Confirmation of the l-forbidden Gamow-Teller decay branch of 39Ca Academic Article uri icon

abstract

  • A search for Gamow-Teller decay branches of 39Ca to excited states in 39K was conducted with a large HPGe detector which observed the decays of 39Ca samples delivered by a helium-jet transport system. A pair of plastic scintillators in front of the HPGe detector were used to reject events due to bremsstrahlung from the 39Ca positrons. With this setup, weak -rays could be observed with a degree of sensitivity not previously achieved. The l-forbidden 1d 3 2 2s 1 2 transition to the first excited state in 39K, was observed with a branching ratio of (2.50 0.27) 10-5. This result agrees with but is more accurate than the only previous measurement. Thus, the ratio of the l-forbidden Gamow-Teller and isovector M1 matrix elements in mass-39 nuclei continues to disagree with theoretical values obtained by Towner and Khanna from calculations involving core-polarization and meson-exchange currents. This leaves very few possibilities to explain the discrepancy between theory and experiment. 1994.

published proceedings

  • Nuclear Physics A

author list (cited authors)

  • Hagberg, E., Alexander, T. K., Neeson, I., Koslowsky, V. T., Ball, G. C., Dyck, G. R., ... Towner, I. S.

citation count

  • 25

complete list of authors

  • Hagberg, E||Alexander, TK||Neeson, I||Koslowsky, VT||Ball, GC||Dyck, GR||Forster, JS||Hardy, JC||Leslie, JR||Mak, HB||Schmeing, H||Towner, IS

publication date

  • May 1994