InterLeptons | A search for new interactions at Belle II using leptons

Summary
Several measurements in the quark and in the lepton flavor sectors have shown anomalies with respect to the standard model expectations and are now referred to as flavor anomalies. The Belle II experiment at the Super-KEKB laboratory in Japan is collecting data by colliding beams of electrons and positrons. The aim of this proposal is to look for physics beyond the standard model at the Belle II experiment by a) searching for the direct production of new light particles, and b) looking for deviations from theoretical predictions when performing precision tests of the standard model. The team will analyse events with leptons and large missing energy in the final states and implement the most advanced analysis techniques including, for the first time, deep learning tools in the identification of signals at the Belle II experiment. First, we will search for invisible decays of a dark Z' boson, a hypothetical particle that might also explain the anomaly reported in the anomalous magnetic moment of the muon. Second, we will test with per mille precision lepton flavor universality by studying leptonic decays of the tau lepton and use the results to constrain new physics models such as those containing a lepton flavor violating Z' boson. Finally, we will search for new physics via lepton flavor violating decays of bottomonium resonances produced in initial state radiation events that, thanks also to an effective field theory approach, will allow us to interpret the search in terms of new physics mass scale and coupling constant, with an approach complementary to that of the LHC.
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More information & hyperlinks
Web resources: https://cordis.europa.eu/project/id/947006
Start date: 01-11-2020
End date: 31-10-2025
Total budget - Public funding: 1 486 137,00 Euro - 1 486 137,00 Euro
Cordis data

Original description

Several measurements in the quark and in the lepton flavor sectors have shown anomalies with respect to the standard model expectations and are now referred to as flavor anomalies. The Belle II experiment at the Super-KEKB laboratory in Japan is collecting data by colliding beams of electrons and positrons. The aim of this proposal is to look for physics beyond the standard model at the Belle II experiment by a) searching for the direct production of new light particles, and b) looking for deviations from theoretical predictions when performing precision tests of the standard model. The team will analyse events with leptons and large missing energy in the final states and implement the most advanced analysis techniques including, for the first time, deep learning tools in the identification of signals at the Belle II experiment. First, we will search for invisible decays of a dark Z' boson, a hypothetical particle that might also explain the anomaly reported in the anomalous magnetic moment of the muon. Second, we will test with per mille precision lepton flavor universality by studying leptonic decays of the tau lepton and use the results to constrain new physics models such as those containing a lepton flavor violating Z' boson. Finally, we will search for new physics via lepton flavor violating decays of bottomonium resonances produced in initial state radiation events that, thanks also to an effective field theory approach, will allow us to interpret the search in terms of new physics mass scale and coupling constant, with an approach complementary to that of the LHC.

Status

SIGNED

Call topic

ERC-2020-STG

Update Date

27-04-2024
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Horizon 2020
H2020-EU.1. EXCELLENT SCIENCE
H2020-EU.1.1. EXCELLENT SCIENCE - European Research Council (ERC)
ERC-2020
ERC-2020-STG