This is the official page of the research team "InterLeptons" at the High Energy Physics Institute of the Austrian Academy of Sciences. The team, led by Dr. Gianluca Inguglia, is funded under the grant agreement nr. 947006 of the Starting Grant award offered by the European Research Council (ERC). The research activities of the team will be described and kept up-to-date on these pages.
The aim InterLeptons is to unveil the new physics nature of the so-called flavor anomalies implementing a bottom-up approach based on the studies of data collected at the Belle II experiment, located in the interaction region of the Super-KEKB collider. The team focuses on final state events containing leptons and a large amount of missing energy. The results of the searches will be interpreted in terms of low mass dark matter, new forces/interactions, and in terms of lepton flavor violating and lepton flavor non-universal couplings.
InterLeptons brings a significant advancement of a new research area in Austria with the potential of revolutionizing particle physics.
After an intense period of data analysis and of internal review within the Belle II Collaboration, we have submitted for publication to the Physical Review Letters the results of our search for invisible Z' boson, in events containing two muons and missing energy in the final state. This search is one of the pillars of the InterLeptons project, for which we have some time ago developed a dedicated machine learning tool, a neural-network-based method that allows to search for the Z' boson by optimizing the selection of signal and rejection of backgrounds available here. Unfortunately, no excess of events was observed, but we could exclude a large region of the parameter space hence improving by orders of magnitude our knowledge of this physics model.
A preprint of the research paper is available here.
It is also important to mention two other results that were released by the Belle II Collaboration with a significant contribution of members of our group.
- The search for an invisible alpha boson, produced in tau decays was also submitted for publication to the Physical Review Letters, the day after the Z' paper, and a preprint is available here.
- The search for an invisible (or very long-lived) dark Higgs boson produced in association to a dark photon decays to a pair of muons. A preprint is available here and the paper was recently accepted for publication in PRL.