April 1997 arXiv papers — page 10

J. E. Amaro, A. M. Lallena, J. Nieves

The radiative pion capture process in nuclei is approached by using a continuum shell-model description of the nucleus, together with a phenomenological treatment of the two particle-two hole effects. It is found that these effects play an important role to reproduce the observed experimental photon energy distribution. This distribution as well as the integ

T. S. Kosmas, Amand Faessler, F. Simkovic, J. D. Vergados

The coherent and incoherent channels of the neutrinoless muon to electron conversion in nuclei, $μ^- (A,Z) \to e^- (A,Z)^*$, are studied throughout the periodic table. The relevant nuclear matrix elements are computed by explicitly constructing all possible final nuclear states in the context of the quasi-particle RPA. The obtained results are discussed in v

T. S. Kosmas, Amand Faessler, J. D. Vergados

The nuclear physics dependence of the exotic $(μ^-,e^-)$ conversion branching ratio $R_{μe^-}$ for the experimentally most interesting nuclei $^{208}Pb$ and $^{48}Ti$, is investigated in various nuclear models. The results thus obtained are combined with the new experimental limits extracted at PSI for these nuclei to put bounds on the elementary particle pa

V. V. Flambaum, D. W. Murray, S. R. Orton

The existence of a nuclear electric octupole moment (EOM) requires both parity and time invariance violation. The EOMs of odd $Z$ nuclei that are induced by a particular T- and P-odd interaction are calculated. We compare such octupole moments with the collective EOMs that can occur in nuclei having a static octupole deformation. A nuclear EOM can induce a p

Ilya Kapovich

We show that if $G$ is a non-elementary torsion-free word hyperbolic group then there exists another word hyperbolic group $G^*$, such that $G$ is a subgroup of $G^*$ but $G$ is not quasiconvex in $G^*$.

K. Behrndt, G. Lopes Cardoso, I. Gaida

We consider axion-free quantum corrected black hole solutions in the context of the heterotic S-T model with half the N=2, D=4 supersymmetries unbroken. We express the perturbatively corrected entropy in terms of the electric and magnetic charges in such a way, that target-space duality invariance is manifest. We also discuss the microscopic origin of partic

R. Medina, N. Berkovits

Pasti, Sorokin and Tonin have recently constructed manifestly Lorentz-invariant actions for self-dual field strengths and for Maxwell fields with manifest electromagnetic duality. Using the method of Deser, Gomberoff, Henneaux and Teitelboim, we generalize these actions in the presence of sources.

I. Krichever, P. Wiegmann, A. Zabrodin

We study algebro-geometric (finite-gap) and elliptic solutions of fully discretized KP or 2D Toda equations. In bilinear form they are Hirota's difference equation for $τ$-functions. Starting from a given algebraic curve, we express the $τ$-function and the Baker-Akhiezer function in terms of the Riemann theta function. We show that the elliptic solution

Ann E. Nelson

I discuss a ``more minimal'' modification of the minimal supersymmetric standard model, in which supersymmetry breaking is connected with the physics of flavor. Flavor Changing Neutral Currents (FCNC) for the first two families are suppressed, and for the third family may be of comparable size to the FCNC in the Standard Model.

Yu. A. Simonov

The light quark propagation in the confining vacuum, described by an (infinite) set of gauge-invariant vacuum correlators, is studied in detail. To keep gauge invariance at each step the system of light quark and heavy antiquark is considered, and the nonlinear equations are written explicitly for the quark propagator in the limit of large $N_c$. For the low

T. Binoth, A. Ghinculov

We study the NNLO radiative corrections of enhanced electroweak strength to the lineshape of the Higgs boson in the processes ($μ^+μ^- \to H \to ZZ$) and ($μ^+μ^- \to H \to t\bar t$), which are of interest for Higgs searches at a possible muon collider. We give the radiative corrections both in the on-shell renormalization scheme and in the pole renormalizat

M. Dasgupta, B. R. Webber

We investigate the power-suppressed corrections to the mean values of various quantities that characterise the shapes of final states in deep inelastic lepton scattering. Our method is based on an analysis of one-loop Feynman graphs containing a massive gluon, which is equivalent to the evaluation of leading infrared renormalon contributions. As in $\ee$ ann

B. L. Ioffe

The nonperturbative $Q^2$- dependence of the sum rules for the structure functions of polarized $e(μ)N$ scattering is discussed. The determination of twist-4 corrections to the structure functions at high $Q^2$ by QCD sum rules is reviewed and critically analyzed. It is found that in the case of the Bjorken sum rule the twist-4 correction is small at $Q^2 >

C. S. Lim

A viable formulation of gauge theory with extra generations in terms of quaternionic fields is presented. For the theory to be acceptable, the number of generations should be equal to or greater than 4. The quark-lepton mass matrices are generalized into quaternionic matrices.It is concluded that explicit CP violation automatically disappears in both strong-

A. F. Krutov, V. E. Troitsky

The calculation of lepton decay constants and electromagnetic form factors of pion and kaon is performed in the framework of relativistic hamiltonian dynamics. The different model wave function is used. Wave function parameters are fixed from fit of mean square radius of meson. The internal quark structure is taken into account by electromagnetic quark form

Guenter Wolf

Initial state radiation (ISR) in deep inelastic scattering of charged leptons on nucleons can lead to substantial shifts in the reconstruction of $Q^2$ and the scaling variables $x$ and $y$. By measuring at least three out of the four variables: energy and production angle of the lepton and the hadron system, the energy of the ISR photon emitted under zero d

S. O. Alexeyev

Black holes are studied in the frames of superstring theory using a non-trivial numerical integration method. A low energy string action containing graviton, dilaton, Gauss-Bonnet and Maxwell contributions is considered. Four-dimensional black hole solutions are studied inside and outside the event horizon. The internal part of the solutions is shown to have

Qiming Li, C. M. Soukoulis, S. Katsoprinakis, E. N. Economou

Scaling of the conductances and the finite-size localization lengths is generalized to anisotropic systems and tested in two dimensional systems. Scaling functions of isotropic systems are recovered once the dimension of the system in each direction is chosen to be proportional to the localization length. It is also shown that the geometric mean of the local

David Pines

I review progress in measurements of the dynamic spin susceptibility in the normal state which yield a new phase diagram and discuss microscopic calculations which yield qualitative, and in many cases, quantitative agreement with the measured changes in the quasiparticle, transport, magnetotransport, and optical properties of the cuprate superconductors as o

Ph. Bourges, L. P. Regnault, Y. Sidis, J. Bossy

Inelastic neutron scattering has been used to determine the dynamic spin fluctuations in an underdoped high temperature superconductor YBCO_{6.8} single crystal. The magnetic resonance, that occurs around 40 meV in overdoped samples, is shifted to a lower energy, E_r= 34 meV. A constant ratio, $E_r/ k_B T_C= 4.9 \pm 0.2$, almost independent of the doping lev

Thomas Prellberg, Barbara Drossel

We study winding angles of oriented polymers with orientation-dependent interaction in two dimensions. Using exact analytical calculations, computer simulations, and phenomenological arguments, we succeed in finding the variance of the winding angle for most of the phase diagram. Our results suggest that the winding angle distribution is a universal quantity

Nigel B. Wilding

We consider the liquid-gas phase boundary in a binary fluid mixture near its critical end point. Using general scaling arguments we show that the diameter of the liquid-gas coexistence curve exhibits singular behaviour as the critical end point is approached. This prediction is tested by means of extensive Monte-Carlo simulations of a symmetrical Lennard-Jon

Wolfgang Kinzel

The cooperative behaviour of interacting neurons and synapses is studied using models and methods from statistical physics. The competition between training error and entropy may lead to discontinuous properties of the neural network. This is demonstrated for a few examples: Perceptron, associative memory, learning from examples, generalization, multilayer n

Tobias Brandes

We investigate the influence of a time dependent, homogeneous electric field on scattering properties of non-interacting electrons in an arbitrary static potential. We develop a method to calculate the (Keldysh) Green's function in two complementary approaches. Starting from a plane wave basis, a formally exact solution is given in terms of the inverse o

Wei-Dong Sheng, Jian Wang, Hong Guo

We have investigated the weakly non-linear quantum transport properties of a two-dimensional quantum conductor. We have developed a numerical scheme which is very general for this purpose. The nonlinear conductance is computed by explicitly evaluating the various partial density of states, the sensitivity and the characteristic potential. Interesting spatial

Luis C. Ho, Alexei V. Filippenko, Wallace L. W. Sargent

We use the sample of emission-line nuclei derived from a recently completed optical spectroscopic survey of nearby galaxies to quantify the incidence of local (z = 0) nuclear activity. Consistent with previous studies, we find detectable amounts of ionized gas in the central few hundred parsecs of most (86%) galaxies. Half of the objects can be classified as

Luis C. Ho, Alexei V. Filippenko, Wallace L. W. Sargent

We have completed an optical spectroscopic survey of the nuclear regions (r < 200 pc) of a large sample of nearby galaxies. Although the main objectives of the survey are to search for low-luminosity active galactic nuclei and to quantify their luminosity function, the database can be used for a variety of other purposes. This paper presents measurements of

Gary A. Bower, Timothy M. Heckman, Andrew S. Wilson, Douglas O. Richstone

We present optical images of the nucleus of the nearby radio galaxy M84 (NGC 4374 = 3C272.1) obtained with the Wide Field/Planetary Camera 2 (WFPC2) aboard the Hubble Space Telescope (HST). Our three images cover the H$α$ + [N II] emission lines as well as the V and I continuum bands. Analysis of these images confirms that the H$α$ + [N II] emission in the c

Paul B. Eskridge, Richard W. Pogge

We have obtained optical spectrophotometry of 11 HII regions in the polar ring of NGC 2685 (the Helix galaxy), and have used these data to study the physical characteristics of the polar-ring HII regions. The HII regions have normal spectra with no suggestion of unusual density, temperature, extinction, or composition. Semi-empirical calculations yield high

Witold Maciejewski, Linda S. Sparke

We show that non-chaotic multiply-periodic particle orbits can exist in a galaxy-like potential where a small fast-tumbling nuclear bar is nested inside a main bar which has a slower pattern speed. We introduce the concept of a loop: a one-dimensional curve such that particles distributed along it at some initial instant return to the same curve (as viewed i

Max Pettini, Linda J. Smith, David L. King, Richard W. Hunstead

We report new observations of ZnII and CrII absorption lines in 10 damped \lya systems (DLAs), mostly at redshift $z_{abs} \simgt 2.5$ . By combining these results with those from our earlier survey (Pettini et al. 1994) and other recent data, we construct a sample of 34 measurements (or upper limits) of the Zn abundance relative to hydrogen [Zn/H]; the samp

Luis C. Ho, Alexei V. Filippenko, Wallace L. W. Sargent

As part of an optical spectroscopic survey of nearby, bright galaxies, we have identified a sample of over 200 emission-line nuclei having optical spectra resembling those of giant extragalactic H II regions. Such &#34;H II nuclei,&#34; powered by young, massive stars, are found in a substantial fraction of nearby galaxies, especially those of late Hubble ty

Luis C. Ho, Alexei V. Filippenko, Wallace L. W. Sargent

We test ideas on fueling of galactic nuclei by bar-driven inflow by comparing the detection rate and intensity of nuclear H II regions and AGNs among barred and unbarred galaxies in a sample of over 300 spirals selected from our recent optical spectroscopic survey of nearby galaxies. Among late-type spirals (Sc-Sm), but not early-type (S0/a-Sbc), we observe

Luis C. Ho, Alexei V. Filippenko, Wallace L. W. Sargent, Chien Y. Peng

We present the results of an optical spectroscopic survey designed to search for low-luminosity, &#34;dwarf&#34; Seyfert nuclei in a magnitude-limited sample of 486 bright, northern galaxies. Moderate-resolution spectra of exceptionally high quality were obtained in part to detect broad H-alpha emission, similar in character to, but much weaker than, the bro

HEGRA Collaboration, A. Daum et al

First results concerning the performance characteristics of the HEGRA IACT array are given, based on stereoscopic observations of the Crab Nebula with four telescopes. The system provides a gamma-ray energy threshold around 0.5 TeV. The Crab signal demonstrates an angular resolution of about 0.1 deg. Shape cuts allow to suppress cosmic ray background by almo

G. Vettolani, E. Zucca, G. Zamorani, A. Cappi

The ESO Slice Project (ESP) is a galaxy redshift survey we have recently completed as an ESO Key-Project. The ESP covers 23.3 square degrees in a region close to the South Galactic Pole. The survey is nearly complete (85%) to the limiting magnitude b_J=19.4 and consists of 3342 galaxies with reliable redshift determination. In this paper, the first in a seri

Dario Fadda, Eric Slezak, Albert Bijaoui

One key issue in several astrophysical problems is the evaluation of the density probability function underlying an observational discrete data set. We here review two non-parametric density estimators which recently appeared in the astrophysical literature, namely the adaptive kernel density estimator and the Maximum Penalized Likelihood technique, and desc

Tim de Zeeuw

A variety of observational approaches have provided evidence for extended halos of dark matter surrounding elliptical galaxies, and for massive dark objects in (some of) their nuclei. What are the properties of the dark halos? How do they relate to the parameters of the luminous matter? What is the demographics of massive central black holes, and what is the

John S. Mulchaey, Michael W. Regan

We use a recent near-infrared imaging survey of samples of Seyfert and normal galaxies to study the role of bars in the fueling of nuclear activity. The active galaxy sample includes Seyfert galaxies in the Revised Shapely-Ames (RSA) and Sandage & Tammann&#39;s (1987) extension to this catalog. The normal galaxies were selected to match the Seyfert sample in

G. A. Medina Tanco, N. Sabalisck, V. Jatenco-Pereira, R. Opher

The Ha peak intensity, velocity shift and velocity dispersion maps of the giant HII region NGC 604 in M 33, obtained by two dimensional high spatial resolution Fabry-Perot observations with TAURUS II at the 4.2 m William Herschel Telescope in Spain (Sabalisck, 1995), are analyzed via two point correlation functions. The whole system seems to rotate as a rigi

S. Ettori, A. C. Fabian, D. A. White

We present an analysis of a mosaic of ROSAT PSPC and Einstein Observatory IPC X-ray observations of 14 clusters and 2 groups of galaxies, enclosed in a sky area 15 degrees by 20 degrees centred on A3558 within the Shapley Supercluster region. From the mass of each cluster, extrapolated to a density contrast of 500, we define 4 large structures: (1) the core

M. Alev, A. Alpar, A. Esendemir, U. Kiziloglu

Using the archival ROSAT PSPC observations, AB Dor is found to be variable in X-rays. The periodic variations are consistent with previously reported rotational period of 0.514 days. The average spectrum of AB Dor is best represented with two-temperature Raymond-Smith model with kT values of 0.19+/-0.07 and 1.17+/-0.02 keV. The quiescent luminosity of the sy

K. Oguiso, M. Zaidenberg

A compact complex manifold $X$ is called elliptically connected if any pair of points in $X$ can be connected by a chain of elliptic or rational curves. We prove that the fundamental group of an elliptically connected compact complex surface is almost abelian. This confirms a conjecture which states that the fundamental group of an elliptically connected Käh

Hursit Onsiper, Sinan Sertoz

In this note, we show that for surfaces admitting suitable fibrations, any given degeneration X / Delta is bimeromorphic to a fiber space over Delta and we apply this result to the study of the degenerate fiber.

A. M. Ghezelbash, V. Karimipour

We define transformation of multiplets of fields (Jordan cells) under the D-dimensional conformal group, and calculate two and three point functions of fields, which show logarithmic behaviour. We also show how by a formal differentiation procedure, one can obtain n-point function of logarithmic field theory from those of ordinary conformal field theory.

Micha Berkooz, Moshe Rozali, Nathan Seiberg

We study the Matrix theory description of M-theory compactified on $T^4$ and $T^5$. M-theory on $T^4$ is described by the six dimensional (2,0) fixed point field theory compactified on a five torus, $\widetilde T^5$. For M-theory on $T^5$ we suggest the existence of a new theory which is compactified on a $\widetilde T^5$. The IR description of this theory i

D. A. Tennant, S. E. Nagler, A. W. Garrett, T. Barnes

Magnetic excitations have been investigated in the spin dimer material VODPO_4 \cdot 1/2 D_2O using inelastic neutron scattering. A dispersionless magnetic mode was observed at an energy of 7.81(4) meV. The wavevector dependence of the scattering intensityfrom this mode is consistent with the excitation of isolated V^{4+} spin dimers with a V-V separation of

Marijn Franx, Garth D. Illingworth, Daniel D. Kelson, Pieter G. van Dokkum

The cluster CL1358+62 displays a prominent red arc in WFPC2 images obtained with the Hubble Space Telescope. Keck spectra of the arc show Ly alpha emission at 7204 Angstrom, a continuum drop blueward of the line, and several absorption lines to the red. We identify the arc as a gravitationally lensed galaxy at a redshift of z=4.92. It is the highest redshift

V. Dobrosavljevic, Elihu Abrahams, E. Miranda, Sudip Chakravarty

We discuss the recently discovered two-dimensional metal-insulator transition in zero magnetic field in the light of the scaling theory of localization. We demonstrate that the observed symmetry relating conductivity and resistivity follows directly from the quantum critical behavior associated with such a transition. In addition, we show that very general s

A. Grassi

Each smooth elliptic Calabi-Yau 4-fold determines both a three-dimensional physical theory (a compactification of ``M-theory&#39;&#39;) and a four-dimensional physical theory (using the ``F-theory&#39;&#39; construction). A key issue in both theories is the calculation of the ``superpotential&#39;&#39;of the theory. We propose a systematic approach to identi

C. Boros, Meng Ta-chung, R. Rittel, Zhang Yang

It is suggested that the colorless systems of interacting soft-gluons in large-rapidity-gap events are open dynamical complex systems in which self-organized criticality and BTW-clusters play an important role. Theoretical arguments and experimental evidences supporting such a statistical approach to deep-inelastic scattering are presented.

I. P. Lokhtin, A. M. Snigirev

The gluon radiation induced by multiple scattering of a hard parton in expanding quark-gluon plasma is investigated. The radiative energy loss of hard parton jet is shown to decrease considerably when angular size of extracted jet goes up, but the fraction of loss survives even for the reasonable wide cone of angles due to the coherent effects taking into ac

E. Deotto, G. C. Ghirardi

We consider the problem of whether there are deterministic theories describing the evolution of an individual physical system in terms of the definite trajectories of its constituent particles and which stay in the same relation to Quantum Mechanics as Bohmian Mechanics but which differ from the latter for what concerns the trajectories followed by the parti

Gouranga C Nayak

We estimate the survival probability of $J/ψ$ in relativistic heavy-ion collisions, using both short-distance QCD and nuclear absorption mechanism. The suppression is found to be almost 100 percent for a thermally equilibrating quark-gluon plasma. The measurement of such a huge suppression of $J/ψ$ may suggest the existence of a deconfined partonic medium, p

D. L. Cox, A. Zawadowski

This review article provides an overview of the physics of the two-channel Kondo impurity model as manifested in two-level systems in metals and certain actinide/lanthanide ions in metals. Basic models are presented, followed by a discussion of the multiplicative renormalization group, numerical renormalization group, non-crossing approximation, conformal fi

Johan Rade

Necessary and sufficient conditions are given for the Palais-Smale Condition C to hold for the Yang-Mills functional for invariant connections on a principal bundle over a compact manifold of any dimension. It is assumed that the connections are invariant under the action of a compact Lie group on the manifold, and that all orbits of the action have codimens

Rui Dilao, Ricardo Schiappa

We solve the Cauchy problem for the relativistic closed string in Minkowski space $M^{3+1}$, including the cases where the initial data has a knot like topology. We give the general conditions for the world sheet of a closed knotted string to be a time periodic surface. In the particular case of zero initial string velocity the period of the world sheet is p

Kikuo Harigaya

Component of photoexcited states with large spatial extent is investigated for optical absorption spectra of the electroluminescent conjugated polymers by using the intermediate exciton theory. We calculate the ratio of oscillator strengths due to long-range excitons with respect to sum of all the oscillator strengths of the absorption as a function of the m

A. Gashi, G. Rasche, G. C. Oades, W. S. Woolcock

Experimental values of the lifetime of the 1s level of pionium and of the difference between the energies of the 2s and 2p levels yield values of the a(0c) and a(cc) elements of the s-wave scattering matrix for the 2-channel (pi+ pi-, pi0 pi0) system at the pi+ pi- threshold. We develop a method for obtaining the isospin invariant quanties a20 - a00 and 2a00

I. Montvay

In a vector-like extension of the minimal standard model with mirror fermions leptoquarks can be bound states of fermion-mirror-fermion pairs held together by a new strong interaction at the TeV scale. The small couplings of leptoquarks to light fermion pairs arise due to mixing. The large $Q^2$ event excess at HERA and also the high $E_T$ jet excess at Teva

Carlos Simpson

We define a closed model category containing the $n$-nerves defined by Tamsamani, and admitting internal $Hom$. This allows us to construct the $n+1$-category $nCAT$ by taking the internal $Hom$ for fibrant objects. We prove a generalized Seifert-Van Kampen theorem for Tamsamani&#39;s Poincaré $n$-groupoid of a topological space. We give a still-speculative

Victor Ginzburg

The purpose of this note is to present a short elementary proof of a theorem due to Faltings and Laumon, saying that the global nilpotent cone is a Lagrangian substack in the cotangent bundle of the moduli space of G-bundles on a complex compact curve. This result plays a crucial role in the Geometric Langlands program, due to Beilinson-Drinfeld, since it in

Luca Salasnich

We study two anyons with Coulomb interaction in a uniform magnetic field $B$. By using the torus quantization we obtain the modified Landau and Zeeman formulas for the two anyons. Then we derive a simple algebraic equation for the full spectral problem up to the second order in $B$.

Lu-Ming Duan, Guang-Can Guo

We show that, there are physical means for cloning two non-orthogonal pure states which are secretly chosen from a certain set $% \$={ | Ψ_0 > , | Ψ_1 > }$. The states are cloned through a unitary evolution together with a measurement. The cloning efficiency can not attain 100%. With some negative measurement results, the cloning fails.

Emil Kowalczyk

All bialgebra structures on twodimensional Galilei algebra are classified. The corresponding Lie-Poisson structures on Galilei group are found.

Jeremy Kepner, Scott Parker, Viktor Decyk

A challenging and fundamental research problem is the better understanding and control of the turbulent transport of heat in present-day tokamak fusion experiments. Recent developments in numerical methods along with enormous gains in computing power have made large-scale simulations an important tool for improving our understanding of this phenomena. Simula

Joel L. Lebowitz, Alexander Rokhlenko

The properties of a partially ionized plasma in a long cylindrical tube subject to a uniform axial electric field are investigated. The plasma is maintained by an external ionizing source balanced by bulk and surface recombinations. Collisions between neutrals, whose density greatly exceeds the density of charged particles, and of neutrals with ions are suff

Ion I. Cot{\u}aescu

A family of relativistic geometric models is defined as a generalization of the actual anti-de Sitter (1+1) model of the relativistic harmonic oscillator. It is shown that all these models lead to the usual harmonic oscillator in the non-relativistic limit, even though their relativistic behavior is quite different. Among quantum models we find a set of mode

Ion I. Cotăescu

A family of geometric models of quantum relativistic rotating oscillator is defined by using a set of one-parameter deformations of the static (3+1) de Sitter or anti-de Sitter metrics. It is shown that all these models lead to the usual isotropic harmonic oscillator in the non-relativistic limit, even though their relativistic behavior is different. As in t

Ion I. Cotăescu

It is shown that the new family of geometric models of the relativistic oscillator, which generalize the anti-de Sitter model, leads to relativistic Pöschl-Teller or Rosen-Morse problems.

Y. Kluger, V. Koch, J. Randrup, X. N. Wang

Disoriented chiral condensates or long wavelength pionic oscillations and their interaction with the thermal environment can be a significant source of dileptons. We calculate the yield of such dilepton production within the linear sigma model, both in a quantal mean-field treatment and in a semi-classical approximation. We then illustrate the basic features

B. M. Pimentel, R. G. Teixeira

We generalize the Hamilton-Jacobi formulation for higher order singular systems and obtain the equations of motion as total differential equations. To do this we first study the constraint structure present in such systems.

David Berenstein, Richard Corrado, Jacques Distler

By identifying the moduli space of coupling constants in the SYM description of toroidal compactifications of M(atrix)-Theory, we construct the M(atrix) description of the moduli spaces of Type IIA string theory compactified on T^n. Addition of theta terms to the M(atrix) SYM produces the shift symmetries necessary to recover the correct global structure of

Edi Halyo

We propose a state in 5+1 super Yang-Mills theory which corresponds to the wrapped transverse five brane of M(atrix) theory on $T^5$. This state is a magnetic flux quantized in units of $1/g_6^2$ through a plane defined by one side of the box and a new direction which is not manifest.

N. P. Chitaia, S. A. Gogilidze, Yu. S. Surovtsev

In the framework of the generalized Hamiltonian formalism by Dirac, the local symmetries of dynamical systems with first- and second-class constraints are investigated. For theories with an algebra of constraints of special form (to which a majority of the physically interesting theories belongs) the method of constructing the generator of local-symmetry tra

Alfredo Herrera-Aguilar, Oleg Kechkin

A new matrix representation for low-energy limit of heterotic string theory reduced to three dimensions is considered. The pair of matrix Ernst Potentials uniquely connected with the coset matrix is derived. The action of the symmetry group on the Ernst potentials is established.

Leonard Susskind

The current understanding of M(atrix) theory is that in the large N limit certain supersymmetric Yang Mills theories become equivalent to M-theory in the infinite momentum frame. In this paper the conjecture is put forward that the equivalence between M and M(atrix) theory is not limited to the large N limit but is valid for finite N. It is argued that a lig

J. L. Hewett

The ability of high energy $e^+e^-$ colliders to indirectly probe the existence of heavy new charged gauge bosons via their exchange in the reaction $e^+e^-\to ν\barνγ$ is investigated. It is shown that examination of the resulting photon energy spectrum with polarized beams can extend the $W&#39;$ search reach above the center of mass energy. [ To appear in

Stephen Godfrey, JoAnne L. Hewett, Lawrence E. Price

We examine the ability of future facilities to discover and interpret non-supersymmetric new phenomena. We first explore explicit manifestations of new physics, including extended gauge sectors, leptoquarks, exotic fermions, and technicolor models. We then take a more general approach where new physics only reveals itself through the existence of effective i

V. Barger, M. S. Berger, J. F. Gunion, T. Han

We summarize the potential of muon colliders to probe fundamental physics. $W^+W^-$, \bar tt, and $Zh$ threshold measurements could determine masses to precisions $\Delta M_W = 6$ MeV, $\Delta m_t = 70$ MeV, and $\Delta m_h = 45$ MeV, to test electroweak radiative corrections. With $s$-channel Higgs production, unique to a muon collider, the Higgs mass could

Hsin-Chia Cheng

Supersymmetric theories generally have new flavor violation sources in the squark and slepton mass matrices. If significant lepton flavor violation exists, selectron and smuon should be nearly degenerate. This leads to the phenomenon of slepton oscillations, which is analogous to neutrino oscillations, if sleptons are produced at the Next Linear Collider. Th

F. Larios, Ehab Malkawi, C. -P. Yuan

A study on the effective anomalous interactions, up to dimension 5, of the top quark with the electroweak gauge bosons is made in the non-linear Chiral Lagrangian approach. Bounds on the anomalous dimension four terms are obtained from their contribution to low energy data. Also, the potential contribution to the production of top quarks at hadron colliders

Yuval Grossman, Yosef Nir, Mihir P. Worah

In a large class of models, the only significant new physics effect on the CP asymmetries in $B \to ψK_S$ and $B \to ππ$ decays is a new contribution to the $B-\bar B$ mixing amplitude. This allows a model independent construction of the CKM Unitarity Triangle (up to hadronic uncertainties). Furthermore, the contributions to the mixing from the Standard Mode

Jennifer A. Adams, Graham G. Ross, Subir Sarkar

Attempts at building an unified description of the strong, weak and electromagnetic interactions usually involve several stages of spontaneous symmetry breaking. We consider the effects of such symmetry breaking during an era of primordial inflation in supergravity models. In cases that these occur along flat directions at intermediate scales there will be a

F. Benatti, R. Floreanini

Available data on measured observables allow deriving estimates for some of the phenomenological parameters that characterize the time-evolution and decay of the neutral kaon system based on the hypothesis of complete positivity. The present experimental uncertainties are still too large to permit a full test of complete positivity.

V. L. Morgunov, V. I. Shevchenko, Yu. A. Simonov

The light-cone Hamiltonian, incorporating the nonperturbative dynamics of the $q\bar q$ system connected by the string is solved numerically. The spectrum is shown to coincide with that of the center-of-mass Hamiltonian within the accuracy of computation, displaying the expected degeneracies of the string states, but an overall shift due to different treatme

M. G. Ryskin, Yu. M. Shabelski

The background due to the direct diffractive dissociation of the photon into the $π^+π^-$-pair to the &#34;elastic&#34; diffractive $ρ^0$-meson production in electron-proton collisions is calculated. At large $Q^2$ the interference between resonant and non-resonant $π^+ π^-$ production changes the $σ^L/σ^T$ ratio with the mass of the $2π$ (i.e. $ρ^0$-meson)

Franz E Schunck, Andrew R Liddle

We investigate the possible gravitational redshift values for boson stars with a self-interaction, studying a wide range of possible masses. We find a limiting value of $z_{lim} \simeq 0.687$ for stable boson star configurations. We compare theoretical expectation with the observational capabilities in several different wavebands, concluding that direct obse

A. Carey, K. Hannabus, V. Mathai, P. McCann

In this paper, we study both the continuous model and the discrete model of the Quantum Hall Effect (QHE) on the hyperbolic plane. The Hall conductivity is identified as a geometric invariant associated to an imprimitivity algebra of observables. We define a twisted analogue of the Kasparov map, which enables us to use the pairing between $K$-theory and cycl

Jose A. Freire, Daniel P. Arovas, Herbert Levine

We use a 1d model of a superfluid based on the Gross-Pitaevskii Lagrangian to illustrate a general numerical method designed to find quantum tunneling rates in extended bosonic systems. Specifically, we study flow past an obstacle and directly solve the imaginary time dynamics to find the ``bounce&#39;&#39; solution connected with the decay of the metastable

A. W. Garrett, S. E. Nagler, D. A. Tennant, B. C. Sales

Magnetic excitations in an array of (VO)_2P_2O_7 single crystals have been measured using inelastic neutron scattering. Until now, (VO)_2P_2O_7 has been thought of as a two-leg antiferromagnetic Heisenberg spin ladder with chains running in the a-direction. The present results show unequivocally that (VO)_2P_2O_7 is best described as an alternating spin-chai

Ariel Dobry, José A. Riera

We study using bosonization techniques the effects of frustration due to competing interactions and of the interchain elastic couplings on the soliton width and soliton structure in spin-Peierls systems. We compare the predictions of this study with numerical results obtained by exact diagonalization of finite chains. We conclude that frustration produces in

D. Bollé, G. Jongen, G. M. Shim

Using a probabilistic approach we study the parallel dynamics of fully connected Q-Ising neural networks for arbitrary Q. A Lyapunov function is shown to exist at zero temperature. A recursive scheme is set up to determine the time evolution of the order parameters through the evolution of the distribution of the local field. As an illustrative example, an e

J. -C. Anglès d&#39;Auriac, N. Sourlas

We study numerically the zero temperature Random Field Ising Model on cubic lattices of various linear sizes $L$ in three dimensions. For each random field configuration we vary the ferromagnetic coupling strength $J$. We find that in the infinite volume limit the magnetization is discontinuous in $J$. The energy and its first $J$ derivative are continuous.

M. I. Molina, J. A Roessler

We study an ideal Bose gas of N atoms contained in a box formed by two identical planar and parallel surfaces S, enclosed by a mantle of height a perpendicular to them. Calling r0 the mean atomic distance, we assume S >> r0^2 while a may be comparable to r0. In the bidimensional limit (a/r0 << 1) we find a macroscopic number of atoms in the condensate at tem

L. W. Bernardi, I. A. Campbell

We determine accurate values of ordering temperatures and critical exponents for Ising Spin Glass transitions in dimension 4, using a combination of finite size scaling and non-equilibrium scaling techniques. We find that the exponents $η$ and $z$ vary with the form of the interaction distribution, indicating non-universality at Ising spin glass transitions.

Giulio Casati, Tomaz Prosen

We study, analytically and numerically, the classical and quantum properties of a nearly spherical 3D billiard. In particular we show the appearence of quantum non ergodic behaviour and of the deviations from Random Matrix Theory predictions which are due to the quantum suppression of classically chaotic diffusion.

E. E. Narimanov, A. Douglas Stone

A semiclassical theory is developed and compared to experiments on the tunneling resonance spectrum for a quantum well in magnetic field tilted with respect to the tunneling direction. As the tilt angle is increased from zero the classical mechanics of an electron trapped within the well undergoes a smooth transition from integrable to chaotic dynamics. Pert

Joseph Betouras, Robert Joynt

The nonlinear magnetization is considered within the Ginzburg-Landau theoretical framework, in the Meissner regime. A calculational method in the case of conventional superconductors (one order parameter) is developed and is extended for the case of two order parameters (s+d mixing). It is confirmed that corrections tou the penetration depth, in the mean fie

C. Pichon, R. C. Cannon

The method originally developed by Kalnajs for the numerical linear stability analysis of round galactic disks is implemented in the regimes of non-analytic transformations between position space and angle-action space, and of vanishing growth rates. This allows effectively any physically plausible disk to be studied, rather than only those having analytic t