269 research outputs found
Type II Seesaw Dominance in Non-supersymmetric and Split Susy SO(10) and Proton Life Time
Recently type II seesaw dominance in a supersymmetric SO(10) framework has
been found useful in explaining large solar and atmospheric mixing angles as
well as larger values of while unifying quark and lepton masses.
An important question in these models is whether there exists consistency
between coupling unification and type II seesaw dominance. Scenarios where this
consistency can be demonstrated have been given in a SUSY framework. In this
paper we give examples where type II dominance occurs in SO(10) models without
supersymmetry but with additional TeV scale particles and also in models with
split-supersummetry. Grand unification is realized in a two-step process via
breaking of SO(10) to SU(5) and then to a TeV scale standard model supplemented
by extra fields and an SU(5) Higgs multiplet at a scale about
GeV to give type-II seesaw. The predictions for proton lifetime in
these models are in the range yrs. to yrs.. A number of recent numerical fits to GUT-scale fermion
masses can be accommodated within this model.Comment: 7 pages LaTeX, 3 figures, related areas: hep-ex, hep-th, astro-ph;
Reference added, typo corrected, version to appear in Physical Review
Sensitivity of T2KK to the non-standard interaction in propagation
Assuming only the non-zero electron and tau neutrino components
, , of the non-standard
matter effect and postulating the atmospheric neutrino constraint
, we study the
sensitivity to the non-standard interaction in neutrino propagation of the T2KK
neutrino long-baseline experiment. It is shown that T2KK can constrain the
parameters , . It is
also shown that if and are large, then T2KK
can determine the Dirac phase and the phase of separately,
due to the information at the two baselines. We also provide an argument that
the components must be small for
the disappearance oscillation probability to be consistent with high-energy
atmospheric neutrino data, which justifies our premise that these quantities
are negligible.Comment: 29 pages, 25 figures, uses revtex4-1. Several places including typos
revised. New references adde
Natural Diagonal Riemannian Almost Product and Para-Hermitian Cotangent Bundles
We obtain the natural diagonal almost product and locally product structures
on the total space of the cotangent bundle of a Riemannian manifold. We find
the Riemannian almost product (locally product) and the (almost) para-Hermitian
cotangent bundles of natural diagonal lift type. We prove the characterization
theorem for the natural diagonal (almost) para-K\"ahlerian structures on the
total spaces of the cotangent bundle.Comment: 10 pages, will appear in Czechoslovak Mathematical Journa
A Unified Algebraic Approach to Classical Yang-Baxter Equation
In this paper, the different operator forms of classical Yang-Baxter equation
are given in the tensor expression through a unified algebraic method. It is
closely related to left-symmetric algebras which play an important role in many
fields in mathematics and mathematical physics. By studying the relations
between left-symmetric algebras and classical Yang-Baxter equation, we can
construct left-symmetric algebras from certain classical r-matrices and
conversely, there is a natural classical r-matrix constructed from a
left-symmetric algebra which corresponds to a parak\"ahler structure in
geometry. Moreover, the former in a special case gives an algebraic
interpretation of the ``left-symmetry'' as a Lie bracket ``left-twisted'' by a
classical r-matrix.Comment: To appear in Journal of Physics A: Mathematical and Theoretica
Special symplectic Lie groups and hypersymplectic Lie groups
A special symplectic Lie group is a triple such that
is a finite-dimensional real Lie group and is a left invariant
symplectic form on which is parallel with respect to a left invariant
affine structure . In this paper starting from a special symplectic Lie
group we show how to ``deform" the standard Lie group structure on the
(co)tangent bundle through the left invariant affine structure such
that the resulting Lie group admits families of left invariant hypersymplectic
structures and thus becomes a hypersymplectic Lie group. We consider the affine
cotangent extension problem and then introduce notions of post-affine structure
and post-left-symmetric algebra which is the underlying algebraic structure of
a special symplectic Lie algebra. Furthermore, we give a kind of double
extensions of special symplectic Lie groups in terms of post-left-symmetric
algebras.Comment: 32 page
Distillation of Liquid Xenon to Remove Krypton
A high performance distillation system to remove krypton from xenon was
constructed, and a purity level of Kr/Xe = was
achieved. This development is crucial in facilitating high sensitivity low
background experiments such as the search for dark matter in the universe.Comment: 15 pages, 11 figure
Status of atmospheric neutrino(mu)<-->neutrino(tau) oscillations and decoherence after the first K2K spectral data
We review the status of nu_mu-->nu_tau flavor transitions of atmospheric
neutrinos in the 92 kton-year data sample collected in the first phase of the
Super-Kamiokande (SK) experiment, in combination with the recent spectral data
from the KEK-to-Kamioka (K2K) accelerator experiment (including 29 single-ring
muon events). We consider a theoretical framework which embeds flavor
oscillations plus hypothetical decoherence effects, and where both standard
oscillations and pure decoherence represent limiting cases. It is found that
standard oscillations provide the best description of the SK+K2K data, and that
the associated mass-mixing parameters are determined at 1 sigma (and d.o.f.=1)
as: Delta m^2=(2.6 +- 0.4)x10^{-3} eV^2 and sin^2(2theta)=1.00+0.00-0.05. As
compared with standard oscillations, the case of pure decoherence is
disfavored, although it cannot be ruled out yet. In the general case,
additional decoherence effects in the nu_mu-->nu_tau channel do not improve the
fit to the SK and K2K data, and upper bounds can be placed on the associated
decoherence parameter. Such indications, presently dominated by SK, could be
strengthened by further K2K data, provided that the current spectral features
are confirmed with higher statistics. A detailed description of the statistical
analysis of SK and K2K data is also given, using the so-called ``pull''
approach to systematic uncertainties.Comment: 18 pages (RevTeX) + 12 figures (PostScript
Measurement of the cross-section and forward-backward charge asymmetry for the b and c-quark in e+e- annihilation with inclusive muons at sqrt(s) = 58 GeV
We have studied inclusive muon events using all the data collected by the
TOPAZ detector at sqrt(s)=58 GeV with an integrated luminosity of 273pb-1. From
1328 inclusive muon events, we measured the ratio R_qq of the cross section for
qq-bar production to the total hadronic cross section and forward-backward
asymmetry A^q_FB for b and c quarks. The obtained results are R_bb =
0.13+-0.02(stat)+-0.01(syst), R_cc = 0.36+-0.05(stat)+-0.05(syst), A^b_FB =
-0.20+-0.16(stat)+-0.01(syst) and A^c_FB = -0.17+-0.14(stat)+-0.02(syst), in
fair agreement with a prediction of the standard model.Comment: To be published in EPJ C. 24 pages, 12 figure
Production in Two-Photon Processes at TRISTAN
We have carried out an inclusive measurement of production
in two-photon processes at TRISTAN. The mean was 58 GeV and the
integrated luminosity was 199 pb. High-statistics samples were
obtained under such conditions as no-, anti-electron, and remnant-jet tags. The
remnant-jet tag, in particular, allowed us, for the first time, to measure the
cross sections separately for the resolved-photon and direct processes.Comment: 20 pages, Latex format, 4 figures and KEK-mark included. Table 1
revised. To be published in Phys. Lett.
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