23,194 research outputs found
Base manifolds for fibrations of projective irreducible symplectic manifolds
Given a projective irreducible symplectic manifold of dimension , a
projective manifold and a surjective holomorphic map with
connected fibers of positive dimension, we prove that is biholomorphic to
the projective space of dimension . The proof is obtained by exploiting two
geometric structures at general points of : the affine structure arising
from the action variables of the Lagrangian fibration and the structure
defined by the variety of minimal rational tangents on the Fano manifold
Form Factors Calculated on the Light-Front
A consistent treatment of decay is given on the
light-front. The to transition form factors are calculated in the
entire physical range of momentum transfer for the first time. The
valence-quark contribution is obtained using relativistic light-front wave
functions. Higher quark-antiquark Fock-state of the -meson bound state is
represented effectively by the configuration, and its effect
is calculated in the chiral perturbation theory. Wave function renormalization
is taken into account consistently. The contribution dominates
near the zero-recoil point ( GeV), and decreases rapidly as
the recoil momentum increases. We find that the calculated form factor
follows approximately a dipole -dependence in the entire range
of momentum transfer.Comment: Revtex, 19 pages, 9 figure
A conserved variable in the perturbed hydrodynamic world model
We introduce a scalar-type perturbation variable which is conserved in
the large-scale limit considering general sign of three-space curvature (),
the cosmological constant (), and time varying equation of state. In a
pressureless medium is {\it exactly conserved} in all scales.Comment: 4 pages, no figure, To appear in Phys. Rev.
Parity violation in deuteron photo-disintegration
We analyze the energy dependence for two types of parity-non-conserving
(PNC) asymmetries in the reaction in the near-threshold
region. The first one is the asymmetry in reaction with circularly polarized
photon beam and unpolarized deuteron target. The second one corresponds to
those with an unpolarized photon beam and polarized target. We find that the
two asymmetries have quite different energy dependence, and their shapes are
sensitive to the PNC-meson exchange coupling constants.
The predictions for the future possible experiments to provide definite
constraints for the PNC-coupling constants are discussed.Comment: 22 pages, 12 figures. Submitted to Phys.Rev.C 10Oct.0
Cosmological Vorticity in a Gravity with Quadratic Order Curvature Couplings
We analyse the evolution of the rotational type cosmological perturbation in
a gravity with general quadratic order gravitational coupling terms. The result
is expressed independently of the generalized nature of the gravity theory, and
is simply interpreted as a conservation of the angular momentum.Comment: 5 pages, revtex, no figure
Unified Analysis of Cosmological Perturbations in Generalized Gravity
In a class of generalized Einstein's gravity theories we derive the equations
and general asymptotic solutions describing the evolution of the perturbed
universe in unified forms. Our gravity theory considers general couplings
between the scalar field and the scalar curvature in the Lagrangian, thus
includes broad classes of generalized gravity theories resulting from recent
attempts for the unification. We analyze both the scalar-type mode and the
gravitational wave in analogous ways. For both modes the large scale evolutions
are characterized by the same conserved quantities which are valid in the
Einstein's gravity. This unified and simple treatment is possible due to our
proper choice of the gauges, or equivalently gauge invariant combinations.Comment: 4 pages, revtex, no figure
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