Precision Analysis of the ${}^{136}$Xe Two-Neutrino $\beta \beta$ Spectrum in KamLAND-Zen and Its Impact on the Quenching of Nuclear Matrix Elements

Abstract

We present a precision analysis of the ${}^{136}$Xe two-neutrino $\beta \beta$ electron spectrum above 0.8 MeV, based on high-statistics data obtained with the KamLAND-Zen experiment. An improved formalism for the two-neutrino $\beta \beta$ rate allows us to measure the ratio of the leading and subleading $2\nu \beta \beta$ nuclear matrix elements (NMEs), ${\xi }_{31}^{2\nu }=-0.26_{-0.25}^{+0.31}$. Theoretical predictions from the nuclear shell model and the majority of the quasiparticle random-phase approximation (QRPA) calculations are consistent with the experimental limit. However, part of the ${\xi }_{31}^{2\nu }$ range allowed by the QRPA is excluded by the present measurement at the 90% confidence level. Our analysis reveals that predicted ${\xi }_{31}^{2\nu }$ values are sensitive to the quenching of NMEs and the competing contributions from low- and high-energy states in the intermediate nucleus. Since these aspects are also at play in neutrinoless $\beta \beta$ decay, ${\xi }_{31}^{2\nu }$ provides new insights towards reliable neutrinoless $\beta \beta$ NMEs.

7 pages, 4 figures

References in corpus (16)

• Double Beta Decay, Majorana Neutrinos, and Neutrino Mass
• Status and Future of Nuclear Matrix Elements for Neutrinoless Double-Beta Decay: A Review
• Phase space factors for double-$\beta$ decay
• Disassembling the Nuclear Matrix Elements of the Neutrinoless double beta Decay
• Nuclear matrix elements for double-β decay
• $0\nu \beta \beta$ and $2\nu \beta \beta$ nuclear matrix elements, QRPA, and isospin symmetry restoration
• Erratum: Assessment of uncertainties in QRPA $0\nu \beta \beta$-decay nuclear matrix elements [Nucl. Phys. A 766, 107 (2006)]
• Average and recommended half-life values for two neutrino double beta decay
• Nuclear Structure Relevant to Neutrinoless Double Beta Decay: 76Ge and 76Se
• Nuclear Structure Relevant to Neutrinoless Double Beta Decay: the Valence Protons in 76Ge and 76Se
• Shell model studies of the ${}^{130}Te$ neutrinoless double-beta decay
• A monopole-optimized effective interaction for tin isotopes
• Overconstrained estimates of neutrinoless double beta decay within the QRPA
• Collectivity in the light Xenon isotopes: A shell model study
• Nuclear Structure Aspects of Neutrinoless Double Beta Decay
• Accurate shell-model nuclear matrix elements for neutrinoless double-beta decay

Cited by in corpus (35)

• 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
• A Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics
• The Future of Solar Neutrinos
• Impact of the leading-order short-range nuclear matrix element on the neutrinoless double-beta decay of medium-mass and heavy nuclei
• Measurement of the 2$\nu \beta \beta$ Decay Half-life of ${}^{130}$Te with CUORE
• Searching for New Physics in Two-Neutrino Double Beta Decay
• Double-Weak Decays of ${}^{124}$Xe and ${}^{136}$Xe in the XENON1T and XENONnT Experiments
• Neutrinoless $\beta \beta$-decay nuclear matrix elements from two-neutrino $\beta \beta$-decay data
• Two-Neutrino Double Beta Decay with Sterile Neutrinos
• Search for Majorana Neutrinos with the Complete KamLAND-Zen Dataset
• Measurement of the ${}^{136}$Xe two-neutrino double beta decay half-life via direct background subtraction in NEXT
• Review of Novel Approaches to Organic Liquid Scintillators in Neutrino Physics
• Measurement of Double Beta Decay Half-life of ${}^{136}$Xe with the PandaX-4T Detector
• Searching for Two-Neutrino and Neutrinoless Double Beta Decay of ${}^{134}$Xe with the PandaX-4T Experiment
• Two-neutrino double-beta decay in pionless effective field theory from a Euclidean finite-volume correlation function
• Neutrinoless double-beta decay from an effective field theory for heavy nuclei
• Search for Majoron-like particles with CUPID-0
• Cosmogenic activation in double beta decay experiments
• Neutrinoless $\beta \beta$ decay nuclear matrix elements complete up to N${}^2$LO in heavy nuclei
• Evaluation of radon adsorption efficiency values in xenon with activated carbon fibers
• Two-neutrino double-beta decay matrix elements based on relativistic nuclear energy density functional
• Theoretical analysis and predictions for the double electron capture of ${}^{124}$Xe
• Development of New Tracking Detector with Fine-grained Nuclear Emulsion for sub-MeV Neutron Measurement
• Comprehensive Review of 2$\beta$ Decay Half-Lives
• Two-neutrino $\beta \beta$ decay of ${}^{136}$Xe to the first excited $0^{+}$ state in ${}^{136}$Ba
• Radiative and exchange corrections for two-neutrino double-beta decay
• Double Beta Decay Experiments at Canfranc Underground Laboratory
• Effects of perturbation for transition operator of double-$\beta$ decay on nuclear matrix element, effective axial-vector current coupling, and half-life
• Probing Dark Sector Particles Coupling to Neutrinos with Double Beta Decay
• Investigation of the cause of the discrepancies between calculated running sums for nuclear matrix elements of two-neutrino double-$\beta$ decay
• Precise ${}^{136}$Xe Double Beta Decay Measurement in PandaX-4T with Implications on the Nuclear Matrix Elements and Majorons
• What can we learn from recent $2\nu \beta \beta$ experiments?
• Search for neutrinoless quadruple beta decay of ${}^{136}$Xe in XMASS-I
• Measurement of the $2\nu \beta \beta$ decay rate and spectral shape of ${}^{100}$Mo from the CUPID-Mo experiment