Laser trapped $^{6}He$ as a probe of the weak interaction and a test of the sudden approximation

International audienceSynopsis Correlations between β decay products are sensitive observables to look for exotic contributions to the weak interaction excluded by the Standard Model of particle physics. To precisely measure the β − ν angular correlation parameter, a βν , in 6 He β decay, the radioactive atoms are trapped in a magneto-optical trap and the momentum of β particles and 6 Li recoil ions are measured in coincidence. The shake-off process, leading to higher charge states of the Li, plays an important role in this observation and must be studied carefully. Its study provides stringent tests of the sudden approximation for atomic calculations in this few electron system