1.4 The decay of ¹⁰⁰Mo to the first excited 0⁺ state of ¹⁰⁰Ru

L. De Braeckeleer, A.W.P. Poon and M. Felton

Recently, two groups have attempted to observe the decay of ¹⁰⁰Mo to the first excited 0⁺ state of ¹⁰⁰Ru (see Fig. 1.4-1). Assuming similar matrix elements as the ones governing the transition to the ground state, one expects a partial half-life of 10²¹ years. Presently the two groups report conflicting results: 6.1^+1.8_-1.1 × 10²⁰ years¹ and a null result at the level of 2 × 10²¹ years². Previous experiments have focused on approaches to creating a very low background by using special materials or by conducting the experiments in underground laboratories. We are currently investigating a different approach. The detection in coincidence, of the two -rays following the decay of ¹⁰⁰Mo to the first excited 0⁺ state of ¹⁰⁰Ru.

A lower limit of 2 × 10²⁰ years has already been obtained.

Fig. 1.4-1. Partial decay scheme of ¹⁰⁰Mo.