Investigation of pair-correlated $0^{+}$ states in ${}^{134}\mathrm{Ba}$ via the ${}^{136}\mathrm{Ba}(p,t)$ reaction

We performed a high resolution study of $0^{+}$ states in ${}^{134}\mathrm{Ba}$ using the ${}^{136}\mathrm{Ba}(p,t)$ two-neutron transfer reaction. Our experiment shows a significant portion of the $L=0$ pair-transfer strength concentrated at excited $0^{+}$ levels in ${}^{134}\mathrm{Ba}$. Potential implications in the context of ${}^{136}\mathrm{Xe}\to {}^{136}\mathrm{Ba}$ neutrinoless double beta decay matrix element calculations are briefly discussed.

Figure 1

Particle identification spectra using energy losses registered in the two proportional counters and the total energy deposited in the plastic scintillator. The triton groups are highlighted. The other particles are mainly deuterons.

Figure 2

Triton spectra corresponding to states in ${}^{134}\mathrm{Ba}$, obtained at ${\theta }_{\mathrm{lab}}={25}^{\circ }$. Peaks from contaminants in the target are marked with asterisks. The $0^{+}$ states observed in this experiment are labeled. The state at 3528 keV (labeled in blue) is reported for the first time in this work.

Figure 3

Measured ${}^{134}\mathrm{Ba}$ ground state angular distribution compared with normalized DWBA predictions obtained using different triton OMPs by Li, Liang, and Cai (2007) [45] and Becchetti and Greenlees (1969) [46, 47].

Figure 4

${}^{136}\mathrm{Ba}(p,t)$ angular distributions for observed $0^{+}$ states in ${}^{134}\mathrm{Ba}$, compared with normalized DWBA predictions for $L=0$ transfer. The DWBA results are obtained using the ${\left(0h_{11/2}\right)}^2$ configuration for the form factor and normalized such that ${(d\sigma /d\mathrm{\Omega })}_{\mathrm{expt}}=N{(d\sigma /d\mathrm{\Omega })}_{\mathrm{DWBA}}$.