942 research outputs found
Dynamical Electroweak Symmetry Breaking in SO(5)xU(1) Gauge-Higgs Unification with Top and Bottom Quarks
An SO(5)xU(1) gauge-Higgs unification model in the Randall-Sundrum warped
space with top and bottom quarks is constructed. Additional fermions on the
Planck brane make exotic particles heavy by effectively changing boundary
conditions of bulk fermions from those determined by orbifold conditions. Gauge
couplings of a top quark multiplet trigger electroweak symmetry breaking by the
Hosotani mechanism, simultaneously giving a top quark the observed mass. The
bottom quark mass is generated by combination of brane interactions and the
Hosotani mechanism, where only one ratio of brane masses is relevant when the
scale of brane masses is much larger than the Kaluza-Klein scale (\sim 1.5
TeV). The Higgs mass is predicted to be 49.9 (53.5) GeV for the warp factor
10^{15} (10^{17}). The Wilson line phase turns out \pi/2 and the Higgs
couplings to W and Z vanish so that the LEP2 bound for the Higgs mass is
evaded. In the flat spacetime limit the electroweak symmetry is unbroken.Comment: 35 pages, 2 figures. A few corrections are mad
Xenopus NM23-X4 regulates retinal gliogenesis through interaction with p27Xic1
Background. In Xenopus retinogenesis, p27Xic1, a Xenopus cyclin dependent kinase inhibitor, functions as a cell fate determinant in both gliogenesis and neurogenesis in a context dependent manner. This activity is essential for co-ordination of determination and cell cycle regulation. However, very little is known about the mechanism regulating the context dependent choice between gliogenesis versus neurogenesis. Results. We have identified NM23-X4, a NM23 family member, as a binding partner of p27Xic1. NM23-X4 is expressed at the periphery of the ciliary marginal zone of the Xenopus retina and the expression overlaps with p27Xic1 at the central side. Our in vivo functional analysis in Xenopus retina has shown that knockdown of NM23-X4 activates gliogenesis. Furthermore, co-overexpression of NM23-X4 with p27Xic1 results in the inhibition of p27Xic1-mediated gliogenesis, through direct interaction of NM23-X4 with the amino-terminal side of p27Xic1. This inhibitory effect on gliogenesis requires serine-150 and histidine-148, which correspond to the important residues for the kinase activities of NM23 family members. Conclusion. This study demonstrates that NM23-X4 functions as an inhibitor of p27Xic1-mediated gliogenesis in Xenopus retina and suggests that this activity contributes to the proper spatio-temporal regulation of gliogenesis
Phase diagram at finite temperature and quark density in the strong coupling limit of lattice QCD for color SU(3)
We study the phase diagram of quark matter at finite temperature (T) and
finite chemical potential (mu) in the strong coupling limit of lattice QCD for
color SU(3). We derive an analytical expression of the effective free energy as
a function of T and mu, including baryon effects. The finite temperature
effects are evaluated by integrating over the temporal link variable exactly in
the Polyakov gauge with anti-periodic boundary condition for fermions. The
obtained phase diagram shows the first order phase transition at low
temperatures and the second order phase transition at high temperatures
separated by the tri-critical point in the chiral limit. Baryon has effects to
reduce the effective free energy and to extend the hadron phase to a larger mu
direction at low temperatures.Comment: 18 pages, 10 figure
Polarization Measurement for Fast Neutrons by a Liquid-Helium Scintillation Detector
開始ページ、終了ページ: 冊子体のページ付
- …