Moduli stabilization with open and closed string fluxes

We study the stabilization of all closed string moduli in the T^6/Z_2 orientifold, using constant internal magnetic fields and 3-form fluxes that preserve N=1 supersymmetry in four dimensions. We first analyze the stabilization of Kahler class and complex structure moduli by turning on magnetic fluxes on different sets of D9 branes that wrap the internal space T^6/Z_2. We present explicit consistent string constructions, satisfying in particular tadpole cancellation, where the radii can take arbitrarily large values by tuning the winding numbers appropriately. We then show that the dilaton-axion modulus can also be fixed by turning on closed string constant 3-form fluxes, consistently with the supersymmetry preserved by the magnetic fields, providing at the same time perturbative values for the string coupling. Finally, several models are presented combining open string magnetic fields that fix part of Kahler class and complex structure moduli, with closed string 3-form fluxes that stabilize the remaining ones together with the dilaton.Comment: 49 pages, a new model added, as well as improvements and reference

Magnetic fluxes and moduli stabilization

Stabilization of closed string moduli in toroidal orientifold compactifications of type IIB string theory are studied using constant internal magnetic fields on D-branes and 3-form fluxes that preserve N=1 supersymmetry in four dimensions. Our analysis corrects and extends previous work by us, and indicates that charged scalar VEV's need to be turned on, in addition to the fluxes, in order to construct a consistent supersymmetric model. As an explicit example, we first show the stabilization of all Kahler class and complex structure moduli by turning on magnetic fluxes on different sets of D9-branes that wrap the internal space T^6 in a compactified type I string theory, when a charged scalar on one of these branes acquires a non-zero VEV. The latter can also be determined by adding extra magnetized branes, as we demonstrate in a subsequent example. In a different model with magnetized D7-branes, in a IIB orientifold on T^6/Z_2, we show the stabilization of all the closed string moduli, including the axion-dilaton at weak string coupling g_s, by turning on appropriate closed string 3-form fluxes.Comment: v2: minor changes, added discussio

Free geometric adjustment of the SECOR Equatorial Network (Solution SECOR-27)

The basic purpose of this experiment is to compute reduced normal equations from the observational data of the SECOR Equatorial Network obtained from DMA/Topographic Center, D/Geodesy, Geosciences Div. Washington, D.C. These reduced normal equations are to be combined with reduced normal equations of other satellite networks of the National Geodetic Satellite Program to provide station coordinates from a single least square adjustment. An individual SECOR solution was also obtained and is presented in this report, using direction constraints computed from BC-4 optical data from stations collocated with SECOR stations. Due to the critical configuration present in the range observations, weighted height constraints were also applied in order to break the near coplanarity of the observing stations

Shear-strain-induced Spatially Varying Super-lattice Structures on Graphite studied by STM

We report on the Scanning Tunneling Microscope (STM) observation of linear fringes together with spatially varying super-lattice structures on (0001) graphite (HOPG) surface. The structure, present in a region of a layer bounded by two straight carbon fibers, varies from a hexagonal lattice of 6nm periodicity to nearly a square lattice of 13nm periodicity. It then changes into a one-dimensional (1-D) fringe-like pattern before relaxing into a pattern-free region. We attribute this surface structure to a shear strain giving rise to a spatially varying rotation of the affected graphite layer relative to the bulk substrate. We propose a simple method to understand these moire patterns by looking at the fixed and rotated lattices in the Fourier transformed k-space. Using this approach we can reproduce the spatially varying 2-D lattice as well as the 1-D fringes by simulation. The 1-D fringes are found to result from a particular spatial dependence of the rotation angle.Comment: 14 pages, 6 figure

Global satellite triangulation and trilateration for the National Geodetic Satellite Program (solutions WN 12, 14 and 16)

A multi-year study and analysis of data from satellites launched specifically for geodetic purposes and from other satellites useful in geodetic studies was conducted. The program of work included theoretical studies and analysis for the geometric determination of station positions derived from photographic observations of both passive and active satellites and from range observations. The current status of data analysis, processing and results are examined

Dilepton Signal of a Type-II Seesaw at CERN LHC: Reveals a TeV Scale B-L Symmetry

We explore the discovery potential of doubly charged Higgs bosons (\xi^{\pm\pm}) at the CERN Large Hadron Collider (LHC). For moderate values of the coupling constants in the original Type-II seesaw model, these doubly-charged Higgs bosons are not accessible by any present or near future collider experiments. In a gauged B-L symmetric model we introduce two triplet scalars to execute a variant of type-II seesaw at the TeV scale. This leads to a clear like-sign dilepton signal in the decay mode of \xi^{\pm\pm} for a small vacuum expectation value (\lsim 10^5 \eV) of the triplet scalar \xi= (\xi^{++}, \xi^+, \xi^0) of mass \lsim 1 \TeV. To be specific, for a mass range of 200-1000 GeV of \xi^{\pm\pm}, the like-sign dilepton signal can be detected at CERN LHC at a center of mass energy 14 TeV with an integrated luminosity > 30 {\rm fb}^{-1}. The same analysis is also pursued with center of mass energies 7 TeV and 10 TeV as well. We also comment on the decay mode of singly charged scalars and neutral B-L gauge boson in this model.Comment: Minor change in Introduction, Z' contribution to the production of doubly charged scalars are explicitly shown, new figures added, new references added. To appear in Physical Review

A rapidly expanding Bose-Einstein condensate: an expanding universe in the lab

We study the dynamics of a supersonically expanding ring-shaped Bose-Einstein condensate both experimentally and theoretically. The expansion redshifts long-wavelength excitations, as in an expanding universe. After expansion, energy in the radial mode leads to the production of bulk topological excitations -- solitons and vortices -- driving the production of a large number of azimuthal phonons and, at late times, causing stochastic persistent currents. These complex nonlinear dynamics, fueled by the energy stored coherently in one mode, are reminiscent of a type of "preheating" that may have taken place at the end of inflation.Comment: 12 pages, 7 figure

Muon anomaly and a lower bound on higgs mass due to a light stabilized radion in the Randall-Sundrum model

We investigate the Randall-Sundrum model with a light stabilized radion (required to fix the size of the extra dimension) in the light of muon anomalous magnetic moment $a_\mu [= \frac{(g - 2)}{2}]$. Using the recent data (obtained from the E821 experiment of the BNL collaboration) which differs by $2.6 \sigma$ from the Standard Model result, we obtain constraints on radion mass \mphi and radion vev \vphi. In the presence of a radion the beta functions \beta(\l) and $\beta(g_t)$ of higgs quartic coupling (\l) and top-Yukawa coupling ($g_t$) gets modified. We find these modified beta functions. Using these beta functions together with the anomaly constrained \mphi and \vphi, we obtain lower bound on higgs mass $m_h$. We compare our result with the present LEP2 bound on $m_h$.Comment: Version to be appeared in IJMP