相关论文: Supersymmetric photonic signals at LEP
The production of single- and multi-photon events has been studied in the reaction e+e- -> gamma (gamma) + invisible particles. The data collected with the DELPHI detector during the years 1999 and 2000 at centre-of-mass energies between…
A search for gravitinos produced in ep collisions is performed using the H1 detector at HERA. The data were taken at a centre-of-mass energy of 319 GeV and correspond to an integrated luminosity of 64.3 pb^{-1} for e^+p collisions and 13.5…
In a supersymmetric large extra dimension scenario, the production of Kaluza-Klein gravitinos accompanied by a photino at e^+ e^- colliders is studied. We assume that a bulk supersymmetry is softly broken on our brane such that the…
A search for charginos and neutralinos, predicted by supersymmetric theories, is performed using a data sample of 182.1 pb-1 taken at a centre-of-mass energy of 189 GeV with the OPAL detector at LEP. No evidence for chargino or neutralino…
In some supergravity models, the superlight gravitino is accompanied by a light weakly coupled scalar (S) and pseudo-scalar (P) particle. The coupling of these particles to matter is inversely proportional to the product of the gravitino…
We consider the sterile neutrino, that is also know as heavy neutral lepton (HNL), interacting with the Standard Model (SM) active neutrino and photon via a transition magnetic moment, the so-called dipole portal, which can be induced from…
In the framework of a particular supergravity model which provides a natural solution to the $\mu$--problem we show how the discovery of a chargino at LEP2 and the measurement of its mass and production cross--section, together with the…
Indirect limits on the mass of the lightest neutralino are derived from the results of searches for charginos, neutralinos, and sleptons performed with data taken by the ALEPH Collaboration at centre-of-mass energies near the Z peak and at…
Although no individual piece of experimental evidence for supersymmetry is compelling so far, several are about as good as they can be with present errors. Most important, all pieces of evidence imply the same values for common parameters…
Supersymmetric theories with gravitino dark matter generally do not allow the high reheating temperature required by thermal leptogenesis without running afoul of relic abundance or big bang nucleosynthesis constraints. We report on a…
We study supersymmetric extensions of the Standard Model with small R-parity and lepton number violating couplings which are naturally consistent with primordial nucleosynthesis, thermal leptogenesis and gravitino dark matter. We consider…
We analyse the events with two same-flavour, opposite-sign leptons + $E_T^{miss}$ + (jets) as expected in pp collisions at LHC within the framework of the minimal Supergravity Model. The objective is the determination of the parameters m_0…
We present a complete and extensive analysis of associated chargino and neutralino production in the framework of a supersymmetric theory augmented by left-right symmetry. This model provides additional gaugino and higgsino states in both…
The four LEP collaborations have performed searches for supersymmetric particles in light gravitino scenarios, when neutralinos and sleptons are produced and may present measurable decay lengths. The highest energy data has been analysed…
An update of the search for sleptons, neutralinos and charginos in the context of scenarios where the lightest supersymmetric particle is the gravitino and the next-to-lightest supersymmetric particle is a slepton, is presented, together…
We study the single chargino production $e^+ e^- \to \tilde \chi^{\pm} \mu^{\mp}$ at linear colliders which occurs through the $\l_{121}$ R-parity violating coupling constant. We focus on the final state containing 4 leptons and some…
We investigate the signal $\gamma\gamma$ + missing energy in a high-energy linear $e^+e^-$ collider, with a view to differentiating between gauge-mediated supersymmetry breaking and the conventional supersymmetric models. Prima facie, there…
We discuss the predictions of a constrained version of the exceptional supersymmetric standard model (cE6SSM), with a universal high energy soft scalar mass, soft trilinear coupling and soft gaugino mass. The spectrum includes a light…
Naturalness arguments applied to supersymmetric theories imply a spectrum containing four light higgsinos \tz_{1,2} and \tw_1^+- with masses ~ 100-300 GeV (the closer to M_Z the more natural). The compressed mass spectrum and associated low…
We study the Minimal Supersymmetric Standard Model (MSSM) with large gluino mass m_{\tilde{g}} >> 1 TeV. In particular, we discuss the LHC supersymmetry discovery signatures with n leptons + jets + E^{miss}_T, n >= 0 for the MSSM with large…