5,588 research outputs found
Inverse scattering and solitons in affine Toda field theories II
New single soliton solutions to the affine Toda field theories are
constructed, exhibiting previously unobserved topological charges. This goes
some of the way in filling the weights of the fundamental representations, but
nevertheless holes in the representations remain. We use the group doublecross
product form of the inverse scattering method, and restrict ourselves to the
rank one solutions.Comment: 19 pages, latex, 12 fig
Flipped Angles and Phases: A Systematic Study
We discuss systematically the fermion mass and mixing matrices in a generic
\linebreak field-theoretical flipped model, with particular
applications to neutrino and baryon number-changing physics. We demonstrate
that the different quark flavour branching ratios in proton decay are related
to the Cabibbo-Kobayashi-Maskawa angles, whereas the lepton flavour branching
ratios are undetermined. The light neutrino mixing angles observable via
oscillation effects are related to the heavy conjugate (right-handed) neutrino
mass matrix, which also plays a key role in cosmological baryogenesis. The
ratios of neutrino and charged lepton decay modes in baryon decay may also be
related to neutrino oscillation parameters. Plausible Ans\"atze for the
generation structure of coupling matrices motivate additional relations between
physical observables, and yield a satisfactory baryon asymmetry.Comment: 13 pages, no figures, latex (twice), CERN-TH.6842/93, UMN-TH-1130/93,
CTP-TAMU-11/9
Inverse scattering and solitons in affine Toda field theories
We implement the inverse scattering method in the case of the affine
Toda field theories, by studying the space-time evolution of simple poles in
the underlying loop group. We find the known single soliton solutions, as well
as additional solutions with non-linear modes of oscillation around the
standard solution, by studying the particularly simple case where the residue
at the pole is a rank one projection. We show that these solutions with extra
modes have the same mass and topological charges as the standard solutions, so
we do not shed any light on the missing topological charge problem in these
models. We also show that the integrated energy-momentum density can be
calculated from the central extension of the loop group.Comment: 28 pages, Latex, 4 figs include
Chaotic dynamics of superconductor vortices in the plastic phase
We present numerical simulation results of driven vortex lattices in presence
of random disorder at zero temperature. We show that the plastic dynamics is
readily understood in the framework of chaos theory. Intermittency "routes to
chaos" have been clearly identified, and positive Lyapunov exponents and
broad-band noise, both characteristic of chaos, are found to coincide with the
differential resistance peak. Furthermore, the fractal dimension of the strange
attractor reveals that the chaotic dynamics of vortices is low-dimensional.Comment: 5 pages, 3 figures Accepted for publication in Physical Review
Letter
Driven flux-line lattices in the presence of weak random columnar disorder: Finite-temperature behavior and dynamical melting of moving Bose glass
We use 3D numerical simulations to explore the phase diagram of driven flux
line lattices in presence of weak random columnar disorder at finite
temperature and high driving force. We show that the moving Bose glass phase
exists in a large range of temperature, up to its melting into a moving vortex
liquid. It is also remarkably stable upon increasing velocity : the dynamical
transition to the correlated moving glass expected at a critical velocity is
not found at any velocity accessible to our simulations. Furthermore, we show
the existence of an effective static tin roof pinning potential in the
direction transverse to motion, which originates from both the transverse
periodicity of the moving lattice and the localization effect due to correlated
disorder. Using a simple model of a single elastic line in such a periodic
potential, we obtain a good description of the transverse field penetration at
surfaces as a function of thickness in the moving Bose glass phase.Comment: 5 pages, 4 figures, New title and minor changes in text and figures.
Accepted for publication in Physical Review
Large Scale Baryon Isocurvature Inhomogeneities
Big bang nucleosynthesis constraints on baryon isocurvature perturbations are
determined. A simple model ignoring the effects of the scale of the
perturbations is first reviewed. This model is then extended to test the claim
that large amplitude perturbations will collapse, forming compact objects and
preventing their baryons from contributing to the observed baryon density. It
is found that baryon isocurvature perturbations are constrained to provide only
a slight increase in the density of baryons in the universe over the standard
homogeneous model. In particular it is found that models which rely on power
laws and the random phase approximation for the power spectrum are incompatible
with big bang nucleosynthesis unless an {\em ad hoc}, small scale cutoff is
included.Comment: 11pages + 8figures, LaTeX (2.09), postscript figures available via
anonymous ftp from oddjob.uchicago.edu:/ftp/ibbn/fig?.ps where ?=1-8 or via
email from [email protected], Fermilab-Pub-94/???-A and UMN-TH-1307/9
Exploration of the MSSM with Non-Universal Higgs Masses
We explore the parameter space of the minimal supersymmetric extension of the
Standard Model (MSSM), allowing the soft supersymmetry-breaking masses of the
Higgs multiplets, m_{1,2}, to be non-universal (NUHM). Compared with the
constrained MSSM (CMSSM) in which m_{1,2} are required to be equal to the soft
supersymmetry-breaking masses m_0 of the squark and slepton masses, the Higgs
mixing parameter mu and the pseudoscalar Higgs mass m_A, which are calculated
in the CMSSM, are free in the NUHM model. We incorporate accelerator and dark
matter constraints in determining allowed regions of the (mu, m_A), (mu, M_2)
and (m_{1/2}, m_0) planes for selected choices of the other NUHM parameters. In
the examples studied, we find that the LSP mass cannot be reduced far below its
limit in the CMSSM, whereas m_A may be as small as allowed by LEP for large tan
\beta. We present in Appendices details of the calculations of
neutralino-slepton, chargino-slepton and neutralino-sneutrino coannihilation
needed in our exploration of the NUHM.Comment: 92 pages LaTeX, 32 eps figures, final version, some changes to
figures pertaining to the b to s gamma constrain
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