150 research outputs found
Through the Looking-Glass: Alice's Adventures in Mirror World
We briefly review the concept of a parallel `mirror' world which has the same
particle physics as the observable world and couples to the latter by gravity
and perhaps other very weak forces. The nucleosynthesis bounds demand that the
mirror world should have a smaller temperature than the ordinary one. By this
reason its evolution should substantially deviate from the standard cosmology
as far as the crucial epochs like baryogenesis, nucleosynthesis etc. are
concerned. In particular, we show that in the context of certain baryogenesis
scenarios, the baryon asymmetry in the mirror world should be larger than in
the observable one. Moreover, we show that mirror baryons could naturally
constitute the dominant dark matter component of the Universe, and discuss its
cosmological implications.Comment: Published in Ian Kogan Memorial Collection "From Fields to Strings:
Circumnavigating Theoretical Physics", Eds. M. Shifman et al., World
Scientific, Singapore, vol. 3, pp. 2147-2195. 49pp., 8 Figure
Unified picture of the particle and sparticle masses in SUSY GUT
The horizontal symmetry can greatly help in solving the flavor
problems in the supersymmetric grand unification. We consider the model and show that it leads to the remarkable relations between the
fermion mass matrices and the soft SUSY breaking terms. Dangerous
supersymmetric contributions to the flavor-changing phenomena are naturally
suppressed. The possible extensions to the model are also
outlined.Comment: Latex, 5 pages - some more discussions adde
Marriage between the baryonic and dark matters
The baryonic and dark matter fractions in the universe can be both generated
by the same baryogenesis mechanism, simultaneously and with comparable amounts,
if dark matter is constituted by the baryons of the mirror world, a parallel
hidden sector with the same (or similar) microphysics as that of the observable
world.Comment: 8 pages, invited talk at the "Dark Side of the Universe" DSU 2006,
Madrid, 19-24 June 200
Neutron-antineutron Oscillation and Baryonic Majoron: Low Scale Spontaneous Baryon Violation
We discuss a possibility that baryon number is spontaneously broken at
low scales, of the order of MeV or even smaller, so that the
neutron-antineutron oscillation can be induced at the experimentally accessible
level. An associated Goldstone particle, baryonic majoron, can have observable
effects in neutron to antineutron transitions in nuclei or dense nuclear
matter. By extending baryon number to symmetry, baryo-majoron can be
identified with the ordinary majoron associated with the spontaneous breaking
of lepton number, with interesting implications for neutrinoless becay
with the majoron emission, etc. We also discuss a hypothesis suggesting that
baryon number maybe spontaneously broken by the QCD itself via the six-quark
condensates.Comment: 8 pages, 5 figure
Neutron--Antineutron Oscillations: Discrete Symmetries and Quark Operators
We analyze status of , and discrete symmetries
in application to neutron-antineutron transitions breaking conservation of
baryon charge by two units. At the level of free particles all these
symmetries are preserved. This includes reflection in spite of the
opposite internal parities usually ascribed to neutron and antineutron.
Explanation, which goes back to the 1937 papers by E. Majorana and by G. Racah,
is based on a definition of parity satisfying , instead of
, and ascribing to both, neutron and antineutron.
We apply this to , and classification of six-quark
operators with . It allows to specify operators
contributing to neutron-antineutron oscillations. Remaining operators
contribute to other processes and, in particular, to
nuclei instability. We also show that presence of external magnetic field does
not induce any new operator mixing the neutron and antineutron provided that
rotational invariance is not broken.Comment: 8 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1506.0509
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