Related papers: Extended Gauge Sectors at Multi-TeV e^+e^- Collide…
We describe how to probe new physics through examination of the form factors describing the Ztt couplings via the scattering process e^-e^+->t+tbar. We focus on experimental methods on how the top quark momentum can be determined and show…
We explore the production of vector leptoquarks ($V$) at the Tevatron, LHC, and SSC through both quark-antiquark and gluon fusion: $q \bar q, gg \to VV$. The cross sections are found to be somewhat larger than for scalar leptoquarks of the…
We study the production of gauge boson pairs at the next generation of linear $e^+e^-$ colliders operating in the $e\gamma$ mode. The processes $e\gamma \rightarrow VV^\prime F$ ($V,V^\prime =W$, $Z$, or $\gamma$ and $F=e$ or $\nu$) can…
Electron positron collisions are a very promising environment to search for new physics, and in particular for dark sector related observables. The most challenging experimental problem in detecting dark sector candidates is the very high…
We discuss the production, at high--energy e$^+$e$^-$ linear colliders, of new heavy fermions predicted by extensions of the Standard Model. We analyze in great details the various signals and the corresponding backgrounds for both pair…
The measurement of Standard Model processes tests the validity of the model at a given scale and is simultaneously sensitive to new physics through loop effects or interference with the Standard Model amplitudes. A variety of studies has…
Several models predict the existence of new resonances in the multi-TeV region, which should be accessible in e+e- collisions by s-channel production. In this paper, we review the phenomenology of some specific models and we present a…
The study of the top quark properties will be an integral part of any particle physics activity at future leptonic colliders. In this proceeding we discuss the possibility of testing composite Higgs scenarios at $e^+e^-$ prototypes through…
I discuss a proposal for a high intensity $e^+e^-$ linear collider operated at low center of mass energies $\sqrt{s}<5$ GeV with high intensity beams. Such a facility would provide high statistics samples of (charmed) vector mesons and…
We study direct searches of additional Higgs bosons in multi-top-quarks events at the LHC Run-II, its luminosity upgraded version with 3000 fb$^{-1}$, and the International Linear Collider (ILC) with the collision energy of 1 TeV.…
After the discovery of the Higgs boson in 2012, particle physics has entered an exciting era. An important question is whether the Standard Model of particle physics correctly describes the scalar sector realized by nature, or whether it is…
I survey the characteristics of hadron colliders as tools to investigate top-quark physics and to explore the 1-TeV scale of electroweak symmetry breaking.
Searches for new low-mass matter and mediator particles have actively been pursued at fixed target experiments and at $e^+e^-$ colliders. It is challenging at the CERN LHC, but they have been searched for in Higgs boson decays and in $B$…
We study the sensitivity reach of $0.5-2$ TeV $e^+ e^-$ linear colliders in the context of the ADD model, in which gravity becomes strong at TeV scale. We include the real emission channel $e^+ e^- \to \gamma G$, as well as the…
Hard processes at the TeV scale exhibit enhanced (double log) EW corrections, that need resummation in view of the high level of precision of Next Linear Colliders. The fact that the weak sector is spontaneously broken causes some…
We bound the coupling of pseudo-scalar particles to Tr G^G_{QCD} using (the lack of) monojet plus missing E_T events at the Tevatron, and estimate the bounds obtainable from LHC. In addition, we revisit the bounds on the coupling to…
We study the possible experimental signatures resulting from a strongly-interacting electroweak sector at $e^-e^-$ colliders, emphasizing the signal enhancement by high beam polarization. We also discuss the unique role for operating the…
There exists a world--wide consensus for a future $e^+e^-$ Linear Collider in the energy range between $\sqrt{s}=500--1000$ GeV as the next large facility in HEP. The Linear Collider has a large physics potential for the discovery of new…
While the triplet-like Higgses up to a few hundred GeV masses are already excluded for a vast region of the model parameter space from the LHC searches, strikingly, there is a region of this parameter space that is beyond the reach of the…
We present a class of models in which the top quark, by mixing with new physics at a higher energy scale, is naturally heavier than the other standard model particles. We take this new physics to be extended color. Our models contain new…