Beamline simulations for the neutron decay facility PERC

by Lilli Löbell (TUM)

Thursday 12 Jun 2025, 09:30 → 10:30 Europe/Berlin

E18/ENE Seminar Room 3268 (TUM PH)

The decay of free neutrons is a powerful tool for precision tests of the Standard Model of particle physics. By determining decay correlation coefficients such as the beta asymmetry $A$, one can contribute to a unitarity test of the first row of the CKM matrix and search for (effective) scalar and tensor as well as right-handed couplings.

The neutron decay spectrometer PERC (Proton Electron Radiation Channel), which is currently set up at the FRM II research reactor, aims to improve the accuracy of several correlation coefficients by one order of magnitude. PERC consists of a 12 m long superconducting magnet system, in which the neutron beam is contained by a non-depolarizing neutron guide. Electrons and protons produced in the neutron decay are guided by the magnetic field towards the main detector, which will initially be a scintillation detector with photomultiplier tube readout.

As the envisaged measurements require a pulsed and polarized neutron beam, the PERC beamline contains a velocity selector, a polarizer and a disc chopper. In this talk I will present simulations of these components and give an update on the current status of PERC and its detector systems.