ISOLDE Seminar

WISArD limits on scalar currents from 32Ar beta-decay

by Victoria Isabel Araujo Escalona (KU Leuven (BE))

Europe/Zurich
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Description

Beta - neutrino correlation measurements are key to research of physics beyond the Standard Model of particle physics. In pure Fermi beta transitions, the beta-neutrino correlation coefficient aβ is sensitive to the presence of scalar currents. Several experiments have been performed with this approach, with a measurement with 32Ar β+ decay being one of the most precise case studies.

An essential contribution to improve the constraints on scalar currents is being developed by the WISArD experiment at ISOLDE/CERN, where measurements of the energy shift of the β-delayed protons emitted from the isobaric analogue state of the 32Ar ground state are performed. To enhance the sensitivity, protons and positrons are guided by a strong magnetic field and measured in coincidence with two different detectors located on both sides of a catcher foil in which the radioactive samples are implanted.

Kinematic energy shifts of the protons in coincidence with positrons, in the same or opposite hemisphere of the catcher foil, will be more or less pronounced as a function of the possible scalar current component of the weak interaction. Details of the apparatus and preliminary results of the experiment will be presented.