Various representations of infrared effective lattice QCD

We study various representations of the infrared effective theory of SU(2) gluodynamics starting from the monopole action derived recently. We determine the coupling constants in the abelian-Higgs model directly from lattice QCD and evaluate the type of the QCD vacuum. The string action is derived using the BKT transformation on the lattice. At the classical level this action reproduces the physical string tension with a good accuracy.Comment: 3 pages, LaTeX, 2 figures; talk presented at LATTICE9

Four-Fermi Effective Operators in Top-Quark Production and Decay

Effects of four-Fermi-type new interactions are studied in top-quark pair production and their subsequent decays at future e^+e^- colliders. Secondary-lepton-energy distributions are calculated for arbitrary longitudinal beam polarizations. An optimal-observables procedure is applied for the determination of new parameters.Comment: Polarized e^- plus unpolarized e^+ collisions were include

Disappearance of the Abrikosov vortex above the deconfining phase transition in SU(2) lattice gauge theory

We calculate the solenoidal magnetic monopole current and electric flux distributions at finite temperature in the presence of a static quark antiquark pair. The simulation was performed using SU(2) lattice gauge theory in the maximal Abelian gauge. We find that the monopole current and electric flux distributions are quite different below and above the finite temperature deconfining phase transition point and agree with predictions of the Ginzburg-Landau effective theory.Comment: 12 pages, Revtex Latex, 6 figures - ps files will be sent upon reques

Abelian Dominance of Chiral Symmetry Breaking in Lattice QCD

Calculations of the chiral condensate on the lattice using staggered fermions and the Lanczos algorithm are presented. Four gauge fields are considered: the quenched non-Abelian field, an Abelian projected field, and monopole and photon fields further decomposed from the Abelian field. Abelian projection is performed in maximal Abelian gauge and in Polyakov gauge. The results show that monopoles in maximal Abelian gauge largely reproduce the chiral condensate values of the full non-Abelian theory, in both SU(2) and SU(3) color.Comment: 13 pages in RevTex including 6 figures, uucompressed, self-extractin

Candidate Coronagraphic Detections of Protoplanetary Disks around Four Young Stars

We present potential detections of H-band scattered light emission around four young star, selected from a total sample of 45 young stars observed with the CIAO coronagraph of the Subaru telescope. Two CTTS, CI Tau and DI Cep, and two WTTS, LkCa 14 and RXJ 0338.3+1020 were detected. In all four cases, the extended emission is within the area of the residual PSF halo, and is revealed only through careful data reduction. We compare the observed extended emission with simulations of the scattered light emission, to evaluate the plausibility and nature of the detected emission.Comment: 9 Figures, 40 page

Scaling and confinement aspects of tadpole improved SU(2) lattice gauge theory and its abelian projection

Using a tadpole improved SU(2) gluodynamics action, the nonabelian potential and the abelian potential after the abelian projection are computed. Rotational invariance is found restored at coarse lattices both in the nonabelian theory and in the effective abelian theory resulting from maximal abelian projection. Asymptotic scaling is tested for the SU(2) string tension. Deviation of the order of $6$ is found, for lattice spacings between 0.27 and 0.06 fm. Evidence for asymptotic scaling and scaling of the monopole density in maximal abelian projection is also seen, but not at coarse lattices. The scaling behavior is compared with analyses of Wilson action results, using bare and renormalized coupling schemes. Using extended monopoles, evidence is found that the gauge dependence of the abelian projection reflects short distance fluctuations, and may thus disappear at large scales.Comment: 28 pages, RevTeX, 12 figures using epsfig (included); accepted for publication in Physical Revie

Probing Top-Quark Couplings at Polarized NLC

The energy spectrum of the lepton(s) in e^+e^- --> tt-bar --> l^{+-} ...../l^+l^-..... at next linear colliders (NLC) is studied for arbitrary longitudinal beam polarizations as a possible test of new physics in top-quark couplings. The most general non-standard couplings for gamma-tt-bar, Ztt-bar and Wtb vertices are considered. Expected precision of the non-standard-parameter determination is estimated applying the optimal-observable procedure.Comment: Final version, To appear in Phys. Rev.

The System of Multi Color-flux-tubes in the Dual Ginzburg-Landau Theory

We study the system of multi color-flux-tubes in terms of the dual Ginzburg -Landau theory. We consider two ideal cases, where the directions of all the color-flux-tubes are the same in one case and alternative in the other case for neighboring flux-tubes. We formulate the system of multi color-flux -tubes by regarding it as the system of two color-flux-tubes penetrating through a two dimensional sphere surface. We find the multi flux-tube configuration becomes uniform above some critical flux-tube number density $\rho_c = 1.3 \sim 1.7 {\rm fm}^{-2}$. On the other hand, the inhomogeneity on the color electric distribution appears when the flux-tube density is smaller than $\rho_c$. We discuss the relation between the inhomogeneity in the color-electric distribution and the flux-tube number density in the multi-flux-tube system created during the QGP formation process in the ultra-relativistic heavy-ion collision.Comment: 17 pages, Revtex, ( 7 figures - available on request from [email protected]