Ab initio correlations between neutrinoless and two-neutrino double-beta decays in $^{48}$Ca

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Hauptverfasser: Lian, X., Ding, C. R., Bai, C. L., Yao, J. M.
Format: Preprint
Veröffentlicht: 2026
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author Lian, X.
Ding, C. R.
Bai, C. L.
Yao, J. M.
author_facet Lian, X.
Ding, C. R.
Bai, C. L.
Yao, J. M.
contents We develop a novel ab initio in-medium no-core configuration-interaction (IM-NCCI) framework for nuclear charge-exchange processes by combining the in-medium similarity renormalization group with chiral nuclear Hamiltonians, and apply it to the $2νββ$ and $0νββ$ decays of $^{48}$Ca. This framework reproduces the locations of several main resonance peaks in the Gamow-Teller (GT) strength distribution for the $^{48}\mathrm{Ca}\to{}^{48}\mathrm{Sc}$ transition. The cumulative GT strength indicates missing contributions from two-body weak currents, corresponding to an effective quenching factor of $q\simeq0.84$. Incorporating this quenching yields a $2νββ$ nuclear matrix element (NME) in excellent agreement with experiment. Applying the same framework to $0νββ$ decay, and including the contribution from short-range operators, we obtain a total NME of $M^{0ν}=1.00\text{-}2.02$. Using 34 non-implausible chiral Hamiltonians, we establish from first principles strong linear correlations between the $0νββ$ NME and the NMEs governing $2νββ$ decay and double GT transitions. Combining these correlation relations within the 95% confidence level with the experimental $2νββ$-decay data yields a constrained prediction of $M^{0ν}=1.30\text{-}1.65$. This work establishes IM-NCCI as a complementary ab initio framework for nuclear weak decays and opens a pathway toward constraining $0νββ$ NMEs in heavier candidate nuclei using experimentally accessible $2νββ$-decay data.
format Preprint
id arxiv_https___arxiv_org_abs_2605_19479
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Ab initio correlations between neutrinoless and two-neutrino double-beta decays in $^{48}$Ca
Lian, X.
Ding, C. R.
Bai, C. L.
Yao, J. M.
Nuclear Theory
High Energy Physics - Phenomenology
Nuclear Experiment
We develop a novel ab initio in-medium no-core configuration-interaction (IM-NCCI) framework for nuclear charge-exchange processes by combining the in-medium similarity renormalization group with chiral nuclear Hamiltonians, and apply it to the $2νββ$ and $0νββ$ decays of $^{48}$Ca. This framework reproduces the locations of several main resonance peaks in the Gamow-Teller (GT) strength distribution for the $^{48}\mathrm{Ca}\to{}^{48}\mathrm{Sc}$ transition. The cumulative GT strength indicates missing contributions from two-body weak currents, corresponding to an effective quenching factor of $q\simeq0.84$. Incorporating this quenching yields a $2νββ$ nuclear matrix element (NME) in excellent agreement with experiment. Applying the same framework to $0νββ$ decay, and including the contribution from short-range operators, we obtain a total NME of $M^{0ν}=1.00\text{-}2.02$. Using 34 non-implausible chiral Hamiltonians, we establish from first principles strong linear correlations between the $0νββ$ NME and the NMEs governing $2νββ$ decay and double GT transitions. Combining these correlation relations within the 95% confidence level with the experimental $2νββ$-decay data yields a constrained prediction of $M^{0ν}=1.30\text{-}1.65$. This work establishes IM-NCCI as a complementary ab initio framework for nuclear weak decays and opens a pathway toward constraining $0νββ$ NMEs in heavier candidate nuclei using experimentally accessible $2νββ$-decay data.
title Ab initio correlations between neutrinoless and two-neutrino double-beta decays in $^{48}$Ca
topic Nuclear Theory
High Energy Physics - Phenomenology
Nuclear Experiment
url https://arxiv.org/abs/2605.19479