Related papers: Bileptons - Present Constraints and Future Prospec…
A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at centre-of-mass energies between 192 and 202 GeV, corresponding to an integrated luminosity of 233.2 pb^-1. Decays into a charm…
I give an overview on models that extend the Standard Model scalar sector by additional gauge singlets or multiplets. I discuss current constraints on such models, as well as possible signatures and discovery prospects at current and future…
The recent analysis of nuclear distortions in DIS off nuclei revealed a breaking of the conventional hard factorization for multijet observable. The related pQCD analysis of distortion effects for jet production in nucleus-nucleus…
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…
The presence of extra scalar singlets is a feature of several motivated extensions of the Standard Model, and the mixing of such a singlet with the Higgs boson is allowed to be quite large by current experiments. In this paper we perform a…
We study the discovery prospects for a doubly charged Higgs boson $H^{\pm\pm}$ in the 2-Higgs Doublet Model with type-II seesaw (2HDMcT) at future $e^+e^-$ colliders. Focusing on the three-body channels $e^+e^- \to…
A search for beyond the standard model spin-0 bosons, $\phi$, that decay into pairs of electrons, muons, or tau leptons is presented. The search targets the associated production of such bosons with a W or Z gauge boson, or a top…
We revisit the theory and constraints on axion-like particles (ALPs) interacting with leptons. We clarify some subtleties in the constraints on ALP parameter space and find several new opportunities for ALP detection. We identify a…
Doubly-charged Higgs bosons ($\Delta^{--}/\Delta^{++}$) appear in several extensions to the Standard Model and can be relatively light. We review the theoretical motivation for these states and present a study of the discovery reach in…
During the LEP2 period the e+e- collider increased its center of mass energy from 161 GeV to 209 GeV and a total integrated luminosity of approximately 700 pb-1 was recorded per experiment. Pairs of W bosons are produced and allow the study…
Scalar partners of quarks and leptons, predicted in supersymmetric models, are searched for in e^+e^- collisions at centre-of-mass energies between 192GeV and 209GeV at LEP. No evidence for any such particle is found in a data sample of 450…
We examine, as model-independently as possible, the production of bileptons at hadron colliders. When a particular model is necessary or useful, we choose the 3-3-1 model. We consider a variety of processes: q anti-q -> Y^{++} Y^{--}, u…
The number of leptons may or may not be a conserved quantity. The Standard Model predicts that it is (in perturbative processes), but there is the well known possibility that new physics violates lepton number in one or two units. The first…
Discovering CP-violating effects in the Higgs sector would constitute an indisputable sign of physics beyond the Standard Model. We derive constraints on the CP-violating Higgs-boson couplings to top and bottom quarks as well as to tau…
Several current measurements of $b \rightarrow s l^+ l^-$ processes are in tension with Standard Model predictions, whereas others (e.g.\ $R_K$ and $R_{K^\ast}$) are in reasonable agreement with them. We examine some recent $Z^\prime$…
In this article we consider the contribution of $R_p$ violating couplings to the process $e^+e^-(\mu^+\mu^-)\to t{\bar c}$ at high energy lepton collider. We show that the present upper bound on the relevant $R_p$ violating coulpings…
I briefly review the Higgs sector in the Standard Model and in its minimal supersymmetric extension. After summarizing the properties of the Higgs bosons, I will discuss the prospects for discovering these particles at the present colliders…
We derive new constraints on the products of explicitly R-parity violating couplings $\lambda$ and $\lambda'$ in MSSM from searches for \mu-e conversion in nuclei. We concentrate on the loop induced photonic coherent conversion mode. For…
Model independent constraints on the mass of an extra neutral gauge boson and its couplings to charged leptons are given for the $e^-e^-$ option of a future linear collider. Analytic exclusion limits are derived in the Born approximation.…
We investigate inclusive Standard Model Higgs boson pair production at lepton and hadron colliders for Higgs boson masses in the range 120 GeV < m_H < 200 GeV. For m_H < 140 GeV we find that hadron colliders have a very limited capability…