Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Neutrino Mass Matrix with Vanishing $\mu$--$\mu$ and $\tau$--$\tau$
  Entries   We revisit our earlier proposal for the form of the neutrino mass matrix: a
two-zero ansatz wherein the CP-violating PMNS phase $\delta$ plays a
surprisingly important role. We review its observable consequences and show how
our ansatz follows from a softly-broken symmetry (muon number minus tau lepton
number) in a see-saw model with three Higgs doublets.

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The categories of this paper are: physics
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The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
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The categories of this paper are: math-ph
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The categories of this paper are: math
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph