Extended Gauge Sectors

Present and future prospects for the discovery of new gauge bosons, $Z'$ and $W'$, are reviewed. Particular attention is paid to hadron and $e^+e^-$ collider searches for the $W'$ of the Left-Right Symmetric Model. (Presented at the {\it Fourth International Conference on Physics Beyond the Standard Model}, Lake Tahoe, CA, December 13-18, 1994.)Comment: 6 pages plus 18 figure, LaTex. Figures soon to be available by anonymous ftp at ftp://preprint.slac.stanford.edu/preprints/hep-ph/ or via WWW at http://libnext.slac.stanford.edu:5080/hep-ph

Generalized twisted sectors of orbifolds

For a finitely generated discrete group $\Gamma$, the $\Gamma$-sectors of an orbifold $Q$ are a disjoint union of orbifolds corresponding to homomorphisms from $\Gamma$ into a groupoid presenting $Q$. Here, we show that the inertia orbifold and $k$-multi-sectors are special cases of the $\Gamma$-sectors, and that the $\Gamma$-sectors are orbifold covers of Leida's fixed-point sectors. In the case of a global quotient, we show that the $\Gamma$-sectors correspond to orbifolds considered by other authors for global quotient orbifolds as well as their direct generalization to the case of an orbifold given by a quotient by a Lie group. Furthermore, we develop a model for the $\Gamma$-sectors corresponding to a generalized loop space.Comment: 24 page

Superselection Sectors of Gravitational Subregions

Motivated by the problem of defining the entanglement entropy of the graviton, we study the division of the phase space of general relativity across subregions. Our key requirement is demanding that the separation into subregions is imaginary---i.e., that entangling surfaces are not physical. This translates into a certain condition on the symplectic form. We find that gravitational subregions that satisfy this condition are bounded by surfaces of extremal area. We characterise the 'centre variables' of the phase space of the graviton in such subsystems, which can be taken to be the conformal class of the induced metric in the boundary, subject to a constraint involving the traceless part of the extrinsic curvature. We argue that this condition works to discard local deformations of the boundary surface to infinitesimally nearby extremal surfaces, that are otherwise available for generic codimension-2 extremal surfaces of dimension $\geq$ 2.Comment: 17 pages. v4: minor corrections, accepted in JHE

Discrete symmetries from hidden sectors

We study the presence of abelian discrete symmetries in globally consistent orientifold compactifications based on rational conformal field theory. We extend previous work [1] by allowing the discrete symmetries to be a linear combination of U(1) gauge factors of the visible as well as the hidden sector. This more general ansatz significantly increases the probability of finding a discrete symmetry in the low energy effective action. Applied to globally consistent MSSM-like Gepner constructions we find multiple models that allow for matter parity or Baryon triality.Comment: 20 page

Electric Flux Sectors and Confinement

We study the fate of static fundamental charges in the thermodynamic limit from Monte-Carlo simulations of SU(2) with suitable boundary conditions.Comment: Presented by L.v.S. at the NATO Advanced Research Workshop "Confinement, Topology, and other Non-Perturbative Aspects of QCD", Jan. 21-27, 2002, Stara Lesna, Slovakia., 8 pages, 4 figures (8 ps-files, epsfig.sty), uses crckapb.cl

Urban Authorities and Economic Sectors

Taxation on businesses, which makes up two thirds of local authorities' revenues, urges them to widen the range of their economic interventions. The communauté d'agglomération Plaine Commune is one of the most dynamic in the Parisian metropolis and has had considerable expertise at their disposal for 10 years. In order to ensure their economic influence, they now endeavour to stimulate and even structure some economic industries. Unfortunately, a local tax reform in progress may well jeopardise the pattern of development which is presented in this article

Phenomenological Constraints on Extended Quark Sectors

We study the flavor physics in two extensions of the quark sector of the Standard Model (SM): a four generation model and a model with a single vector--like down--type quark (VDQ). In our analysis we take into account the experimental constraints from tree--level charged current processes, rare Kaon decay processes, rare B decay processes, the $Z\to b \bar{b}$ decay, $K$, $B$ and $D$ mass differences, and the CP violating parameters \frac \epsilon^\prime}{\epsilon}, $\epsilon_K$ and $a_{\psi K}$. All the constraints are taken at two sigma. We find bounds on parameters which can be used to represent the New Physics contributions in these models ($\lambda_{t^ \prime}^{bd}$, $\lambda_{t^ \prime}^{bs}$ and $\lambda_{t^ \prime}^{sd}$ in the four--generation model, and $U_{bd}$, $U_{bs}$ and $U_{sd}$ in the VDQ model) due to all the above constraints. In both models the predicted ranges for $a_{SL}$ (the CP asymmetry in semi-leptonic decays), $\Delta M_D$, $B(K^+\to\pi^+ \nu \bar{\nu})$, $B(K_L\to\pi^0 \nu \bar{\nu})$ and $B(K_L\to \mu \bar{\mu})_{SD}$ can be significantly higher than the predictions of the SM, while the allowed ranges for $a_{\psi K}$ and for $\Delta m_{B_S}$ are consistent with the SM prediction.Comment: 22 pages, 5 figures (v3: added a reference, updated a reference, added missing units