Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 2-Group Global Symmetries and Anomalies in Six-Dimensional Quantum Field
  Theories   We examine six-dimensional quantum field theories through the lens of
higher-form global symmetries. Every Yang-Mills gauge theory in six dimensions,
with field strength $f^{(2)}$, naturally gives rise to a continuous 1-form
global symmetry associated with the 2-form instanton current $J^{(2)} \sim *
\text{Tr} \left( f^{(2)} \wedge f^{(2)}\right)$. We show that suitable mixed
anomalies involving the gauge field $f^{(2)}$ and ordinary 0-form global
symmetries, such as flavor or Poincar\'e symmetries, lead to continuous 2-group
global symmetries, which allow two flavor currents or two stress tensors to
fuse into the 2-form current $J^{(2)}$. We discuss several features of 2-group
symmetry in six dimensions, many of which parallel the four-dimensional case.
The majority of six-dimensional supersymmetric conformal field theories (SCFTs)
and little string theories have infrared phases with non-abelian gauge fields.
We show that the mixed anomalies leading to 2-group symmetries can be present
in little string theories, but that they are necessarily absent in SCFTs. This
allows us to establish a previously conjectured algorithm for computing the 't
Hooft anomalies of most SCFTs from the spectrum of weakly-coupled massless
particles on the tensor branch of these theories. We then apply this
understanding to prove that the $a$-type Weyl anomaly of all SCFTs with a
tensor branch must be positive, $a > 0$.

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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: cs
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The categories of this paper are: mtrl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: physics
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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol