Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 'Majorana mass' fermions as untrue Majorana particles, rather endowed
  with pseudoscalar-type charges than genuinely neutral   The idea of a `Majorana mass' to make a chiral neutrino really neutral is
here reconsidered. It is pointed out that such an approach, unlike Majorana's
(non-chiral) old one, does not strictly lead, in general, to a true
self-conjugate particle. This can be seen on directly using the basic
definition (or fundamental representation) of charge conjugation $C$ in Quantum
Field Theory, as an operation just acting on annihilation and creation
operators and just expressing particle--antiparticle interchange. It is found,
indeed, that the `active' and `sterile' whole fields which can be obtained from
mixing the chiral components of two mutually charge-conjugate Dirac fields are
themselves `charge conjugate' to each other (rather than individually
self-conjugate). These fields, taken as mass eigenfields (as in the `Majorana
mass' case), are shown to describe particles carrying pseudoscalar-type charges
and being neutral relative to scalar-type charges only. For them, `$CP$
symmetry' would be nothing but pure mirror symmetry, and $C$ violation (already
implied in their respective `active' and `sterile' behaviors) should then
involve time-reversal violation as well. The new (no longer strictly
chargeless) `Majorana mass' neutrino model still proves, however, neither to
affect the usual expectation for a neutrinoless double $\beta$-decay, nor to
prevent `active' and `sterile' neutrino varieties from generally taking
different mass values. One has, on the other hand, that any fermion being just
a genuine (i.e. really self-conjugate) Majorana particle cannot truly exist in
two distinct $-$ `active' and `sterile' $-$ versions, and it can further bear
only a unified mass kind which may at once be said to be either a
`Majorana-like' or a `Dirac-like' mass kind.

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The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys