Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spontaneous Lorentz Violation via QED with Non-Exact Gauge Invariance   We reconsider an alternative theory of the QED with the photon as a massless
vector Nambu-Goldstone boson and show that the underlying spontaneous Lorentz
violation caused by the vector field vacuum expectation value, while being
superficial in gauge invariant theory, becomes physically significant in the
QED with a tiny gauge non-invariance. This leads, through special dispersion
relations appearing for charged fermions, to a new class of phenomena which
could be of distinctive observational interest in particle physics and
astrophysics. They include a significant change in the GZK cutoff for UHE
cosmic-ray nucleons, stability of high-energy pions and W bosons, modification
of nucleon beta decays, and some others.

1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess