WISArD experiment

The Weak Interaction Studies with 32Ar Decay (WISArD) experiment is a permanent experimental setup located in the ISOLDE facility, at CERN.

[1] In the absence of online isotope production during Long Shutdown 2, the experimental setup has also been used to measure the shape of the beta energy spectrum.

[2] A goal of the experiment is to search for physics beyond the Standard Model (SM) by expanding the existing limits on currents in the weak interaction.

By comparing the energy of the protons emitted, in the same and in opposite hemispheres of the experimental setup with respect to the beta particle, a kinematical shift between the two cases can be measured.

This kinematical shift carries the information needed to deduce the beta-neutrino correlation and thus provides access to physics beyond the Standard Model.

[6] The WISArD beam transport system consists of ion-source (IBL), horizontal (HBL), vertical (VBL) and solenoid magnet (SBL) beamlines.

[7][3] Furthermore, a better compact microchannel plate (MCP) was designed to measure the position and the extension of the argon beam, information needed for reaching a desired precision level for the correlation coefficient.

[3] The results from the first beta-neutrino correlation campaign with 32Ar in November 2018 showed the proof-of-principle by successfully measuring the proton kinematic energy shift and testing the system.