November 1997 arXiv papers — page 4

J. A. Oller, E. Oset, A. De Pace, P. Fernandez de Cordoba

We present calculations for Δexcitation in the (K^+,K^+) reaction in nuclei. The background from quasielastic K^+ scattering in the Δregion is also evaluated and shown to be quite small in some kinematical regions, so as to allow for a clean identification of the Δexcitation strength. Nuclear effects tied to the Δrenormalization in the nucleus are considered

Stanislaw Mrowczynski

Using the kinetic theory we discuss how the particle and energy densities of the quark-gluon plasma fluctuate in a space-time cell. The fluctuations in the equilibrium plasma and in that one from the early stage of ultrarelativistic heavy-ion collisions are estimated. Within the physically interesting values of the parameters involved the fluctuations appear

Carlos A. Bertulani, Moshe Gai

We study the breakup reactions of 8B projectiles in high energy (50 and 250 MeV/u) collisions with heavy nuclear targets (208Pb). The intrinsic nuclear wave functions are calculated using a simple model, as well as a simple optical potential. We demonstrate that nuclear effects are negligible and evaluate the contributions of various (E1, E2 and M1) multipol

Joseph Shipman

This paper reviews connections between physics and computation, and explores their implications. The main topics are computational "hardness" of physical systems, computational status of fundamental theories, quantum computation, and the Universe as a computer.

M. Gomes, L. C. Malacarne, A. J. da Silva

We study the exact equivalence between the self-dual model minimally coupled with a Dirac field and the Maxwell-Chern-Simons model with non-minimal magnetic coupling to fermions. We show that the fermion sectors of the models are equivalent only if a Thirring like interaction is included. Using functional methods we verify that, up to renormalizations, the e

Ali H. Chamseddine, Mikhail S. Volkov

We study static, spherically symmetric, and purely magnetic solutions of the N=4 gauged supergravity in four dimensions. A systematic analysis of the supersymmetry conditions reveals solutions which preserve 1/4 of the supersymmetries and are characterized by a BPS-monopole-type gauge field and a globally hyperbolic, everywhere regular geometry. We show that

M. N. Chernodub, M. I. Polikarpov

The monopole confinement mechanism in the abelian projection of lattice gluodynamics is reviewed. The main topics are: the abelian projection on the lattice and in the continuum, a numerical study of the abelian monopoles in the lattice gauge theory. Additionally, we briefly review the notation of differential forms, duality, and the BKT transformation in th

Dilip Kumar Ghosh, Sreerup Raychaudhuri

At an e-γcollider, a selectron \tilde{e}_{L,R} may be produced in association with a (lightest) neutralino \tildeχ_1. Decay of the selectron may be expected to yield a final state with an electron and another \tildeχ_1. If R-parity is violated, these two neutralinos will decay, giving rise to distinctive signatures, which are identified and studied.

J. A. Coarasa, David Garcia, Jaume Guasch, Ricardo A. Jimenez

Observing a heavy charged Higgs boson produced in the near future at the Tevatron or at the LHC would be instant evidence of physics beyond the Standard Model. Whether such a Higgs boson would be supersymmetric or not it could only be decided after accurate prediction of its properties. Here we compute the decay width of the dominant decay of such a boson, n

Lisa Randall

Inflation is a promising solution to many problems of the standard Big-Bang cosmology. Nevertheless, inflationary models have proved less compelling. In this chapter, we discuss why supersymmetry has led to more natural models of inflation. We pay particular attention to multifield models, both with a high and a low Hubble parameter.

P. H. Chankowski

We review the available constraints on the low energy supersymmetry. The bulk of the electroweak data is well screened from supersymmetric loop effects, due to the structure of the theory, even with superpartners generically light, ${\cal O}(M_Z)$. The only exception are the left-handed squarks of the third generation which have to be $\simgt {\cal O}(300$ G

J. -M. Gerard, J. Weyers

We present a simple isospin invariant parametrization for $(B \to Kπ)$ decay amplitudes which consistently includes CP violation and (quasi-elastic) hadronic final states interactions. We find that the observed $(B \to Kπ)$ decays do not lead to a significant bound on the angle $γ$ of the unitarity triangle. On the other hand, we claim that a sizeable CP vio

H. J. Schreiber

We summarize discovery potentials for the Standard Model Higgs boson produced in e^+e^- collisions and measurements of its detailed properties. Prospects for Higgs boson detection within the Minimal Supersymmetric Standard Model are also discussed.

M. Steinhauser

In this contribution three-loop QCD corrections to current correlators are considered. The application of the large momentum procedure, which provides a systematic expansion in $(m^2/q^2)^n$, allows the computation of terms up to $n=6$ for the vector and axial-vector correlator and up to $n=4$ for the scalar and pseudo-scalar correlator. Some physical applic

Mannque Rho

I describe how effective chiral Lagrangian field theories work for nuclei and nuclear matter by going from the deuteron to dense hadronic matter via BR scaling and Landau Fermi-liquid fixed point parameters, with possible applications to relativistic heavy-ion processes and compact ``nuclear stars.''

M. Steinhauser

A Higgs boson in the intermediate mass range is considered. An effective Lagrangian approach is used in order to evaluate the top-induced QCD corrections of order $α_s^3$ to the decay into light quarks and $O(α_s^4)$ corrections to the gluonic decay mode. The connection to the decoupling relations for $α_s$ and the light quark masses is discussed.

A. Bartl, H. Eberl, S. Kraml, W. Majerotto

We discuss the supersymmetric O(alpha_s) QCD corrections to e+ e- -> squark_i + antisquark_j (i,j = 1,2) and to squark_i -> q' + chargino_j, q + neutralino_k (i,j = 1,2; k = 1...4) within the Minimal Supersymmetric Standard Model. In particular we consider the squarks of the third generation stop_i and sbottom_i including the left-right mixing. In the on

Chaejun Song, Dong-Pil Min, Mannque Rho

We show that effective chiral Lagrangians endowed with Brown-Rho scaling can be mapped to Landau Fermi-liquid fixed point theory in a way consistent with general constraints following from thermodynamics. This provides a unified scheme to treat, starting from normal nuclear matter, hadronic matter under extreme conditions that is encountered in relativistic

Paolo Gondolo, Joakim Edsjo

We give an overview of our precise calculation of the relic density of the lightest neutralino, in which we included relativistic Boltzmann averaging, subthreshold and resonant annihilations, and coannihilation processes with charginos and neutralinos.

L. Lönnblad, T. Sjöstrand

We present new algorithms for simulating Bose-Einstein correlations among final-state bosons in an event generator. The algorithms are all based on introducing Bose-Einstein correlations as a shift of final-state momenta among identical bosons, and differ only in the way energy and momentum conservation is ensured. The benefits and shortcomings of this appro

F. Coester, K. Dannbom, D. O. Riska

A family of simply solvable covariant quark models for the baryons is presented. With optimal parameter choices the models reproduce the empirical spectra of the baryons in all flavor sectors to an accuracy of a few percent. Complete spectra are obtained for all states of the strange, charm and beauty hyperons with $L \leq 2$. The magnetic moments and axial

L. Pasquali, M. H. Reno, I. Sarcevic

The charm contribution to the atmospheric fluxes of muons and muon neutrinos may be enhanced by as much as a factor of 10 when one includes the contributions of D->pi,K->leptons and folds in uncertainties in the charm cross section and energy distribution. In the energy range considered here, from 100 GeV to 10 TeV, the charm contribution is small compared t

Kurt Riesselmann

This contribution reviews the latest results of the perturbative calculations of heavy-Higgs amplitudes. A comparison of perturbative results with nonperturbative lattice calculations is made, and the theoretical uncertainties of the lower and upper bound on the Standard Model Higgs mass are presented.

Toshiaki Ito, Naotoshi Okamura, Morimitsu Tanimoto

We propose the Fritzsch-Branco-Silva-Marcos type fermion mass matrix, which is a typical texture in the nearest-neighbor interaction form, in SU(5) GUT. By evolution of the mass matrices with SU(5) GUT relations in the minimal SUSY standard model, we obtain predictions for the unitarity triangle of CP violation as well as the quark flavor mixing angles, whic

J. Blümlein, B. Geyer, D. Robaschik

The non-singlet and singlet anomalous dimensions of the twist--2 light-ray operators for unpolarized and polarized deep inelastic scattering are calculated in $O(α_s)$. We apply these results for the derivation of evolution equations for partition functions, structure functions, and wave functions which are defined as Fourier transforms of the matrix element

Yong Liu, Jing-Ling Chen

Based on the relation between CP-violation phase and the other three mixing angles in Cabibbo-Kobayashi-Maskawa matrix postulated by us before, a new constraint on the parameters of Wolfenstein's parametrization is given. The result is consistent with the relative experimental results and can be further put to the more precise tests in future.

A. Abada, O. Azi, A. Tadji

We calculate the damping rate for transverse gluons with {\nineti finite} soft momentum to leading order in perturbative hot QCD. The internal momenta of the one-loop contributing diagrams are soft. This means we have to use effective vertices and propagators which incorporate the so-called hard thermal loops. We expand the damping rate in powers of the inco

Paul B. Mackenzie, Sinead M. Ryan, James N. Simone

We study Bs and Ds spectroscopy in quenched lattice QCD using the Fermilab approach to heavy quarks. We obtain results at four lattice spacings, $a$, using $O(a)$-improved Wilson quarks. We compare and contrast the various methods for heavy quarks on the lattice, discussing discussing which methods work best for different physical systems and the ease with w

ZEUS Collaboration

Charged particles ($h^\pm$) and \kz mesons have been studied in photoproduced events containing at least one jet of $E_T > 8$ GeV in a pseudorapidity interval (--0.5, 0.5) in the ZEUS laboratory frame. Distributions are presented in terms of transverse momentum, pseudorapidity and distance of the particle from the axis of a jet. The properties of \hpm within

D. V. Ahluwalia

It is argued that (a) In the quantum realm test-particle masses have non-trivial observability which induces a non-geometric element in gravity, (b) Any theory of quantum gravity, on fundamental grounds, must contain an element of non-locality that makes position measurements non-commutative, and (c) The classical notion of free fall does not readily general

Li-Xin Li, J. Richard Gott, III

In this paper we find a self-consistent vacuum for Misner space. For this "adapted" Rindler vacuum the renormalized stress-energy tensor is zero throughout the Misner space. A point-like particle detector traveling on a timelike geodesic in a Misner space with this vacuum detects nothing. Misner space with this vacuum thus creates no problems for tim

T. Kloesch, T. Strobl

A classification of the maximally extended solutions for 1+1 gravity models (comprising e.g. generalized dilaton gravity as well as models with non-trivial torsion) is presented. No restrictions are placed on the topology of the arising solutions, and indeed it is found that for generic models solutions on non-compact surfaces of arbitrary genus with an arbi

Hideyuki Tagoshi, Shuhei Mano, Eiichi Takasugi

When a particle moves around a Kerr black hole, it radiates gravitational waves.Some of these waves are absorbed by the black hole. We calculate such absorption of gravitational waves induced by a particle of mass mu in a circular orbit on an equatorial plane around a Kerr black hole of mass M. We assume that the velocity of the particle v is much smaller th

Alexander Chebotarev, Franco Fagnola

The conservativity of a minimal quantum dynamical semigroup is proved whenever there exists a ``reference'' subharmonic operator bounded from below by the dissipative part of the infinitesimal generator. We discuss applications of this criteria in mathematical physics and quantum probability.

D. Burghelea, L. Friedlander, T. Kappeler

For a closed manifold equipped with a Riemannian metric, a triangulation, a representation of its fundamental group on an Hilbert module of finite type (over of finite von Neumann algebra), and a Hermitian structure on the flat bundle associated to the representation, one defines a numerical invariant, the relative torsion. The relative torsion is a positive

D. M. Stamper-Kurn, M. R. Andrews, A. P. Chikkatur, S. Inouye

Bose-Einstein condensates of sodium atoms have been confined in an optical dipole trap using a single focused infrared laser beam. This eliminates the restrictions of magnetic traps for further studies of atom lasers and Bose-Einstein condensates. More than five million condensed atoms were transferred into the optical trap. Densities of up to $3 \times 10^{

P. Henelius, S. M. Girvin

The effects of randomness and dimerization on the spin-1/2 XX chain are studied by a mapping to free fermions. Results are presented for the transverse and longitudinal components of the average and typical spin and string correlation functions. Contrary to previous numerical evidence, the decay exponents of all the above correlation functions are found to b

Branko Stojkovic, David Pines

We report on a simple calculation of the magnetotransport in cuprate superconductors, based on the nearly antiferromagnetic Fermi liquid (spin fluctuation) model. We find that the model explains all important features seen experimentally: the violation of K"ohler's rule, the close relationship between the Hall angle and the magnetoresistance, the tem

Dingping Li

We study the hierarchical wave functions on a sphere and on a torus. We simplify some wave functions on a sphere or a torus using the analytic properties of wave functions. The open question, the construction of the wave function for quasielectron excitations on a torus, is also solved in this paper.

Eric Jeckelmann

The one-dimensional extended Peierls-Hubbard model is studied at several band fillings using the density matrix renormalization group method. Results show that the ground state evolves from a Mott-Peierls insulator with a correlation gap at half-filling to a soliton lattice with a small band gap away from half-filling. It is also confirmed that the ground st

Malte Henkel, Dragi Karevski

A new realization of the conformal algebra is studied which mimics the behaviour of a statistical system on a discrete albeit infinite lattice. The two-point function is found from the requirement that it transforms covariantly under this realization. The result is in agreement with explicit lattice calculations of the $(1+1)D$ Ising model and the $d-$dimens

F. Naef, X. Zotos

In this paper, we study the spin and energy dynamic correlations of the one dimensional spin 1/2 Heisenberg model, using mostly exact diagonalization numerical techniques. In particular, observing that the uniform spin and energy currents decay to finite values at long times, we argue for the absence of spin and energy diffusion in the easy plane anisotropic

J. C. Cuevas, A. Levy Yeyati, A. Martin-Rodero

We present a theoretical approach which allows to determine the number and orbital character of the conducting channels in metallic atomic contacts. We show how the conducting channels arise from the atomic orbitals having a significant contribution to the bands around the Fermi level. Our theory predicts that the number of conducting channels with non negli

L. Santen, A. Schadschneider

The cellular automaton model for traffic flow exhibits a jamming transition from a free-flow phase to a congested phase. In the deterministic case this transition corresponds to a critical point with diverging correlation length. We present data from numerical simulations which suggest the absence of critical behavior in the presence of noise. The transition

X. H. Wang, K. A. Chao

We have investigated the quantum admittance of an ultrasmall tunnel junction with arbitrary tunneling strength under an electromagnetic environment. Using the functional integral approach a close analytical expression of the quantum admittance is derived for a general electromagnetic environment. We then consider a specific controllable environment where a r

V. I. Yukalov

A method is developed for solving nonlinear systems of differential, or integrodifferential, equations with stochastic fields. The method makes it possible to give an accurate solution for an interesting physical problem: What are the peculiarities of nonlinear spin dynamics in nonequilibrium nuclear magnets coupled with a resonator? Evolution equations for

Erik Aurell

The motion of a conducting electron in a quantum dot with one or several dislocations in the underlying crystal lattice is considered in the continuum picture, where dislocations are represented by torsion of space. The possible effects of torsion are investigated on the levels of classical motion, non-relativistic quantum motion, and spin-torsion coupling t

W. Z. Wang, A. R. Bishop, J. T. Gammel, R. N. Silver

Quantum breathers are studied numerically in several electron-phonon coupled finite chain systems, in which the coupling results in intrinsic nonlinearity but with varying degrees of nonadiabaticity. As for quantum nonlinear lattice systems, we find that quantum breathers can exist as eigenstates of the system Hamiltonians. Optical responses are calculated a

Gongwen Peng, Jens-Uwe Sommer, Alexander Blumen

We investigate numerically, using the bond-fluctuation model, the adsorption of many random AB--copolymers with excluded volume interactions at the interface between two solvents. We find two regimes, controlled by the total number of polymers. In the first (dilute) regime, the copolymers near the interface extend parallel to it, while in the second regime t

D. J. Crary, M. H. Finger, C. Kouveliotou, F. van der Hooft

We have used the Fourier cross spectra of Cyg X-1, as obtained with BATSE during a period of almost 2000 days, to estimate the phase (or time) lags between X-ray flux variations in the 20-50 keV and the 50-100 keV bands as a function of Fourier frequency, nu. We find that these lag spectra do not depend on source state, as measured by the fractional rms vari

Richard Barvainis

A brief overview is given of the current status of molecular emission line observations at high redshift. New observations are presented of CO in the gravitationally lensed quasar MG 0414+0534 (detected) and the unlensed quasar PG 1634+706 (not detected). Also noted are the results of a partially completed search for water maser emission in several redshift

Stephen D. Burns

Large scale structure and microwave background anisotropies are studied for warm dark matter models. Two warm dark matter candidates are considered: gravitinos and sterile neutrinos. Linear large scale structure properties such as $σ_{8}$ and the excess power are calculated, as well as microwave background anisotropies. A rather robust feature of warm dark m

Stephen D. Burns

Isentropic and isocurvature axion inflationary perturbations are studied in detail. If isocurvature perturbations are present, COBE requires the inflationary Hubble constant to be rather small, $H_{I} \stackrel{<}{\sim} 10^{12}$GeV, regardless of the inflation model. Microwave background anisotropies are calculated for CDM models with a mixture of axion and

Thaisa Storchi-Bergmann, Henrique R. Schmitt, Daniela Calzetti, Anne L. Kinney

We investigate two chemical abundance calibrations for the narrow-line-region (NLR) of active galaxies in terms of three easily observable optical emission-line ratios, namely, [OIII]$λλ$4959,5007/H$β$, [NII]$λλ$6548,84/H$α$ and [OII]$\lambda3727/$[OIII]$λλ$4959,5007. The calibrations are obtained from a grid of models on the assumption that the main process

Rene A. Ong, Corbin E. Covault

The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a telescope designed to explore the gamma-ray sky between 20 and 250 GeV using the atmospheric Cherenkov technique. STACEE is currently under construction. When completed, it will use 48 large heliostat mirrors at the solar research facility at Sandia National Laboratories (Albuquerque, NM)

A. E. Sansom, R. N. Proctor

We follow the chemical evolution of a galaxy through star formation and its feedback into the inter-stellar medium, starting from primordial gas and allowing for gas to inflow into the region being modelled. We attempt to reproduce observed spectral line-strengths for early-type galaxies to constrain their star formation histories. The efficiencies and times

H. C. Ford, Z. I. Tsvetanov, L. Ferrarese, W. Jaffe

After correcting spherical aberration in the Hubble Space Telescope in 1993, the central masses of galaxies can be measured with a resolution 5 to 10 times better than can be achieved at the best terrestrial sites. This improvement in resolution is decisive for detecting the gravitational signature of massive black holes in galaxy nuclei. The discovery of sm

Limin Lu, Wallace L. W. Sargent, Thomas A. Barlow

Damped Lyman-alpha systems seen in spectra of background quasars are generally thought to represent high redshift counterparts of present-day galaxies. We summarize observations of heavy element abundances in damped Lyman-alpha systems. The results of a systematic search for CO and C II* absorption in 17 damped Lyman-alpha systems are also presented using ob

N. Langer, A. Heger

In this paper, we investigate the evolutionary status of B[e]~stars from the point of view of stellar evolution theory. We try to answer to the question of how massive hot supergiants --- i.e. evolved stars --- can be capable of producing a circumstellar disk. We find and discuss three possibilities: very massive evolved main sequence stars close to critical

D. Dal Fiume, M. Orlandini, G. Cusumano, S. Del Sordo

The X-ray pulsar Her X-1 was observed for more than two orbital cycles near the maximum of the 35 day X-ray intensity cycle by the Narrow Field Instruments on-board the BeppoSAX satellite. We present the first simultaneous measurement of the 0.1-200 keV spectrum. Three distinct continuum components are evident in the phase averaged spectrum: a low energy exc

J-L. Atteia

Studies using the GRB brightness as a distance indicator require a measure of brightness with a small intrinsic dispersion (close to a standard candle). There is unfortunately no general agreement on the definition of such a quantity. We show here that the comparison of the size-frequency curves obtained with various measures of brightness can be used to sel

Mark R. Metzger, Paul L. Schechter

We present results of a survey of a 6-square-degree region near l=60, b=0 to search for distant Milky Way Cepheids. Few MW Cepheids are known at distances >~ R_0, limiting large-scale MW disk models derived from Cepheid kinematics; this work was designed to find a sample of distant Cepheids for use in such models. The survey was conducted in the V and I band

J. J. M. in &#39;t Zand, A. Baykal, T. E. Strohmayer

X-ray observations of the accreting X-ray pulsar 4U~1907+09, obtained during February 1996 with the Proportional Counter Array on the Rossi X-ray Timing Experiment (RXTE), have enabled the first measurement of the intrinsic pulse period Ppulse since 1984: Ppulse=440.341[+0.012,-0.017] s. 4U 1907+09 is in a binary system with a blue supergiant. The orbital pa

A. R. Petrosian, V. G. Gurzadyan, M. A. Hendry, E. Nikoghossian

The results of an analysis of the substructure of 1 degree field galaxies of the Virgo cluster by means of the S-tree technique developed by Gurzadyan et al, are represented. The existence of 3 main subgroups is shown and their dynamical parameters are obtained. The mass centers of the subgroups appear to be aligned in the direction parallel to the elongatio

M. J. Drinkwater, J. K. Webb, J. D. Barrow, V. V. Flambaum

Recent detections of high-redshift absorption by both atomic hydrogen and molecular gas in the radio spectra of quasars have provided a powerful tool to measure possible temporal and spatial variations of physical `constants&#39; in the Universe. We have compared the frequency of high-redshift Hydrogen 21 cm absorption with that of associated molecular absor

Shulim Kaliman

The Zariski theorem says that for every hypersurface in a complex projective (resp. affine) space of dimension at least 3 and for every generic plane in the projective (resp. affine) space the natural embedding generates an isomorphism of the fundamental groups of the complements to the hypersurface in the plane and in the space. If a family of hypersurfaces

Viacheslav V. Nikulin

It was recently understood that from the point of view of automorphic Lorentzian Kac-Moody algebras and some aspects of Mirror Symmetry, interesting hyperbolic root systems should have restricted arithmetic type and a generalized lattice Weyl vector. One can consider hyperbolic root systems with these properties as an appropriate hyperbolic analog of the cla

S. T. R. Pinho, C. P. C. Prado, O. Kinouchi

We report some numerical simulations to investigate the existence of a self-organized critical (SOC) state in a random-neighbor version of the OFC model for a range of parameters corresponding to a non-conservative case. In contrast to a recent work, we do not find any evidence of SOC. We use a more realistic distribution of energy among sites to perform som

W. Vincent Liu

We consider the low-energy collective excitations at finite temperature of Bose--Einstein condensed gases (and liquids as well). A most general model-independent effective Lagrangian is written down according to a prescription obtained from the breakdown of the global symmetry U(1). To show how the theory predicts easily, we derive the momentum and temperatu

Xiaofeng Guo

We calculate the nuclear enhancement in Drell-Yan transverse momentum distribution in hadron-nucleus collisions. In terms of multiple scattering picture, we compute the contributions from double scattering. Applying the generalized factorization theorem, we express the nuclear enhancement in terms of twist-4 nuclear parton correlation functions. We demonstra

Greg W. Anderson, Sean M. Carroll

We propose a simple model in which the cosmological dark matter consists of particles whose mass increases with the scale factor of the universe. The particle mass is generated by the expectation value of a scalar field which does not have a stable vacuum state, but which is effectively stabilized by the rest energy of the ambient particles. As the universe

J. Wahle, N. Blümer, J. Schlipf, K. Held

A systematic investigation of the microscopic conditions stabilizing itinerant ferromagnetism of correlated electrons in a single-band model is presented. Quantitative results are obtained by quantum Monte Carlo simulations for a model with Hubbard interaction U and direct Heisenberg exchange interaction F within the dynamical mean-field theory. Special emph

Ioannis Giannakis, James T. Liu

We derive sum rules for the magnetic and electric dipole moments of all particle states of an N=2 supermultiplet. For short representations, we find agreement with previously determined N=1 sum rules, while there is added freedom for long representations (expressed as certain scalar expectation values). With mild assumptions we find the simple result that th

Ho-Meoyng Choi, Chueng-Ryong Ji

Both the mass spectra and the wave functions of the light pseudoscalar ($π,K,η,η&#39;$) and vector($ρ,K^{*},ω,ϕ$) mesons are analyzed within the framework of the light-cone constituent quark model. A gaussian radial wave function is used as a trial function of the variational principle for a QCD motivated Hamiltonian which includes not only the Coulomb plus

Paul H. Frampton, Masayasu Harada

Explicit expressions are derived for the oblique parameters $S$ and $T$ in certain extensions of the standard model. In particular, we consider leptoquarks and bileptons, and find phenomenological constraints on their allowed masses. Leptoquarks suggested by the neutral and charged current anomalies at HERA can give improved agreement with both $S$ and $T$.

M. L. Swartz

The construction of a computer code to calculate the cross sections for the spin-polarized processes e-gamma=>e-gamma,e-gamma-gamma,e-e+e- to order-alpha**3 is described. The code calculates cross sections for circularly-polarized initial-state photons and arbitrarily polarized initial-state electrons. The application of the code to the SLD Compton polarimet

C. M. Hull

Using U-duality, the properties of the matrix theories corresponding to the compactification of M-theory on $T^d$ are investigated. The couplings of the $d+1$ dimensional effective Super-Yang-Mills theory to all the M-theory moduli is deduced and the spectrum of BPS branes in the SYM gives the corresponding spectrum of the matrix theory.Known results are rec

D. C. Brody, L. P. Hughston

An exact stochastic model for the thermalisation of quantum states is proposed. The model has various physically appealing properties. The dynamics are characterised by an underlying Schrodinger evolution, together with a nonlinear term driving the system towards an asymptotic equilibrium state and a stochastic term reflecting fluctuations. There are two fre

R. N. Mohapatra

A muon collider is expected to produce a high intensity neutrino beam which is an admixture of either $ν_μ+\bar{ν_e}$ or $\barν_μ +ν_e$ which can can be directed to underground detectors far away from the source. It will not only allow a probe of the $ν_e-ν_μ$ as well as $ν_μ-ν_τ$ oscillations in a range of mixing angle and $Δm^2$ not probed heretofore but i

V. N. Plechko

We apply a new anticommuting path integral technique to clarify the fermionic structure of the 2D Ising model with quenched site dilution. In the $N$-replica scheme, the model is explicitly reformulated as a theory of interacting fermions on a lattice. An unusual feature is that the leading term of interaction in the exact lattice theory is of order $2N$ in

T. Han, H. -J. He, C. -P. Yuan

We study new physics effects to the quartic gauge boson couplings formulated by the electroweak chiral Lagrangian. Five next-to-leading order operators characterize the anomalous quartic gauge interactions which involve pure Goldstone boson dynamics for the electroweak symmetry breaking. We estimate the typical size of these couplings in different strongly-i

Yao-Zhong Zhang, Huan-Qiang Zhou

New classes of integrable boundary conditions for the q-deformed (or two-parameter) supersymmetric U model are presented. The boundary systems are solved by using the coordinate space Bethe ansatz technique and Bethe ansatz equations are derived.

Claus Slotta, Ulrich Heinz

We analyze the spatial and temporal resolving power of two-photon intensity interferometry for the light emitting source in single bubble sonoluminescence (SBSL). We show that bubble sizes between several 10 nm and 3 um can be resolved by measuring the transverse correlation function, but that a direct determination of the flash duration via the longitudinal

Robert Alicki

The reinterpretation of quantum mechanical formalism in terms of a classical model with a continuous material &#34;$Ψ$-field&#34; acting upon a point-like particle which is subjected to large friction and random forces is proposed. This model gives a mechanism for sudden &#34;quantum jumps&#34; and provides a simple explanation of &#34;Schrödinger Cat&#34; p

V. D. Gershun

Explicit construction of the second order left differential calculi on the quantum group and its subgroups are obtained with the property of the natural reduction: the differential calculus on the quantum group $GL_q(2,C)$ has to contain the 3-dimensional differential calculi on the quantum subgroup $SL_q(2,C)$, the differential calculi on the Borel subgroup

Todd P. Meyrath Daniel F. V. James

We examine the properties of cold ions confined by a Paul trap in a linear crystal configuration, a system of considerable current interest due to its application to practical quantum computation. Using a combination of theoretical and numerical calculation, a semi- empirical formula for the positions of the ions is derived.

P. K. Panda, R. Sahu

A nonperturbative field theoretic calculation has been made for the $s$-shell hypernuclei. Here we dress the $Λ$- and $Σ$- hypernuclei with off-mass shell pion pairs. The analysis replaces the scalar isoscalar potential by quantum coherent states. The binding energies of $^{4+nΛ}$He $(n=0,1,2)$ agree quite well with the RMF result of Greiner. The experimenta

Wayne N. Polyzou

A class of nucleon-nucleon interactions which are exactly phase equivalent to a given realistic nucleon-nucleon interaction are exhibited. These interaction have the property that the RMS radius of the deuteron can be made arbitrarily large without changing any of the scattering or bound-state observables. With this construction it is possible to find realis

Stephen Wainger, James Wright, Sarah Ziesler

We consider singular integrals associated to a classical Calderón-Zygmund kernel $K$ and a hypersurface given by the graph of $φ(ψ(t))$ where $φ$ is an arbitrary $C^1$ function and $ψ$ is a smooth convex function of finite type. We give a characterization of those Calderón-Zygmund kernels $K$ and convex functions $ψ$ so that the associated singular integral

Anthony Carbery, Steve Hofmann, James Wright

We introduce an analogue of Calderón&#39;s first commutator along a parabola, and establish its $L^2$ boundedness under essentially sharp hypotheses.

Fedor Nazarov, Sergei Treil, Alexander Volberg

In the paper we consider Calderón-Zygmund operators in nonhomogeneous spaces. We are going to prove the analogs of classical results for homogeneous spaces. Namely, we prove that a Calderón-Zygmund operator is of weak type if it is bounded in $L^2$. We also prove several versions of Cotlar&#39;s inequality for maximal singular operator. One version of Cotlar

Vladimir Tolstykh

We prove that the automorphism group of an arbitrary non-abelian free group is complete. It generalizes the result by J.Dyer and E.Formanek (1975) stating the completeness of automorphism group of finitely generated free groups. Using the description of involutions in automorphism groups of free groups (J. Dyer, P. Scott, 1975) we obtain a group-theoretic ch

Frank Gronwald

The metric-affine gauge theory of gravity provides a broad framework in which gauge theories of gravity can be formulated. In this article we fit metric-affine gravity into the covariant BRST--antifield formalism in order to obtain gauge fixed quantum actions. As an example the gauge fixing of a general two-dimensional model of metric-affine gravity is worke

G. Cleaver, M. Cvetic, J. R. Espinosa, L. Everett

We develop techniques to classify D- and F-flat directions for N=1 supersymmetric string vacua of the perturbative heterotic string theory, which possess an anomalous U(1) gauge group at the tree level. Genus-one corrections generate a Fayet-Iliopoulos term for the D-term of U(1)_A, which is canceled by non-zero vacuum expectation values (VEVs) of certain ma

Yuhsuke Yoshida

A geometrical analysis is given of Dirichlet fourbrane creation, when sixbrane crosses fivebrane in M-theory. A special property of the Taub-NUT space leads to the consequence. When brane configurations are considered for four dimensional N=2 field theories, sixbrane contributes to the beta-function through the Dirac string of the Taub-NUT space.

Wolfgang Lucha, Michael Moser

An arbitrary renormalizable quantum field theory is considered as finite if its dimensionless couplings conspire to yield, at every order of its perturbative expansion, no ultraviolet-divergent renormalizations of the physical parameters of the theory. The &#34;finiteness conditions&#34; resulting from these requirements form highly complicated, non-linear s

Jose D. Edelstein, Carlos Nunez

We discuss on the possible existence of a supersymmetric invariance in purely fermionic planar systems and its relation to the fermion-boson mapping in three-dimensional quantum field theory. We consider, as a very simple example, the bosonization of free massive fermions and show that, under certain conditions on the masses, this model displays a supersymme

H. Fort, R. Gambini

We show how the gauge invariant formulation of QCD in terms of loops is free from a hidden $θ$ parameter and offers an alternative way to solve the $U(1)_A$ puzzle.

P. Valtancoli

We propose an extension of a recent non-perturbative method suited for solving the N-body problem in (2+1)-gravity to the case of Chern-Simons supergravity. Coupling with supersymmetric point particles is obtained implicitly by extending the DJH matching conditions of gravity. The consistent solution of the interacting case is obtained by building a general

Friedemann Brandt

The formulation of the local BRST cohomology on infinite jet bundles and its relation and reduction to gauge covariant algebras are reviewed. As an illustration, we compute the local BRST cohomology for geodesic motion in (pseudo-) Riemannian manifolds and discuss briefly the result (symmetries, constants of the motion, consistent deformations).