125 research outputs found

    Effects of quarks on the formation and evolution of Z(3) walls and strings in relativistic heavy-ion collisions

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    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 AdS5AdS_{5} with external field and flat 4d Universe

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    We describe spontaneous creation of the Brane World in AdS5AdS_{5} 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

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    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

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    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

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    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

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    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 ms=227±5, mc=1440±10, mb=4715±20m_s = 227 \pm 5,~ m_c = 1440 \pm 10,~ m_b = 4715 \pm 20. The chiral SU3SU_3 model[23] makes it possible to estimate from here the uu- and dd-quark masses to be mu=6.2±0.2m_u = 6.2 \pm 0.2~ Mev and md=11.1±0.4m_d = 11.1 \pm 0.4 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

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    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

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    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

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    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?

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    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 Ï„\tau 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.
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