Z-peaked excess in goldstini scenarios

We study a possible explanation of a 3.0 $sigma$ excess recently reported by the ATLAS Collaboration in events with Z-peaked same-flavour opposite-sign lepton pair, jets and large missing transverse momentum in the context of gauge-mediated SUSY breaking with more than one hidden sector, the so-called goldstini scenario. In a certain parameter space, the gluino two-body decay chain $tilde gto gtildechi^0_{1,2}to gZtilde G$ becomes dominant, where $tildechi^0_{1,2}$ and $tilde G$ are the Higgsino-like neutralino and the massive pseudo-goldstino, respectively, and gluino pair production can contribute to the signal. We find that a mass spectrum such as $m_{tilde g}sim 1000$ GeV, $m_{tildechi^0_{1,2}}sim 800$ GeV and $m_{tilde G}sim 600$ GeV demonstrates the rate and the distributions of the excess, without conflicting with the stringent constraints from jets plus missing energy analyses and with the CMS constraint on the identical final state.

High-energy long-lived resonance of electrons in fractal-like semiconductor heterostructures

A fractal-like alignment of quantum wells is shown to accommodate resonant states with long lifetimes. For the parameters of the semiconductor heterostructure GaAs/Al$_{0.4}$Ga$_{0.6}$As with the well depth 300meV, a resonant state of the energy as high as 44meV with the lifetime as long as 2.8{mu}s is shown to be achievable.