Nathal Severijns

TL;DR: In this article, the longitudinal polarization of positrons emitted along and opposite to the nuclear spin direction has been measured in the decay of polarized N-12 and a lower bound of 310 GeV/c(2) at 90% CL on the mass of a possible right-handed gauge boson contributing to the electroweak interaction was provided.

TL;DR: In this paper, the Larmor frequency shift proportional to the electric-field strength for 199Hg atoms contained in a volume permeated with aligned magnetic and electric fields was measured.

Abstract: An array of 16 laser-pumped scalar Cs magnetometers was part of the neutron electric dipole moment (nEDM) experiment taking data at the Paul Scherrer Institute in 2015 and 2016. It was deployed to measure the gradients of the experiment's magnetic field and to monitor their temporal evolution. The originality of the array lies in its compact design, in which a single near-infrared diode laser drives all magnetometers that are located in a high-vacuum chamber, with a selection of the sensors mounted on a high-voltage electrode. We describe details of the Cs sensors' construction and modes of operation, emphasizing the accuracy and sensitivity of the magnetic-field readout. We present two applications of the magnetometer array directly beneficial to the nEDM experiment: (i) the implementation of a strategy to correct for the drift of the vertical magnetic-field gradient and (ii) a procedure to homogenize the magnetic field. The first reduces the uncertainty of the nEDM result. The second enables transverse neutron spin relaxation times exceeding 1500 s, improving the statistical sensitivity of the nEDM experiment by about 35% and effectively increasing the rate of nEDM data taking by a factor of 1.8.

TL;DR: In this article, the dominant forbidden transitions in the antineutrino spectra of the fission actinides from 4 MeV onward were studied using the nuclear shell model.

TL;DR: Comparing data with several theoretical models shows that anisotropic emission in favored decays from near-spherical nuclei can well be explained within the shell model, implying that it is mainly determined by the structure of the decaying nucleus.