Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Heavy-Neutrino Chirality Enhancement of the Decay $K_L -> e\mu $ in
  Left-Right Symmetric Models   We study the decay $K_L -> e\mu$ in minimal extensions of the Standard Model
based on the gauge groups $SU(2)_L x U(1)_Y$ and $SU(2)_R x SU(2)_L x
U(1)_{B-L}$, in which heavy Majorana neutrinos are present. In $SU(2)_L x
U(1)_Y$ models with chiral neutral singlets, $B(K_L -> e\mu )$ cannot be much
larger than $5 x 10^{-15}$ without violating other low-energy constraints. In
$SU(2)_L x SU(2)_R x U(1)_{B-L}$ models, we find that heavy-neutrino-chirality
enhancements due to the presence of left-handed and right- handed currents can
give rise to a branching ratio close to the present experimental limit $B(K_L
-> e \mu)< 3.3 x 10^{-11}$.

12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
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The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg