Related papers: TLEP: A High-Performance Circular e+e- Collider to…
The Large Electron-Positron (LEP) collider experiments have constrained the mass of the Standard Model (SM) Higgs boson to be above 114.4 GeV. This bound applies to all extensions of the SM where the coupling of a Higgs boson to the Z boson…
The search for physics beyond the Standard Model motivates new high-energy accelerators, which will require high luminosities in order to produce interesting new heavy particles. Using the Higgs boson and supersymmetry as examples, we…
The problems of the origin of mass and of electro-weak symmetry breaking are central to the programme of research in particle physics, at present and in the coming decades. This paper reviews the potential of high energy, high luminosity…
``All future $e^+e^-$ Higgs factories have similar reach for the precise measurement of the Higgs boson properties.'': this popular statement has often led to the impression that all $\rm e^+e^-$ options are scientifically equivalent when…
A ring-based Higgs factory with a center-of-mass energy of 240 GeV residing in the existing LEP tunnel is studied at a level of concrete lattice. We found that low-emittance lattice is essential to mitigate the effect of beamstrahlung on…
The Large Hadron Collider, a 7 + 7 TeV proton-proton collider under construction at CERN (the European Laboratory for Particle Physics in Geneva), will take experiments squarely into a new energy domain where mysteries of the electroweak…
We describe the physics potential of $e^+e^-$ linear colliders in this report. These machines are planned to operate in the first phase at a center-of --mass energy of 500 GeV, before being scaled up to about 1 TeV. In the second phase of…
Assuming perturbativity up to a high energy scale $\sim 10^{16}$ GeV, we demonstrate that a future $e^+e^-$ linear collider operating at $\sqrt{s} =$ 500 GeV with $\int{\cal L}=$ 500 fb$^{-1}$ per year (such as the recently proposed TESLA…
The proposed $e^+e^-$ collider offers an ideal environment for precise estimation of Higgs boson properties which are of utmost importance to validate the Standard Model of particle physics. We investigate $hVV$ couplings, where $V\in…
We investigate the possibility of probing the triplet Higgs boson sector via single charged Higgs production in the process $e^+ e^- \to H^+ l \nu_l$, at high energy electron-positron colliders, using the tree level $H^+W^-Z$ coupling which…
This Snowmass 2021 contributed paper discusses a Higgs-Energy LEptoN (HELEN) $e^+e^-$ linear collider based on advances superconducting radio frequency technology. The proposed collider offers cost and AC power savings, smaller footprint…
The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have collected 2465 pb-1 of e+e- collision data at energies between 189 and 209 GeV, of which 542 pb-1 were collected above 206 GeV. Searches for the Standard Model Higgs boson have…
A search for the Standard Model Higgs boson has been performed with the OPAL detector at LEP based on the full data sample collected at sqrt(s) = 192-209 GeV in 1999 and 2000, corresponding to an integrated luminosity of approximately 426…
The latest preliminary results of the searches for Higgs bosons and Supersymmetric particles at LEP are reviewed. The results include the data-taking in 1999 up to center-of-mass energies of 196 GeV. The combination of the results from the…
As stated in the 2019 European Strategy for Particle Physics (ESPP), it is of the utmost importance that the HL-LHC upgrade of the accelerator and the experiments be successfully completed in a timely manner. All necessary efforts should be…
A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at a centre-of-mass energy of 188.6 GeV, corresponding to an integrated luminosity of 176.4 pb^-1. Higgs decays into a charm and a…
This report summarizes a study of the physics potential of the CLIC e+e- linear collider operating at centre-of-mass energies from 1 TeV to 5 TeV with luminosity of the order of 10^35 cm^-2 s^-1. First, the CLIC collider complex is…
The $s$-channel resonant production of the Higgs boson at a 125 GeV muon collider enables a unique way to determine the Higgs properties. However, a clear picture of the achievable Higgs precision has not yet been established. We perform a…
The electron-positron stage of the Future Circular Collider, FCC-ee, is a frontier factory for Higgs, top, electroweak, and flavour physics. It is designed to operate in a 100 km circular tunnel built at CERN, and will serve as the first…
In this talk we present a short overview of top physics at the electron-proton (ep) colliders. Currently, the proposed ep collider is the Large Hadron Electron Collider (LHeC), which is a combination of 60 GeV electron beam and 7 TeV proton…