the detectors, provide with great precision the beam crossing angle, the centre-of-mass energy spread, and the $e^+$ and $e^-$ energy difference. Monitoring methods to minimize absolute error and relative uncertainties are discussed. The impact on the physics measurements is given. A programme of further simulations, design, monitoring and R&D is outlined.

Resolution and linearity of the position measurement of Pisa multi-electrode silicon detectors are presented. The detectors are operated in slightly underdepleted mode and take advantage of their intrinsic resistivity for resistive charge partition between adjacent strips. 22 μm resolution is achieved with readout lines spaced 300 μm. Possible applications in colliding beam experiments for the detection of secondary vertices are discussed.

A new GeSi active target is presently used in the NA1 experiment at CERN to study photoproduction of charmed particles and to measure their lifetimes. Some general comments on the active target technique are made.

The first stage of the FCC (Future Circular Collider) is a high-luminosity electron-positron collider (FCC-ee) with centre-of-mass energy ranging from 88 to 365 GeV, to study with high precision the Z, W, Higgs and top particles, with samples of $5 \times 10^{12}$ Z bosons, $10^8$ W pairs, $10^6$ Higgs bosons and $10^6$ top quark pairs. A cornerstone of the physics program lays in the precise (ppm) measurements of the W and Z masses and widths, as well as forward-backward asymmetries. To this effect the centre-of-mass energy distribution should be determined with the high precision. This document describes the capacity offered by FCC-ee, starting with transverse polarization of the beams around the Z pole and the W pair threshold. A running scheme based on regular measurements of the beam energy by resonant depolarization of pilot bunches, during physics data taking, is proposed. The design for polarization wigglers, polarimeter and depolarizer is outlined. The $e^\pm$ beam energies will be monitored with a relative precision of $10^{-6}$. The centre-of-mass energy is derived subject to further corrections, related to the beam acceleration, synchrotron radiation and beamstrahlung; these effects are identified and evaluated. Dimuon events $e^+e^- \to \mu^+ \mu^-$, recorded in the detectors, provide with great precision the beam crossing angle, the centre-of-mass energy spread, and the $e^+$ and $e^-$ energy difference. Monitoring methods to minimize absolute error and relative uncertainties are discussed. The impact on the physics measurements is given. A programme of further simulations, design, monitoring and R&D is outlined.

The active detectors of the ALEPH hadron calorimeter at LEP consist of plastic streamer tubes developed in Frascati. The standard gas mixture for the operation of such devices is argon-isobutane (3070). However, in underground experiments, for safety reasons, one has to reduce the hydrocarbon content. Therefore a study of the behaviour of streamer tubes operated with a Ar/CO2/n-pentane mixture has been performed. The influence of gas composition on efficiency, charge distribution and stability of operation has been investigated, and the results of these tests are presented.

A measurement of the lifetime of theΛ c baryon photoproduced coherently off a Germanium-Silicon target is presented. A signal ofΛ c →ΔK*→pKππ0 has been observed and the two different decay diagrams for this process are compared. A sample of 9Λ c decays gives a lifetime of 1.1 −0.4 +0.8 10−13 s.

The precise measurement of physics observables and the test of their consistency within the standard model (SM) are an invaluable approach, complemented by direct searches for new particles, to determine the existence of physics beyond the standard model (BSM). Studies of massive electroweak gauge bosons (W and Z bosons) are a promising target for indirect BSM searches, since the interactions of photons and gluons are strongly constrained by the unbroken gauge symmetries. They can be divided into two categories: (a) Fermion scattering processes mediated by s- or t-channel W/Z bosons, also known as electroweak precision measurements; and (b) multi-boson processes, which include production of two or more vector bosons in fermion-antifermion annihilation, as well as vector boson scattering (VBS) processes. The latter categories can test modifications of gauge-boson self-interactions, and the sensitivity is typically improved with increased collision energy. This report evaluates the achievable precision of a range of future experiments, which depend on the statistics of the collected data sample, the experimental and theoretical systematic uncertainties, and their correlations. In addition it presents a combined interpretation of these results, together with similar studies in the Higgs and top sector, in the Standard Model effective field theory (SMEFT) framework. This framework provides a model-independent prescription to put generic constraints on new physics and to study and combine large sets of experimental observables, assuming that the new physics scales are significantly higher than the EW scale.

These proceedings collect the presentations given at the first three meetings of the INFN "Workshop on Monte Carlo's, Physics and Simulations at the LHC", held at the Frascati National Laboratories in 2006. The first part of these proceedings contains pedagogical introductions to several basic topics of both theoretical and experimental high pT LHC physics. The second part collects more specialised presentations.

The Standard Model of Electroweak Interactions Z Physics at Tree Level Z Physics at One Loop for Final Leptonic States Z Physics at One Loop for Final Hadronic States Accelerators and Detectors for Z and W Physics The Z Lineshape Z Decays to Heavy Quarks Asymmetries at the Z Pole Electroweak Measurements with W Bosons The Top Quark and Its Mass The Search for the Higgs Boson and Tests of the Electroweak Interaction Conclusions and Perspectives.

The prospects for electroweak precision measurements at the Future Circular Collider with electron-positron beams (FCC-ee) are discussed. The Z mass and width, as well as the value of the electroweak mixing angle, can be measured with very high precision at the Z pole thanks to an instantaneous luminosity five to six order of magnitudes larger than LEP. At centre-of-mass energies around 160 GeV, corresponding to the WW production threshold, the W mass can be determined very precisely with high-statistics cross section measurements at several energy points. Similarly, a very precise determination of the top mass can be provided by an energy scan at the $\mathrm{t \bar t}$ production threshold, around 350 GeV.

The measurements of the properties of the $Z$ boson performed with the large data samples collected at LEP and SLC challenge the standard model of the electroweak interaction with unprecedented precision. The $Z$ mass is measured to 2 parts in ${10}^{5},$ while other relevant electroweak observables such as the electroweak mixing angle, which is related to the strength of the neutral current, are measured with an accuracy of 1 part in ${10}^{3}.$ At this level of precision the effects of electroweak radiative corrections and in particular of the nontrivial loop contributions are visible. Assuming the validity of the standard model, the top mass can be predicted with a precision of about 10% and with a value in good agreement with the direct measurements. The global fit of electroweak data constrains the mass of the Higgs boson, giving an indirect indication of a relatively light Higgs. The overall agreement of the data with the predictions of the standard model is good, considerably limiting the room available for new physics. This paper describes the experimental techniques that led to such a thorough test of the electroweak theory. The basic theoretical concepts are reviewed and the measurements compared with theoretical predictions.

The CMS Physics Analysis Toolkit (PAT) is presented. The PAT is a high-level analysis layer enabling the development of common analysis efforts across and within Physics Analysis Groups. It aims at fulfilling the needs of most CMS analyses, providing both ease-of-use for the beginner and flexibility for the advanced user. The main PAT concepts are described in detail and some examples from physics analyses are given.

Measurements of the forward-backward production asymmetry of heavy quarks in Z decays provide a precise determination of $\sin^2\!\theta_{\rm{W,eff}}^{\rm{lept}}$ . The asymmetries are sensitive to QCD effects, in particular hard gluon radiation. In this paper QCD corrections for $A_{\mathrm{FB}}^{{b\bar{b}}}$ and $A_{\mathrm{FB}}^{{c\bar c}}$ are discussed. The interplay between the experimental techniques used to measure the asymmetries and the QCD effects is investigated using simulated events. A procedure to estimate the correction needed for experimental measurements is proposed, and some specific examples are given.

The response to pions of an ALEPH electromagnetic calorimeter petal combined with the ALEPH hadron calorimeter prototype has been studied in the energy range between 2 and 30 GeV. The resolution of the combined calorimeters was found to be lower than that for the hadron calorimeter alone at low energies and approached this value at higher energies.

Multi-electrode germanium detectors are being used as an active target for decay path measurements of charmed mesons. The procedure used to fabricate such detectors is described and a brief analysis of their performance is given.

The four LEP experiments ALEPH, DELPHI, L3 and OPAL successfully recorded e+e- collision data during the years 1989 to 2000. As part of the ordinary evolution in High Energy Physics, these experiments can not be repeated and their data is therefore unique. This article briefly reviews the data preservation efforts undertaken by the four experiments beyond the end of data taking. The current status of the preserved data and associated tools is summarised.

This Report summarizes the results of the activities in 2014 of the Standard Model Working Group within the workshop "What Next" of INFN. We present a framework, general questions, and some indications of possible answers on the main issue for Standard Model physics in the LHC era and in view of possible future accelerators.

This note presents a combination of published and preliminary electroweak results from the four LEP collaborations and the SLD collaboration which were prepared for the 2004 summer conferences. Averages from Z resonance results are derived for hadronic and leptonic cross sections, the leptonic forward-backward asymmetries, the {tau} polarization asymmetries, the b{bar b} and c{bar c} partial widths and forward-backward asymmetries and the q{bar q} charge asymmetry. Above the Z resonance, averages are derived for di-fermion cross sections and forward-backward asymmetries, photon-pair, W-pair, Z-pair, single-W and single-Z cross sections, electroweak gauge boson couplings, W mass and width and W decay branching ratios. Also, an investigation of the interference of photon and Z-boson exchange is presented, and colour reconnection and Bose-Einstein correlation analyses in W-pair production are combined. The main changes with respect to the experimental results presented in summer 2003 are updates to the W branching fractions and four-fermion cross sections measured at LEP-2, and the SLD/LEP heavy-flavour results measured at the Z pole. The results are compared with precise electroweak measurements from other experiments, notably the final result on the electroweak mixing angle determined in neutrino-nucleon scattering by the NuTeV collaboration, the latest result in atomic parity violation in Caesium, and the measurement of the electroweak mixing angle in Moller scattering. The parameters of the Standard Model are evaluated, first using the combined LEP electroweak measurements, and then using the full set of high-Q{sup 2} electroweak results.

The data collected by the LHC experiments are unique and present an opportunity and a challenge for a long-term preservation and re-use. The CMS experiment has defined a policy for the data preservation and access to its data and is starting its implementation. This note describes the driving principles of the policy and summarises the actions and activities which are planned in the starting phase of the project.

We report the characterisation and performance of a low cost muon tracking system consisting of plastic scintillator bars and Silicon Photomultipliers equipped with a customised front-end electronics based on a fast preamplifier network. This system can be used as a detector test bench for astroparticle physics and for educational and outreach purposes. We investigated the device behaviour in self-trigger and coincidence mode, without using LED and pulse generators, showing that with a relatively simple set up a complete characterisation work can be carried out. A high definition oscilloscope, which can easily be found in many university physics or engineering departments, has been used for triggering and data acquisition. Its capabilities have been exploited to discriminate real particles from the background.

A measurement of the lifetime of D0-mesons photoproduced coherently off a germanium target is presented. Signals have been observed for the production of D0 into several channels and for D*+ → D0π+. A sample of 58 D0 decays gives a lifetime of (3.4−0.5+0.6 ± 0.3) · 10−13 s.

This document answers in simple terms many FAQs about FCC-ee, including comparisons with other colliders. It complements the FCC-ee CDR and the FCC Physics CDR by addressing many questions from non-experts and clarifying issues raised during the European Strategy symposium in Granada, with a view to informing discussions in the period between now and the final endorsement by the CERN Council in 2020 of the European Strategy Group recommendations. This document will be regularly updated as more questions appear or new information becomes available.

In this paper the capability of GHEISHA as hadron shower generator is investigated and discussed by comparing the test run data from the ALEPH hadron calorimeter prototype with the Monte Carlo simulation developed in the GEANT3 framework. The results on muon, electron and pion simulation are reported. The longitudinal development of hadron showers is well reproduced and saturation effects are also explained. The resolution of the calorimeter for incident pions as computed by the Monte Carlo method is slightly larger than what observed.

The status of the construction of the Compact Muon Solenoid (CMS), a multi-purpose detector due to operate at the Large Hadron Collider, is briefly discussed. Details are given on the recent steps forward in the construction of the Silicon Strip Tracker, the Electromagnetic Calorimeter and the superconducting magnet. The rôle of CMS as a tool for b physics is briefly outlined.

Hadronic showers in an iron-streamer tube sampling calorimeter have been studied for energies ranging between 3 and 25 GeV. Longitudinal and transverse energy distributions have been parametrized and compared with those determined for iron-scintillator calorimeters.

The impressive progress on the knowledge of lepton and quark electroweak couplings over the LEP and SLC decade is reviewed.The experimental methods for measuring the forward-backward asymmetry of charged-fermion pairproduction are described, for different fermion species.The precise measurements of the left-right asymmetry and of tau polarisation at the Z resonance are also reminded.After discussing the determination of the Weinberg electroweak mixing angle, lepton and quark couplings are extracted by combining asymmetry and polarisation measurements with measurements of partial decay widths of the Z boson, performed at LEP in the same years.

The prospects for electroweak precision measurements at the Future Circular Collider with electron-positron beams (FCC-ee) are discussed. The Z mass and width, as well as the value of the electroweak mixing angle, can be measured with very high precision at the Z pole thanks to an instantaneous luminosity five to six order of magnitudes larger than LEP. At centre-of-mass energies around 160 GeV, corresponding to the WW production threshold, the W mass can be determined very precisely with high-statistics cross section measurements at several energy points. Similarly, a very precise determination of the top mass can be provided by an energy scan at the tt‾ production threshold, around 350 GeV.

Because of a luminosity of up to five orders of magnitude larger than at LEP, electroweak precision measurements at the FCC-ee -- the Future Circular Collider with electron-positron beams -- would provide improvements by orders of magnitude over the present status and constitute a broad search for the existence of new, weakly interacting particles up to very high energy scales. The FCC-ee will address centre-of-mass energies ranging from below the Z pole to the $\mathrm{t\bar{t}}$ threshold and above. At energies around the Z pole, the Z-boson mass and width can be measured to better than 100 keV each. Asymmetry measurements at the Z pole allow improvements in the determination of the weak mixing angle by at least a factor 30 to $\delta\sin^2\theta\mathrm{_W^{eff}}\simeq 6\times 10^{-6}$. A determination of the electromagnetic coupling constant at the Z energy scale, $\alpha_\mathrm{QED}(m_\mathrm{Z}^2)$, to a relative precision of $3\times 10^{-5}$ can be obtained via measurement of the forward-backward asymmetry of lepton pairs at two energy points $\pm 3.2\,\textrm{GeV}$ away from the Z peak. At energies around the WW threshold, high-statistic cross section measurements can provide a determination of the W mass to 300 keV. The key breakthrough advantage of the FCC-ee in these achievements, beside the large luminosity, is the possibility of a continous, precise determination of the beam energy by resonant depolarization at the Z peak and at the WW threshold. Precise measurements of the hadronic branching fractions of the Z and W bosons allow for considerably improvements in the determination of the strong coupling constant down to a precision of $\delta\alpha_\mathrm{s}(m_\mathrm{Z}^2)\simeq 0.0001$. An energy scan around the 350 GeV $\mathrm{t\bar{t}}$ threshold allows a 10 MeV measurement of the top-quark mass.

The prospects for electroweak precision measurements at the Future Circular Collider with electron-positron beams (FCC-ee) are discussed. The Z mass and width, as well as the value of the electroweak mixing angle, can be measured with very high precision at the Z pole thanks to an instantaneous luminosity five to six order of magnitudes larger than LEP. At centre-of-mass energies around 160 GeV, corresponding to the WW production threshold, the W mass can be determined very precisely with high-statistics cross section measurements at several energy points. Similarly, a very precise determination of the top mass can be provided by an energy scan at the $\mathrm{t \bar t}$ production threshold, around 350 GeV.

The gas gain monitoring system of the Aleph hadron calorimeter is described. The dependence of the charge response to a) the ratio between the pressure to temperature and b) the gas mixture parameters (Ar/CO2 ratio and isobutane percentage) have been determined. The total gain variation is measured with a precision of about 0.4%.

The status of top physics at the Large Hadron Collider is discussed, with particular attention on measurements of top production cross sections, including associate production of top quarks and electroweak bosons, and on measurements of the top mass.

The inner portion of the CMS microstrip Tracker consists of 3540 silicon detector modules; its construction has been under full responsibility of seven INFN (Istituto Nazionale di Fisica Nucleare) and University laboratories in Italy. In this note procedures and strategies, which were developed and perfected to qualify the Tracker Inner Barrel and Inner Disks modules for installation, are described. In particular the tests required to select highly reliable detector modules are illustrated and a summary of the results from the full Inner Tracker module test is presented. 1) INFN sez. di Catania and Universita di Catania, Italy 2) INFN sez. di Perugia and Universita di Perugia, Italy 3) INFN sez. di Pisa and Scuola Normale Superiore di Pisa, Italy 4) INFN sez. di Pisa and Universita di Pisa, Italy 5) INFN sez. di Pisa, Italy 6) INFN sez. di Torino and Universita di Torino, Italy 7) INFN sez. di Torino, Italy 8) INFN sez. di Firenze, Italy 9) INFN sez. di Bari and Dipartimento Interateneo di Fisica di Bari, Italy 10) INFN sez. di Bari, Italy 11) INFN sez. di Padova, Italy 12) INFN sez. di Firenze and Universita di Firenze, Italy 13) INFN sez. di Padova and Universita di Padova, Italy 14) INFN sez. di Perugia, Italy a) On leave from ISS, Bucharest, Romania b) On leave from IFIN-HH, Bucharest, Romania c) Corresponding Author

These proceedings collect the presentations given at the first three meetings of the INFN "Workshop on Monte Carlo's, Physics and Simulations at the LHC", held at the Frascati National Laboratories in 2006. The first part of these proceedings contains pedagogical introductions to several basic topics of both theoretical and experimental high pT LHC physics. The second part collects more specialised presentations.

A short account of the conference summary is given, focused on new physics results presented during the parallel and plenary sessions at ICHEP2022.

The four LEP experiments ALEPH, DELPHI, L3 and OPAL successfully recorded e+e- collision data during the years 1989 to 2000. As part of the ordinary evolution in High Energy Physics, these experiments can not be repeated and their data is therefore unique. This article briefly reviews the data preservation efforts undertaken by the four experiments beyond the end of data taking. The current status of the preserved data and associated tools is summarised.

Prospects and opportunities for particle physics accelerators at the energy frontier are reviewed. In particular, the main features characterizing hadron and lepton collider facilities proposed at CERN and in other known laboratories are discussed. Представлены перспективы развития и возможности физики ускорителей в области сверхвысоких энергий. Основное внимание уделено рассмотрению возможностей адронных и лептонных коллайдеров, планируемых в ЦЕРНе и других мировых центрах.

The status of precision measurements in the electroweak sector is briefly reviewed. Emphasis is given on final LEP results using data collected at the Z and beyond the WW production threshold. A common analysis of electroweak observables sets at 260 GeV/c2 the upper limit on the mass of the Standard Model Higgs boson (95% CL). The current bounds on trilinear WWZ and WWγ anomalous couplings at LEP are discussed and compared with perspectives at future accelerators. The rôle of LHC as a top factory is briefly discussed.

This note presents a combination of published and preliminary electroweak results from the four LEP collaborations and the SLD collaboration which were prepared for the 1997 summer conferences. Averages are derived for hadronic and leptonic cross-sections, the leptonic forward-backward asymmetries, the {tau} polarisation asymmetries, the b{bar b} and c{bar c} partial widths and forward-backward asymmetries and the q{bar q} charge asymmetry. The major changes with respect to results presented last year are updated results of A{sub LR} from SLD, and the inclusion of the first direct measurements of the W mass and triple-gauge-boson couplings performed at LEP. The results are compared with precise electroweak measurements from other experiments. The parameters of the Standard Model are evaluated, first using the combined LEP electroweak measurements, and then using the full set of electroweak results.