Experimental setup for Weak Interaction Studies with Radioactive ion-beams WISArD

The article describes the commissioning and technical development of the Weak Interaction Studies with 32Ar Decay (WISArD) experiment, installed at the radioactive ion-beam facility ISOLDE/CERN. The experiment aims to extend the present limits on scalar and tensor currents in the weak interaction and hence search for physics beyond the Standard Model. The evaluation of these limits relies on measuring the proton energy in beta-delayed proton emission, sensitive to both the beta-neutrino angular correlation coefficient a ⠌⠗ and the Fierz interference term b. The method tries to improve previous studies by considering the positron-proton coincidences when determining the kinematic shift in the energy of the emitted protons. Using this coincidence technique, the a ⠌⠗ and b coefficients will be measured at the per mil level. Simulations were employed to optimize the ion beam transport efficiency and validate proof-of-principle results obtained in November 2018 (Nov2018). Upgrades are ongoing, and we are looking into improvements to the overall performance of the setup.

Automated summary

The article discusses the Weak Interaction Studies with 32Ar Decay (WISArD) experiment, which aims to extend the limits on scalar and tensor currents in the weak interaction and search for physics beyond the Standard Model. The evaluation of these limits relies on measuring the proton energy in beta-delayed proton emission, and the method tries to improve previous studies by considering positron-proton coincidences. Simulations were used to optimize the ion beam transport efficiency and validate proof-of-principle results obtained in November 2018. Upgrades are ongoing to improve the overall performance of the setup.