292 research outputs found
Can Measurements of Electric Dipole Moments Determine the Seesaw Parameters?
In the context of the supersymmetrized seesaw mechanism embedded in the
Minimal Supersymmetric Standard Model (MSSM), complex neutrino Yukawa couplings
can induce Electric Dipole Moments (EDMs) for the charged leptons, providing an
additional route to seesaw parameters. However, the complex neutrino Yukawa
matrix is not the only possible source of CP violation. Even in the framework
of Constrained MSSM (CMSSM), there are additional sources, usually attributed
to the phases of the trilinear soft supersymmetry breaking couplings and the
mu-term, which contribute not only to the electron EDM but also to the EDMs of
neutron and heavy nuclei. In this work, by combining bounds on various EDMs, we
analyze how the sources of CP violation can be discriminated by the present and
planned EDM experiments.Comment: 26 pages, 9 figures; added reference
Dipolar Bose-Einstein condensate soliton on a two-dimensional optical lattice
Using a three-dimensional mean-field model we study one-dimensional dipolar
Bose-Einstein condensate (BEC) solitons on a weak two-dimensional (2D) square
and triangular optical lattice (OL) potentials placed perpendicular to the
polarization direction. The stabilization against collapse and expansion of
these solitons for a fixed dipolar interaction and a fixed number of atoms is
possible for short-range atomic interaction lying between two critical limits.
The solitons collapse below the lower limit and escapes to infinity above the
upper limit. One can also stabilize identical tiny BEC solitons arranged on the
2D square OL sites forming a stable 2D array of interacting droplets when the
OL sites are filled with a filling factor of 1/2 or less. Such an array is
unstable when the filling factor is made more than 1/2 by occupying two
adjacent sites of OL. These stable 2D arrays of dipolar superfluid BEC solitons
are quite similar to the recently studied dipolar Mott insulator states on 2D
lattice in the Bose-Hubbard model by Capogrosso-Sansone et al. [B.
Capogrosso-Sansone, C. Trefzger, M. Lewenstein, P. Zoller, G. Pupillo, Phys.
Rev. Lett. 104 (2010) 125301].Comment: 8 pages, 5 figures and 2 table
Reaction and Axial Vector Coupling
The reaction is studied in the region of low
to investigate the effect of deuteron structure and width of the
resonance on the differential cross section. The results are used to extract
the axial vector coupling from the experimental data on
this reaction. The possibility to determine this coupling from electroweak
interaction experiments with high intensity electron accelerators is discussed.Comment: 14 pages, REVTEX, 5 figure
Effects of Large CP violating phases on g_{\m}-2 in MSSM
Effects of CP violation on the supersymmetric electro-weak correction to the
anomalous magnetic moment of the muon are investigated with the most general
allowed set of CP violating phases in MSSM. The analysis includes contributions
from the chargino and the neutralino exchanges to the muon anomaly. The
supersymmetric contributions depend only on specific combinations of CP phases.
The independent set of such phases is classified. We analyse the effects of the
phases under the EDM constraints and show that large CP violating phases can
drastically affect the magnitude of the supersymmetric electro-weak
contribution to and may even affect its overall sign.Comment: 26 pages Latex file including 4 figure
Weak Isospin Violations in Charged and Neutral Higgs Couplings from SUSY Loop Corrections
Supersymmetric QCD and supersymmetric electroweak loop corrections to the
violations of weak isospin to Yukawa couplings are investigated. Specifically
it involves an analysis of the supersymmetric loop corrections to the Higgs
couplings to the third generation quarks and leptons. Here we analyze the SUSY
loop corrections to the charged Higgs couplings which are then compared with
the supersymmetric loop corrections to the neutral Higgs couplings previously
computed. It is found that the weak isospin violations can be quite
significant, i.e, as much as 40-50% or more of the total loop correction to the
Yukawa coupling. The effects of CP phases are also studied and it is found that
these effects can either enhance or suppress the weak isospin violations. We
also investigate the weak isospin violation effects on the branching ratio
and show that the effects
are sensitive to CP phases. Thus an accurate measurement of this branching
ratio along with the branching ratio of the neutral Higgs boson decays can
provide a measure of weak isospin violation along with providing a clue to the
presence of supersymmetry.Comment: 20 pages, 9 figure
Stability of the Minimal Heterotic Standard Model Bundle
The observable sector of the "minimal heterotic standard model" has precisely
the matter spectrum of the MSSM: three families of quarks and leptons, each
with a right-handed neutrino, and one Higgs-Higgs conjugate pair. In this
paper, it is explicitly proven that the SU(4) holomorphic vector bundle leading
to the MSSM spectrum in the observable sector is slope-stable.Comment: LaTeX, 19 page
The modulation effect for supersymmetric dark matter detection with asymmetric velocity dispersion
The detection of the theoretically expected dark matter is central to
particle physics cosmology. Current fashionable supersymmetric models provide a
natural dark matter candidate which is the lightest supersymmetric particle
(LSP). Such models combined with fairly well understood physics like the quark
substructure of the nucleon and the nuclear form factor and the spin response
function of the nucleus, permit the evaluation of the event rate for
LSP-nucleus elastic scattering. The thus obtained event rates are, however,
very low or even undetectable. So it is imperative to exploit the modulation
effect, i.e. the dependence of the event rate on the earth's annual motion. In
this review we study such a modulation effect in directional and undirectional
experiments. We calculate both the differential and the total rates using
symmetric as well as asymmetric velocity distributions. We find that in the
symmetric case the modulation amplitude is small, less than 0.07. There exist,
however, regions of the phase space and experimental conditions such that the
effect can become larger. The inclusion of asymmetry, with a realistic enhanced
velocity dispersion in the galactocentric direction, yields the bonus of an
enhanced modulation effect, with an amplitude which for certain parameters can
become as large as 0.46.Comment: 35 LATEX pages, 7 Tables, 8 PostScript Figures include
Wetting films on chemically heterogeneous substrates
Based on a microscopic density functional theory we investigate the
morphology of thin liquidlike wetting films adsorbed on substrates endowed with
well-defined chemical heterogeneities. As paradigmatic cases we focus on a
single chemical step and on a single stripe. In view of applications in
microfluidics the accuracy of guiding liquids by chemical microchannels is
discussed. Finally we give a general prescription of how to investigate
theoretically the wetting properties of substrates with arbitrary chemical
structures.Comment: 56 pages, RevTeX, 20 Figure
Numerical simulations of the Warm-Hot Intergalactic Medium
In this paper we review the current predictions of numerical simulations for
the origin and observability of the warm hot intergalactic medium (WHIM), the
diffuse gas that contains up to 50 per cent of the baryons at z~0. During
structure formation, gravitational accretion shocks emerging from collapsing
regions gradually heat the intergalactic medium (IGM) to temperatures in the
range T~10^5-10^7 K. The WHIM is predicted to radiate most of its energy in the
ultraviolet (UV) and X-ray bands and to contribute a significant fraction of
the soft X-ray background emission. While O VI and C IV absorption systems
arising in the cooler fraction of the WHIM with T~10^5-10^5.5 K are seen in
FUSE and HST observations, models agree that current X-ray telescopes such as
Chandra and XMM-Newton do not have enough sensitivity to detect the hotter
WHIM. However, future missions such as Constellation-X and XEUS might be able
to detect both emission lines and absorption systems from highly ionised atoms
such as O VII, O VIII and Fe XVII.Comment: 18 pages, 5 figures, accepted for publication in Space Science
Reviews, special issue "Clusters of galaxies: beyond the thermal view",
Editor J.S. Kaastra, Chapter 14; work done by an international team at the
International Space Science Institute (ISSI), Bern, organised by J.S.
Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke
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