Speaker
Michelle Dunlop
(U)
Description
High precision measurements of superallowed Fermi beta transitions between 0$^+$ isobaric analogue states allow for stringent tests of the electroweak interaction described by the Standard Model. Particularly, these transitions provide an experimental probe of the unitary of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, the Conserved-Vector-Current (CVC) hypothesis, as well as set limits on the existence of scalar currents in the weak interaction. Half-life measurements for the lightest of the superallowed emitters are of particular interest as it is the low-Z superallowed decays that are most sensitive to a possible scalar current contribution.
There are two methods for measuring the superallowed $\beta$ decay half-life of $^{10}$C: via directly counting the $\beta$ particles or measuring the $\gamma$-ray activity following $\beta$ decay. Previous results for the $^{10}$C half-life measured via these two methods differ at the 1.5$\sigma$ level, prompting simultaneous and independent measurements of the $^{10}$C half-life using both techniques. Since $^{10}$C is the lightest nucleus for which superallowed $\beta$ decay is possible, a high precision measurement of its half-life is essential for obtaining an upper limit on the presence of scalar currents in the weak interaction.
In October 2013, $^{10}$C half-life measurements via both gamma-ray photo-peak and direct beta counting were performed at TRIUMF's Isotope Separator and Accelerator (ISAC) facility using the 8$\pi$ spectrometer and a $4\pi$ gas proportional $\beta$ counter at the ISAC General Purpose Station. The 8$\pi$ $\gamma$-ray spectrometer consists of 20 High Purity Germanium (HPGe) detectors as well as the Zero Degree $\beta$ detector, a fast plastic scintillator located at the end of the beam line within the 8$\pi$.
This presentation will highlight the importance of these measurements and preliminary half-life results for $^{10}$C will be presented.
Primary author
Michelle Dunlop
(U)
Co-authors
A. B. Garnsworthy
(TRIUMF)
A. Diaz Varela
(University of Guelph)
A. J. Radich
(University of Guelph)
A. MacLean
(University of Guelph)
A. T. Laffoley
(University of Guelph)
A. Valencik
(Saint Mary’s University)
B. Hadinia
(University of Guelph)
B. Mills
(TRIUMF)
C. Andreoiu
(Simon Fraser University)
C. E. Svensson
(University of Guelph)
C. Unswroth
(TRIUMF)
D. Jamieson
(University of Guelph)
D. Miller
(TRIUMF)
E. F. Zganjar
(Louisiana State University)
E. Rand
(University of Guelph)
G. C. Ball
(TRIUMF)
G. F. Grinyer
(Grand Acc´el´erateur National d’Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3)
J. Park
(TRIUMF)
J.R. Leslie
(Queen’s University)
M. M. Rajabali
(TRIUMF)
P. Bender
(TRIUMF)
P. Garrett
(University of Guelph)
R. A. E. Austin
(Saint Mary’s University)
R. Dunlop
(University of Guelph)
T. Ballast
(TRIUMF)
V. Bildstein
(University of Guelph)
Z. Wang
(TRIUMF)
