Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superluminal neutrinos and domain walls   In this letter, we propose that the recent measurement of superluminal
neutrinos in OPERA could be explained by the existence of a domain wall which
is left behind after the phase transition of some scalar field in the universe.
The scalar field couples to the neutrino and photon field with different
effective couplings. It causes different effective metrics and the emergence of
superluminal neutrinos. Moreover, if the supernova and the earth are in the
same plane parallel to the wall, or the thickness of the wall is much smaller
than the distance from the supernova to the earth, the contradiction between
OPERA and SN1987a can be reconciled.

22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga