WISARD, beta-delayed proton decay as a probe for weak interaction studies

With this project we will search for the possible existence of an as yet unobserved (scalar) form of the weak interaction, the force in Nature responsible for the type of radioactivity producing beta radiation. For this, the energy will be determined of protons that are emitted following this beta radiation, in the decay of the radioactive isotope 32Ar. More specifically, the energy difference will be determined between protons that are emitted in two opposite directions with respect to the direction of the preceding beta radiation. This is the first time that this method will be applied to protons. It is potentially more sensitive to the new physics searched for than methods that have previously been employed for this. In the measurements to be performed a 0.1% precision is aimed at. At this level of precision our measurements will constitute an alternative way to search for this new form of the weak interaction compared to the measurements performed at the LHC accelerator at CERN, with similar sensitivity but in a very different energy region. A few competing experiments in nuclear beta decay, with very similar aims as ours, are currently being prepared at other research institutes. However, these will use very different measurement techniques. Therefore, possible instrumental (systematic) effects will be very different for all measurements, allowing to reach an even higher accuracy than will be possible in each individual project.