Related papers: Physics case for an $e^+e^-$ collider at 500 GeV a…
Light higgsinos with mass ~100-400 GeV are well-motivated from naturalness considerations within supersymmetric models. However, at hadron colliders such as CERN LHC, they are rather difficult to search for due to the small visible energy…
The International Linear Collider (ILC) is a proposed electron -- positron collider with a collision energy of $\sqrt{s}$ = 500 GeV in the baseline configuration. The ILC physics program takes full advantage of the fact that the machine can…
The production and decay of heavy charged Higgs bosons at a 800 GeV e+e- linear collider have been studied. The analysis of the H+H- -> tb tb, expected to be dominant in the MSSM, and H+H- -> W+h0 W-h0 decay modes leading to the same final…
Physics issues at the upcoming and planned colliders are discussed. We critically review the the different arguments that suggest that New Physics is bound to materialise at the TeV scale and why we should keep an open minded approach. The…
``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…
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…
The physics at the planned $e^+e^-$ colliders is discussed around three main topics corresponding to different manifestations of symmetry breaking: $W$ physics in the no Higgs scenario, studies of the properties of the Higgs and precision…
We study double Higgs production in the $e^+ e^-$ and $\gamma \gamma$ modes of the linear collider. It is also shown how one can probe the scalar potential in these reactions. We discuss the effective longitudinal $W$ approximation in…
Two photon processes are a wonderful by-product of an $e^+e^-$ collider at any energy. Two photon reactions probe the very structure of matter. A machine operating below 2 GeV has the potential to reveal the Higgs sector of the strong…
We calculate the cross sections for the production of Higgs particles in association with a photon in $e^+ e^-$ collisions, $e^+ e^- \to \gamma+$Higgs, allowing for the longitudinal polarization of the initial electron and positron beams.…
Our goal is to investigate the charged Higgs phenomenology in the framework of 2HDM at the upcoming $e^+e^-$ and muon colliders. We are primarily concerned with the associated production processes with a fermion pair: $\ell^+ \ell^- \to…
A feasibility study of the measurement of the top-Higgs Yukawa coupling at a future linear e+e- collider operating at sqrt(s)=800 GeV is presented. As compared to previous existing studies, much effort has been put in a ``realistic…
We discuss the sensitivity of the processes e+e- to b b(bar), e+e- to t t(bar) and gamma gamma to H to certain residual New Physics interactions affecting the heavy quark and Higgs boson sector. With a linear collider of 500 GeV, one should…
High-energy data has been accumulating over the last ten years, and it should not be ignored when making decisions about the future experimental program. In particular, we argue that the electroweak data collected at LEP, SLC and Tevatron…
In this paper we compare $H^+H^-$ and $W^+W^-$ into four-fermion production at centre-of-mass energies typical of LEP2 and somewhat larger. The theoretical framework considered is the Minimal Supersymmetric Standard Model. The interest in…
We consider the possibility of a 120x120 GeV e+e- ring collider in the LHC tunnel. A luminosity of 10^34/cm2/s can be obtained with a luminosity life time of a few minutes. A high operation efficiency would require two machines: a low…
We study the effects of new physics in double Higgs production at future $e^+ e^-$ colliders. In the Standard Model the chiral limit ($m_e=0$) plays an important role for this process, being responsible for the smallness of the tree-level…
We studied the feasibility of measurement of Higgs pair creation in a gamma gamma collider. We found the optimum collision energy is around 270 GeV from the sensitivity study with Higgs boson mass of 120 GeV/c^2. Main backgrounds are gamma…
The littlest Higgs model with T-parity predicts the existence of the T-odd particles, which can only be produced in pair. We consider pair production of the T-odd leptons in future high energy linear $e^{+}e^{-}$ collider ($ILC$). Our…
Some of the most interesting Higgs-production processes at future e+ e- colliders are of the type e+ e- -> f anti-f H. We present a calculation of the complete O(alpha) corrections to these processes in the Standard Model for final-state…