Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Non-Mesonic Weak Decay of Double-Lambda Hypernuclei: A Microscopic
  Approach   The non--mesonic weak decay of double--$\Lambda$ hypernuclei is studied
within a microscopic diagrammatic approach. Besides the nucleon--induced
mechanism, $\Lambda N\to nN$, widely studied in single--$\Lambda$ hypernuclei,
additional hyperon--induced mechanisms, $\Lambda \Lambda\to \Lambda n$,
$\Lambda \Lambda\to \Sigma^0 n$ and $\Lambda \Lambda\to \Sigma^-p$, are
accessible in double--$\Lambda$ hypernuclei and are investigated here. As in
previous works on single--$\Lambda$ hypernuclei, we adopt a nuclear matter
formalism extended to finite nuclei via the local density approximation and a
one--meson exchange weak transition potential (including the ground state
pseudoscalar and vector octets mesons) supplemented by correlated and
uncorrelated two--pion--exchange contributions. The weak decay rates are
evaluated for hypernuclei in the region of the experimentally accessible light
hypernuclei $^{10}_{\Lambda\Lambda}$Be and $^{13}_{\Lambda\Lambda}$B. Our
predictions are compared with a few previous evaluations. The rate for the
$\Lambda \Lambda\to \Lambda n$ decay is dominated by $K$--, $K^*$-- and
$\eta$--exchange and turns out to be about 2.5\% of the free $\Lambda$ decay
rate, $\Gamma_{\Lambda}^{\rm free}$, while the total rate for the $\Lambda
\Lambda\to \Sigma^0 n$ and $\Lambda \Lambda\to \Sigma^- p$ decays, dominated by
$\pi$--exchange, amounts to about 0.25\% of $\Gamma_{\Lambda}^{\rm free}$. The
experimental measurement of these decays would be essential for the beginning
of a systematic study of the non--mesonic decay of strangeness $-2$
hypernuclei. This field of research could also shed light on the possible
existence and nature of the $H$--dibaryon.

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The categories of this paper are: solv-int
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-th
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: mtrl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: physics
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The categories of this paper are: comp-gas
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The categories of this paper are: cs
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The categories of this paper are: q-alg
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The categories of this paper are: eess