July 1995 arXiv papers — page 2

L. Chayes, V. J. Emery, S. A. Kivelson, Z. Nussinov

We study the effects of weak long-ranged antiferromagnetic interactions of strength $Q$ on a spin model with predominant short-ranged ferromagnetic interactions. In three dimensions, this model exhibits an avoided critical point in the sense that the critical temperature $T_c(Q=0)$ is strictly greater than $\lim_{Q\to 0} T_c(Q)$. The behavior of this system

Redouane Fakir

It is generally accepted that a first ever direct detection of gravity waves would herald a new era in astronomy and in fundamental physics. Ever since the early sixties, increasingly larger human and material resources are being invested in the detection effort. Unfortunately, the gravity wave effects one has had to exploit so far are extraordinarily small

Yoshiko Hayakawa

In this paper we focus on determining for which degenerations the central fibre is at finite distance with respect to Weil-Petersson metric. We obtain a simple condition on the limiting mixed Hodge structure. Then we combine the result with the canonical mixed Hodge structure of the central fibre and obtain a simple cohomological condition for the central fi

Werner Ebeling, Alexander Neiman, Thorsten Pöschel

We investigate symbolic sequences and in particular information carriers as e.g. books and DNA--strings. First the higher order Shannon entropies are calculated, a characteristic root law is detected. Then the algorithmic entropy is estimated by using Lempel--Ziv compression algorithms. In the third section the correlation function for distant letters, the l

Y. Georgelin, T. Masson, J. -C. Wallet

We apply a recently proposed definition of a linear connection in non commutative geometry based on the natural bimodule structure of the algebra of differential forms to the case of the two-parameter quantum plane. We find that there exists a non trivial family of linear connections only when the two parameters obeys a specific relation.

Carsten Gundlach

By fine-tuning generic Cauchy data, critical phenomena have recently been discovered in the black hole/no black hole "phase transition" of various gravitating systems. For the spherisymmetric real scalar field system, we find the "critical" spacetime separating the two phases by demanding discrete scale-invariance, analyticity, and an additio

Nimai C. Mukhopadhyay, J. -F. Zhang, M. Benmerrouche

We discuss the eta and eta prime photo- and electroproduction as a way to probe the nucleon resonance structure.

G. Giugliarelli, A. L. Stella

Depinning of an interface from a random self--affine substrate with roughness exponent $ζ_S$ is studied in systems with short--range interactions. In 2$D$ transfer matrix results show that for $ζ_S<1/2$ depinning falls in the universality class of the flat case. When $ζ_S$ exceeds the roughness ($ζ_0=1/2$) of the interface in the bulk, geometrical disorder b

P. Taxil, J. M. Virey

A new handed interaction between subconstituents of quarks could be at the origin of some small parity violating effects in one-jet inclusive production. Within a few years, the Relativistic Heavy Ion Collider (RHIC) will be used as a polarized proton-proton collider. In this context, we analyse the possibilities of disentangling some new parity violating ef

G. Bimonte, E. Ercolessi, G. Landi, F. Lizzi

We consider finite approximations of a topological space $M$ by noncommutative lattices of points. These lattices are structure spaces of noncommutative $C^*$-algebras which in turn approximate the algebra $\cc(M)$ of continuous functions on $M$. We show how to recover the space $M$ and the algebra $\cc(M)$ from a projective system of noncommutative lattices

G. Bimonte, E. Ercolessi, G. Landi, F. Lizzi

We address the problem of the continuum limit for a system of Hausdorff lattices (namely lattices of isolated points) approximating a topological space $M$. The correct framework is that of projective systems. The projective limit is a universal space from which $M$ can be recovered as a quotient. We dualize the construction to approximate the algebra ${\cal

A. R. Tumanyan, Kh. A. Simonyan, R. L. Mkrtchyan, A. Ts. Amatuni

The circuit arrangement of the proposed coaxial ring cyclotron (CRC) is described, and its main advantages, such as simple injection technique, several injected beams summation option, high efficiency, are considered. The proposed proton accelerator is a perspective machine for the solution of the main problems of the present day nuclear power engineering as

G. V. Kraniotis

We study the constraints from the $b{\rightarrow}sγ$ decay in the parameter space of effective supergravities from orbifold string theory and with minimal supesymmetric particle content. Both the general dilaton-dominated universal scenario as well as a non-universal scenario for the soft terms are investigated. It is found that the recently reported CLEO up

Katsushi Ito, Sung-Kil Yang

We calculate the prepotential of the low-energy effective action for $N=2$ $SU(2)$ supersymmetric Yang-Mills theory with $N_f$ massless hypermultiplets ($N_f=1,\, 2,\, 3$). The precise evaluation of the instanton corrections is performed by making use of the Picard-Fuchs equations associated with elliptic curves. The flavor dependence of the instanton effect

K. A. Mader, A. Zunger

We consider (AlAs)_n/(GaAs)_n superlattices with random thickness fluctuations Delta-n around the nominal period n. Using three-dimensional pseudopotential plane-wave band theory, we show that (i) any amount Delta-n/n of thickness fluctuations leads to band-edge wavefunction localization, (ii) for small Delta-n/n the SL band gap is pinned at the gap level pr

Moti Gitik, William Mitchell

We prove several results giving lower bounds for the large cardinal strength of a failure of the singular cardinal hypothesis. The main result is the following theorem: Theorem: Suppose $κ$ is a singular strong limit cardinal and $2^κ>= λ$ where $λ$ is not the successor of a cardinal of cofinality at most $κ$. (i) If $\cofinality(κ)>\gw$ then $o(κ)\geλ$. (ii

R. S. Bhalla, A. K. Kapoor, P. K. Panigrahi

Using quantum Hamilton-Jacobi formalism of Leacock and Padgett, we show how to obtain the exact eigenvalues for supersymmetric (SUSY) potentials.

Bong H. Lian, Shing-Tung Yau

As a continuation of \lianyaufour, we study modular properties of the periods, the mirror maps and Yukawa couplings for multi-moduli Calabi-Yau varieties. In Part A of this paper, motivated by the recent work of Kachru-Vafa, we degenerate a three-moduli family of Calabi-Yau toric varieties along a codimension one subfamily which can be described by the vanis

A. A. Slavnov

A four dimensional fermion determinant is presented as a path integral of the exponent of a local five dimensional action describing constrained bosonic system. The construction is carried out both in the continuum theory and in the lattice model.

Bong H. Lian, Shing-Tung Yau

Motivated by the recent work of Kachru-Vafa in string theory, we study in Part A of this paper, certain identities involving modular forms, hypergeometric series, and more generally series solutions to Fuchsian equations. The identity which arises in string theory is the simpliest of its kind. There are nontrivial generalizations of the identity which appear

Bruno Iochum, Daniel Kastler, Thomas Schucker

Recently Connes has proposed a new geometric version of the standard model including a non-commutative charge conjugation. We present a systematic analysis of the relations among masses and coupling constants in this approach. In particular, for a given top mass, the Higgs mass is constrained to lie in an interval. Therefore this constraint is locally stable

Dong Sup Soh, Kyung Hyun Cho, Sang Pyo Kim

A recurrence relation of Riccati-type differential equations known in supersymmetric quantum mechanics is investigated to find exactly solvable potentials. Taking some simple {\it ansätze}, we find new classes of solvable potentials as well as reproducing the known shape-invariant ones.

Masako Asano, Saburo Higuchi

We study the relation between lattice construction and surgery construction of three-dimensional topological field theories. We show that a class of the Chung-Fukuma-Shapere theory on the lattice has representation theoretic reformulation which is closely related to the Altschuler-Coste theory constructed by surgery. There is a similar relation between the T

F. DeJongh, P. Sphicas

The extraction of the CKM angle $α$ from the asymmetry in $B^0 \to π^+π^-$ vs ${\bar B^0} \to π^+π^-$ suffers from a currently unknown penguin contribution. Experimentally, one can determine the magnitude and phase of the CP asymmetry from a time-dependent analysis of tagged events, and the average rate for $B^0$ and $\bar{B}^0$ decays to $π^+π^-$ from untag

Gautam Rupak, Elizabeth H. Simmons

Current LEP data on rare $Z$ decays constrain nonminimal technicolor models that contain light neutral pseudo-Nambu-Goldstone bosons ($P^a$). We discuss the production and decay of such particles, and show how LEP data on $γγγ$, $γ+ E\!\!\!/ $ and $γ+$hadrons constrain the size of the technicolor gauge group and the strength of the $ZγP^a$ coupling. The limi

Gerhard Buchalla, Isard Dunietz, Hitoshi Yamamoto

The b -> c cbar s transition is usually believed to hadronize predominantly in Bbar -> X_c Ds(*)- with the Ds(*)- originating from the virtual W. We demonstrate in a variety of independent ways that other hadronization processes cannot be neglected. The invariant mass of cbar s has sizable phase-space beyond m_D+m_K. The rate for Bbar -> D Dbar Kbar X could

Arnd Leike, Sabine Riemann, Tord Riemann

We present a method for a common treatment of $Z&#39;$ exchange, QED corrections, and weak loops in $e^+ e^-$ annihilation. QED corrections are taken into account by convoluting a hard-scattering cross section containing $γ,\ Z,$ and $Z&#39;$ exchange. Weak corrections and $ZZ&#39;$ mixing are treated simultaneously by a generalization of weak form factors.

Christian Cavata, Bernard Pire

This paper presents a brief overview of the physics with the 15-30~GeV continuous beam electron facility proposed by the European community of nuclear physicists to study the quark and gluon structure of hadrons.

Giampiero Esposito, Gennaro Miele, Luigi Rosa

Zeta-function regularization is applied to evaluate the one-loop effective potential for SO(10) grand-unified theories in de Sitter cosmologies. When the Higgs scalar field belongs to the 210-dimensional irreducible representation of SO(10), attention is focused on the mass matrix relevant for the SU(3)xSU(2)xU(1) symmetry-breaking direction, to agree with l

Sudhansu S. Mandal, S. Ramaswamy, V. Ravishankar

We study quantum Hall systems (mainly the integer case) at finite temperatures and show that there is a novel temperature dependence even for a pure system, thanks to the `anomalous&#39; nature of generators of translation. The deviation of Hall conductivity from its zero temperature value is controlled by a parameter $T_0 =πρ/m^\ast N$ which is sample speci

B. O. Wells, R. J. Birgeneau, F. C. Chou, Y. Endoh

A high temperature electrochemical oxidation process has been used to produce large single crystals of $La_2CuO_{4 + δ}$ suitable for neutron scattering experiments. Below room temperature the oxygen-rich phases have structural superlattice scattering peaks which indicate new periodicities ranging from 2 to 6.6 layers perpendicular to the copper oxide planes

Z. Gajek, J. Jedrzejewski, R. Lemanski

The Falicov-Kimball model of spinless quantum electrons hopping on a 1-dimensional lattice and of immobile classical ions occupying some lattice sites, with only intrasite coupling between those particles, have been studied at zero temperature by means of well-controlled numerical procedures. For selected values of the unique coupling parameter $U$ the restr

S. Fujimoto, N. Kawakami, S. -K. Yang

Exact critical exponents of the Green functions for pseudo-fermions and slave bosons in the SU($N$) Anderson model with $U\rightarrow\infty$ are obtained by using the Bethe ansatz solution and boundary conformal field theory. They are evaluated exactly for mixed valence systems and Kondo systems with crystalline fields. The results agree with the prediction

Victor L&#39;vov, Itamar Procaccia

Fusion rules in turbulence specify the analytic structure of many-point correlation functions of the turbulent field when a group of coordinates coalesce. We show that the existence of flux equilibrium in fully developed turbulent systems combined with a direct cascade induces universal fusion rules. In certain examples these fusion rules suffice to compute

Zoltan Haiman, Anne A. Thoul, Abraham Loeb

We investigate the early formation of bound objects with masses comparable to the cosmological Jeans mass (10^5 solar masses). We follow the growth of isolated spherically symmetric density peaks starting from the linear perturbative regime. The initial parameters correspond to density peaks of various widths and heights in a Cold Dark Matter cosmology. We u

Brian Rush, Matthew A. Malkan

(I) We observed eight Seyfert~2s and two X--ray--weak Seyfert~1/QSOs with the ROSAT PSPC, and one Seyfert~2 with the ROSAT HRI. These targets were selected from the Extended 12\um\ Galaxy Sample. (II) Both Seyfert~1/QSOs vary by factors of 1.5---2. The photon indices steepen in the more luminous state, consistent with the variability being mainly due to the

Fay Dowker, Jerome Gauntlett, Gary Gibbons, Gary Horowitz

Magnetic fields in five-dimensional Kaluza-Klein theory compactified on a circle correspond to ``twisted&#39;&#39; identifications of five dimensional Minkowski space. We show that a five dimensional generalisation of the Kerr solution can be analytically continued to construct an instanton that gives rise to two possible decay modes of a magnetic field. One

Brendan Hassett

The main geometric result of this paper is that given any family of surfaces of general type f:X-->B, for sufficiently large n the fiber product X^n_B dominates a variety of general type. This result is especially interesting when it is combined with Lang&#39;s Conjecture. This states that for a variety V of general type over a number field K, the K rational

Edmond L. Berger, Xiaofeng Guo, Jianwei Qiu

We provide complete analytic expressions for the inclusive prompt photon production cross section in hadronic final states of $e^+e^-$ annihilation reactions through one-loop order in quantum chromodynamics perturbation theory. Computed explicitly are direct photon production through first order in the electromagnetic strength $α_{em}$ and the quark-to-photo

H. David Politzer

Bose statistics imply a substantial enhancement at small angles for light scattering off a cold, Bose gas. The enhancement increases dramatically at the Bose-Einstein temperature. This phenomenon could be utilized to eliminate almost entirely the heating of the gas by a weak probe light beam.

David I. Kaiser

An analytic means of studying the resonant decay of the inflaton field is developed for the case of background expansion, $H \neq 0$. It is shown that the parametric resonance in the inflaton&#39;s decay need not disappear when the expansion of the universe is taken into account, although the total number of particles produced is fewer than in the $H \simeq

V. Gogohia, Gy. Kluge, M. Prisznyák

Basic chiral QCD parameters (the pion decay constant, the quark and gluon condensates, the dynamically generated quark mass, etc) as well as the vacuum energy density (up to the sign, by definition, the bag constant) have been calculated from first principles within a recently proposed zero modes enhancement (ZME) model of the true QCD vacuum. Our unique inp

V. Gogohia

A new zero modes enhancement (ZME) model of the true QCD vacuum is breifly described. It makes possible to analytically investigate and calculate numerically low-energy QCD structure from first principles. Expressions of basic chiral QCD parameters (the pion decay constant, the quark and gluon condensates, the dynamically generated quark mass, etc) as well a

Victor L&#39;vov, Itamar Procaccia

Elements of the analytic structure of anomalous scaling and intermittency in fully developed hydrodynamic turbulence are described. We focus here on the structure functions of velocity differences that satisfy inertial range scaling laws $S_n(R)\sim R^{ζ_n}$, and the correlation of energy dissipation $K_{εε}(R) \sim R^{-μ}$. The goal is to understand the exp

Victor L&#39;vov, Itamar Procaccia

In paper I of this series on fluid turbulence we showed that exact resummations of the perturbative theory of the structure functions of velocity differences result in a finite (order by order) theory. These findings exclude any known perturbative mechanism for anomalous scaling of the velocity structure functions. In this paper we continue to build the theo

T. S. Evans, A. J. Gill, R. J. Rivers

We examine string (vortex) formation at a quench for a weakly-coupled global U(1) theory when the excitation spectrum is non-relativistic. It is so similar to vortex production in the corresponding relativistic plasma as to reinforce arguments for the similarity of vortex production in the early universe and in low-temperature many-body physics.

John Ellis, G. L Fogli, E. Lisi

We present a new global fit to precision electroweak data, including new low- and high-energy data and analyzing the radiative corrections arising from the minimal symmetry breaking sectors of the Standard Model (SM) and its supersymmetric extension (MSSM). It is shown that present data favor a Higgs mass of O(M_Z): M_H = 76+152-50 GeV. We confront our analy

C. Jarzynski, G. F. Bertsch

When the Vlasov equation is investigated numerically using the method of test particles, the particle-particle interactions that inevitably arise in the simulation (but are not present in the Vlasov equation itself) result in an accumulation of errors which eventually drive the collection of test particles toward a state of classical thermal equilibrium. We

J. M. F. Labastida, E. Perez

Polynomial invariants corresponding to the fundamental representation of the gauge group $SO(N)$ are computed for arbitrary torus knots in the framework of Chern-Simons gauge theory making use of knot operators. As a result, a formula which relates the Kauffman and the HOMFLY polynomials for torus knots is presented.

Yan V. Fyodorov, H. -J. Sommers

We derive the explicit expression for the distribution of resonance widths in a chaotic quantum system coupled to continua via M equivalent open channels. It describes a crossover from the $χ^2$ distribution (regime of isolated resonances) to a broad power-like distribution typical for the regime of overlapping resonances. The first moment is found to reprod

J. M. F. Labastida, M. Mariño

We present an explicit expression for the topological invariants associated to $SU(2)$ monopoles in the fundamental representation on spin four-manifolds. The computation of these invariants is based on the analysis of their corresponding topological quantum field theory, and it turns out that they can be expressed in terms of Seiberg-Witten invariants. In t

Felix M. Lev

In the Bjorken limit of the present theory of deep inelastic scattering (DIS) the structure functions (up to anomalous dimensions and perturbative QCD corrections) are described by the parton model. However the current operator in the parton model does not properly commute with the representation operators corresponding to the Lorentz group, space reflection

Valter Moretti, Luciano Vanzo

The Wightman functions in the Rindler portion of Minkowski space-time are presented for any value of the temperature and for massless spin fields up to s=1 and the renormalized stress tensor relative to Minkowski vacuum is discussed. A gauge ambiguity in the vector case is pointed out.

Miguel A. Martin-Delgado, German Sierra

We apply real-space RG methods to study two quantum group invariant Hamiltonians, that of the XXZ model and the Ising model in a transverse field defined in an open chain with appropiate boundary terms. The quantum group symmetry is preserved under the RG transformation except for the appearence of a quantum group anomalous term which vanishes in the classic

K. Hagiwara, S. Matsumoto, Y. Yamada

The supersymmetric one-loop contribution to the quark-lepton universality violation in the low-energy charged current weak interactions is studied. It is shown that the recent experimental data with the 1-$σ$ deviation from the universality may be explained by the existence of the light sleptons ($<220$GeV) and relatively light chargino and neutralinos ($<60

V. Bernard, N. Kaiser, Ulf-G. Meißner

In the framework of heavy baryon chiral perturbation theory, we give thIn the framework of heavy baryon chiral perturbation theory, we give the chiral expansion for the $πN \to ππN$ threshold amplitudes $D_1$ and $D_2$ to quadratic order in the pion mass. The theoretical results agree within one standard deviation with the empirical values. We also derive a

Nobuki Maeda

Under general assumptions, we present a low-energy effective action for the quantum Hall state when edges exist. It is shown that the chiral edge current is necessary to make the effective action to be gauge invariant. However the chiral edge current is irrelevant to the Hall current. The exactly quantized value of $σ_{xy}$ is observed only when the Hall cur

Alexander Kyatkin

We calculate the shape of the photon spectrum for $B\rightarrow X_{s}+γ$ decay in the presence of a background chromomagnetic field for the case of SU(2) gauge group. The effect of the external field resembles the Zeeman effect - the parton model peak is split into two slightly assymetric peaks, located around the kinematic endpoint. We investigate the analy

Leonid Positselski

It is proved that any strictly exceptional collection generating the derived category of coherent sheaves on a smooth projective variety X with \rk K_0(X) = \dim X + 1 constists of locally free sheaves up to a common shift.

Yadin Y. Goldschmidt

In this paper we expand our previous investigation of a quantum particle subject to the action of a random potential plus a fixed harmonic potential at a finite temperature T. In the classical limit the system reduces to a well-known ``toy&#39;&#39; model for an interface in a random medium. It also applies to a single quantum particle like an an electron su

Thierry Masson

We define and study noncommutative generalizations of submanifolds and quotient manifolds, for the derivation-based differential calculus introduced by M.~Dubois-Violette and P.~Michor. We give examples to illustrate these definitions.

R. B. Zhang

Methods are developed for systematically constructing the finite dimensional irreducible representations of the super Yangian Y(gl(M|N)) associated with the Lie superalgebra gl(M|N). It is also shown that every finite dimensional irreducible representation of Y(gl(M|N)) is of highest weight type, and is uniquely characterized by a highest weight. The necessa

Vladimir Kanovei

We prove that in Solovay model every OD equivalence E on reals either admits an OD reduction to the equality on the set of all countable (of length < omega_1) binary sequences, or continuously embeds E_0, the Vitali equivalence. If E is a Sigma_1^1 (resp. Sigma_1^2) relation then the reduction in the ``either&#39;&#39; part can be chosen in the class of all

JM Figueroa-O&#39;Farrill

The BRST cohomology of any topological conformal field theory admits the structure of a Batalin--Vilkovisky algebra, and string theories are no exception. Let us say that two topological conformal field theories are ``cohomologically equivalent&#39;&#39; if their BRST cohomologies are isomorphic as Batalin--Vilkovisky algebras. What we show in this paper is

Franco Ferrari

The main result of this paper is the construction of a conformally covariant operator in two dimensions acting on scalar fields and containing fourth order derivatives. In this way it is possible to derive a class of Lagrangians invariant under conformal transformations. They define conformal field theories satisfying equations of the biharmonic type. Two ki

Sumit R. Das, Samir D. Mathur

In the 1-dimensional matrix model one identifies the tachyon field in the asymptotic region with a nonlocal transform of the density of fermions. But there is a problem in relating the classical tachyon field with the surface profile of the fermi fluid if a fold forms in the fermi surface. Besides the collective field additional variables $w_j(x)$ are requir

Ian I. Kogan, Alex Kovner

The mean field like gauge invariant variational method formulated recently, is applied to a topologically massive QED in 3 dimensions. We find that the theory has a phase transition in the Chern Simons coefficient $n$. The phase transition is of the Berezinsky-Kosterlitz - Thouless type, and is triggered by the liberation of Polyakov monopoles, which for $n>

Gordon Baym, Dietrich Bödeker, Larry McLerran

The electroweak phase transition, if proceeding through nucleation and growth of bubbles, should generate large scale turbulent flow, which in turn generates magnetic turbulence and hence magnetic fields on the scale of turbulent flow. We discuss the seeding of this turbulent field by the motion of the dipole charge layers in the phase transition bubble wall

Alan Kostelecky, Stuart Samuel

Around one second after the big bang, neutrino decoupling and $e^+$-$e^-$ annihilation distort the Fermi-Dirac spectrum of neutrino energies. Assuming neutrinos have masses and can mix, we compute the distortions using nonequilibrium thermodynamics and the Boltzmann equation. The flavor behavior of neutrinos is studied during and following the generation of

V. Barger, W. -Y. Keung, R. J. N. Phillips

If sneutrinos are the lightest supersymmetry partners and $R$-parity is not conserved, the process $e^+e^- \to \tilde {\bar\nu} \tilde {\nu}$ can have striking signatures due to the decay modes $\tilde{\nu}\to\ell^+\ell'^-$ or $\tilde{\nu}\to q \bar q'$. We present cross section formulas and discuss event rates and detection at the upgraded $e^+e^-$ collider

S. Veseli, M. G. Olsson

We present a simple and straightforward method for relating the form factors in HQET, as defined by the covariant trace formalism, to the overlaps of the rest frame wave functions of the light degrees of freedom. We also point out several inconsistencies present in recent calculations of the radiative rare $B$ decays, and also show how these can be fixed eve

V. S. Fadin, V. A. Khoze, A. D. Martin, W. J. Stirling

The QED Coulomb correction is one of the most important corrections to the e+ e- --> W+ W- total cross section near threshold. We calculate these corrections through second order, and discuss the implications for extracting M_W from a threshold cross section measurement at LEP2. Analytic expressions are derived in various kinematic limits.

Andrzej Czarnecki, William J. Marciano

One loop electroweak radiative corrections to left-right parity violating Møller scattering ($e^-e^-\to e^-e^-$) asymmetries are presented. They reduce the standard model (tree level) prediction by 40$\pm 3$ \% where the main shift and uncertainty stem from hadronic vacuum polarization loops. A similar reduction also occurs for the electron-electron atomic p

Jan Kalinowski

In this talk I discuss three-body decays of the SUSY Higgs bosons which proceed via intermediate two-body states in which one of the particles is off-mass-shell. Some of these decays will be shown to have substantial branching ratios in some range of the SUSY parameter space.

David Atwood, Laura Reina, Amarjit Soni

The prospect of observing the flavor changing decay $\fH\to t\bar c$ of a neutral Higgs boson produced via $s$-channel and its subsequent decay into $t\bar c$ is considered at a $μ^+μ^-$ collider. Numerical estimates are given in the context of a two Higgs doublet model with flavor changing couplings. It is found that for many values of the model parameters

Frank X. Lee, Richard M. Woloshyn, Howard D. Trottier

Calculations of the chiral condensate $\langle \barψ ψ\rangle$ on the lattice using staggered fermions and the Lanczos algorithm are presented. Three gauge fields are considered: the quenched non-Abelian field, the Abelian field projected in the maximal Abelian gauge, and the monopole field further decomposed from the Abelian field. The results show that the

Mariusz P. Dabrowski

It is shown that growing-entropy stiff-fluid Kantowski-Sachs universes become time-symmetric (if they start with time-asymmetric phase) and isotropize. Isotropization happens without any inflationary era during the evolution since there is no cosmological term here. It seems that this approach is an alternative to inflation since the universe gets bigger and

Jolien Creighton, Robert Mann

We present a quasilocal formalism, based on the one proposed by Brown and York, for dilaton gravity with Yang-Mills fields. For solutions possessing sufficient symmetry, we define conserved quantities such as mass, angular momentum, and charge. We also present a micro-canonical action and use it to arrive at a quasilocal version of the first law of thermodyn

Victor Matveev, Robert Shrock

We study the complex-temperature phase diagram of the square-lattice Ising model for nonzero external magnetic field $H$, i.e. for $0 \le μ\le \infty$, where $μ=e^{-2βH}$. We also carry out a similar analysis for $-\infty \le μ\le 0$. The results for the interval $-1 \le μ\le 1$ provide a new way of continuously connecting the two known exact solutions of th

Dmitrii L. Maslov

It is shown that the conductance of a weakly disordered Luttinger-liquid quantum wire connected to non-interacting leads is affected by electron-electron interactions in the wire. This is in contrast to the case of a perfect wire the conductance of which is given by $e^2/h$ regardless of interactions in the wire. The disorder-induced correction to the conduc

Karin Dahmen, James P. Sethna

We study the zero temperature random field Ising model as a model for noise and avalanches in hysteretic systems. Tuning the amount of disorder in the system, we find an ordinary critical point with avalanches on all length scales. Using a mapping to the pure Ising model, we Borel sum the $6-ε$ expansion to $O(ε^5)$ for the correlation length exponent. We sk

D. W. Snoke, J. D. Crawford

We show that hysteresis can occur in the transition between a neutral plasma and the insulating gas consisting of neutral pairs bound by Coulomb attraction. Since the transition depends sensitively on the screening length in the plasma, regions of bistability occur in density--temperature phase space. We present numerical results which indicate where these r

I. N. Kozin, I. M. Pavlichenkov

A classical microscopic theory of rovibrational motion at high angular momenta in symmetrical non-linear molecules AB$_2$ is derived within the framework of small oscillations near the stationary states of a rotating molecule. The full-dimensional analysis including stretching vibrations has confirmed the existence of the bifurcation predicted previously by

Victor L&#39;vov, Itamar Procaccia

This paper is the first in a series of three papers that aim at understanding the scaling behaviour of hydrodynamic turbulence. We present in this paper a perturbative theory for the structure functions and the response functions of the hydrodynamic velocity field in real space and time. Starting from the Navier-Stokes equations (at high Reynolds number Re)

Alfred Gautschy, Hans-Günter Ludwig, Bernd Freytag

Results of nonradial, nonadiabatic pulsation calculations on hydrogen-rich white dwarf models are presented. In contrast to earlier attempts, the modeling builds on hydrodynamically simulated convective surface layers supplemented with standard interior models. Based on our stellar models and despite of various simple attempts to couple convection and pulsat

Harvey B. Richer, Gregory G. Fahlman, Rodrigo A. Ibata, Peter B. Stetson

With the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope, we have discovered in M4 (NGC 6121, C 1620-264) the first extensive sequence of cooling white dwarfs seen in a globular cluster. Adopting a distance modulus of (m-M)_V = 12.65 and a reddening of E(B-V) = 0.37, we show that the sequence, which extends over 9 < M_U < 13, is comprised

Michael J. West, Christine Jones, William Forman

We have examined the spatial distribution of substructure in clusters of galaxies using Einstein X-ray observations. Subclusters are found to have a markedly anisotropic distribution that reflects the surrounding matter distribution on supercluster scales. Our results suggest a picture in which cluster formation proceeds by mergers of subclusters along large

R. Maoli, V. Ferrucci, F. Melchiorri, M. Signore

The possibility to detect cosmological signals from the post-recombination Universe is one of the main aims of modern cosmology. In a previous paper we emphasized the role that elastic resonant scattering through LiH molecules can have in dumping primary CBR anisotropies and raising secondary signals. Here we extend our analysis to all the evolutionary stage

Kurt Riesselmann

The amplitudes for $2\rightarrow 2$ scattering processes involving longitudinally polarized gauge bosons $( W_L^\pm, Z_L )$ and the Higgs boson are analyzed up to two loops. Assuming $M_H >> M_W$, the trilinear Higgs coupling, $λv$, is dominant for energies of $\sqrt{s}$ < 1.5 -- 2 $M_H$. For larger values of $\sqrt{s}$, the quartic coupling, $λ$, becomes do

M. Henningson

We consider the low-energy effective action for the Coulomb phase of an $N = 2$ supersymmetric gauge theory with a rank one gauge group. The $N = 2$ superspace formalism is naturally invariant under an $SL(2, {\bf Z})$ group of duality transformations, regardless of the form of the action. The leading and next to leading terms in the long distance expansion

Nikolaos A Batakis

The tracing of cosmological relics from the early string dynamics may enhance the theory and provide new perspectives on the major cosmological problems. This point is illustrated in a leading-order Bianchi-type $VII_0$ string background, wherein spatial isotropy can be claimed as such a relic. A much finer one, descending from a premordial gravitational wav

S. N. Laughton, A. C. C. Coolen, D. Sherrington

We develop further a recent dynamical replica theory to describe the dynamics of the Sherrington-Kirkpatrick spin-glass in terms of closed evolution equations for macroscopic order parameters. We show how microscopic memory effects can be included in the formalism through the introduction of a dynamic order parameter function: the joint spin-field distributi

J. Anandan

A quantum equivalence principle is formulated by means of a gravitational phase operator which is an element of the Poincare group. This is applied to the spinning cosmic string which suggests that it may (but not necessarily) contain gravitational torsion. A new exact solution of the Einstein- Cartan-Sciama-Kibble equations for the gravitational field with

F. Cardarelli, I. Grach, I. Narodetskii, E. Pace

The charge form factor of $π$ and $K$ mesons is evaluated adopting a relativistic constituent quark model based on the light-front formalism. The relevance of the high-momentum components of the meson wave function, for values of the momentum transfer accessible to $CEBAF$ energies, is illustrated. The predictions for the elastic form factor of $π$ and $K$ m

E. G. Floratos, G. K. Leontaris, S. Lola

We discuss aspects of the low energy phenomenology of the MSSM, in the large $\tan β $ regime. We explore the regions of the parameter space where the $h_t$ and $h_b$ Yukawa couplings exhibit a fixed point structure, using previous analytic solutions for these couplings. Expressions for the parameters $A_{t}$ and $A_{b}$ and the renormalised soft mass terms

Zheng Huang, Xin-Nian Wang

We calculate the thermally averaged rates for the $η$-$π$ conversion and $η$ scattering using the Di Vecchia-Veneziano model and t&#39; Hooft model, which incorporate explicitly the $U(1)_A$ anomaly. Assuming an exponential suppression of the $U(1)_A$ anomaly, we also take into account the partial restoration of $U(1)_A$ symmetry at high temperatures. We fin

David S. Graff, Katherine Freese

We re-examine a deep {\it Hubble Space Telescope} pencil-beam search for red dwarfs, stars just massive enough to burn Hydrogen. The authors of this search (Bahcall, Flynn, Gould \& Kirhakos 1994) found that red dwarfs make up less than 6\% of the galactic halo. First, we extrapolate this result to include brown dwarfs, stars not quite massive enough to burn

James Anglin, Salman Habib

It has long been recognized that the dynamics of linear quantum systems is classical in the Wigner representation. Yet many conceptually important linear problems are typically analyzed using such generally applicable techniques as influence functionals and Bogoliubov transformations. In this Letter we point out that the classical equations of motion provide

Michel Dubois-Violette, Thierry Masson

We analyse the structure of the first order operators in bimodules introduced by A. Connes. We apply this analysis to the theory of connections on bimodules generalizing thereby several proposals.

T. D. Palev, N. I. Stoilova

New solutions of the quantum Yang-Baxter equation, depending in general on three arbitrary parameters, are written down. They are based on the root of unity representations of the quantum orthosymplectic superalgebra \\U, which were found recently. Representations of the braid group $B_N$ are defined within any $N^{th}$ tensorial power of root of 1 \\U modul