Soft Gamma Rays from Heavy WIMPs

We propose an explanation of the galactic center gamma ray excess by supersymmetric WIMPs as heavy as 500 GeV. The lightest neutralino annihilates into vector-like leptons or quarks which cascade decay through intermediate Higgs bosons. Due to the long decay chains, the gamma ray spectrum is much softer than naively expected and peaks at GeV energies. The model predicts correlated diboson and dijet signatures to be tested at the LHC.Comment: 8 pages, 8 figures; v2: focus on gamma ray excess, matches published versio

Making Digital File Management Successful: A Grounded Model of DFM Adoption in the Public Sector

File management is crucial for the viability of public sector authorities. The success of digital file management (DFM) is influenced by employees\u27 IT adoption. There is a gap in research on employee perceptions of IT adoption in public sector authorities in the European Union (EU). For this reason, this study examines the adoption of the DFM system ‘E File Bund’ (GER: E-Akte Bund), based on a critical case selection of German federal authorities in the EU, and aims to identify the characteristics that determine the adoption of DFM in the public sector from employees\u27 perspective. Fifteen semi structured interviews with users and experts from German federal authorities are conducted and analyzed using the Grounded Theory Methodology (GTM). The primary contribution is a grounded model of the phenomenon DFM adoption. The results provide valuable insights for authorities, practitioners and researchers to enhance DFM adoption and contribute to the digital transformation of the public sector

Engineering of Neutral Excitons and Exciton Complexes in Transition Metal Dichalcogenide Monolayers through External Dielectric Screening

In order to fully exploit the potential of transition metal dichalcogenide monolayers (TMD-MLs), the well-controlled creation of atomically sharp lateral heterojunctions within these materials is highly desirable. A promising approach to create such heterojunctions is the local modulation of the electronic structure of an intrinsic TMD-ML via dielectric screening induced by its surrounding materials. For the realization of this non-invasive approach, an in-depth understanding of such dielectric effects is required. We report on the modulations of excitonic transitions in TMD-MLs through the effect of dielectric environments including low-k and high-k dielectric materials. We present absolute tuning ranges as large as 37 meV for the optical band gaps of WSe 2 and MoSe 2 MLs and relative tuning ranges on the order of 30% for the binding energies of neutral excitons in WSe 2 MLs. The findings suggest the possibility to reduce the electronic band gap of WSe 2 MLs by 120 meV, paving the way towards dielectrically defined lateral heterojunctions.Comment: 11 pages + 6 pages supporting informatio