title: Limits on Lorentz violation from forbidden β decays.
abstract: Forbidden (slow) β decays offer new opportunities to test the invariance of the weak interaction under Lorentz transformations. Within a general effective field theory framework we analyze and reinterpret the only two relevant experiments, performed in the 1970s, dedicated to search for a preferred direction in space in first- and second-forbidden β decays. We show that the results of these experiments put strong and unique limits on Lorentz violation, and in particular on the presence of several interactions in the modern Lorentz-violating standard model extension. We discuss prospects to improve on these limits.
authors.affiliation: KVI, University of Groningen, Zernikelaan 25, NL-9747 AA Groningen, Netherlands.
authors.forename: J P
authors.initials: JP
authors.lastname: Noordmans
authors.forename: H W
authors.initials: HW
authors.lastname: Wilschut
authors.forename: R G E
authors.initials: RG
authors.lastname: Timmermans