Related papers: Supersymmetric Signals in Electron-Photon Collisio…
If in a supersymmetric model, the lightest chargino is nearly degenerate with the lightest neutralino, the former can decay into the latter alongwith a soft pion (or a lepton-neutrino pair). Near degeneracy of the chargino and neutralino…
The spin of supersymmetric particles can be determined at $e^+e^-$ colliders unambiguously. This is demonstrated for a characteristic set of non-colored supersymmetric particles -- smuons, selectrons, and charginos/neutralinos. The analysis…
We investigate a scenario inspired by natural supersymmetry, where neutrino data is explained within a low-scale seesaw scenario. For this the Minimal Supersymmetric Standard Model is extended by adding light right-handed neutrinos and…
At an e-\gamma collider, a selectron \tilde{e}_{L,R} may be produced in association with a (lightest) neutralino \tilde{\chi}_1. Decay of the selectron may be expected to yield a final state with an electron and another \tilde{\chi}_1. If…
The fundamental nature of Dark Matter remains one of the major mysteries of modern physics. Some models postulate the existence of a massive gauge boson, a "dark photon" ($A^\prime$), that may allow Dark Matter particles to interact with…
The chargino $\tilde{\chi}^\pm_{1,2}$ system can be reconstructed completely in $e^+e^-$ collisions. By measuring the total cross sections and the asymmetries with polarized beams in $e^+e^-\to\tilde{\chi}_i^+ \tilde{\chi}_j^- [i,j=1,2]$,…
Drees and Godbole have proposed that, at the interaction point of an e+e- linear collider, one expects a high rate of hadron production by gamma-gamma collisions, providing an additional background to studies in e+e- annihilation. Using a…
We confront the generally small cross sections for gluino pair production in e^+e^- annihilation with the much larger ones in photon-photon scattering at a multi-TeV linear collider like CERN CLIC. The larger rates and the steeper rise of…
It is shown that in a large class of E(6) models, either an e+e- collider operating at $\rs \geq 1.5$ TeV must find a signal for the production of exotic leptons, or a collider operating at $\rs \geq 300$ GeV must find at least one light…
A search for electroweak production of supersymmetric particles is performed in two-lepton and three-lepton final states using recursive jigsaw reconstruction. The search uses data collected in 2015 and 2016 by the ATLAS experiment in…
We consider the production of a single right-handed gauge boson $W_R$ in the high-energy $e^-\gamma$ collisions with polarized beams. If the associated neutrino is light, the reaction will give the best discovery reach for $W_R$ in the Next…
We investigate the sensitivity to the effective operators describing interactions between dark matter particles and photons at future high energy $e^+e^-$ colliders via the $\gamma+ \slashed{E}$ channel. Such operators could be useful to…
The STAR collaboration has observed an excess production of $e^+e^-$ pairs in relativistic heavy ion collisions, over the expectations from hadronic production models. The excess pairs have transverse momenta $p_T < 150\ {\rm MeV}/c$ and…
Two photons can annihilate into a neutral pion-like resonance via the anomaly coupling, just like $\pi^0\gamma\gamma$ in QCD. In some strongly interacting electroweak symmetry breaking models, e.g., technicolor type models, there often…
The emission of $\nu\bar\nu$ pairs off electrons in a polarized ultra-intense electromagnetic (e.g.\ laser) wave field is analyzed. We elaborate on the significance of non-linear electrodynamics effects (i.e., multi-photon processes) and…
The top-charm associated productions via $e^+ e^-$, $e^- \gamma$ and $\gamma \gamma$ collisions at linear colliders, which are extremely suppressed in the Standard Model (SM), could be significantly enhanced in some extensions of the SM. In…
In this work we advocate a set of novel azimuthal-angle-related observables associated with exclusive hadron production from two-photon fusion at $e^+ e^-$ colliders, taking the $\gamma\gamma\to \pi\pi$ as a benchmark process. As a direct…
When dense high-energy lepton bunches collide, the beam particles can experience rest-frame electromagnetic fields which greatly exceed the QED critical one. Here it is demonstrated that beamstrahlung efficiently converts lepton energy to…
If sneutrinos are the lightest supersymmetry partners and $R$-parity is not conserved, the process $e^+e^- \to \tilde {\bar\nu} \tilde {\nu}$ can have striking signatures due to the decay modes $\tilde{\nu}\to\ell^+\ell'^-$ or…
Single $W$-boson production in $e^-\gamma$ collisions with polarized beams is investigated. In the framework of the Standard Model the updated estimates for the measurement precision of photon anomalous coupling parameters $ \kappa_{…