Related papers: Discrimination of SUSY breaking models using singl…
The minimal $U(1)_X$ extension of the Standard Model (SM) is a well-motivated new physics scenario, where anomaly cancellation dictates new neutral gauge boson ($Z^\prime$) couplings with the SM fermions in terms of the $U(1)_X$ charges of…
We study the collider phenomenology of the minimal unified version of the supersymmetry breaking scheme called Tree-level Gauge Mediation. We identify a peculiar source of gaugino mass non-universality related to the necessary…
Two-photon processes in electron-positron collisions of the form $e^+e^-\to e^+e^-X$ are a well-established tool for probing hadronic structure and provide a direct access to non-vector states in $e^+e^-$ collisions. Collisions of quasi…
Minimal supersymmetric SU(5) with exact unification is naively inconsistent with proton decay constraints. However, it can be made viable by a gravity-induced non-renormalizable operator connecting the adjoint Higgs boson and adjoint vector…
We provide a simple solution to the $\mu/B_\mu$ problem in the gauge-mediated Next-to-Minimal Supersymmetric Standard Model. In this model the messenger sector contains one pair of $3+\bar 3$ and one pair of $2+\bar 2$ messengers. These two…
Littlest Higgs model predicts some extra particles beyond the Standard Model. Among them, an extra neutral gauge boson A_H is lightest and its mass could be a few hundred GeV. We study production and decay of A_H at future e^+ e^- inear…
Supersymmetric models are typically taken to have $\mu$ parameter and all soft supersymmetry breaking parameters at or near the weak scale. We point out that a small window of allowed values exists in which $\mu$ and the electroweak gaugino…
In the context of supersymmetric $SO(10)$ grand unified models, it is shown that the gauge symmetry breaking as well as a natural doublet--triplet splitting can be achieved with a minimal Higgs system consisting of a single adjoint and a…
Single- and multi-photon events with missing energy are selected in 619/pb of data collected by the L3 detector at LEP at centre-of-mass energies between 189GeV and 209GeV. The cross sections of the process e^+e^- -> nu nu gamma (gamma) are…
Recently N. Arkani-Hamed and S. Dimopoulos proposed a supersymmetric model \cite{Arkani-Hamed:2004fb}, dubbed "Split Supersymmetry" in Ref. \cite{Giudice:2004tc}, which can remove most of the unpleasant shortcomings of TeV Supersymmetry. In…
We report on a study of the physics potential of linear $e^+e^-$ colliders. Although a linear collider (LC) would support a broad physics program, we focus on the contributions that could help elucidate the origin of electroweak symmetry…
We study the problem of selecting between different mechanisms of supersymmetry breaking in the Minimal Supersymmetric Standard Model using current data. We evaluate the Bayesian evidence of four supersymmetry breaking scenarios: mSUGRA,…
We investigate models of supersymmetric grand unification based on the gauge group SU(5). We consider models with non-universal gaugino masses and confront them with low energy constraints, including the Higgs boson mass and the Dark Matter…
Supersymmetric models with a strongly interacting superconformal hidden sector (HS) may drive soft SUSY breaking scalar masses, bilinear soft term B\mu and Higgs combinations m_{H_{u,d}}^2+\mu^2 to small values at some intermediate scale,…
The ultrarelativistic collisions of heavy ions provide rich spectrum of possibilities to discuss the response of the nucleus to photons. Newly published neutron and proton multiplicities measured in the ALICE experiment in ultraperipheral…
Linear collider designs are optimized for \ep\ collisions. However, from the physics point of view, \lc s may also be advantageously operated in an \ee, \eg\ or \pp\ mode. These options, which have not been available up to now, will provide…
Our aim is to establish some signatures of the extra gauge boson ${Z^\prime}$, predicted in two versions of ${SU (3)_C \times SU (3)_L \times U (1)_X}$ model and to show possible differences between these signatures. First, by considering…
The minimal supersymmetric SO(10) model, in which not only the gauge but also the third generation fermion Yukawa couplings are unified, provides a simple and highly predictive theoretical scenario for the understanding of the origin of the…
After a lightning review of current bounds on the masses of supersymmetric particles, we describe strategies that may be helpful for extracting signals from the production of squarks, gluinos or top squarks, and from associated…
In this work, we study the impact of electroweak and Higgs precision measurements at future electron-positron colliders on several typical supersymmetric models, including the Constrained Minimal Supersymmetric Standard Model (CMSSM),…