125 research outputs found
Effects of quarks on the formation and evolution of Z(3) walls and strings in relativistic heavy-ion collisions
We investigate the effects of explicit breaking of Z(3) symmetry due to the
presence of dynamical quarks on the formation and evolution of Z(3) walls and
associated QGP strings within Polyakov loop model. We carry out numerical
simulations of the first order quark-hadron phase transition via bubble
nucleation (which may be appropriate, for example, at finite baryon chemical
potential) in the context of relativistic heavy-ion collision experiments.
Using appropriate shifting of the order parameter in the Polyakov loop
effective potential, we calculate the bubble profiles using bounce technique,
for the true vacuum as well as for the metastable Z(3) vacua, and estimate the
associated nucleation probabilities. These different bubbles are then nucleated
and evolved and resulting formation and dynamics of Z(3) walls and QGP strings
is studied. We discuss various implications of the existence of these Z(3)
interfaces and the QGP strings, especially in view of the effects of the
explicit breaking of the Z(3) symmetry on the formation and dynamical evolution
of these objects.Comment: 17 pages, 9 figures, PDFLate
Big Bang in with external field and flat 4d Universe
We describe spontaneous creation of the Brane World in with
external field. The resulting Brane World consists of a flat 4d spatially
finite expanding Universe and curved expanding "regulator" branes. No negative
tension branes are involved.Comment: Latex, 11 pages, 5 eps figures, references adde
A comprehensive analysis of the dark matter direct detection experiments in the mirror dark matter framework
Mirror dark matter offers a framework to explain the existing dark matter
direct detection experiments. Here we confront this theory with the most recent
experimental data, paying attention to the various known systematic
uncertainties, in quenching factor, detector resolution, galactic rotational
velocity and velocity dispersion. We perform a detailed analysis of the DAMA
and CoGeNT experiments assuming a negligible channeling fraction and find that
the data can be fully explained within the mirror dark matter framework. We
also show that the mirror dark matter candidate can explain recent data from
the CDMS/Ge, EdelweissII and CRESSTII experiments and we point out ways in
which the theory can be further tested in the near future.Comment: about 30 page
Phenomenology of 10^32 Dark Sectors
We postulate an exact permutation symmetry acting on 10^32 Standard Model
copies as the largest possible symmetry extension of the Standard Model. This
setup automatically lowers the fundamental gravity cutoff down to TeV, and
thus, accounts for the quantum stability of the weak scale. We study the
phenomenology of this framework and show that below TeV energies the copies are
well hidden, obeying all the existing observational bounds. Nevertheless, we
identify a potential low energy window into the hidden world, the oscillation
of the neutron into its dark copies. At the same time, proton decay can be
suppressed by gauging the diagonal baryon number of the different copies. This
framework offers an alternative approach to several particle physics questions.
For example, we suggest a novel mechanism for generating naturally small
neutrino masses that are suppressed by the number of neutrino species. The
mirror copies of the Standard Model naturally house dark matter candidates. The
general experimentally observable prediction of this scenario is an emergence
of strong gravitational effects at the LHC. The low energy permutation symmetry
powerfully constrains the form of this new gravitational physics and allows to
make observational predictions, such as, production of micro black-holes with
very peculiar properties.Comment: 36 pages. v2, note added on oscillation of neutral state, Refs. adde
Equivalence principle and experimental tests of gravitational spin effects
We study the possibility of experimental testing the manifestations of
equivalence principle in spin-gravity interactions. We reconsider the earlier
experimental data and get the first experimental bound on anomalous
gravitomagnetic moment. The spin coupling to the Earth's rotation may also be
explored at the extensions of neutron EDM and g-2 experiments. The spin
coupling to the terrestrial gravity produces a considerable effect which may be
discovered at the planned deuteron EDM experiment. The Earth's rotation should
also be taken into account in optical experiments on a search for axionlike
particles.Comment: 12 pages, version to appear in Physical Review
Relativistic quantum model of confinement and the current quark masses
We consider a relativistic quantum model of confined massive spinning quarks
and antiquarks which describes leading Regge trajectories of mesons. The quarks
are described by the Dirac equations and the gluon contribution is approximated
by the Nambu-Goto straight-line string. The string tension and the current
quark masses are the main parameters of the model. Additional parameters are
phenomenological constants which approximate nonstring short-range
contributions. Comparison of the measured meson masses with the model
predictions allows one to determine the current quark masses (in MeV) to be
. The chiral
model[23] makes it possible to estimate from here the - and -quark masses
to be ~ Mev and Mev.Comment: 15 pages, LATEX, 2 tables. (submitted to Phys.Rev.D
Possible types of the evolution of vacuum shells around the de Sitter space
All possible evolution scenarios of a thin vacuum shell surrounding the
spherically symmetric de Sitter space have been determined and the
corresponding global geometries have been constructed. Such configurations can
appear at the final stage of the cosmological phase transition, when isolated
regions (islands) of the old vacuum remain. The islands of the old vacuum are
absorbed by the new vacuum, expand unlimitedly, or form black holes and
wormholes depending on the sizes of the islands as well as on the density and
velocity of the shells surrounding the islands.Comment: 3 pages, 1 figur
Statistics of resonance poles, phase shifts and time delays in quantum chaotic scattering for systems with broken time reversal invariance
Assuming the validity of random matrices for describing the statistics of a
closed chaotic quantum system, we study analytically some statistical
properties of the S-matrix characterizing scattering in its open counterpart.
In the first part of the paper we attempt to expose systematically ideas
underlying the so-called stochastic (Heidelberg) approach to chaotic quantum
scattering. Then we concentrate on systems with broken time-reversal invariance
coupled to continua via M open channels. By using the supersymmetry method we
derive:
(i) an explicit expression for the density of S-matrix poles (resonances) in
the complex energy plane
(ii) an explicit expression for the parametric correlation function of
densities of eigenphases of the S-matrix.
We use it to find the distribution of derivatives of these eigenphases with
respect to the energy ("partial delay times" ) as well as with respect to an
arbitrary external parameter.Comment: 51 pages, RevTEX , three figures are available on request. To be
published in the special issue of the Journal of Mathematical Physic
Particle decay in false vacuum
We revisit the problem of decay of a metastable vacuum induced by the
presence of a particle. For the bosons of the `master field' the problem is
solved in any number of dimensions in terms of the spontaneous decay rate of
the false vacuum, while for a fermion we find a closed expression for the decay
rate in (1+1) dimensions. It is shown that in the (1+1) dimensional case an
infrared problem of one-loop correction to the decay rate of a boson is
resolved due to a cancellation between soft modes of the field. We also find
the boson decay rate in the `sine-Gordon staircase' model in the limits of
strong and weak coupling.Comment: 19 pages, 2 figure
Neutron - Mirror Neutron Oscillations: How Fast Might They Be?
We discuss the phenomenological implications of the neutron (n) oscillation
into the mirror neutron (n'), a hypothetical particle exactly degenerate in
mass with the neutron but sterile to normal matter. We show that the present
experimental data allow a maximal n-n' oscillation in vacuum with a
characteristic time much shorter than the neutron lifetime, in fact as
small as 1 sec. This phenomenon may manifest in neutron disappearance and
regeneration experiments perfectly accessible to present experimental
capabilities and may also have interesting astrophysical consequences, in
particular for the propagation of ultra high energy cosmic rays.Comment: 4 pages, 1 figure; revtex; matches paper published by P.R.
- …