Internal gamma decay and the superallowed branching ratio for the beta(+) emitter (38)K(m). Academic Article uri icon


  • The branching ratio for the superallowed beta(+) decay of (38)K(m) was measured at TRIUMF's ISAC radioactive ion beam facility. The M3 internal transition between the isomer and the ground state of (38)K(m) was observed with a branching ratio of 330(43) ppm. A search for the nonanalogue beta-decay branch to the first excited 0(+) state in (38)Ar was also performed and yielded an upper limit of < or =12 ppm at 90% C.L. These measurements lead to a revised superallowed branching ratio for (38)K(m) of 99.967(4)%, and increase the (38)K(m) ft value by its entire quoted uncertainty to ft=3052.1(10) s. Implications for tests of the nuclear-structure dependent corrections in superallowed beta decays and the extraction of the Cabibbo-Kobayashi-Maskawa matrix element V(ud) are discussed.

published proceedings

  • Phys Rev Lett

author list (cited authors)

  • Leach, K. G., Svensson, C. E., Ball, G. C., Leslie, J. R., Austin, R., Bandyopadhyay, D., ... Wong, J.

citation count

  • 17

complete list of authors

  • Leach, KG||Svensson, CE||Ball, GC||Leslie, JR||Austin, RAE||Bandyopadhyay, D||Barton, C||Bassiachvilli, E||Ettenauer, S||Finlay, P||Garrett, PE||Grinyer, GF||Hackman, G||Melconian, D||Morton, AC||Mythili, S||Newman, O||Pearson, CJ||Pearson, MR||Phillips, AA||Savajols, H||Schumaker, MA||Wong, J

publication date

  • May 2008