197471755
Anomalous WWH couplings in gammagamma collision with initial beams and final state polarizations
119379927
Top Quark Spin Polarization in ep Collision
We discuss the degree of spin polarization of single top quarks produced via $Wg$ fusion process in $ep$ collision at TESLA+HERAp and CLIC+LHC energies $\sqrt{s}=1.6$ and 5.3 TeV. For $eb \to t \bar{\nu}$ subprocess we show that the top quark spin is completely polarized when the spin basis is chosen in the direction of the incoming positron beam in the rest frame of top quark. A description on how to combine the cross sections of $e^{+}b\to t\bar{\nu}$ and $e^{+}g\to t\bar{b}\bar{\nu}$ processes is given. $e^{+}$-beam direction is taken to be the favorite top quark spin decomposition axis in its rest frame and it is found to be comparable with the ones in $pp$ collision. It is argued that theoretical simplicity and experimental clearness are the advantage of $ep$ collision.
120011918
Screen transversal lightlike submanifolds of indefinite Kaehler manifolds
Abstract In a spacetime, all geodesic curves fall into one of three classes; spacelike, timelike and null (lightlike) geodesic according to their tangent vectors have positive, negative or vanishing Lorentzian lengths. However, by far the most interesting curves are null curves which represent the motion of zero restmass test particles. In this paper, as a generalization of real null curves of indefinite Kaehler manifolds, we introduce screen transversal lightlike submanifolds. Then, we study the geometry of this new class (and its subspaces) and give examples.
124417933
SEMI-INVARIANT RIEMANNIAN MAPS TO KÄHLER MANIFOLDS
This paper has two aims. First, we show that the usual notion of umbilical maps between Riemannian manifolds does not work for Riemannian maps. Then we introduce a new notion of umbilical Riemannian maps between Riemannian manifolds and give a method on how to construct examples of umbilical Riemannian maps. In the second part, as a generalization of CR-submanifolds, holomorphic submersions, anti-invariant submersions, invariant Riemannian maps and anti-invariant Riemannian maps, we introduce semi-invariant Riemannian maps from Riemannian manifolds to almost Hermitian manifolds, give examples and investigate the geometry of distributions which are arisen from definition. We also obtain a decomposition theorem and give necessary and sufficient conditions for a semi-invariant Riemannian map to be totally geodesic. Then we study the geometry of umbilical semi-invariant Riemannian maps and obtain a classification theorem for such Riemannian maps.