Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effective Lagrangian Approach to Weak Radiative Decays of Heavy Hadrons   Motivated by the observation of the decay $\bar{B}\to \bar{K}^*\gamma$ by
CLEO, we have systematically analyzed the two-body weak radiative decays of
bottom and charmed hadrons. There exist two types of weak radiative decays: One
proceeds through the short-distance $b\to s\gamma$ transition and the other
occurs through $W$-exchange accompanied by a photon emission. Effective
Lagrangians are derived for the $W$-exchange bremsstrahlung processes at the
quark level and then applied to various weak electromagnetic decays of heavy
hadrons. Predictions for the branching ratios of $\bar{B}^0\to D^{*0}
\gamma,~\Lambda_b^0\to\Sigma_c^0\gamma,~\Xi_b^0\to \Xi_c^0\gamma$ and
$\Xi_b^0\to\xip_c^0\gamma$ are given. In particular, we found ${\cal
B}(\bar{B}^0 \to D^{*0}\gamma)\approx 0.9\times 10^{-6}$. Order of magnitude
estimates for the weak radiative decays of charmed hadrons: $~D^0\to
\bar{K}^{*0}\gamma,~\Lambda_c^+\to\Sigma^+\gamma$ and $\Xi_c^0\to\Xi^0\gamma$
are also presented. Within this approach, the decay asymmetry for antitriplet
to antitriplet heavy baryon weak radiative transitions is uniquely predicted by
heavy quark symmetry. The electromagnetic penguin contribution to
$\Lambda_b^0\to\Lambda\gamma$ is estimated by two different methods and its
branching ratio is found to be of order $1\times 10^{-5}$. We conclude that
weak radiative decays of bottom hadrons are dominated by the short-distance
$b\to s\gamma$ mechanism.

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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: comp-gas
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The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: math
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The categories of this paper are: cs
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The categories of this paper are: physics
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The categories of this paper are: supr-con