Related papers: LEP $e^{+}\,e^{-}\,\rightarrow\,\mu^{+}\, \mu^{-}\…
We derive the low-energy electroweak effective lagrangian for the case of additional heavy, unmixed, sequential fermions. Present LEP1 data still allow for the presence of a new quark and/or lepton doublet with masses greater than $M_Z/2$,…
Gravity can become strong at the TeV scale in the theory of extra dimensions. An effective Lagrangian can be used to describe the gravitational interactions below a cut-off scale. In this work, we study the associated production of the…
We study the potentiality of the CERN Large Hadron Collider (LHC) to unravel the existence of first generation scalar leptoquarks. Working with the most general $SU(2)_L \otimes U(1)_Y$ invariant leptoquark interactions, we analyze in…
The discovery potential for detecting new heavy Majorana and Dirac neutrinos at some recently proposed high energy $e^+e^-$ colliders is discussed. These new particles are suggested by grand unified theories and superstring-inspired models.…
The production of three electroweak gauge bosons in high-energy $e^+e^-$ collisions offers a window on anomalous quartic gauge boson couplings. We investigate the effect of three possible anomalous couplings on the cross sections for…
We report the first search for a non-standard-model resonance decaying into $\tau$ pairs in $e^{+}e^{-}\rightarrow \mu^{+}\mu^{-} \tau^+\tau^-$ events in the 3.6-10 GeV/$c^{2}$ mass range. We use a 62.8 fb$^{-1}$ sample of $e^+e^-$…
We study the possible signature for lepton-flavor violation processes in the scalar-lepton sector of the minimal supersymmetric model at future electron-photon colliders. We find that an $\egm$ collider can provide a good opportunity to…
Strange multi-baryonic clusters are an exiting possibility to explore the properties of cold dense baryonic matter. Recent results on searches for exotic narrow resonances with $\Lambda$ hyperon subsystems are reviewed. The observation of…
We present a numerical estimate of the $\gamma^* \gamma^*$ total cross section at the designed 500 GeV $e^+e^-$ Linear Collider, based upon the BFKL Pomeron. We find that the event rate is substantial provided electrons scattered under…
The expected experimental precision of the rates and asymmetries in the Future Circular Collider with electron positron beams (FCC-ee) in the centre of the mass energy range 88-365GeV considered for construction in CERN, will be better by a…
The physics potential of discovering and exploring supersymmetry at future e^+e^- linear colliders is reviewed. Such colliders are planned to start to operate at a center-of-mass energy of 500 GeV to 800 GeV, with a final energy of about 2…
A search for $\bar\nu_{\mu}\to \bar\nu_{e}$ oscillations has been conducted at the Los Alamos Meson Physics Facility by using $\bar\nu_\mu$ from $\mu^+$ decay at rest. The $\bar\nu_e$ are detected via the reaction $\bar\nu_e\,p \rightarrow…
This paper studies the possibility to measure the centre of mass energy using e+e- -> Z,gamma -> mu+mu-,gamma events at the ILC. With L = 100 fb^-1 at sqrt(s) = 350 GeV a relative error of around 10^{-4} is possible. The potentially largest…
We examine various aspects of supersymmetric particle production at linear $e^+e^-$ colliders operating at a centre of mass energy of $\sqrt{s}=500$ GeV, and integrated luminosity of $\int {\cal L}dt=20-50$ fb$^{-1}$. Working within the…
An electron-positron collider operating at a center-of-mass energy $E_{CM}$ can collect events at all lower energies through initial-state radiation (ISR or radiative return). We explore the capabilities for radiative return studies by a…
The complete tree level cross section for the process $e^+e^- \to e^- \bar\nu_e u \bar{d}$ is computed using the GRACE system, a program package for automatic amplitude calculation. Special attention is brought to the gauge violation…
Complementary to the conventional experimental studies on $N^*$ from $\pi N$ and $\gamma^{(*)}N$ reactions, the $e^+e^-$, $pp$ and $p\bar p$ collisions can give novel insights into these $N^*$ resonances. While the $e^+e^-$ collisions…
This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e+e- -> ffbar process for centre-of-mass energies above the Z resonance, from sqrt(s) ~ 130 -…
We classify the possible deviations from the Standard Model in the QED-dominated $\mathrm{e^+e^-}\rightarrow\gamma\gamma$ process under the assumption of a preserved $SU(2)_L \times U(1)_Y$ symmetry. We find that the only deviations really…
In this paper, we present detailed studies on the feasibility at $pp$, $e^-p$ and $e^+e^-$ colliders for model-independent sensitivity estimates on the total cross-section and on the anomalous $\tau^+\tau^-\gamma$ interaction through the…