244 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
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
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
Differential Expression of GADD45\u3ci\u3eβ\u3c/i\u3e in Normal and Osteoarthritic Cartilage: Potential Role in Homeostasis of Articular Chondrocytes
Objective—Our previous study suggested that growth arrest and DNA damage–inducible protein 45β (GADD45β) prolonged the survival of hypertrophic chondrocytes in the developing mouse embryo. This study was undertaken, therefore, to investigate whether GADD45β plays a role in adult articular cartilage.
Methods—Gene expression profiles of cartilage from patients with late-stage osteoarthritis (OA) were compared with those from patients with early OA and normal controls in 2 separate microarray analyses. Histologic features of cartilage were graded using the Mankin scale, and GADD45β was localized by immunohistochemistry. Human chondrocytes were transduced with small interfering RNA (siRNA)–GADD45β or GADD45β-FLAG. GADD45β and COL2A1 messenger RNA (mRNA) levels were analyzed by real-time reverse transcriptase–polymerase chain reaction, and promoter activities were analyzed by transient transfection. Cell death was detected by Hoechst 33342 staining of condensed chromatin.
Results—GADD45β was expressed at higher levels in cartilage from normal donors and patients with early OA than in cartilage from patients with late-stage OA. All chondrocyte nuclei in normal cartilage immunostained for GADD45β. In early OA cartilage, GADD45β was distributed variably in chondrocyte clusters, in middle and deep zone cells, and in osteophytes. In contrast, COL2A1, other collagen genes, and factors associated with skeletal development were up-regulated in late OA, compared with early OA or normal cartilage. In overexpression and knockdown experiments, GADD45β down-regulated COL2A1 mRNA and promoter activity. NF-κB overexpression increased GADD45β promoter activity, and siRNA-GADD45β decreased cell survival per se and enhanced tumor necrosis factor α–induced cell death in human articular chondrocytes.
Conclusion—These observations suggest that GADD45β might play an important role in regulating chondrocyte homeostasis by modulating collagen gene expression and promoting cell survival in normal adult cartilage and in early OA
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.
Measurement of the forward-backward asymmetries for charm- and bottom-quark pair productions at =58GeV with electron tagging
We have measured, with electron tagging, the forward-backward asymmetries of
charm- and bottom-quark pair productions at =58.01GeV, based on
23,783 hadronic events selected from a data sample of 197pb taken with
the TOPAZ detector at TRISTAN. The measured forward-backward asymmetries are
and , which are consistent with the standard model
predictions.Comment: 19 pages, Latex format (article), 5 figures included. to be published
in Phys. Lett.
Indications of Neutrino Oscillation in a 250 km Long-baseline Experiment
The K2K experiment observes indications of neutrino oscillation: a reduction
of flux together with a distortion of the energy spectrum. Fifty-six
beam neutrino events are observed in Super-Kamiokande (SK), 250 km from the
neutrino production point, with an expectation of .
Twenty-nine one ring -like events are used to reconstruct the neutrino
energy spectrum, which is better matched to the expected spectrum with neutrino
oscillation than without. The probability that the observed flux at SK is
explained by statistical fluctuation without neutrino oscillation is less than
1%.Comment: 5 pages, 3 figures embedded, LaTeX with RevTeX style, accepted for
publication in PRL on December 13, 200
Measurement of inclusive electron cross section in collisions at TRISTAN
We have studied open charm production in collisions with the
TOPAZ detector at the TRISTAN collider. In this study, charm
quarks were identified by electrons (and positrons) from semi-leptonic decays
of charmed hadrons. The data corresponded to an integrated luminosity of 95.3
pb at a center-of-mass energy of 58 GeV. The results are presented as
the cross sections of inclusive electron production in
collisions with an anti-tag condition, as well as the subprocess cross
sections, which correspond to resolved-photon processes. The latter were
measured by using a sub-sample with remnant jets. A comparison with various
theoretical predictions based on direct and resolved-photon processes showed
that our data prefer that with relatively large gluon contents in a photon at
small , with the next-to-leading order correction, and with a
charm-quark mass of 1.3 GeV.Comment: 26 pages, Latex format (article), 5 figures included, to be published
in Phys. Lett.
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