May 1993 arXiv papers

Nguyen Anh Ky

In the present paper we construct all typical finite-dimensional representations of the quantum Lie superalgebra $U_{q}[gl(2/2)]$ at generic deformation parameter $q$. As in the non-deformed case the finite-dimensional $U_{q}[gl(2/2)]$-module $W^{q}$ obtained is irreducible and can be decomposed into finite-dimensional irreducible $U_{q}[gl(2)\oplus gl(2)]$-

A. P. Nersessian

The transparent way for the invariant (Hamiltonian) description of equivariant localization of the integrals over phase space is proposed. It uses the odd symplectic structure, constructed over tangent bundle of the phase space and permits straightforward generalization for the path integrals. Simultaneously the method of supersymmetrization for a wide class

V. M. Belyaev, A. Khodjamirian, R. Rückl

We calculate the form factors for the heavy-to-light transitions $B\rightarrow \pi,K $ by means of QCD sum rules using $\pi$ and $K$ light-cone wave functions. Higher twist contributions as well as gluonic corrections are taken into account. The sensitivity to the shape of the leading-twist wave functions and effects of SU(3)-breaking are discussed. The resu

Aleksander A. Belov, Karen D. Chaltikian

A new version of quantum Miura transformation on the lattice is proposed, based on the lattice Kac-Moody algebra. A possibility of existence of the Sugawara construction on the lattice is discussed.

S. A. Coon, M. T. Pena

In this paper we give explicit formulae in momentum and coordinate space for the three-nucleon potentials due to $ρ$ and $π$ meson exchange, derived from off-mass-shell meson-nucleon scattering amplitudes which are constrained by the symmetries of QCD and by the experimental data. Those potentials have already been applied to nuclear matter calculations. Her

John H. Schwarz, Ashoke Sen

Target space duality (T duality), which interchanges Kaluza--Klein and winding-mode excitations of the compactified heterotic string, is realized as a symmetry of a world-sheet action. Axion-dilaton duality (S duality), a conjectured nonperturbative SL(2,Z) symmetry of the same theory, plays an analogous role for five-branes. We describe a soliton spectrum p

Simeon Vishik

This paper is devoted to a proof of a generalized Ray-Singer conjecture for a manifold with boundary (the Dirichlet and the Neumann boundary conditions are independently given on each connected component of the boundary and the transmission boundary condition is given on the interior boundary). The Ray-Singer conjecture \cite{RS} claims that for a closed man

Doron Gepner

Recently, a class of solvable interaction round the face lattice models (IRF) were constructed for an arbitrary rational conformal field theory (RCFT) and an arbitrary field in it. The Boltzmann weights of the lattice models are related in the extreme ultra violet limit to the braiding matrices of the rational conformal field theory. In this note we use thes

Wolfgang A. Schnizer

Representations of Quantum Groups U_q (g_n), g_n any semi simple Lie algebra of rank n, are constructed from arbitrary representations of rank n-1 quantum groups for q a root of unity. Representations which have the maximal dimension and number of free parameters for irreducible representations arise as special cases.

Katsumi Itoh, Hiroshi Kunitomo, Nobuyoshi Ohta, Makoto Sakaguchi

We study the BRST cohomology for $SL(2,R)/U(1)$ coset model, which describes an exact string black hole solution. It is shown that the physical spectrum could contain not only the extra discrete states corresponding to those in $c=1$ two-dimensional gravity but also many additional new states with ghost number $N_{FP}= -1 \sim 2$. We also discuss characters

Q. P. Xu

We derive a Bjorken sum rule for semileptonic $Ω_b$ decays to ground and low-lying negative-parity excited charmed baryon states, in the heavy quark limit. We discuss the restriction from this sum rule on form factors and compare it with some models.

D. F. Wang

In this work we introduce one dimensional multi-component Hubbard model of 1/r hopping and U on-site energy. The wavefunctions, the spectrum and the thermodynamics are studied for this model in the strong interaction limit $U=\infty$. In this limit, the system is a special example of $SU(N)$ Luttinger liquids, exhibiting spin-charge separation in the full Hi

Jörg R. Weimar, Jean-Pierre Boon

We introduce a new class of cellular automata to model reaction-diffusion systems in a quantitatively correct way. The construction of the CA from the reaction-diffusion equation relies on a moving average procedure to implement diffusion, and a probabilistic table-lookup for the reactive part. The applicability of the new CA is demonstrated using the Ginzbu

Taekoon Lee

We point out that heavy fermion production through the fusion of the longitudinal gauge bosons might be relevant in probing the strongly interacting symmetry breaking sector of the electroweak interactions, by showing the dependence of the one loop amplititude for ($ w^{+} w^{-} \rightarrow \overline{t} t $) on the symmetry breaking mechanism. The one loop a

Stephen Hwang, Henric Rhedin

We consider a BRST approach to G/H coset WZNW models, {\it i.e.} a formulation in which the coset is defined by a BRST condition. We will give the precise ingrediences needed for this formulation. Then we will prove the equivalence of this approach to the conventional coset formulation by solving the the BRST cohomology. This will reveal a remarkable connect

D. F. Wang Joseph Henry, Q. F. Zhong, P. Coleman Serin

In this work, we study the wavefunctions of the one dimensional $1/r$ Hubbard model in the strong interaction limit $U =\infty$. A set of Gutzwiller-Jastorw wavefunctions are shown to be eigen-functions of the Hamiltonian. The entire excitation spectrum and the thermodynamics are also studied in terms of more generalized Jastrow wavefunctions. For the wavefu

Kiyoshi Ezawa

The discussions on the modular invariance in section 5 are refined.

Helen Au-Yang, Jacques H. H. Perk

We consider the N to infinity limits of the N-state chiral Potts model. We find new weights that satisfy the star-triangle relations with spin variables either taking all the integer values or having values from a continous interval. The models provide chiral generalizations of Zamolodchikov's Fishnet Model. (For the more complete version, see math.QA/99

F. T. Brandt, J. Frenkel, J. C. Taylor

For the quark-gluon plasma, an energy-momentum tensor is found corresponding to the high-temperature Braaten-Pisarski effective action. The tensor is found by considering the interaction of the plasma with a weak gravitational field and the positivity of the energy is studied. In addition, the complete effective action in curved spacetime is written down.

V. V. Nesterenko

Two integrals along the world trajectory of its curvature and torsion are added to the standard action for the point-like spinless relativistic particle. Since here the three-dimensional space-time is considered at the beginning, the torsion of the world curve is defined with a sign in contrast to the previous consideration: V. V. Nesterenko, J. Math. Phys.

A. M. Chervyakov, V. V. Nesterenko

To overcome the difficulties with the energy indefiniteness in field theories with higher derivatives, it is supposed to use the mechanical analogy, the Timoshenko theory of the transverse flexural vibrations of beams or rods well known in mechanical engineering. It enables one to introduce the notion of a "mechanical" energy in such field models tha

J. N. Tavares

We use Chen iterated line integrals to construct a topological algebra ${\cal A}_p$ of separating functions on the {\it Group of Loops} ${\bf L}{\cal M}_p$. ${\cal A}_p$ has an Hopf algebra structure which allows the construction of a group structure on its spectrum. We call this topological group, the group of generalized loops $\widetilde {{\bf L}{\cal M}_

R. Floreanini, R. Percacci

In a four dimensional theory of gravity with lagrangian quadratic in curvature and torsion, we compute the effective action for metrics of the form $g_{μν}=ρ^2δ_{μν}$, with $ρ$ constant. Using standard field-theoretic methods we find that one loop quantum effects produce a nontrivial effective potential for $ρ$. We explain this unexpected result by showing h

Kanehisa Takasaki

A higher dimensional analogue of the KP hierarchy is presented. Fundamental constituents of the theory are pseudo-differential operators with Moyal algebraic coefficients. The new hierarchy can be interpreted as large-$N$ limit of multi-component ($\gl(N)$ symmetric) KP hierarchies. Actually, two different hierarchies are constructed. The first hierarchy con

V. Del Duca, C. R. Schmidt

We study higher order corrections to Higgs production with an associated jet at SSC energies, using the resummation of the leading logarithmic contributions to multiple gluon emissions due to Lipatov and collaborators. We find a considerable enhancement of Higgs production at large transverse momenta.

Jacques Distler, Soo-Jong Rey

Kaplan recently proposed a novel lattice chiral gauge theory in which the bare theory is defined on $(2n+1)$-dimensions, but the continuum theory emerges in $2n$-dimensions. We explore whether the resulting theory reproduces all the features of continuum chiral gauge theory in the case of two-dimensional axial Schwinger model. We find that one can arrange fo

Gunter Schuetz, Sven Sandow

We consider systems of particles hopping stochastically on $d$-dimensional lattices with space-dependent probabilities. We map the master equation onto an evolution equation in a Fock space where the dynamics are given by a quantum Hamiltonian (continuous time) or a transfer matrix resp. (discrete time). We show that under certain conditions the time-depende

Wayne Hu, Douglas Scott, Joseph Silk

The ionization history of the universe provides a major source of ambiguity in constraining cosmological models using small angular scale microwave background anisotropies. To clarify these issues, we consider a complete treatment of Compton scattering to second order, an approach which may be applicable to other astrophysical situations. We find that only t

S. W. Hawking, J. D. Hayward

The formation and evaporation of two dimensional black holes are discussed. It is shown that if the radiation in minimal scalars has positive energy, there must be a global event horizon or a naked singularity. The former would imply loss of quantum coherence while the latter would lead to an even worse breakdown of predictability. CPT invariance would sugge

Michele Maggiore

We investigate the relationship between the generalized uncertainty principle in quantum gravity and the quantum deformation of the Poincaré algebra. We find that a deformed Newton-Wigner position operator and the generators of spatial translations and rotations of the deformed Poincaré algebra obey a deformed Heisenberg algebra from which the generalized un

I. Ya. Aref'eva, G. E. Arutyunov

To construct a quantum group gauge theory one needs an algebra which is invariant under gauge transformations. The existence of this invariant algebra is closely related with the existence of a differential algebra $δ_{\cal H} G_{q}$ compatible with the Hopf algebra structure. It is shown that $δ_{\cal H} G_{q}$ exists only for the quantum group $U_{q}(N)$ a

Boris Spokoiny

We generalize the stochastic approach to quasi-power-law inflationary Universes,obtain the corresponding Langevin and Fokker-Planck equations for the scalar field driving inflation and find stationary solutions to the above FP equation.

Boris Spokoiny

We develop a stochastic approach to a non de Sitter Universe in a gauge-invariant way and obtain a system of Langevin-type equations which may be considered to be renormalization group equations for the long wave parts of the scalar fields and metric. We investigate in detail the case of generalized power-law inflation that appears in the model of the deflat

V. G. Makhankov

The outlook of a simple method to generate localized (soliton-like) potentials of time-dependent Schrodinger type equations is given. The conditions are discussed for the potentials to be real and nonsingular. For the derivative Schrodinger equation also is discussed its relation to the Ishimori-II model. Some pecular soliton solutions of nonlinear Schroding

Ovid C. Jacob

Recently \REF\dk{Simon Dalley and Igor Klebanov,'Light Cone Quantization of the $c=2$ Matrix Model', PUPT-1333, hepth@xxx/920705} \refend Dalley and Klebanov proposed a light-cone quantized study of the $c=2$ matrix model, but which ignores $k^{+}=0$ contributions. Since the non-critical string limit of the matrix model involves taking the parameters

I. A. Batalin, I. V. Tyutin

The unified constrained dynamics is formulated without making use of the Dirac splitting of constraint classes. The strengthened, completely--closed, version of the unified constraint algebra generating equations is given. The fundamental phase variable supercommutators are included into the unified algebra as well. The truncated generating operator is defin

F. Anton, A. Abdurrahman, J. Bordes

In this letter we present an operator formalism for Closed String Field Theory based on closed half-strings. Our results indicate that the restricted polyhedra of the classical non-polynomial string field theory, can be represented as traces of infinite matrices, with operator insertions that reparametrise the half-strings.

P. Menotti, D. Seminara

We give the general solution of the stationary problem of 2+1 dimensional gravity in presence of extended sources, also endowed with angular momentum. We solve explicitly the compact support property of the energy momentum tensor and we apply the results to the study of closed time-like curves. In the case of rotational symmetry we prove that the weak energy

Lev Vaidman

It is shown that the joint measurements of some physical variables corresponding to commuting operators performed on pre- and post-selected quantum systems invariably disturb each other. The significance of this result for recent proofs of the impossibility of realistic Lorentz invariant interpretation of quantum theory (without assumption of locality) is di

G. L. Huang, C. R. Lee

We study the anyon statistics of a $2 + 1$ dimensional Maxwell-Chern-Simons (MCS) gauge theory by using a systemmetic metheod, the Breit Hamiltonian formalism.

D. I. Olive, N. Turok, J. W. R. Underwood

Affine Toda theories with imaginary couplings associate with any simple Lie algebra ${\bf g}$ generalisations of Sine Gordon theory which are likewise integrable and possess soliton solutions. The solitons are \lq\lq created" by exponentials of quantities $\hat F^i(z)$ which lie in the untwisted affine Kac-Moody algebra ${\bf\hat g}$ and ad-diagonalise t

K. Kajantie, K. Rummukainen, M. Shaposhnikov

We study the finite temperature electroweak phase transition with lattice perturbation theory and Monte Carlo techniques. Dimensional reduction is used to approximate the full four-dimensional SU(2) + a fundamental doublet Higgs theory by an effective three-dimensional SU(2) + adjoint Higgs + fundamental Higgs theory with coefficients depending on temperatur

N. K. Mondal, D. P. Roy

There is a strong correlation between the $p_T$ and isolation of the lepton coming from $B$ decay. Consequently the isolated lepton background from $B$ decay goes down rapidly with increasing lepton $p_T$; and there is a $p_T$ cutoff beyond which it effectively vanishes. For the isolation cut of $E^{AC}_T < 10$ GeV, appropriate for LHC, the lepton $p_T$ cuto

Lisa Randall, Eric Sather

We study the rate for the production of ${B B^\pm π^\mp}$, where the sign of the charged pion tags the flavor content of the neutral $B$ meson. We estimate this branching ratio, employing the heavy meson chiral effective theory. We find that at center of mass energy of approximately 12 GeV, a $B$ meson pair should be produced as often with and without an acc

H. Baer, F. Paige, S. Protopopescu, X. Tata

We review the physics assumptions and input used in ISAJET~7.0 / ISA\-SUSY~1.0 that are relevant for simulating fundamental processes within the framework of the Minimal Supersymmetric Standard Model (MSSM) at $p\bar p$ and $pp$ colliders. After a brief discussion of the underlying MSSM framework, we discuss event simulation and list the sparticle production

Tao Chen, S. Teitel

The helicity modulus for a fluctuating type II superconductor is computed within the elastic medium approximation, as a probe of superconducting phase coherence and the Meissner effect in the mixed state. We argue that at the vortex line lattice melting transition, there remains superconducting coherence parallel to the applied magnetic field, provided the v

R. J. Radtke, K. Levin, H. -B. Schuttler, M. R. Norman

There is a great deal of interest in attributing the high critical temperatures of the cuprates to either the proximity of the Fermi level to a van Hove singularity or to structure of the superconducting pairing potential in momentum space far from the Fermi surface. We examine these ideas by calculating the critical temperature Tc for model Einstein-phonon-

R. J. Radtke, K. Levin, H. -B. Schuttler, M. R. Norman

We address the question of whether anisotropic superconductivity is compatible with the evidently weak sensitivity of the critical temperature Tc to sample quality in the high-Tc copper oxides. We examine this issue quantitatively by solving the strong-coupling Eliashberg equations numerically as well as analytically for s-wave impurity scattering within the

C. Buzano, A. Maritan, A. Pelizzola

The random--anisotropy Blume--Emery--Griffiths model, which has been proposed to describe the critical behavior of $^3$He--$^4$He mixtures in a porous medium, is studied in the pair approximation of the cluster variation method extended to disordered systems. Several new features, with respect to mean field theory, are found, including a rich ground state, a

G. Filatrella, B. A. Malomed, R. D. Parmentier

The inverse ac Josephson effect involves rf-induced (Shapiro) steps that cross over the zero-current axis; the phenomenon is of interest in voltage standard applications. The standard analysis of the step height in current, which yields the well-known Bessel-function dependence on an effective ac drive amplitude, is valid only when the drive frequency is lar

Robert S. Maier, Daniel L. Stein

We study the trajectories followed by a particle subjected to weak noise when escaping from the domain of attraction of a stable fixed point. If detailed balance is absent, a _focus_ may occur along the most probable exit path, leading to a breakdown of symmetry (if present). The exit trajectory bifurcates, and the exit location distribution may become `skew

Robert S. Maier

This is the transcript of a talk given at the 1992 Complex Systems Summer School. The theory of large fluctuations of stochastically perturbed continuous-time dynamical systems is reviewed, and the large fluctuations of two stochastic models arising in computer science are analysed. One is a stochastic model of a communications network, resembling an Etherne

L O&#39;C Drury, F A Aharonian, H J Voelk

Gamma ray production in supernova remnants is discussed on the basis of current ideas about cosmic ray acceleration.

Kevin Krisciunas

What astronomer could not use his own surname because his father was beheaded for sorcery? Who built the only observatory worth $5 billion in today&#39;s money? Who had worse luck than YOU travelling thousands of miles NOT to observe an astronomical event? Who had one of his books bound in human skin at the request of his most ardent fan? Is there an anti-co

H-Y Cheng, C-Y Cheung, W. Dimm, G-L Lin

We study in detail the prediction for the semileptonic decays $\bar{B} \to D (D^*) π\ell \barν$ by heavy quark and chiral symmetry. The branching ratio for $\bar{B} \to D π\ell \barν$ is quite significant, as big as $(0.5-1)\%$. The branching ratio for $\bar{B} \to D^* π\ell \barν$ is only of order $10^{-4}-10^{-5}$. Numerical results for various single part

B. Holdom

A new mechanism is presented for the generation of quark and lepton masses, based on a heavy fourth family and a new sector of massless fermions. The massless fermions have only discrete chiral symmetries and they are confined by the metacolor force. The resulting electroweak corrections may be smaller than in technicolor theories.

Marco A. C. Kneipp, David I. Olive

Affine Toda theory is a relativistic integrable theory in two dimensions possessing solutions describing a number of different species of solitons when the coupling is chosen to be imaginary. These nevertheless carry real energy and momentum. To each species of soliton there has to correspond an antisoliton species. There are two different ways of realising

A. A. Bel&#39;kov, A. V. Lanyov, A. Schaale

The amplitudes of $K \rightarrow πγ^* \rightarrow πe^+e^-$ and $K \rightarrow ππγ$ decays have been calculated within chiral Lagrangian approach including higher-order derivative terms and meson loops. The selfconsistency of the simultaneous description of the experimental data on the nonleptonic and radiative kaon decays have been demonstrated. We estimate

Yutaka Matsuo

The dynamics of the 3 dimensional perfect fluid is equivalent to the motion of vortex filaments or &#34;strings&#34;. We study the action principle and find that it is described by the Hopf term of the nonlinear sigma model. The Poisson bracket structure is described by the loop algebra, for example, the Virasoro algebra or the analogue of O(3) current algeb

Z. Hasiewicz, P. Siemion

We show that a large class of physical theories which has been under intensive investigation recently, share the same geometric features in their Hamiltonian formulation. These dynamical systems range from harmonic oscillations to WZW-like models and to the KdV dynamics on $Diff_oS^1$. To the same class belong also the Hamiltonian systems on groups of maps.

A. Bianconi, S. Boffi, D. E. Kharzeev

We discuss the unexpected enhancement of the $N^*$ electroproduction on nuclei recently observed in the $(γ^*,pπ^-)$ measurement. A mechanism which is able to explain this result is proposed. To clarify the situation, we suggest to perform a new kind of experiment within well specified kinematic conditions.

Carlos Castro

A new local world volume supersymmetric Lagrangian for the bosonic membrane is presented. The starting Lagrangian is the one constructed by Dolan and Tchrakian with vanishing cosmological constant, with quadratic and quartic derivative terms. Our Lagrangian differs from the one constructed by Lindstrom and Rocek in the fact that it is polynomial in the field

D. E. Berenstein, L. F. Urrutia

Starting from the characteristic polynomial for ordinary matrices we give a combinatorial deduction of the Mandelstam identities and viceversa, thus showing that the two sets of relations are equivalent. We are able to extend this construction to supermatrices in such a way that we obtain the Mandelstam identities in this case, once the corresponding charact

Daniel Kabat, Miguel Ortiz

We investigate the canonical quantization of gravity coupled to pointlike matter in 2+1 dimensions. Starting from the usual point particle action in the first order formalism, we introduce auxiliary variables which make the action locally Poincaré invariant. A Hamiltonian analysis shows that the gauge group is actually larger than the Poincaré group -- certa

Demosthenes Ellinas

Operator angle-action variables are studied in the frame of the SU(2) algebra, and their eigenstates and coherent states are discussed. The quantum mechanical addition of action-angle variables is shown to lead to a novel non commutative Hopf algebra. The group contraction is used to make the connection with the harmonic oscillator.

Mikhail V. Saveliev, Svetlana A. Savelieva

We discuss an infinite--dimensional kählerian manifold associated with the area--preserving diffeomorphisms on two--dimensional torus, and, correspondingly, with a continuous limit of the $A_r$--Toda system. In particular, a continuous limit of the $A_r$--Grassmannians and a related Plücker type formula are introduced as relevant notions for $W_{\infty}$--ge

J. Perez-Mercader

Quantum fluctuations, through quantum corrections, have the potential to lead to irreversibility in quantum field theory. We consider the virtual ``charge&#34; distribution generated by quantum corrections in the leading log, short range approximation, and adopt for it a statistical interpretation. This virtual charge density has fractal structure, and it is

E. Laenen, E. Levin

We consider the inclusive cross section for jet production with large transverse momentum in deep-inelastic scattering. This process has been proposed as a probe of small-x physics, particularly the measurement of `hot spots&#39; inside the proton. We present a numerical calculation of this process, taking into account a larger phase space. The theoretical r

V. Barger, R. J. N. Phillips

A survey is made of some recent ideas and progress in the phenomenological applications of Supersymmetry (SUSY). We describe the success of SUSY-GUT models, the expected experimental signatures and present limits on SUSY partner particles, and the phenomenology of Higgs bosons in the minimal SUSY model.}

Patrick J. O&#39;Donnell, Utpal Sarkar

We study the relation between the Majorana neutrino mass matrices and the neutrinoless double beta decay when CP is not conserved. We give an explicit form of the decay rate in terms of a rephasing invariant quantity and demonstrate that in the presence of CP violation it is impossible to have vanishing neutrinoless double beta decay in the case of two neutr

J. Pappademos, U. Sukhatme, A. Pagnamenta

Starting from a potential with a continuum of energy eigenstates, we show how the methods of supersymmetric quantum mechanics can be used to generate families of potentials with bound states in the continuum [BICs]. We also find the corresponding wave functions. Our method preserves the spectrum of the original potential except it adds these discrete BICs at

A. Djouadi, M. Spira, P. M. Zerwas

Two--photon decays of Higgs bosons are important channels for the search of these particles in the intermediate mass range at the $pp$ colliders LHC and SSC. Dynamical aspects of the Higgs coupling to two photons can also be studied by means of the $γγ$ fusion of Higgs particles at high--energy e$^+$e$^-$ linear colliders. Extending earlier analyses which ha

D. Grasso, M. Pietroni, A. Riotto

We investigate the implications of neutrino electromagnetic dipole moments for the radiative decay $π\rightarrow e νγ$. We show that the dominant new effect comes from the interference between the amplitude of the process with the photon emitted by the neutrino and the structure dependent standard amplitude. Such interference takes place only if the massive

A. A. Bel&#39;kov, G. Bohm, D. Ebert, A. V. Lanyov

We present an analysis of the enhancement of CP-violating charge asymmetries in $K \rightarrow 3π$ decays. Calculations of decay amplitudes are performed on the basis of bosonized strong and weak Lagrangians derived from QCD-motivated quark Lagrangians. We show that the interplay of fourth-order contributions of chiral Lagrangians for strong interactions and

M. Knecht, H. Sazdjian, J. Stern, N. H. Fuchs

$Kπ$ scattering and $K_{μ4}$ decays are studied at leading order of improved chiral perturbation theory. It is shown that high precision $K_{μ4}$ experiments at, e.g., DA$Φ$NE should allow for a direct measurement of the quark mass ratio $m_s$/${\hat m}$.

Marc Knecht

In the low energy domain, Chiral Perturbation Theory parametrizes the small chiral symmetry breaking effects, produced by the quark masses $m_u$, $m_d$ and $m_s$, in terms of order parameters of massless QCD. The latter can then, in principle, be measured in high precision, low energy experiments. We discuss several relevant processes and possible improvemen

A. A. Bel&#39;kov, D. Ebert, A. V. Lanyov, A. Schaale

In this paper there we describe the calculational background of deriving a strong meson Lagrangian from the Nambu--Jona-Lasinio quark model using the computer algebra systems FORM and REDUCE in recursive algorithms, based on the heat-kernel method for the calculation of the quark determinant.

Thomas Wynter, Lisa Randall

We examine constraints on a simple neutrino model in which there are three massless and three massive Dirac neutrinos and in which the left handed neutrinos are linear combinations of doublet and singlet neutrinos. We examine constraints from direct decays into heavy neutrinos, indirect effects on electroweak parameters, and flavor changing processes. We com

K. F. Liu, S. J. Dong, T. Draper, J. M. Wu

Results for the isovector axial form factors of the proton from a lattice QCD calculation are presented for both point-split and local currents. They are obtained on a quenched $16^{3} \times 24$ lattice at $β= 6.0$ with Wilson fermions for a range of quark masses from strange to charm. We determine the finite lattice renormalization for both the local and p

C. Gong, B. Mueller, T. S. Biro

Applying a variational method to a Gaussian wave ansatz, we have derived a set of semi-classical evolution equations for SU(2) lattice gauge fields, which take the classical form in the limit of a vanishing width of the Gaussian wave packet. These equations are used to study the quantum effects on the classical evolutions of the lattice gauge fields.

C. Bernard, T. Blum, T. DeGrand, C. Detar

We have carried out spectrum calculations with two flavors of dynamical Kogut-Susskind quarks on four lattice sizes from $8^3\times 24$ to $16^3\times24$ at couplings that correspond to chiral symmetry restoration for a lattice with 6 time slices. We estimate that the linear spatial sizes of the lattices range from 1.8 to 3.6 fm. We find significant finite s

M. Asorey, J. G. Esteve, J. Salas

We analyze the finite size scaling of the $q$-state clock model in the $q \rightarrow \infty$ limit. The behaviors of the specific heat, Binder-Landau and U4 cumulants agree with the Borgs-Kotecký ansätz for first order phase transitions. However, we find that the leading correction to the position of the extremal points of these quantities is not universal.

M. Asorey, J. G. Esteve, J. Salas

We analyze the exact behavior of the renormalization group flow in one-dimensional clock-models which undergo first order phase transitions by the presence of complex interactions. The flow, defined by decimation, is shown to be single-valued and continuous throughout its domain of definition, which contains the transition points. This fact is in disagreemen

V. A. Kozlov, A. V. Samokhvalov

The new type of solutions of the London equation for type-II superconductors is obtained to describe the ring-shaped (toroidal) Abrikosov vortices. The specific feature of these solutions is the self-consistent localization of both the supercurrent and the magnetic field, enabling one to construct compact magnetic structures inside a superconductor. The toru

K. Jauregui, W. Haeusler, B. Kramer, PTB Braunschweig

The one-- and two-- particle densities of up to four interacting electrons with spin, confined within a quasi one--dimensional ``quantum dot&#39;&#39; are calculated by numerical diagonalization. The transition from a dense homogeneous charge distribution to a dilute localized Wigner--type electron arrangement is investigated. The influence of the long range

C. Yeung, Y. Oono, A. Shinozaki

The nonlinear equations describing phase ordering dynamics can be closed by assuming the existence of an underlying Gaussian stochastic field which is nonlinearly related to the observable order parameter field. We discuss the relation between different implementations of the Gaussian assumption and consider the limitations of this assumption for phase order

I. G. Kevrekidis, R. Rico-Martinez, R. E. Ecke, R. M. Farber

We use nonlinear signal processing techniques, based on artificial neural networks, to construct an empirical mapping from experimental Rayleigh-Benard convection data in the quasiperiodic regime. The data, in the form of a one-parameter sequence of Poincare sections in the interior of a mode-locked region (resonance horn), are indicative of a complicated in

V. Karas, D. Vokrouhlicky

This preprint is based on two articles accepted by MNRAS and ApJ. Our aim is to study the evolution of the orbit of a star under the influence of interactions with an accretion disc in an AGN. The model considered consists of a low-mass compact object orbiting a supermassive black hole and colliding periodically with the accretion disc. Gravitational field o

Yu. L. Dokshitzer, V. A. Khoze, L. H. Orr, W. J. Stirling

The pattern of soft photon radiation in $\ee\to\ww$ has a rich structure, with contributions from photon emission off the initial state and off the final state particles both before and after decay. In particular, the interference between the contributions involving the decaying $W$&#39;s depends on the decay width. We review the theoretical result for the r

F. T. Brandt, J. Frenkel

We show generally that in thermal gravity, the one-particle irreducible 2-point function depends on the choice of the basic graviton fields. We derive the relevant properties of a physical graviton self-energy, which is independent of the parametrization of the graviton field. An explicit expression for the graviton self-energy at high-temperature is given t

A Donnachie, P V Landshoff

A fit is made to the data for the proton structure function up to Q^2=10 GeV^2, including the real gamma p total cross-section. It is economical and simple, and its form is motivated by physical principles. It is extrapolated down to very small values of x. Data for the ratio (nu W_2^n/nu W_2^p) are also fitted. A FORTRAN program for the fit to (nu W_2^p) is

A Zhitnitsky

Starting from the 4-dimensional gluodynamics, we discuss the statistical ensemble of torons ( the toron is a self-dual solution with fractional topological number; it can be understood as a point defect) which interact strongly. It is shown that the effective Lagrangian describing this statistical ensemble possesses the fourth derivative kinetic term and lea

Seungoh Ryu, A. Kapitulnik, S. Doniach

The effects of columnar pins on the flux lines in a model High-Tc superconductor in an applied field are studied through Monte Carlo simulations. An analytic solution for a single line case is obtained and compared with the simulation results. By introducing a tilted potential, we study simulated ``IV&#34; characteristics and the results indicate a distinct

Valeriy V. Dvoeglazov

In the framework of the Joos-Weinberg 2(2S+1)- theory for massless particles, the dynamical invariants have been derived from the Lagrangian density which is considered to be a 4- vector. A la Majorana interpretation of the 6- component &#34;spinors&#34;, the field operators of S=1 particles, as the left- and right-circularly polarized radiation, leads us to

Mark B. Mineev-Weinstein, Silvina Ponce Dawson

We present a new class of exact solutions for the so-called {\it Laplacian Growth Equation} describing the zero-surface-tension limit of a variety of 2D pattern formation problems. Contrary to common belief, we prove that these solutions are free of finite-time singularities (cusps) for quite general initial conditions and may well describe real fingering in

Gilbert Baumslag

The object of this paper is to describe a simple method for proving that certain groups are residually torsion-free nilpotent, to describe some new parafree groups and to raise some new problems in honour of the memory of Wilhelm Magnus.

M. Werneck de Oliveira, M. Schweda, S. P. Sorella REF

We show that the bosonic string theory quantized in the Beltrami parametrization possesses a supersymmetric structure like the vector-supersymmetry already observed in topological field theories.

H. Awata, S. Odake, J. Shiraishi

We construct a realization of the quantum affine algebra $U_q(\widehat{sl_N})$ of an arbitrary level $k$ in terms of free boson fields. In the $q\!\rightarrow\! 1$ limit this realization becomes the Wakimoto realization of $\widehat{sl_N}$. The screening currents and the vertex operators(primary fields) are also constructed; the former commutes with $U_q(\wi

V. V. Mangazeev, Yu. G. Stroganov

As is known, tetrahedron equations lead to the commuting family of transfer-matrices and provide the integrability of corresponding three-dimensional lattice models. We present the modified version of these equations which give the commuting family of more complicated two-layer transfer-matrices. In the static limit we have succeeded in constructing the solu

R. M. Kashaev, Yu. G. Stroganov

A generalization of the Yang-Baxter equation is proposed. It enables to construct integrable two-dimensional lattice models with commuting two-layer transfer matrices, while single-layer ones are not necessarily commutative. Explicit solutions to the generalized equations are found. They are related with Botzmann weights of the $sl(3)$ chiral Potts model.