Speaker
Description
PIONEER is a next-generation precision experiment proposed at the Paul Scherrer Institute to perform high precision measurements of rare pion decays. By improving the precision on the experimental result on the charged pion branching ratio to electrons vs. muons and the pion beta decay by an order of magnitude, PIONEER will provide a pristine test of Lepton Flavour Universality and the Cabibbo angle anomaly. In addition, various exotic rare decays involving sterile neutrinos and axions will be searched for with unprecedented sensitivity.
In the PIONEER experiment design, an intense pion beam is stopped in a segmented, instrumented (active) target (ATAR). The proposed technology for the ATAR is based on low-gain avalanche detectors (LGADs), which can provide precise spatial and temporal resolution for particle tracks and thus separate even very closely spaced decays and decay products. More specifically, trench-insulated and AC-coupled LGADs are being investigated as sensors for this detector. The proposed experiment desing will also include a ~2π sr, 25 radiation length (X0) electromagnetic calorimeter, for which two alternative designs - liquid Xe or LYSO:Ce crystal scintillators - are actively explored. An additional cylindrical tracker surrounding the ATAR, based on micro-patterned gas detector technology (µ-RWELL), will be used to link the locations of pions stopping in the target to showers in the calorimeter.
This presentation will briefly introduce the theoretical motivations for PIONEER, as well as the ongoing simulations efforts to precisely determine the detector performance, informing decisions on the experiment design. It will focus on results from beam test campaigns aimed at the investigation of different aspects of the experiment setup: the beamline itself, sensors for the ATAR, and calibration measurements of the LYSO calorimeter crystal prototypes. In addition, new developments on the path to a multi-layer prototype ATAR system with sensor and readout electronics will be presented.
| Collaboration | PIONEER |
|---|---|
| Role of Submitter | The presenter will be selected later by the Collaboration |
