相关论文: Single-photon signals at LEP in supersymmetric mod…
We explore and contrast the single-photon and diphoton signals expected at LEP 2, that arise from neutralino-gravitino (e^+ e^- -> chi + gravitino -> gamma + E_miss) and neutralino-neutralino (e^+ e^- -> chi + chi -> gamma + gamma + E_miss)…
We examine the possibility that some anomalous acoplanar diphoton events observed at LEP may be consistent with the predictions of our previously proposed one-parameter no-scale supergravity model with a light gravitino, via the process…
The production of invisible pairs of lightest neutralinos accompanied by a large-angle hard photon in the reaction $e^+ e^- \to \chi^0_1 \chi^0_1 \gamma$ is studied at LEP2 energies. The most general gaugino/higgsino composition of the…
We search for inclusive high $E_T$ diphoton events with large missing transverse energy in $p\bar{p}$ collisions at $\sqrt{s}$=1.8 TeV. Such events are expected from pair production of charginos and neutralinos within the framework of the…
Single and multi-photon events with missing energy are analysed using data collected with the L3 detector at LEP at a centre-of-mass energy of 189 GeV, for a total of 176 pb^{-1} of integrated luminosity. The cross section of the process…
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…
We have analyzed the single $\eegg + \slashchar{E}_T$ event at CDF and found that the expected rate and kinematics are consistent with selectron pair production. We consider two classes of general low-energy supersymmetric theories, where…
A search was performed for charginos with masses close to the mass of the lightest neutralino in e+e- collisions at centre-of-mass energies of 189-209 GeV recorded by the OPAL detector at LEP. Events were selected if they had an observed…
We present a unified no-scale supergravity model with a light gravitino that can naturally explain the observed $ee\gamma\gamma$ event at CDF via right-handed selectron pair-production. The full spectrum of our model can be described in…
We revisit the monophoton plus missing energy signature at $e^+e^-$ colliders in supersymmetric (SUSY) models where the gravitino is very light. There are two possible processes which provide the signal: gravitino pair production and…
If the gravitino G is very light and all the other supersymmetric particles are above threshold, supersymmetry may still be found at colliders, by looking at processes with only gravitinos and ordinary particles in the final state. We…
Photonic events with large missing energy have been observed in e+e- collisions at a centre-of-mass energy of 189GeV using the OPAL detector at LEP. Results are presented for event topologies consistent with a single photon or with an…
We explore two possible interpretations for the CDF $ee\gamma\gamma+E_T\hskip-13pt/\quad$ event in the context of a recently proposed one-parameter no-scale supergravity model with a light gravitino. We delineate the region in parameter…
We consider a general class of models with gauge-mediated supersymmetry breaking in which the gravitino is the lightest supersymmetric particle. Several qualitatively different scenarios arise for the phenomenology of such models, depending…
We propose an analysis of LEP constraints on radiative neutralino decays into a light gravitino, based on the plane of the Higgs mixing parameter mu and the SU(2) gaugino mass M_2. The preliminary LEP 2W constraints in the (mu, M_2) plane…
We study a distinct supersymmetric signal of multi-photons in association with jets and missing transverse energy. At least one of these photons has the origin in displaced vertex, thus delayed and non-pointing. We consider a supersymmetric…
The signatures for low energy supersymmetry breaking at the Tevatron are investigated. It is natural that the lightest standard model superpartner is an electroweak neutralino, which decays to an essentially massless Goldstino and photon,…
We analyze the prospects for discovering supersymmetry at the Fermilab Tevatron and CERN LEP colliders in the scenario that the lightest supersymmetric particle is a gravitino of mass < 1 keV. We consider in particular the case that the…
We show that the process $e^+e^- \to \gamma+$ missing energy, arising from the pair production of neutralinos, can probe the $\gamma-\tilde\gamma- \gravitino$ as well as the $Z-\tilde Z-\gravitino$ couplings in Gauge Mediated Supersymmetry…
We present a refined and expanded analysis of the CDF $ee\gamma\gamma + \Et$ event as superpartner production, assuming the lightest neutralino is the lightest supersymmetric particle. A general low-energy Lagrangian is constrained by a…