September 1999 arXiv papers — page 12

Goro Hatayama, Atsuo Kuniba, Masato Okado, Taichiro Takagi

The combinatorial R matrices are obtained for a family {B_l} of crystals for U'_q(C^{(1)}_n) and U'_q(A^{(2)}_{2n-1}), where B_l is the crystal of the irreducible module corresponding to the one-row Young diagram of length l. The isomorphism B_l\otimes B_k \simeq B_k \otimes B_l and the energy function are described explicitly in terms of a C_n-analo

Michael Anshelevich

We interpret the Central Limit Theorem as a fixed point theorem for a certain operator, and consider the problem of linearizing this operator. In classical as well as in free probability theory, we consider two methods giving such a linearization, and interpret the result as a weak form of the CLT. In the classical case the analysis involves dilation operato

D. Shklyarov, S. Sinel'shchikov, L. Vaksman

The present work considers one of the simplest homogeneous spaces of the quantum group SU(1,1), the q-analogue of the unit disc in ${\Bbb C}$. We state without proofs q-analogues of Cauchy-Green formulae, integral representations of eigenfunctions of the Laplace-Beltrami operator, Green functions for Poisson equation and an inversion formula for Fourier tran

Brian Harbourne

Let $F$ be a line bundle on the blow-up $X$ of $P^2$ at $r$ general points $p_1, ..., p_r$ and let $L$ be the pullback to $X$ of the line bundle coming from a line on $P^2$. Under reasonable hypotheses that are conjectured always to hold if the points $p_1, ..., p_r$ are sufficiently general, it is shown that the computation of the dimension of the cokernel

Seungjoon Hyun

We find the explicit expression of the supercharges of eleven dimensional supergraviton on the background geometry of gravitational waves in asymptotically light-like compactified spacetime. We perform the calculations order by order in the fermions $\p$, while retaining all orders in bosonic degrees of freedom, and get the closed form up to $\p^5$ order. Th

Harold Blas, L. A. Ferreira

We consider a two-dimensional integrable and conformally invariant field theory possessing two Dirac spinors and three scalar fields. The interaction couples bilinear terms in the spinors to exponentials of the scalars. Its integrability properties are based on the sl(2) affine Kac-Moody algebra, and it is a simple example of the so-called conformal affine T

A. L. Cotrone

We present a Z_2 x Z_2 four dimensional orientifold in which supersymmetry is broken by a temperature-like Scherk-Schwarz mechanism. As usual in this type of models, at the tree-level the breaking affects only the branes tangent to the direction involved by the SS deformation, and it can propagate only through radiative corrections to other sectors, where th

Ricardo Amorim, Ronaldo Thibes

By using the field-antifield formalism, we show that the method of Batalin, Fradkin, Fradkina and Tyutin to convert Hamiltonian systems submitted to second class constraints introduces compensating fields which do not belong to the BRST cohomology at ghost number one. This assures that the gauge symmetries which arise from the BFFT procedure are not obstruct

J. Kijowski, G. Rudolph, M. Rudolph

A procedure for reducing the functional integral of QED to an integral over bosonic gauge invariant fields is presented. Next, a certain averaging method for this integral, giving a tractable effective quantum field theory, is proposed. Finally, the current-current propagator and the chiral anomaly are calculated within this new formulation. These results ar

B. Stefanski

In this short note we review the construction and role of Wess-Zumino couplings of Dirichlet branes and Orientifold planes, and show how these combine to give the Green-Schwarz anomaly cancelling terms.

Anton Kapustin

We study global worldsheet anomalies for open strings ending on several coincident D-branes in the presence of a B-field. We show that cancellation of anomalies is made possible by a correlation between the t'Hooft magnetic flux on the D-branes and the topological class of the B-field. One application of our results is a proper understanding of the geome

S. Ferrara, A. Zaffaroni

We review the unitarity bounds and the multiplet shortening of UIR's of 4 dimensional superconformal algebras $SU(2,2|N)$, ($N=1,2,4$) in view of their dual role in the AdS/SCFT correspondence. Some applications to KK spectra, non-perturbative states and stringy states are given.

Ludger Hannibal, Carl von Ossietzky

The paper is withdrawn because the analysis appeared to be incomplete.

Ioannis P. Zois

We introduce a new invariant for foliations using the even pairing between K-homology and cyclic homology and discuss some possible applications in physics.

Nima Arkani-Hamed, Yuval Grossman, Martin Schmaltz

We point out a dramatic new experimental signature for a class of theories with extra dimensions, where quarks and leptons are localized at slightly separated parallel ``walls'' whereas gauge and Higgs fields live in the bulk of the extra dimensions. The separation forbids direct local couplings between quarks and leptons, allowing for an elegant sol

K. T. Mahanthappa, Sechul Oh

We present a combined study of the muon anomalous magnetic moment, $a_μ \equiv (g-2)_μ /2$, and $b \to s γ$ decay in the minimal supersymmetric standard model with gauge-mediated supersymmetry-breaking. Combining new experimental data on $a_μ$ and the branching ratio for $b \to s γ$, useful limits on the parameter space of these models are derived. Bounds on

J. J. van der Bij, A. Ghinculov

We discuss the meaning of anomalous vector boson self couplings. Implications of present experimental constraints for future colliders are discussed. Results for triple vector boson production at the LHC are given.

D. P. Kirilova, M. V. Chizhov

We have provided a numerical study of the influence of the resonant active-sterile neutrino oscillations between electron and sterile neutrinos, on the primordial production of helium-4. The evolution of the neutrino ensembles was followed selfconsistently with the evolution of the nucleons, using exact kinetic equations for the neutrino density matrix and t

M. Bleicher, E. Zabrodin, C. Spieles, S. A. Bass

Hadron-hadron collisions at high energies are investigated in the Ultra-relativistic-Quantum-Molecular-Dynamics approach (UrQMD). This microscopic transport model is designed to study pp, pA and A+A collisions. It describes the phenomenology of hadronic interactions at low and intermediate energies ($\sqrt s <5$ GeV) in terms of interactions between known ha

A. Abd El-Hady, J. H. Muñoz, J. P. Vary

We make predictions for the exclusive semileptonic and the non-leptonic decay widths of the B_c meson. We evaluate the B_c semileptonic form factors for different decay channels in a relativistic model, and use factorization to obtain the non-leptonic decay widths.

G. Radel, A. De Roeck

A feasibility study to extract the polarised gluon density from di-jet events at HERA in next-to-leading order is presented. It is shown that when taking next-to-leading order effects into account the asymmetries at HERA remain measurable and sensitive to the polarised gluon distribution. They can be used to extract the polarised gluon density in the proton

R. Kaminski, L. Lesniak, B. Loiseau

Scalar-isoscalar mesons are studied using an unitary model in three channels: pi-pi, K-anti K and an effective 2pi-2pi. All the solutions, fitted to the pi-pi and K-anti K data, exhibit a wide f0(500), a narrow f0(980) and two relatively narrow resonances, lying on different sheets between 1300 MeV and 1500 MeV. These latter states are similar to the f0(1370

Mark Jack, Tord Riemann

We discuss 2f production at LC energies (f \neq t). This type of reaction has a big event number and may give interesting hints to the existence and perhaps to details of New Physics like susy, LQ, Z&#39;, etc. {For} any search the radiative corrections have to be controlled carefully. An interesting challenge for theoreticians could also be the Giga-Z optio

P. Taxil, E. Tugcu, J. -M. Virey, A. De Roeck

The search and the identification of Scalar Leptoquarks are analyzed for the HERA collider. We emphasize the relevance of having polarized beams and we make some remarks on the usefulness of en collisions.

Xiao-Gang He, German Valencia

The gluon dipole operator, $O_{11}$, has received much attention recently because it can have a large coefficient in some SUSY extensions of the standard model. We find that the commonly used matrix element of $O_{11}$ of Bertolini, Eeg and Fabbrichesi is in rough (but accidental) numerical agreement with an estimate based on dimensional analysis.

PACS Collaboration, A. Ali Khan, S. Aoki, R. Burkhalter

We present results on an analysis of the decay constants fB and fBs with two flavours of sea quark. The calculation has been carried out on 3 different bare gauge couplings and 4 sea quark masses at each gauge coupling, with m_pi/m_rho ranging from 0.8 to 0.6. We employ the Fermilab formalism to perform calculations with heavy quarks whose mass is in the ran

J. A. Coarasa, Jaume Guasch, Joan Sola

We shortly review the top quark decay into charged Higgs, and present new results on its production at the upgraded Tevatron. We have computed the MSSM cross-section for single charged Higgs in association with the top quark beyond the regime of on-shell t t-bar production followed by the decay t -> H+ b. Our results are higher than recent results in the lit

Carlo Giunti

It is shown that at least four massive neutrinos are needed in order to accommodate the evidences in favor of neutrino oscillations found in solar and atmospheric neutrino experiments and in the LSND experiment. Among all four-neutrino schemes, only two are compatible with the results of all neutrino oscillation experiments. These two schemes have a mass spe

I. P. Ivanov

In this work the production of vector mesons in diffractive DIS is analyzed, with an emphasis on the impact of the internal spin structure of a vector meson upon its virtual photoproduction rate. We derived the full sets of s-channel helicity conserving and violating amplitudes for pure S and D wave vector mesons and found a striking difference between S and

Sharada Iyer, Mary Hall Reno, Ina Sarcevic

We propose a novel approach for studying $ν_μ\to ν_τ$ oscillations with extragalactic neutrinos. Active Galactic Nuclei and Gamma Ray Bursts are believed to be sources of ultrahigh energy muon neutrinos. With distances of 100 Mpc or more, they provide an unusually long baseline for possible detection of $ν_μ\to ν_τ$ with mixing parameters $Δm^2$ down to $10^

W. Bardeen, A. Duncan, E. Eichten, H. Thacker

Preliminary results of a study of quenched chiral logarithms at beta=5.7 are presented. Four independent determinations of the quenched chiral log parameter delta are obtained. Two of these are from estimates of the eta-prime mass, one from the residue of the hairpin diagram and the other from the topological susceptibility combined with the Witten-Veneziano

M. Alford

I discuss the zero temperature phase diagram of QCD, as a function of baryon density and strange quark mass. The noteworthy points are that at sufficiently high density chiral symmetry is always restored, and at low strange quark mass there need be no phase transition between nuclear matter and quark matter. I comment on the possibility that introducing a st

UKQCD Collaboration, G. Douglas

We derive the form factors relevant for decays of pseudo-scalar mesons corresponding to the semi-leptonic decay B->D l nu. The simulations are performed in the quenched approximation at beta=6.0 and beta=6.2 using a non-perturbatively improved clover action. The slope of the Isgur Wise function and |Vcb| are extracted from the form factors.

Shigemi Ohta, Matthew Wingate

We present numerical evidence that the SU(4) pure-gauge dynamics has a finite-temperature first-order phase transition. For a $6\times 20^3$ lattice, this transition occurs at the inverse-square coupling of $8/g^2 \sim 10.79$. Below this and above the known bulk phase transition at $8/g^2 \sim 10.2$ is a confined phase in which we find two different string t

M. Teper

I review recent (and some not so recent) results on the topological susceptibility (with and without fermions), the eta-prime mass, topology and chiral symmetry breaking, vacuum topological structure, and the possible role of instantons in confinement.

Laszlo B. Szabados

The Chern-Simons functionals built from various connections determined by the initial data $h_{μν}$, $χ_{μν}$ on a 3-manifold $Σ$ are investigated. First it is shown that for asymptotically flat data sets the logarithmic fall-off for $h_{μν}$ and $rχ_{μν}$ is the necessary and sufficient condition of the existence of these functionals. The functional $Y_{k,l

Janna Levin, Rachel O&#39;Reilly, E. J. Copeland

The stability of binary orbits can significantly shape the gravity wave signal which future Earth-based interferometers hope to detect. The inner most stable circular orbit has been of interest as it marks the transition from the late inspiral to final plunge. We consider purely relativistic orbits beyond the circular assumption. Homoclinic orbits are of par

Nils Andersson, Kostas Glampedakis

We discuss the late-time behaviour of a dynamically perturbed Kerr black hole. We present analytic results for near extreme Kerr black holes that show that the large number of virtually undamped quasinormal modes that exist for nonzero values of the azimuthal eigenvalue m combine in such a way that the field oscillates with an amplitude that decays as 1/t at

Seiji Yunoki, Takashi Hotta, Elbio Dagotto

The two-orbital model for manganites with both non-cooperative and cooperative Jahn-Teller phonons is studied at hole density x=0.5 using Monte Carlo techniques. The phase diagram is obtained varying the electron-phonon coupling and the $\rm t_{2g}$-spins exchange. The insulating CE-type charge- and orbital-ordered state with the $z$-axis charge $stacking$ o

F. Comas, Nelson Studart

High electric-field transport parameters are calculated using an analytical Fokker-Planck approach (FPA), where transport is modeled as a drift-diffusion process in energy space. We have applied the theory to the case of Si, taking into account the six intervalley phonons, aiming to test the FPA. The obtained results show a quite reasonable agreement with ex

Daniel C. Hong

We explore the consequences of the excluded volume interaction of hard spheres at high densities and present a theory for excited granular materials. We first demonstrate that, in the presence of gravity, the granular density crosses over from Boltzmann to Fermi statistics, when temperature is decreased in the weak excitation limit. Comparisons of numerical

Oleg Derzhko, Johannes Richter, Oles&#39; Zaburannyi

We use continued fractions for a study of the thermodynamic properties of the periodic nonuniform spin-1/2 isotropic XY chain in a non-random/random (Lorentzian) transverse field. The obtained results permit to examine the influence of a magnetic field and randomness on the spin-Peierls dimerization.

Arnaud Buhot, Mirta B. Gordon

Upper and lower bounds for the typical storage capacity of a constructive algorithm, the Tilinglike Learning Algorithm for the Parity Machine [M. Biehl and M. Opper, Phys. Rev. A {\bf 44} 6888 (1991)], are determined in the asymptotic limit of large training set sizes. The properties of a perceptron with threshold, learning a training set of patterns having

S. N. Dorogovtsev, J. F. F. Mendes

We solve a one-dimensional sandpile problem analytically in a thick flow regime when the pile evolution may be described by a set of linear equations. We demonstrate that, if an income flow is constant, a space periodicity takes place while the sandpile evolves even for a pile of only one type of particles. Hence, grains are piling layer by layer. The thickn

A. E. Hansen, S. Pedersen, A. Kristensen, C. B. Sorensen

We have investigated the Aharonov-Bohm effect in mesoscopic semiconductor GaAs/GaAlAs rings in low magnetic fields. The oscillatory magnetoconductance of these systems is systematically studied as a function of electron density. We observe phase-shifts of $π$ in the magnetoconductance oscillations, and halving of the fundamental $h/e$ period, as the density

Jean-Philippe Bouchaud, Marc Potters

We show how one can actually take advantage of the strongly non-Gaussian nature of the fluctuations of financial assets to simplify the calculation of the Value-at-Risk of complex non linear portfolios. The resulting equations are not hard to solve numerically, and should allow fast VaR and $Δ$VaR estimates of large portfolios, where {\it by construction} th

M. Girlanda, M. Governale, M. Macucci, G. Iannaccone

We present evidence that operation of QCA (Quantum Cellular Automaton) cells with four dots is possible with an occupancy of 4N+2 electrons per cell (N being an integer). We show that interaction between cells can be described in terms of a revised formula for cell polarization, which is based only on the difference between diagonal occupancies. We validate

A. -M. Dare, G. Albinet

We study the magnetic properties of the 3d Hubbard model at half-filling in the TPSC formalism, previously developed for the 2d model. We focus on the Néel transition approached from the disordered side and on the paramagnetic phase. We find a very good quantitative agreement with Dynamical Mean-Field results for the isotropic 3d model. Calculations on finit

Bosiljka Tadic

We study numerically scaling properties of the distribution of cumulative energy dissipated in an avalanche and the dynamic phase transition in a stochastic directed cellular automaton [B. Tadić and D. Dhar, Phys. Rev. Lett. {\bf 79}, 1519 (1997)] in d=1+1 dimensions. In the critical steady state occurring for the probability of toppling $p\ge p^\star$= 0.70

Xiang-Qian Luo, C. Huang, J. Jiang, H. Jirari

Monte Carlo techniques have been widely employed in statistical physics as well as in quantum theory in the Lagrangian formulation. However, in some areas of application to quantum theories computational progress has been slow. Here we present a recently developed approach: the Monte Carlo Hamiltonian method, designed to overcome the difficulties of the conv

Antoine Georges, Olivier Parcollet, Subir Sachdev

A full mean field solution of a quantum Heisenberg spin glass model is presented in a large-N limit. A spin glass transition is found for all values of the spin S. The quantum critical regime associated with the quantum transition at S=0, and the various regimes in the spin glass phase at high spin are analyzed. The specific heat is shown to vanish linearly

J. P. Eisenstein, M. P. Lilly, K. B. Cooper, L. N. Pfeiffer

Recent magneto-transport experiments on ultra-high mobility 2D electron systems in GaAs/AlGaAs heterostructures have revealed the existence of whole new classes of correlated many-electron states in highly excited Landau levels. These new states, which appear only at extremely low temperatures, are distinctly different from the familiar fractional quantum Ha

Wentao Lu, Lorenza Viola, Kristi Pance, Michael Rose

We describe a wave-mechanical implementation of classically chaotic n-disk scattering based on thin 2-D microwave cavities. Two, three, and four-disk scattering are investigated in detail. The experiments, which are able to probe the stationary Green&#39;s function of the system, yield both frequencies and widths of the low-lying quantum resonances. The obse

H. Takayama, H. Yoshino, T. Komori

Using Monte Carlo simulations, we have studied aging phenomena in three-dimensional Gaussian Ising spin-glass model focusing on quasi-equilibrium behavior of the spin auto-correlation functions. Weak violation of the time translational invariance in the quasi-equilibrium regime is analyzed in terms of effective stiffness for droplet excitations in the presen

V. Ferrari, M. J. Rozenberg, R. Weht

We deduce a model relevant for the anomalous metallic state of Sr doped manganites at low temperatures within the ferromagnetic phase. It provides a natural explanation to several anomalous features observed experimentally, such as the vanishing Drude contribution in optical conductivity, the pseudo-gap in the density of states, an the unusual dispersion obs

Jens Bolte, Stefan Keppeler

We study the properties of the two-point spectral form factor for classically chaotic systems with spin 1/2 in the semiclassical limit, with a suitable semiclassical trace formula as our principal tool. To this end we introduce a regularized form factor and discuss the limit in which the so-called diagonal approximation can be recovered. The incorporation of

Frank C. van den Bosch

We present new semi-analytical models for the formation of disk galaxies with the purpose of investigating the origin of the near-infrared Tully-Fisher (TF) relation. The models assume that disks are formed by cooling of the baryons inside dark halos with realistic density profiles, and that the baryons conserve their specific angular momentum. Only gas with

Inese I. Ivans

We present a chemical composition analysis of three dozen giant stars in the nearby ``CN-bimodal&#39;&#39; mildly metal-poor (<[Fe/H]> = -1.18) globular cluster M4. The analysis combined traditional spectroscopic abundance methods with modifications to the line-depth ratio technique pioneered by Gray (1994). Silicon and aluminum are found to be primordially

Inese I. Ivans, Bruce Carney, Luisa de Almeida, Chris Sneden

We present preliminary abundance analyses of a group of high-velocity metal-poor stars. This report describes our work in progress. We examine the derived abundances in the context of previous studies of metal-poor stars with unusual abundances and/or extreme galactocentric orbits. Included in this sample are BD+80 245, a star previously known to have unusua

N. V. Voshchinnikov, E. Kruegel

We model the positional dependence of the optical polarization (BVRI-bands) in the circumstellar disc of beta Pictoris as observed by Gledhill et al. (1991) and Wolstencroft et al. (1995). The particles are spherical, have a size distribution n(a) \sim a^{-q} and their number density decreases with distance from the star as r^{-s}. We consider both compact a

Olaf Wucknitz, Sjur Refsdal

We discuss a simple parameter degeneracy in lens models which follows directly from the well known mass sheet degeneracy and prevents determining the radial mass distribution from lensing alone for many systems. For cosmological important systems like 1115+080 it is shown that no exact value of H0 can be determined without assuming a mass index beta.

Alberto Franceschini, Guenther Hasinger, Takamitsu Miyaji, Diego Malquori

We compare the evolution with cosmic time of the star-formation rate per comoving volume in galaxies and of the volume emissivity by Active Galactic Nuclei, as a clue to understand the relationship between black hole accretion and the formation of the surrounding structure. We find an interesting similarity between the evolution rates for the total populatio

S. Moehler, A. V. Sweigart, M. Catelan

We report the first results of an ongoing spectroscopic survey of blue horizontal branch stars in the metal-rich ([Fe/H] ~ -0.5) globular clusters NGC 6388 and NGC 6441. Based on data obtained with the ESO-New Technology Telescope (NTT), we provide gravities and temperatures for four stars in NGC 6388 and three stars in NGC 6441. These results are marginally

Jean-Paul Zahn

All numerical simulations of compressible convection reveal the presence of strong downwards directed flows. Thanks to helioseismology, such plumes have now been detected also at the top of the solar convection zone, on super- granular scales. Their properties may be crudely described by adopting Taylor&#39;s turbulent entrainment hypothesis, whose validity

D. Barthes, X. Luri, R. Alvarez, M. O. Mennessier

The absolute K magnitudes and kinematic parameters of about 350 oxygen-rich Long-Period Variable stars are calibrated, by means of an up-to-date maximum-likelihood method, using Hipparcos parallaxes and proper motions together with radial velocities and, as additional data, periods and V-K colour indices. Four groups, differing by their kinematics and mean m

Akira Tokuhisa, Toshitaka Kajino

Gamma-ray bursts (GRBs) are presumed to be powered by still unknown central engines for the timescales in the range $1ms \sim$ a few s. We propose that the GRB central engines would be a viable site for strong meson synchrotron emission if they were the compact astrophysical objects such as neutron stars or rotating black holes with extremely strong magnetic

Junxian. Wang, Youyuan. Zhou, Tinggui. Wang

We present an analysis of the Fe K line profile of NGC 4151 by using long ASCA observation data obtained in May 1995. The unprecedented good data quality, which is much better in the energy band around 6.4 keV than that of the famous 4.2-day ASCA observation of MCG -6-30-15 in July 1994, offers a unique opportunity to study the details of Fe K line profile.

W. N. Brandt, A. Comastri, S. C. Gallagher, R. M. Sambruna

We present results from a BeppoSAX observation of the BAL QSO CSO 755, observed as part of our program to investigate the X-ray properties of highly polarized BAL QSOs. CSO 755 is clearly detected by the BeppoSAX MECS, making it the highest redshift (z=2.88) and most optically luminous (M_V=-27.4) BAL QSO seen in X-rays. It is detected in several energy band

Victoria M. Kaspi, Deepto Chakrabarty, Julia Steinberger

We report on long-term X-ray timing of two anomalous X-ray pulsars, 1RXS J170849.0-400910 and 1E 2259+586, using the Rossi X-ray Timing Explorer. In monthly observations made over 1.4 yr and 2.6 yr for the two pulsars, respectively, we have obtained phase-coherent timing solutions which imply that these objects have been rotating with great stability through

J. D. Monnier, P. G. Tuthill, W. C. Danchi

We present the first near-infrared images of dusty Wolf-Rayet star WR 98a. Aperture masking interferometry has been utilized to recover images at the diffraction-limit of the Keck-I telescope, ~<50 mas at 2.2 micron. Multi-epoch observations spanning about one year have resolved the dust shell into a ``pinwheel&#39;&#39; nebula, the second example of a new c

P. Monaco, P. Salucci, L. Danese

We show that the mass function of black holes expected from the past quasar activity (both visible and obscured) is consistent with the number of dormant black holes found in the bulges of nearby galaxies. The joint formation of quasars and bulges is addressed by means of an analytical model for galaxy formation, based on the hierarchical clustering of cold

D0 collaboration, B. Abbott

We report a measurement of the W boson mass based on an integrated luminosity of 82/pb from p-pbar collisions at sqrt(s) = 1.8 TeV recorded in 1994-1995 by the D0 detector at the Fermilab Tevatron. We identify W bosons by their decays to e-nu, where the electron is detected in the forward calorimeters. We extract the mass by fitting the transverse mass and t

Robin Shakeshaft, Bernard Piraux

When the Hamiltonian of a system is represented by a finite matrix, constructed from a discrete basis, the matrix representation of the resolvent covers only one branch. We show how all branches can be specified by the phase of a complex unit of time. This permits the Hamiltonian matrix to be constructed on a real basis; the only duty of the basis is to span

Finn Larsen

All regular four-dimensional black holes are constructed in the theory obtained by Kaluza-Klein reduction of five-dimensional Einstein gravity. They are interpreted in string theory as rotating bound states of D0- and D6-branes. Conservation of angular momentum is important for the stability of the bound states. The thermodynamics, the duality symmetries, an

David Atwood, Shaouly Bar-Shalom, Amarjit Soni

We consider the production of gravitons via two photon and electron-photon fusion in Kaluza-Klein theories which allow TeV scale gravitational interactions. We show that at electron-positron colliders, the processes l+l- -> l+ l- graviton, with l=e, mu, can lead to a new signal of low energy gravity of the form l+l- -> l+l- + missing energy which is well abo

N. Chamoun, H. Vucetich

The weak interaction contribution to the proton neutron mass difference is computed using a generalization of Cottingham&#39;s formula. When included in the analysis of the Eotvos experiment, this contribution reduces the bound on a possible weak interactions violation to the equivalence principle by one order of magnitude.

Peter M. Woods, Chryssa Kouveliotou, Jan van Paradijs, Michael S. Briggs

We present evidence for burst emission from SGR 1900+14 with a power-law high energy spectrum extending beyond 500 keV. Unlike previous detections of high energy photons during bursts from SGRs, these emissions are not associated with high-luminosity burst intervals. Not only is the emission hard, but the spectra are better fit by Band&#39;s GRB function rat

R. N. Mohapatra, A. Pérez-Lorenzana

We present a new way to break parity symmetry in left-right symmetric models using boundary conditions on the fields residing in the fifth dimension. We also discuss the connection between the limits on the size of extra dimensions and the scale of right handed symmetry breaking obtained from the analysis of neutrinoless double beta decay in the case where t

A. Giveon, D. Kutasov

A double scaling limit can be defined in string theory on a Calabi-Yau (CY) manifold by approaching a point in moduli space where the CY space develops an isolated singularity and at the same time taking the string coupling to zero, while keeping a particular combination of the two parameters fixed. This leads to a decoupled theory without gravity which has

Igor R. Klebanov, Nikita A. Nekrasov, Samson L. Shatashvili

We study a ${\IZ}_2$ orbifold of Type 0B string theory by reflection of six of the coordinates (this theory may also be thought of as a ${\IZ}_4$ orbifold of Type IIB string theory by a rotation by $π$ in three independent planes). We show that the only massless mode localized on the fixed fourplane $\IR^{3,1}$ is a U(1) gauge field. After introducing D3-bra

Sara Seager, Dimitar D. Sasselov, Douglas Scott

We have developed an improved recombination calculation of H, HeI, and HeII in the early Universe which involves a line-by-line treatment of each atomic level. We find two major differences compared with previous calculations. Firstly, the ionization fraction x_e is approximately 10% smaller for redshifts <~800, due to non-equilibrium processes in the excite

Lauro Moscardini, Sabino Matarrese, Francesco Lucchin, Piero Rosati

(abridged) We present a model to predict the clustering properties of X-ray clusters in flux-limited surveys. Our technique correctly accounts for past light-cone effects on the observed clustering and follows the non-linear evolution in redshift of the underlying DM correlation function and cluster bias factor. The conversion of the limiting flux of a surve

David H. Lyth

Moduli, modulini and the gravitino have gravitational-strength interactions, and thermal collisions after reheating create all of them with roughly the same abundance. With their mass of order $100\GeV$, corresponding to gravity-mediated supersymmetry breaking, this leads to the well-known bound $γT\sub R\lsim 10^9\GeV$ on the reheat temperature, where $γ\le

Subir Mukhopadhyay, Koushik Ray

We study D1-branes on the fourfold $\C^4/(\Z_2\times\Z_2\times\Z_2)$, in the presence of discrete torsion. Discrete torsion is incorporated in the gauge theory of the D1-branes by considering a projective representation of the finite group $\Z_2\times\Z_2\times\Z_2$. The corresponding orbifold is then deformed by perturbing the F-flatness condition of the ga

A. Belyaev, M. Drees, J. K. Mizukoshi

We study the potential of hadron colliders in the search for the pair production of neutral Higgs bosons in the framework of the Minimal Supersymmetric Standard Model. We perform a detailed signal and background analysis, working out efficient kinematical cuts for the extraction of the signal. The important role of squark loop contributions to the signal is

Konstantin Klemm, Stefan Bornholdt, Heinz Georg Schuster

A learning algorithm for multilayer neural networks based on biologically plausible mechanisms is studied. Motivated by findings in experimental neurobiology, we consider synaptic averaging in the induction of plasticity changes, which happen on a slower time scale than firing dynamics. This mechanism is shown to enable learning of the exclusive-OR (XOR) pro

Pierre-Antoine Bares, Mauro Mobilia

We propose a simple method that allows, in one dimension, to solve exactly a wide class of classical stochastic many-body systems far from equilibrium. For the sake of illustration and without loss of generality, we focus on a model that describes the asymmetric diffusion of hard core particles in the presence of an external source and instantaneous annihila

U. Ellwanger

We derive the analogue of the vanishing of the cosmological constant in 3+1 dimensions, T_0^0 = 0, in terms of an integral over components of the energy-momentum tensor of a 4+1 dimensional universe with parallel three-branes, and an additional constraint local to the branes. The basic ingredients are the existence of a static solution of the Einstein equati

M. Adler, T. Shiota, P. van Moerbeke

Consider the evolution $$ \frac{\pl m_\iy}{\pl t_n}=\Lb^n m_\iy, \frac{\pl m_\iy}{\pl s_n}=-m_\iy(\Lb^\top)^n, $$ on bi- or semi-infinite matrices $m_\iy=m_\iy(t,s)$, with skew-symmetric initial data $m_{\iy}(0,0)$. Then, $m_\iy(t,-t)$ is skew-symmetric, and so the determinants of the successive &#34;upper-left corners&#34; vanish or are squares of Pfaffians

Robert B. Griffiths

A central principle of consistent histories quantum theory, the requirement that quantum descriptions be based upon a single framework (or family), is employed to show that there is no conflict between consistent histories and a no-hidden-variables theorem of Bell, and Kochen and Specker, contrary to a recent claim by Bassi and Ghirardi. The argument makes u

W. D. Heiss

Level repulsion is associated with exceptional points which are square root singularities of the energies as functions of a (complex) interaction parameter. This is also valid for resonance state energies. Using this concept it is argued that level anti-crossing (crossing) must imply crossing (anti-crossing) of the corresponding widths of the resonance state

D. Bruss, M. Cinchetti, G. M. D&#39;Ariano, C. Macchiavello

We consider an N -> M quantum cloning transformation acting on pure two-level states lying on the equator of the Bloch sphere. An upper bound for its fidelity is presented, by establishing a connection between optimal phase covariant cloning and phase estimation. We give the explicit form of a cloning transformation that achieves the bound for the case N=1,

M. C. de Oliveira, S. S. Mizrahi, V. V. Dodonov

We discuss the problem of the information transfer (exchange of states configuration) between two interacting quantum systems along their evolution in time. We consider the specific case of two modes of the electromagnetic field with rotating wave coupling interaction (up-conversion in a nonlinear crystal). We verify that for certain initial states of the fi

Toshihiko Ono

This paper proposes a basic theory on physical reality and a new foundation for quantum mechanics and classical mechanics. It presents a scenario not only to solve the problem of the arbitrariness on the operator ordering for the quantization procedure, but also to clarify how the classical-limit occurs. This paper is the first of the three papers into which

Jason A. Maddi, Timothy P. Dinneen, Harvey Gould

A method of slowing, accelerating, cooling, and bunching molecules and neutral atoms using time-varying electric field gradients is demonstrated with cesium atoms in a fountain. The effects are measured and found to be in agreement with calculation. Time-varying electric field gradient slowing and cooling is applicable to atoms that have large dipole polariz

A. A. Ketsaris

We advance an universal approach to the construction of kinematics in non-inertial and, in particular, rotating reference frames. On its basis a 10-dimensional space including three projections of velocity vector and three turn angles in geometric space as additional coordinates to time and geometric coordinates is introduced. In a specific case, the turns i

J. Browaeys, J. -C. Bacri, R. Perzynski, M. I. Shliomis

Wave resistance is the drag force associated to the emission of waves by a moving disturbance at a fluid free surface. In the case of capillary-gravity waves it undergoes a transition from zero to a finite value as the speed of the disturbance is increased. For the first time an experiment is designed in order to obtain the wave resistance as a function of s

R. Machleidt

The deuteron, NN analyzing powers A_y, and the singlet scattering length show great sensitivity to the $πNN$ coupling constant $g_π$. While the pp A_y data favor $g^2_π/4π\leq 13.6$, the np A_y data and the deuteron quadrupole moment imply $g^2_π/4π\geq 14.0$. The two diverging values could be reconciled by the assumption of (substantial) charge-splitting of

Frank Daniel Steffen

A systematic investigation of hard thermal photon spectra from central ultra-relativistic heavy ion collisions is presented with emphasis on the effects of bremsstrahlung processes in the quark-gluon plasma (QGP). Bremsstrahlung photon production in the quark-gluon plasma has recently been considered within the Braaten-Pisarski method in thermal QCD, where r

Neven Simicevic

The negative values for the squares of both electron and muon neutrino masses obtained in recent experiments are explained as a possible consequence of a change in metric within the weak-interaction volume in the energy-momentum representation. Using a model inspired by a combination of the general theory of relativity and the theory of deformation for conti