Speaker
Description
The search for physics beyond the standard electroweak model (SM), despite its remarkable success at the most elementary level, still continues on three frontiers - high-energy, precision and cosmic. The reason is the many yet unanswered questions such as the origin of parity violation [1].
Considering the precision frontier, experiments with radioactive nuclei offer large variety of nuclear states with optimal sensitivity to study the beta-neutrino angular correlation coefficient (a$_{\beta\nu}$) that are still competitive to today's high-energy and cosmic experiments. In particular, studies performed in pure transitions, Fermi or Gamow-Teller provide a direct probe to the presence of scalar or tensor currents, respectively. Measurements of this kind have been performed in various nuclear systems in the past [2], with $^{32}$Ar being one of the most precisely known to date.
The experiment WISArD (Weak Interaction Studies with $^{32}$Ar Decay) [3] is currently being prepared at ISOLDE/CERN, and will focus on determining a$_{\beta\nu}$ through beta-proton coincidence measurements. The ground state in $^{32}$Ar beta decays via the super-allowed Fermi transition to the isobaric analogue state in $^{32}$Cl which subsequently decays by proton emission. Measured kinematic shift of emitted protons reflects the energy spectrum of the recoiling nuclei after the previous beta-decay which depends on the character of the weak interaction. To enhance the measurement sensitivity emitted particles will be guided by a strong magnetic field. In this contribution the layout of the setup will be presented as well as preliminary results from a proof-of-principle campaign performed in the fall of 2018. Furthermore, a discussion about the potential precision at reach applying this technique will be given.
[1] M. Gonz\'{a}lez-Alonso, O. Naviliat-Cuncic, N. Severijns, Prog. Part. Nucl. Phys 104, (2019) 165.
[2] E. G. Adelberger, {\it et al.}, Phys. Rev. Lett. 83, (1999) 1299.
[3] B. Blank, {\it et al.}, CERN-INTC-2016 (2016).
