Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Isospin amplitudes in $\Lambda_b^0\to J/\psi \Lambda(\Sigma^0)$ and
  $\Xi_b^0\to J/\psi \Xi^0(\Lambda)$ decays   Ratios of isospin amplitudes in hadron decays are a useful probe of the
interplay between weak and strong interactions, and allow searches for physics
beyond the Standard Model. We present the first results on isospin amplitudes
in $b$-baryon decays, using data corresponding to an integrated luminosity of
8.5 fb$^{-1}$, collected with the LHCb detector in $pp$ collisions at center of
mass energies of 7, 8 and 13 TeV. The isospin amplitude ratio
$|A_1(\Lambda_b^0\to J/\psi \Sigma^0)/A_0(\Lambda_b^0\to J/\psi\Lambda)|$,
where the subscript on $A$ indicates the final-state isospin, is measured to be
less than 1/21.8 at 95\% confidence level. The Cabibbo suppressed $\Xi_b^0\to
J/\psi\Lambda$ decay is observed for the first time, allowing for the
measurement $|A_0(\Xi_b^0\to J/\psi\Lambda)/A_{1/2}(\Xi_b^0\to J/\psi\Xi^0)|
=0.37 \pm 0.06\pm 0.02$, where the uncertainties are statistical and
systematic, respectively.

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The categories of this paper are: astro-ph
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
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The categories of this paper are: plasm-ph
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The categories of this paper are: econ
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The categories of this paper are: mtrl-th
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The categories of this paper are: supr-con
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The categories of this paper are: nlin
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The categories of this paper are: gr-qc
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The categories of this paper are: comp-gas
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The categories of this paper are: physics
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The categories of this paper are: hep-th
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th