${}^{138}\mathrm{Ba}(d,\alpha )$ study of states in ${}^{136}\mathrm{Cs}$: Implications for new physics searches with xenon detectors

Abstract

We used the ${}^{138}$Ba$(d,\alpha )$ reaction to carry out an in-depth study of states in ${}^{136}$Cs, up to around 2.5~MeV. In this work, we place emphasis on hitherto unobserved states below the first $1^{+}$ level, which are important in the context of solar neutrino and fermionic dark matter (FDM) detection in large-scale xenon experiments. We identify for the first time candidate metastable states in ${}^{136}$Cs, which would allow a real-time detection of solar neutrino and FDM events in xenon detectors, with high background suppression. Our results are also compared with shell-model calculations performed with three Hamiltonians that were previously used to evaluate the nuclear matrix element (NME) for ${}^{136}$Xe neutrinoless double beta decay. We find that one of these Hamiltonians, which also systematically underestimates the NME compared to the others, dramatically fails to describe the observed low-energy ${}^{136}$Cs spectrum, while the other two show reasonably good agreement.

References in corpus (18)

• Status and Future of Nuclear Matrix Elements for Neutrinoless Double-Beta Decay: A Review
• Search for New Physics in Electronic Recoil Data from XENONnT
• Toward the discovery of matter creation with neutrinoless double-beta decay
• Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen
• NEXO: Neutrinoless double beta decay search beyond $10^{28}$ year half-life sensitivity
• Shell model studies of the ${}^{130}Te$ neutrinoless double-beta decay
• A monopole-optimized effective interaction for tin isotopes
• Collectivity in the light Xenon isotopes: A shell model study
• A Search for Light Fermionic Dark Matter Absorption on Electrons in PandaX-4T
• Beyond-mean-field approaches for nuclear neutrinoless double beta decay in the standard mechanism
• Nuclear Structure Aspects of Neutrinoless Double Beta Decay
• Neutrinoless $\beta \beta$-decay nuclear matrix elements from two-neutrino $\beta \beta$-decay data
• First Directional Measurement of sub-MeV Solar Neutrinos with Borexino
• Projected sensitivities of the LUX-ZEPLIN (LZ) experiment to new physics via low-energy electron recoils
• Search for MeV Electron Recoils from Dark Matter in EXO-200
• Observation of low-lying isomeric states in ${}^{136}$Cs: a new avenue for dark matter and solar neutrino detection in xenon detectors
• Spectroscopy of states in ${}^{136}\mathrm{Ba}$ using the ${}^{138}\mathrm{Ba}(\mathrm{p},\mathrm{t})$ reaction
• Proton capture on ${}^{30}$P in novae: On the existence of states at $6.40$ MeV and $6.65$ MeV in ${}^{31}$S

Cited by in corpus (3)

• Observation of low-lying isomeric states in ${}^{136}$Cs: a new avenue for dark matter and solar neutrino detection in xenon detectors
• Supernova electron-neutrino interactions with xenon in the nEXO detector
• Two-neutrino $\beta \beta$ decay to excited states at next-to-leading order