title: FT values measured to ±0.1% for superallowed beta transitions: metrology at sub-second time scales.
abstract: Because of angular-momentum conservation, superallowed β decay between 0(+) analog states involves only the vector part of the weak interaction, so its measured ft value can be used to determine the vector coupling constant, G(V). If many such transitions are measured, then the constancy of G(V) can be established and several important tests made on fundamentals of the electroweak Standard Model. We have developed apparatus that allows us to measure half-lives to ±0.03% and branching ratios to ±0.1% or better, for cyclotron-produced activities with half-lives as short as 100 ms. We present an overview of the equipment and a summary of more than 10 years of results.
authors.affiliation: Cyclotron Institute, Texas A&M University, College Station, TX 77845-3366, USA. Electronic address: hardy@comp.tamu.edu.
authors.forename: J C
authors.initials: JC
authors.lastname: Hardy
authors.affiliation: Cyclotron Institute, Texas A&M University, College Station, TX 77845-3366, USA.
authors.forename: V E
authors.initials: VE
authors.lastname: Iacob
authors.affiliation: Cyclotron Institute, Texas A&M University, College Station, TX 77845-3366, USA.
authors.forename: H I
authors.initials: HI
authors.lastname: Park
authors.affiliation: Cyclotron Institute, Texas A&M University, College Station, TX 77845-3366, USA.
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.affiliation: Cyclotron Institute, Texas A&M University, College Station, TX 77845-3366, USA.
authors.forename: N
authors.initials: N
authors.lastname: Nica
authors.affiliation: Cyclotron Institute, Texas A&M University, College Station, TX 77845-3366, USA.
authors.forename: V
authors.initials: V
authors.lastname: Horvat
authors.affiliation: Cyclotron Institute, Texas A&M University, College Station, TX 77845-3366, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Tribble
authors.affiliation: Cyclotron Institute, Texas A&M University, College Station, TX 77845-3366, USA.
authors.forename: I S
authors.initials: IS
authors.lastname: Towner
keywords: Beta decay; Branching ratios; Half lives