Alpha-Core Breakup in the Strong Decay of ΛΛ6He to a Deeply Bound H Dibaryon
Abstract
We investigate the effect of α-core breakup on the strong conversion of 6ΛΛHe into a deeply bound H dibaryon. In addition to the coherent H+4He channel, we evaluate the open final states H+p+3H, H+n+3He, and H+d+d using a translationally invariant Gaussian cluster description, including spin-isospin recoupling and full nonrelativistic three-body phase-space integrations. The breakup widths are normalized to Gal's intact-α result. At BΛΛH=176 MeV, corresponding to mH≃2055 MeV, the summed breakup width exceeds the intact-α width by a factor Rbr=2.49×103. The resulting inclusive width and lifetime are Γinc=3.87×10−4 eV and τinc=1.70×10−12 s, respectively, compared with τα=4.25×10−9 s for the intact-α channel alone. The mass-dependent calculation shows that the inclusive lifetime crosses the characteristic hypernuclear weak-decay timescale near mH≃2020 MeV and increases rapidly as the H mass decreases. In the representative dark-matter-motivated interval 1865≤ mH≤1885 MeV, we obtain 6.59×10−4≲τinc≲ 6.80×10−3 s, far exceeding the weak-decay timescale. Thus, although core breakup can dominate the inclusive strong width near mH≃2055 MeV, weakly decaying double-Λ hypernuclei remain compatible, within the present framework, with a deeply bound uuddss state in the mass range relevant to sexaquark dark matter.
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BibTeX
@misc{shahrbaf2026alphacore,
title = {{Alpha-Core Breakup in the Strong Decay of \(_ΛΛ^6\mathrmHe\) to a Deeply Bound \(H\) Dibaryon}},
author = {Mahboubeh Shahrbaf and Makoto Oka},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.17117},
eprint = {2609.17117},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.17117},
}
RIS
TY - UNPB
TI - Alpha-Core Breakup in the Strong Decay of _ΛΛ^6He to a Deeply Bound H Dibaryon
AU - Mahboubeh Shahrbaf
AU - Makoto Oka
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.17117
UR - https://arxiv.org/abs/2609.17117
AB - We investigate the effect of α-core breakup on the strong conversion of ^6_ΛΛHe into a deeply bound H dibaryon. In addition to the coherent H+^4He channel, we evaluate the open final states H+p+^3H, H+n+^3He, and H+d+d using a translationally invariant Gaussian cluster description, including spin-isospin recoupling and full nonrelativistic three-body phase-space integrations. The breakup widths are normalized to Gal's intact-α result. At B_ΛΛ^H=176 MeV, corresponding to m_H≃2055 MeV, the summed breakup width exceeds the intact-α width by a factor R_br=2.49×10^3. The resulting inclusive width and lifetime are Γ_inc=3.87×10^−4 eV and τ_inc=1.70×10^−12 s, respectively, compared with τ_α=4.25×10^−9 s for the intact-α channel alone. The mass-dependent calculation shows that the inclusive lifetime crosses the characteristic hypernuclear weak-decay timescale near m_H≃2020 MeV and increases rapidly as the H mass decreases. In the representative dark-matter-motivated interval 1865≤ m_H≤1885 MeV, we obtain 6.59×10^−4≲τ_inc≲ 6.80×10^−3 s, far exceeding the weak-decay timescale. Thus, although core breakup can dominate the inclusive strong width near m_H≃2055 MeV, weakly decaying double-Λ hypernuclei remain compatible, within the present framework, with a deeply bound uuddss state in the mass range relevant to sexaquark dark matter.
ER -