Bibliographic Details
| Title: |
$\beta^-$ decay $Q$-value measurement of $^{136}$Cs and its implications to neutrino studies |
| Authors: |
Ge, Z., Eronen, T., de Roubin, A., Ramalho, M., Kostensalo, J., Kotila, J., Suhonen, J., Nesterenko, D. A., Kankainen, A., Ascher, P., Beliuskina, O., Flayol, M., Gerbaux, M., Grévy, S., Hukkanen, M., Husson, A., Jaries, A., Jokinen, A., Moore, I. D., Pirinen, P., Romero, J., Stryjczyk, M., Virtanen, V., Zadvornaya, A. |
| Source: |
Phys. Rev. C 108, 045502 (2023) |
| Publication Year: |
2023 |
| Collection: |
Nuclear Experiment |
| Subject Terms: |
Nuclear Experiment |
| More Details: |
The $\beta^-$ decay $Q$-value of $^{136}$Cs ($J^\pi = 5^+$, $t_{1/2} \approx 13$~days) was measured with the JYFLTRAP Penning trap setup at the Ion Guide Isotope Separator On-Line (IGISOL) facility of the University of Jyv\"askyl\"a, Finland. The mono-isotopic samples required in the measurements were prepared with a new scheme utilised for the cleaning, based on the coupling of dipolar excitation with Ramsey's method of time-separated oscillatory fields and the phase-imaging ion-cyclotron-resonance (PI-ICR) technique. The $Q$ value is determined to be 2536.83(45) keV, which is $\sim$4 times more precise and 11.4(20) keV ($\sim$ 6$\sigma$) smaller than the adopted value in the most recent Atomic Mass Evaluation AME2020. The daughter, $^{136}$Ba, has a 4$^+$ state at 2544.481(24) keV and a $3^-$ state at 2532.653(23) keV, both of which can potentially be ultralow $Q$-value end-states for the $^{136}$Cs decay. With our new ground-to-ground state $Q$ value, the decay energies to these two states become -7.65(45) keV and 4.18(45) keV, respectively. The former is confirmed to be negative at the level of $\sim$ 17$\sigma$, which verifies that this transition is not a suitable candidate for neutrino mass determination. On the other hand, the slightly negative $Q$ value makes this transition an interesting candidate for the study of virtual $\beta$-$\gamma$ transitions. The decay to the 3$^{-}$ state is validated to have a positive low $Q$ value which makes it a viable candidate for neutrino mass determination. For this transition, we obtained a shell-model-based half-life estimate of $2.1_{-0.8}^{+1.6}\times10^{12}$ yr.
Comment: 9 pages, 8 figures |
| Document Type: |
Working Paper |
| DOI: |
10.1103/PhysRevC.108.045502 |
| Access URL: |
http://arxiv.org/abs/2306.04604 |
| Accession Number: |
edsarx.2306.04604 |
| Database: |
arXiv |
