bluuebunny/crossref_metadata_2025 huggingface dataset:
Geometry of locating sounds from differences in travel time: Isodiachrons
Authors: Spiesberger John L.
Published: November 2004

Calling animals may be located from measurements of the differences in acoustic travel time at pairs of receivers. For inhomogeneous fields of speed, locations can be made with better accuracy when the location algorithm allows the speed to vary from path to path. A new geometrical shape, called an isodiachron, is described. It is the locus of points corresponding to a constant difference in travel time along straight paths between the animal and two receivers. Its properties allow an interpretation for locations when the speed differs from path to path. An algorithm has been developed for finding the location of calling animals by intersecting isodiachrons from data collected at pairs of receivers. When the sound speed field is spatially homogeneous, isodiachrons become hyperboloids. Unlike a hyperboloid that extends to infinity, an isodiachron is confined to a finite region of space when the speeds differ between the animal and each of two receivers. Its shape is significantly different than a hyperboloid for cases of practical interest. Isodiachrons can be used to better understand locations of calling animals and other sounds in the sea, Earth, and air.
Guided wave propagation in three-layer pavement structures
Authors: Ryden Nils , Lowe Michael J. S.
Published: November 2004

A study on guided waves in a layered half-space with large velocity contrasts and a decreasing velocity with depth is presented. Multiple mode dispersion curves are calculated in the complex wave number domain, taking into consideration the attenuation caused by leakage into the underlying half-space. The excitability of the modes by a vertical point force on the surface is also calculated. Results show that the measurable wave field at the surface of a pavement structure is dominated by leaky quasi-Lamb waves in the top and second layers. The fundamental antisymmetric mode of vibration is the dominating mode generated in the stiff top layer. This mode drives the complete system and continuity across the boundaries generates higher order modes in the embedded second layer. The interaction of leaky Lamb waves in the first two layers results in large variations in the excitability and the attenuation, so that only the waves corresponding to certain portions of the dispersion curves are measurable remote from the source at the pavement surface. It is concluded that these portions of dispersion curves can be individually resolved in practice, by using multichannel processing techniques. This holds the potential for a refined nondestructive testing technique for pavements.
PREPROCESSING IN ATTRACTOR NEURAL NETWORKS
Authors: CARVALHAES C.G. , COSTA A.T. , PENNA T.J.P.
Published: November 2004

Preprocessing the input patterns seems the simplest approach to invariant pattern recognition by neural networks. The Fourier transform has been proposed as an appropriate and elegant preprocessor. Nevertheless, we show in this work that the performance of this kind of preprocessor is strongly affected by the number of stored informations. This is so because the phase of the Fourier transform plays a more important role than the amplitude in the recognition process.
FLUID FLOW IN A DIRECTED POROUS MEDIA
Authors: ONODY R.N.
Published: November 2004

We present a modified site invasion percolation with a biased growth rule to model a fluid flow in porous media with a privileged direction. The effects of the modifications are systematically analyzed in computer simulations and a number of characteristics parameters such as acceptance profiles and linear mass density are obtained. The asymptotic behavior and scaling relations are also discussed and the associated exponents are numerically estimated.
TOPOLOGICAL ZERO MODES IN MONTE CARLO SIMULATIONS
Authors: DILGER H.
Published: November 2004

We present an improvement of global Metropolis updating steps, the instanton hits, used in a hybrid Monte Carlo simulation of the two-flavor Schwinger model with staggered fermions. These hits are designed to change the topological sector of the gauge field. In order to match these hits to an unquenched simulation with pseudofermions, the approximate zero mode structure of the lattice Dirac operator has to be considered explicitly.
SIMD ALGORITHM FOR MATRIX TRANSPOSITION
Authors: CABIBBO N. , PAOLUCCI P.S.
Published: November 2004

We present an algorithm for matrix transposition on SIMD machines and its implementation on the APE 100/Quadrics parallel processors.
MOLECULAR DYNAMICS AND MONTE CARLO METHODS APPLIED TO THE SIMULATION OF THIN FILMS GROWTH
Authors: MAZZONE A.M.
Published: November 2004

In our work a comparative study is made of molecular dynamics and Monte Carlo methods applied to the growth of a thin Fe epilayer on an Ag substrate. This comparison centres on the physics of the computational approaches and of the results.
EFFICIENT MONTE CARLO SIMULATION OF BIOLOGICAL AGING
Authors: PENNA T.J.P. , STAUFFER D.
Published: November 2004

A bit-string model of biological life-histories is parallelized, with hundreds of millions of individuals. It gives the desired drastic decay of survival probabilities with increasing age for 32 age intervals.
INTEGRATION WITH QUASIRANDOM SEQUENCES: NUMERICAL EXPERIENCE
Authors: SOBOL’ ILYA M. , SHUKHMAN BORIS V.
Published: November 2004

Numerical experiments with two multivariable integrands and various quasirandom sequences are described. The integrands were introduced as models of Monte Carlo algorithms for particle tracking with or without statistical weights. Though analytically both integrands are very similar, the corresponding integration errors behave quite differently.

From these experiments together with earlier ones (that are briefly summarized in the paper) several non-standard conclusions are drawn both on quasirandom sequences and on types of integrands.
THE MARKOFF AUTOMATON: A NEW ALGORITHM FOR SIMULATING THE TIME-EVOLUTION OF LARGE STOCHASTIC DYNAMIC SYSTEMS
Authors: FRICKE THOMAS , WENDT DIETMAR
Published: November 2004

We describe a new algorithm for simulating complex Markoff processes. We have used a reaction-cell method in order to simulate arbitrary reactions. It can be used for any kind of RDS on arbitrary topologies, including fractal dimensions or configurations not being related to any spatial geometry. The events within a single cell are managed by an event handler which has been implemented independently of the system studied. The method is exact on the Markoff level including the correct treatment of finite numbers of molecules.

To demonstrate its properties, we apply it on a very simple reaction-diffusion-systems (RDS). The chemical equations [Formula: see text] and [Formula: see text] in 1 to 4 dimensions serve as models for systems whose dynamics on an intermediate time scale are governed by fluctuations. We compare our results to the analytic approach by the scaling ansatz. The simulations confirm the exponents of the A+B system within statistical errors, including the logarithmic corrections in the dimension d=2.

The method is able to simulate the crossover from the reaction to diffusion limited regime, which is defined be a crossover time depending on the system size.
ALGEBRAIC PROGRAMMING IN THE HAMILTONIAN TREATMENT OF AN INFLATIONARY MODEL
Authors: VULCANOV DUMITRU N.
Published: November 2004

This article presents new procedures in REDUCE language using the EXCALC package (adapted for IBM-PC machines) for algebraic programming in the Hamiltonian formulation of inflationary models based on a scalar field non-minimally coupled with gravity. The (3+1)-dimensional split of the action functional of the model and the constraint and dynamic equations are obtained. These equations are transposed in computer procedures. The results obtained after processing some examples of initial space-time models are presented here.
CONSERVING ALGORITHMS FOR REAL-TIME NONABELIAN LATTICE GAUGE THEORIES
Authors: BIRÓ T.S.
Published: November 2004

A class of numerical algorithms for solving the classical equations of motion in lattice gauge field theories which exactly fulfill the constraints imposed by the unitarity of the local group elements, by the local color charge conservation (Gauss law) and by the total energy conservation is constructed. The performance of these constrained algorithms is comparatively discussed.
MONTE CARLO METHOD FOR SPIN MODELS WITH LONG-RANGE INTERACTIONS
Authors: LUIJTEN ERIK , BLÖTE HENK W.J.
Published: November 2004

We introduce a Monte Carlo method for the simulation of spin models with ferromagnetic long-range interactions in which the amount of time per spin-flip operation is independent of the system size, in spite of the fact that the interactions between each spin and all other spins are taken into account. We work out two algorithms for the q-state Potts model and discuss the generalization to systems with other interactions and to O (n) models. We illustrate the method with a simulation of the mean-field Ising model, for which we have also analytically calculated the leading finite-size correction to the dimensionless amplitude ratio 2/ at the critical temperature.
USING AN ANALOG NEURAL NETWORK TO TRIGGER ON TAU LEPTONS AT CDF
Authors: CONWAY J.S. , LOOMIS C.
Published: November 2004

At the Collider Detector at Fermilab (CDF), we have designed and implemented a trigger for tau leptons using analog neural network electronics. Tau leptons offer a fertile area of research both for standard model tests and for new physics searches. Because the bulk of tau leptons decay into hadrons, it is challenging to distinguish them from ordinary hadron jets. Neural networks are well suited to this type of difficult classification problem. In this case, software simulations show that an efficiency of 15% with a rejection factor of 100 could be obtained. The input to the network is a 5×5×2 array of calorimeter tower energies surrounding the seed tower of a cluster. If the network’s single output exceeds a tunable threshold, the event is passed to the next stage of the trigger. An existing system based on the Intel ETANN (Electrically Trainable Analog Neural Network) chip was used to implement the tau lepton neural network trigger. The performance of the trigger in current CDF data will be presented.
RESULTS FROM A NEURAL TRIGGER BASED ON THE MA16 MICROPROCESSOR
Authors: BALDANZA C. , BEICHTER J. , BISI F. , BRUELS N. , BRUSCHINI C. , COTTA-RAMUSINO A. , D’ANTONE I. , MALFERRARI L. , MAZZANTI P. , MUSICO P. , NOVELLI P. , ODORICI F. , ODORICO R. , PASSASEO M. , ZUFFA M.
Published: November 2004

Results from a neural-network trigger based on the digital MA16 chip of Siemens are reported. The neural trigger has been applied to data from the WA92 experiment, looking for beauty particles, which have been collected during a run in which a neural trigger module based on Intel’s analog neural chip ETANN operated, as already reported. The MA16 has a precision of 16 bits for input variables, 16 bits for weights, 16 bits for scalar multipliers modifying the transfer function shape, 47 bits for thresholds, 53 bits for internal calculations, 38 bits for the output. Of the latter only 16 bits are used in the MA16 board, as input to the transfer function inplemented on 16-bit addressable EPROM’s. The MA16 board operated at 50 MHz, yielding a response time for a 16 input variable net of 3 μs for a Fisher discriminant (1-layer net) and of 6 μs for a 2-layer net. Results are compared with those previously obtained with the ETANN trigger.
USING GENETICS IN PARTICLE PHYSICS
Authors: ORGANTINI GIOVANNI
Published: November 2004

Following an idea derived from techniques used to simulate biological processes I developped a method to optimize selection algorithms in particle physics.
NUMERICAL SIMULATION OF THE SU(3) WESS–ZUMINO TERM IN TWO AND FOUR DIMENSIONS
Authors: BAAQUIE B. E. , LAI C. H.
Published: November 2004

We give a method for numerically evaluating the Wess–Zumino (WZ) term for an arbitrary SU(3) field configuration. We check the accuracy of the numerical method by evaluating the WZ-term for the 2π-rotation of a Skyrmion field configuration.
DELAUNAY TRIANGULATIONS IN THE PLANE WITH ${\mathcal O} (\sqrt{N} \log N)$ STORAGE REQUIREMENTS
Authors: KARTASHOV A. , FOLK R.
Published: November 2004

We present a straightforward iterative algorithm constructing the planar Delaunay triangulation in [Formula: see text] time. The algorithm proceeds iteratively by adding new points one by one to a partial point set pre-ordered by one coordinate and adjusting the partial diagram correspondingly. We introduce the techniques of safe fragments, showing that the larger part of a partial digram cannot be changed by adding further points; in the average case of a random point set the amount of information which need be stored in memory at any moment does not exceed [Formula: see text]. The computational overhead for the memory management is linear in N. In particular, this makes very large Delaunay triangulations (and Voronoi tessellations) accessible for simulations on personal computers.
COUPLED DIPOLE SIMULATIONS OF ELASTIC LIGHT SCATTERING ON PARALLEL SYSTEMS
Authors: HOEKSTRA A. G. , SLOOT P. M. A.
Published: November 2004

The Coupled Dipole method is used to simulate Elastic Light Scattering from arbitrary shaped particles. To facilitate simulation of relative large particles, such as human white blood cells, the number of dipoles required for the simulation is approximately 105 to 106. In order to carry out such simulations, very powerful computers are necessary. We have designed a parallel version of the Coupled Dipole method, and have implemented it on a distributed memory parallel computer, a Parsytec PowerXplorer, containing 32 PowerPC-601 processors. The efficiency of the parallel implementation is investigated for simulations of model particles. Scattering by a sphere, modelled with 33552 dipoles, is simulated and compared with analytical Mie theory. Finally the suitability of the Coupled Dipole method to simulate Elastic Light Scattering from larger particles, such as white blood cells, is discussed.
STUDY OF A MA16-BASED VERTEX TRIGGER FOR THE CDF EXPERIMENT
Authors: ODORICO R.
Published: November 2004

A Neural Network trigger for [Formula: see text] events based on the SVT microvertex processor of experiment CDF at Fermilab is presented. It exploits correlations among track impact parameters and azimuths calculated by the SVT from the SVX microvertex detector data. The neural trigger is meant for implementation on the systolic Siemens microprocessor MA16, which has already been used in a neural-network trigger for experiment WA92 at CERN. A suitable set of input variables is found, which allows a viable solution for the preprocessing task using standard electronic components. The response time of the neural-network stage of the trigger, including preprocessing, can be estimated ~10 μs. Its precise value depends on the quantitative specifications of the output signals of the SVT, which is still in development. The performance of the neural-network trigger is found to be significantly better than that of a conventional trigger exclusively based on impact parameter data.
CHIRALLY EXTENDED QUANTUM CHROMODYNAMICS
Authors: BROWER RICHARD C. , SHEN YUE , TAN CHUNG-I
Published: November 2004

We propose an extended Quantum Chromodynamics (XQCD) Lagrangian in which the fermions are coupled to elementary scalar fields through a Yukawa coupling which preserves chiral invariance. Our principle motivation is to find a new lattice formulation for QCD which avoids the source of critical slowing down usually encountered as the bare quark mass is tuned to the chiral limit. The phase diagram and the weak coupling limit for XQCD are studied. They suggest a conjecture that the continuum limit of XQCD is the same as the continuum limit of conventional lattice formulation of QCD. As examples of such universality, we present the large N solutions of two prototype models for XQCD, in which the mass of the spurious pion and sigma resonance go to infinity with the cut-off. Even if the universality conjecture turns out to be false, we believe that XQCD will still be useful as a low energy effective action for QCD phenomenology on the lattice. Numerical simulations are recommended to further investigate the possible benefits of XQCD in extracting QCD predictions.
MULTI-SPIN CODING OF THE MONTE CARLO SIMULATION OF THE THREE-STATE RANDOM POTTS MODEL AND THE BLOCK-SPIN TRANSFORMATION
Authors: KIKUCHI MACOTO , OKABE YUTAKA
Published: November 2004

The multi-spin coding of the Monte Carlo simulation of the three-state Potts model on the simple cubic lattice is presented. The ferromagnetic (F) model, the antiferromagnetic (AF) model, and the random mixture of the F and AF couplings are treated. The multispin coding technique is also applied to the block-spin transformation. The block-spin transformation of the F Potts model is simply realized by the majority rule, whereas the AF three-state Potts model is transformed to the block spin having a six-fold symmetry.
SIMULATIONS OF THE IMMUNOLOGICAL SHAPE SPACE: INFLUENCE OF THE INTERACTION RANGE IN AN ISING-LIKE MODEL
Authors: MEYER HARTMUT
Published: November 2004

Stauffer7 has replaced the window automata rules — applied by de Boer, Segel and Perelson2 for simulating the immunological shape space — by probabilistic rules, very similar to the ones of the ferromagnetic Ising Model. Based on this model, we extend the interaction range to more than nearest neighbors and find phase transitions not only in higher dimensions, but also in two dimensions, Biologically these phase transitions correspond to a transition from a reasonable to a non-reasonable behavior of the whole immune network.
DYNAMICAL CRITICAL BEHAVIOR OF THE FOUR-DIMENSIONAL ISING MODEL
Authors: ADLER JOAN , STAUFFER DIETRICH
Published: November 2004

Monte Carlo simulations of the Glauber dynamics in the four-dimensional Ising model with up to 3124 spins agree with the theoretically expected logarithmic corrections to mean field behavior, if we assume J/kBTc = 0.14970, consistent with some series analysis.
PARTITION FUNCTION ZEROS OF AN ISING SPIN GLASS
Authors: DAMGAARD P. H. , LACKI J.
Published: November 2004

We study the pattern of zeros emerging from exact partition function evaluations of Ising spin glasses on conventional finite lattices of varying sizes. A large number of random bond configurations are probed in the framework of quenched averages. This study is motivated by the relationship between hierarchical lattice models whose partition function zeros fall on Julia sets and chaotic renormalization group flows in such models with frustration, and by the possible connection of the latter with spin glass behavior. In any finite volume, the simultaneous distribution of the zeros of all partition functions can be viewed as part of the more general problem of finding the location of all the zeros of a certain class of random polynomials with positive integer coefficients. Some aspects of this problem have been studied in various areas of mathematics, and we show in particular how polynomial mappings which are used in graph theory to classify graphs, may help in characterizing the distribution of zeros. We finally discuss the possible limiting set of these zeros as the volume is sent to infinity.
GENETIC ALGORITHMS AND OBJECT-ORIENTED PROGRAMMING
Authors: STEEB W.-H. , SOLMS F. , SHI TAN KIAT
Published: November 2004

Genetic algorithms were invented to mimic some of the processes observed in natural evolution. We give a survey on this research field. In particular problems with constraints are studied. Furthermore, problems from statistical mechanics are discussed. An implementation using object-oriented programming is given.
THE CORRELATION FUNCTIONS OF THE (D4, A6) CONFORMAL MODEL
Authors: BALASKA S. , DEMMOUCHE K.
Published: November 2004

In this work, we exploit the operator content of the (D4, A6) conformal algebra. By constructing a Z2-invariants fusion rules of a chosen subalgebra and by resolving the bootstrap equations consistent with these rules, we determine the structure constants of the subalgebra.
ON THE LARGE N LIMIT, WILSON LOOPS, CONFINEMENT AND COMPOSITE ANTISYMMETRIC TENSOR FIELD THEORIES
Authors: CASTRO CARLOS
Published: November 2004

A novel approach to evaluate the Wilson loops associated with a SU (∞) gauge theory in terms of pure string degrees of freedom is presented. It is based on the Guendelman–Nissimov–Pacheva formulation of composite antisymmetric tensor field theories of area (volume) preserving diffeomorphisms which admit p-brane solutions and which provide a new route to scale-symmetry breaking and confinement in Yang–Mills theory. The quantum effects are discussed and we evaluate the vacuum expectation values (VEV) of the Wilson loops in the large N limit of the quenched reduced SU (N) Yang–Mills theory in terms of a path integral involving pure string degrees of freedom. The quenched approximation is necessary to avoid a crumpling of the string worldsheet giving rise to very large Hausdorff dimensions as pointed out by Olesen. The approach is also consistent with the recent results based on the AdS/CFT correspondence and dual QCD models (dual Higgs model with dual Dirac strings). More general Loop wave equations in C-spaces (Clifford manifolds) are proposed in terms of generalized holographic variables that contain the dynamics of an aggregate of closed branes (p-loops) of various dimensionalities. This allows us to construct the higher-dimensional version of Wilson loops in terms of antisymmetric tensor fields of arbitrary rank which couple to p-branes of different dimensionality.
STRONGLY COUPLED N=1 SUPERSYMMETRIC SO(Nc) GAUGE THEORIES WITHOUT MAGNETIC DEGREES OF FREEDOM
Authors: YASUÈ MASAKI
Published: November 2004

In strongly coupled supersymmetric SO (Nc) gauge theories with Nf-quarks for Nc-2≤Nf(≤3(Nc-2)/2), their low-energy physics can be described by Nambu–Goldstone superfields associated with dynamical flavor symmetry breaking, which should be compared with the absence of flavor symmetry breaking in the conventional description in terms of magnetic degrees of freedom. The presence of the flavor symmetry breaking is confirmed by the well-known instanton effects in SO (Nc) with Nf=Nc-2, which are also described by our proposed effective superpotential. For Nf≥Nc-1, our effective superpotentials utilize baryonic configurations as well as mesons composed of two quarks. The baryonic configurations are supplied by "diquarks" made of Nc-1 quarks for Nf=Nc-1 and by baryons composed of Nc quarks for Nc≥Nf. It is argued that our effective superpotentials exhibit the holomorphic decoupling property, the anomaly-matching property and correct description of instanton effects in SO (Nc) when Nf-Nc+2 quarks become massive if Nf≥Nc-1.
COSMOLOGICAL TERM AND EXTENDED LOOP REPRESENTATION OF QUANTUM GRAVITY
Authors: SHAO D. , SHAO L. , SAITO M. , SHAO C. G. , NODA H.
Published: November 2004

The cosmological term is formulated in the framework of the extended loop representation and its particularization from the extended loop to the loop representations is given. The properties of the Gauss self-linking number are investigated. It is shown that the phase factor of the Kauffman bracket satisfies the Mandelstam identities, the diffeomorphism constraint and the Hamiltonian constraint with the cosmological constant in the extended loop calculus.
GAUGING SL(2, R) AND SL(2, R)×U(1) BY THEIR NILPOTENT SUBGROUPS
Authors: ALIMOHAMMADI M. , ARDALAN F. , ARFAEI H.
Published: November 2004

We consider the gauging of SL(2, R) and SL(2, R)×U(1) WZNW model by their nilpotent subgroups. The resulting space-times of the corresponding sigma models are seen to collapse to the one-dimensional Liouville theory in the first case, and lead to an extremal three-dimensional black string in the second case. We show that these results are also obtained by boosting the Witten black hole solution and Horne and Horowitz black string solution respectively.
NEUTRINO MASS AND MIXING: THE IMPACT OF EXCITED STATE CONTRIBUTIONS ON CAPTURE RATES OF Ga DETECTORS
Authors: KAR KAMALES , GOSWAMI SRUBABATI , RAYCHAUDHURI AMITAVA
Published: November 2004

In this paper we calculate the neutrino absorption cross-sections for the reaction 71Ga(ν, e−)71Ge using two simple nuclear models to account for the giant GT resonances. In both models the excited state contributions are found to have significant ranges of variation and affect the solar neutrino capture rates. Nonetheless, the regions in the neutrino mixing angle-mass squared difference plane allowed by the data from the Gallium detectors, when taken together with those from the Chlorine and Kamioka experiments, are found to be comparatively stable.
A BILOCAL FIELD APPROACH TO THE LARGE N EXPANSION OF TWO-DIMENSIONAL (GAUGE) THEORIES
Authors: CAVICCHI MARCO
Published: November 2004

We consider a wide class of two-dimensional models as gauge theories, the Gross-Neveu model, O(N) and CPN−1-like models using a formalism based on the introduction of bilocal fields that permits us to perform easily the large N expansion of this set of models in a unified and general way. We mainly discuss the SU(N) gauge field theory minimally coupled to fermionic plus bosonic matter in the fundamental representation, and we obtain within the path integral approach exact equations for the particle spectrum, also in the presence of renormalizable polynomial potentials. Finally, we discuss the correspondence between this new approach and the one previously used in the context of the O(N) vector models.
THRESHOLD EFFECTS AND PERTURBATIVE UNIFICATION
Authors: BASTERO-GIL M. , MANÍAS V. , PÉREZ-MERCADER J.
Published: November 2004

We discuss the effect of the renormalization prescription in the computation of the unification point for running coupling constants. We explore the effects of threshold crossing on the β functions. We compute the running of the coupling constants of the Standard Model, between mz and Mp, using a mass-dependent subtraction procedure, and then compare the results with [Formula: see text] and with the θ function approximation. We also do this for the minimal supersymmetric extension of the Standard Model. In the latter, the bounds on SUSY masses that one obtains by requiring perturbative unification are dependent, to some extent, on the procedure.
STATUS OF HIGHER-ORDER CORRECTIONS IN THE STANDARD ELECTROWEAK THEORY
Authors: KNIEHL BERND A.
Published: November 2004

We review recent theoretical progress in the computation of radiative corrections beyond one loop within the standard model of electroweak interactions, in both the gauge and Higgs sectors. In the gauge sector, we discuss universal corrections of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text], and those due to virtual [Formula: see text]-threshold effects, as well as specific corrections to [Formula: see text] of [Formula: see text], [Formula: see text] and [Formula: see text] including finite-mb effects. We also present an update of the hadronic contributions to Δα. Theoretical uncertainties, other than those due to the lack of knowledge of MH and mt, are estimated. In the Higgs sector, we report on the [Formula: see text] corrections to [Formula: see text] including those which are specific for the [Formula: see text] mode, the [Formula: see text] corrections to [Formula: see text] including the finite-mq terms, and the [Formula: see text] corrections to Γ(H → gg).
EXCLUSIVE PRODUCTION OF HEAVY MESON PAIRS IN e+e− ANNIHILATION
Authors: KISELEV V. V.
Published: November 2004

A constituent quark model is used to calculate the exclusive pair production of [Formula: see text] and [Formula: see text] mesons in e+e− annihilation. It allows one to illuminate the meaning of the 1/mb,c corrections to the leading order of the effective heavy quark theory.
CORRELATION FUNCTIONS AND MULTICRITICAL FLOWS IN c<1 STRING THEORY
Authors: GOVINDARAJAN SURESH , JAYARAMAN T. , JOHN VARGHESE
Published: November 2004

We compute all string tree level correlation functions of vertex operators in c < 1 string theory. This is done by using the ring structure of the theory. In order to study the multicritical behavior, we calculate the correlation functions after perturbation by physical vertex operators. We show that the (2k − 1, 2) models can be obtained from the (1, 2) model and the minimal models can be obtained from the (1, p) model by perturbing the action with appropriate physical operators. Our results are consistent with known results from matrix models.
ON THE SYMMETRIES OF HAMILTONIAN SYSTEMS
Authors: MUKHANOV V. , WIPF A.
Published: November 2004

In this paper we show how the well-known local symmetries of Lagrangian systems, and in particular the diffeomorphism invariance, emerge in the Hamiltonian formulation. We show that only the constraints which are linear in the momenta generate transformations which correspond to symmetries of the corresponding Lagrangian system. The non-linear constraints (which we have, for instance, in gravity, supergravity and string theory) generate the dynamics of the corresponding Lagrangian system. Only in a very special combination with "trivial" transformations proportional to the equations of motion do they lead to symmetry transformations. We show the importance of these special "trivial" transformations for the interconnection theorems which relate the symmetries of a system with its dynamics. We prove these theorems for general Hamiltonian systems. We apply the developed formalism to concrete physically relevant systems, in particular those which are diffeomorphism-invariant. The connection between the parameters of the symmetry transformations in the Hamiltonian and Lagrangian formalisms is found. The possible applications of our results are discussed.
THE CUTOFF λϕ4 O(N) MODEL IN THE LARGE N LIMIT
Authors: NUNES JOÃO P. , SCHNITZER HOWARD J.
Published: November 2004

A cutoff version of the λϕ4 O(N) model is considered to leading order in 1/N with particular attention paid to the effective potential, which is surprisingly rich in structure. With suitable restriction on a background classical field, one finds a phenomenologically viable model with spontaneously broken symmetry, a potential bounded below, and amplitudes free of tachyons. The model has an O(N − 1) singlet resonance in both weak and strong couplings, which can be interpreted as the Higgs meson in applications. Further, an unphysical resonance, which can be used to define a triviality scale for the model, appears at a mass above the cutoff mass Λ. The phenomenological aspects of our discussion are consistent with previous studies, whose results are obtained by somewhat different methods. The question of the double-scaling limit for the cutoff model is considered as an application of the effective potential. It is shown that the double-scaling limit is not possible.
PREPOTENTIALS FOR (2, 2) SUPERGRAVITY
Authors: GRISARU MARCUS T. , WEHLAU MARCIA E.
Published: November 2004

We present a complete solution to the constraints for two-dimensional N = 2 supergravity in N = 2 superspace. We obtain explicit expressions for the covariant derivatives in terms of the vector superfield Hm and, for the two versions of minimal (2,2) supergravity, a chiral or twisted chiral scalar superfield ϕ.
LIOUVILLE THEORY AND SPECIAL COADJOINT VIRASORO ORBITS
Authors: GORSKY A. , JOHANSEN A.
Published: November 2004

We describe the Hamiltonian reduction of the coadjoint Kac–Moody orbits to the Virasoro coadjoint orbits explicitly in terms of the Lagrangian approach for the Wess–Zumino–Novikov–Witten theory. While a relation of the coadjoint Virasoro orbit Diff S1/ SL (2, R) to the Liouville theory has already been studied, we analyze the role of special coadjoint Virasoro orbits Diff [Formula: see text]corresponding to stabilizers generated by the vector fields with double zeros. The orbits with stabilizers with single zeros do not appear in the model. We find an interpretation of zeros xi of the vector field of stabilizer [Formula: see text] and additional parameters qi, i = 1, …, n, in terms of quantum mechanics for n-point particles on the circle. We argue that the special orbits are generated by insertions of "wrong sign" Liouville exponential into the path integral. The additional parmeters qi are naturally interpreted as accessory parameters for the uniformization map. Summing up the contributions of the special Virasoro orbits we get the integrable sinh–Gordon type theory.
ON STATE COUNTING AND CHARACTERS
Authors: DASMAHAPATRA SRINANDAN
Published: November 2004

We outline the relationship between the thermodynamic densities and quasiparticle descriptions of spectra of RSOS models with an underlying Bethe equation. We use this to prove completeness of states in some cases and then give an algorithm for the construction of branching functions of their emergent conformal field theories. Starting from the Bethe equations of Dn type, we discuss some aspects of the Zn lattice models.
N = 1, 2 SUPER-NLS HIERARCHIES AS SUPER-KP COSET REDUCTIONS
Authors: TOPPAN F.
Published: November 2004

We define consistent finite-superfield reductions of the N = 1, 2 super-KP hierarchies via the coset approach we have already developed for reducing the bosonic KP hierarchy [generating for example the NLS hierarchy from the [Formula: see text] coset]. We work in a manifestly supersymmetric framework and illustrate our method by treating explicitly the N = 1, 2 super-NLS hierarchies. With respect to the bosonic case the ordinary covariant derivative is now replaced by a spinorial one which contains a spin-[Formula: see text] superfield. Each coset reduction is associated with a rational super-[Formula: see text] algebra encoding a nonlinear super-[Formula: see text]-algebra structure. In the N = 2 case two conjugate sets of super-Lax operators, equations of motion and infinite Hamiltonians in involution are derived. Modified hierarchies are obtained from the original ones via free-field mappings [just as an m-NLS equation arises from representing the [Formula: see text] algebra through the classical Wakimoto free fields].
A QUANTUM ANALOG OF THE BOSON–FERMION CORRESPONDENCE
Authors: BOUGOURZI A. HAMID , VINET LUC
Published: November 2004

We review the classical boson-fermion correspondence in the context of the [Formula: see text] current algebra at level 2. This particular algebra is ideal for exhibiting this correspondence because it can be realized either in terms of three real bosonic fields or in terms of one real and one complex fermionic field. We also derive a fermionic realization of the quantum current algebra [Formula: see text] at level 2 and by comparing this realization with the existing bosonic one we extend the classical correspondence to the quantum case.
INDUCED CONNECTIONS IN FIELD THEORY: THE ODD-DIMENSIONAL YANG–MILLS CASE
Authors: GIULINI DOMENICO
Published: November 2004

We consider SU(N) Yang–Mills theories in (2n + 1)-dimensional Euclidean space–time, where N ≥ n+1, coupled to an even flavor number of Dirac fermions. After integration over the fermionic degrees of freedom, the wave functional for the gauge field inherits a nontrivial U(1) connection which we compute in the limit of infinite fermion mass. Its Chern class turns out to be just half the flavor number, so that the wave functional now becomes a section in a nontrivial complex line bundle. The topological origin of this phenomenon is explained in both the Lagrangian and the Hamiltonian picture.
LOCAL GAUGE FIELDS BASED ON A YANG–MILLS THEORY IN LOOP SPACE
Authors: DEGUCHI SHINICHI , NAKAJIMA TADAHITO
Published: November 2004

We construct a Yang–Mills theory in loop space (the space of all loops in Minkowski space) with the Kac–Moody gauge group in such a way that the theory possesses reparametrization invariance. On the basis of the Yang–Mills theory, we derive the usual Yang–Mills theory and a non-Abelian Stueckelberg formalism extended to local antisymmetric and symmetric tensor fields of the second rank. The local Yang–Mills field and the second-rank tensor fields are regarded as components of a Yang–Mills field on the loop space.
THE HOMFLY POLYNOMIAL FOR TORUS LINKS FROM CHERN–SIMONS GAUGE THEORY
Authors: LABASTIDA J. M. F. , MARIÑO M.
Published: November 2004

Polynomial invariants corresponding to the fundamental representation of the gauge group SU(N) are computed for arbitrary torus knots and links in the framework of Chern–Simons gauge theory making use of knot operators. As a result, a formula for the HOMFLY polynomial for arbitrary torus links is presented.
ON p – q DUALITY AND EXPLICIT SOLUTIONS IN c ≤ 1 2D GRAVITY MODELS
Authors: KHARCHEV S. , MARSHAKOV A.
Published: November 2004

We study the role of integral representations in the description of nonperturbative solutions to c ≤ 1 string theory. A generic solution is determined by two functions, W(x) and Q(x), which behave at infinity like xp and xq respectively. The integral formula for arbitrary (p, q) models is derived, which explicitly realizes a duality transformation between (p, q) and (q, p) 2D gravity solutions. We also discuss the exact solutions to the string equation and reduction condition and present several explicit examples.
A CLASS OF (0,0) NON-SUPERSYMMETRIC HETEROTIC STRING COMPACTIFICATIONS FROM N=2 MINIMAL SUPERCONFORMAL THEORIES WITH c=9
Authors: HATZINIKITAS AGAPITOS
Published: November 2004

Models which do not preserve N=1 space-time SUSY are constructed in the framework of tensoring of N=2 minimal superconformal theories quotiented by discrete symmetries. We concentrate on those models based on the standard [Formula: see text] affine invariants, and as quotient groups we use the Zk+2 symmetry groups of the minimal theories at level k. In our analysis we investigate the way in which the usual generalized GSO projection must be modified in order to incorporate discrete torsions responsible for the N=1 space-time breaking. We also determine the number of massless 27’s and [Formula: see text] of E6, and the number of chiral superfields transforming as singlets under E6. A discussion on the massless spectrum of a specific model reveals some interesting phenomenological implications.
CURRENT ALGEBRA APPROACH TO HEAVY TOP EFFECTS IN δρ
Authors: DEGRASSI GIUSEPPE , FANCHIOTTI SERGIO , GAMBINO PAOLO
Published: November 2004

The [Formula: see text] correction to the ρ parameter is computed using the current algebra formulation of radiative corrections. This approach is proved to be equivalent to the effective Lagrangian method proposed by Barbieri et al. The same framework is then applied to the calculation of the [Formula: see text] correction to the ratio of neutral-to-charged-current amplitudes in an SU(2) model. In this model the [Formula: see text] contribution is shown to be numerically comparable to the leading [Formula: see text] term for realistic values of the top mass.
ROLE OF PCAC AND THE CHIRAL ANOMALY IN THE RARE DECAY Z0→π0γ
Authors: CHATTERJEE DEBASHIS , GHOSH SUBIR , RAYCHAUDHURI SREERUP
Published: November 2004

Apart from the textbook case of π0→γγ, nonobservation of the rare decay Z0→π0γ is perhaps the only other experimental evidence for a chiral anomaly in the standard electroweak model and is of particular interest since it involves the weak interaction. We critically review earlier predictions for this decay and provide complete formulae for the decay width in both the direct and the current-algebraic formalism. Also, effects obtained by varying the mass of the loop fermion are illustrated.
BRST QUANTIZATION AND THE PRODUCT FORMULA FOR THE RAY-SINGER TORSION
Authors: NASH CHARLES , O’CONNOR DENJOE
Published: November 2004

We give a quantum field theoretic derivation of the formula obeyed by the Ray-Singer torsion on product manifolds. Such a derivation has proved elusive up to now. We use a BRST formalism which introduces the idea of an infinite dimensional Universal Gauge Fermion, and is of independent interest, being applicable to situations other than the ones considered here. We are led to a new class of Fermionic topological field theories. Our methods are also applicable to combinatorially defined manifolds and methods of discrete approximation, such as the use of a simplicial lattice or finite elements. The topological field theories discussed provide a natural link between the combinatorial and analytic torsion.
GAUGE DEPENDENCE OF AN EFFECTIVE POTENTIAL AND A VANISHING  IN HOT QCD
Authors: SAWAYANAGI HIROHUMI
Published: November 2004

We calculate correctly the leading and next-to-leading terms of an effective potential in hot QCD. It is shown that, although the potential is gauge-variant, the position of its minimum, which becomes =0, is gauge-invariant. We also comment on the expectation value of the Polyakov loop.
ALGEBRAIC ASPECTS OF THE BETHE ANSATZ
Authors: FADDEEV L.D.
Published: November 2004

In this article an introduction to the algebraic aspects of the Bethe ansatz is given. The applications to the seminal spin 1/2 XXX model are discussed in detail and the generalization to higher spin as well as XXZ and the lattice sine-Gordon model are indicated. The origin of quantum groups and their appearance in CFT models are explained. The text can be considered as a guide to the research papers in this field.
SPLIT INVOLUTION COUPLED TO ACTUAL GAUGE SYMMETRY
Authors: BATALIN I.A. , TYUTIN I.V. , LYAKHOVICH S.L.
Published: November 2004

The split involution quantization scheme, proposed previously for pure second class constraints only, is extended to cover the case of the presence of irreducible first class constraints. The explicit Sp (2) symmetry property of the formalism is retained. The constraint-algebra-generating equations are formulated and the unitarizing Hamiltonian is constructed. Physical operators and states are defined in the sense of the new equivalence criterion which is a natural counterpart of Dirac’s weak equality concept as applied to the first class quantities.
V AND A STRUCTURES OF THE $t\bar{t}Z$ VERTEX AND TOP QUARK POLARIZATION
Authors: TERAZAWA OSAMU
Published: November 2004

We calculate the energy distributions of decay products in semileptonic decay of t quarks, by taking into account the polarizations and spin-spin correlations of the t quarks. The distributions will provide useful information about the V and A structures of t quarks.
EQUATION OF STELLAR STRUCTURE IN HAYASHI’S NEW GENERAL RELATIVITY
Authors: ZHANG C.M. , ZHAO P.D.
Published: November 2004

The general form of the parallelism tetrad field in the Schwarzschild coordinate system is presented in the framework of Hayashi’s gravitation theory with torsion. In the case of the symmetric energy-momentum tensor, we obtain the approximated equation of stellar structure, which, as a limit, is the Oppenheimer-Volkoff equation for hydrostatic equilibrium in general relativity.
SEMICLASSICAL GRAVITY WITH A NONMINIMALLY COUPLED SCALAR FIELD
Authors: SANYAL ABHIK KUMAR
Published: November 2004

Semiclassical approximation to the Wheeler-DeWitt equation which corresponds to gravity with a nonminimally coupled scalar field is carried out. To the leading order, the vacuum Einstein equation, along with the functional Schrödinger equation for the matter field propagating in the background of classical curved space, is obtained. The Schrödinger equation is solved for a quartic potential. It is observed that the wave functional admits the wormhole boundary condition even for large negative values of the coupling constant ∊. For conformal coupling, ∊=1/6, the Hawking-Page wormhole solution is recovered.
THE CHIRAL U(1) SYMMETRY IN LATTICE QCD WITH WILSON FERMIONS
Authors: UNGARELLI CARLO
Published: November 2004

The properties of singlet flavor chiral symmetry of lattice QCD with Wilson fermions are analyzed. We show that a suitable U(1) axial current can be defined, satisfying, in the continuum limit, the Adler-Bell-Jackiw anomaly. Moreover, the renormalization properties of composite operators which appear in U(1) chiral Ward identities are discussed. Finally, starting from the renormalized Ward identities for the axial U(1) current, we analyze a definition of topological susceptibility suitable for nonperturbative studies and discuss preliminary numerical results.
FROM RELATIVISTIC VECTOR MESONS IN CONSTANT MAGNETIC FIELDS TO NONRELATIVISTIC (PSEUDO)SUPERSYMMETRIES
Authors: BECKERS J. , DEBERGH N.
Published: November 2004

Results coming from the study of relativistic vector mesons interacting with a constant magnetic field are examined through Johnson-Lippmann implications on one-dimensional oscillatorlike systems. We obtain specific nonrelativistic Hamiltonians showing new properties in quantum mechanics and leading to superpositions of bosons and pseudofermions. Moreover, two “potentials” are introduced and discussed in comparison with recent developments usually obtained in p=2 parasupersymmetric quantum mechanics. Pseudofermions are also examined, particularly with respect to orthofermions.
HIGH pT JET PRODUCTION IN pp COLLISIONS
Authors: ESKOLA K.J. , WANG X.-N.
Published: November 2004

Production rates of large pT jets inpp collisions at RHIC and LHC energies are studied using the next-to-leading order calculation of S.D. Ellis, Z. Kunszt and D. Soper. The computed inclusive one-jet cross sections are compared against the CERN and Fermilab jet data from [Formula: see text] and pp collisions. The dependence of the results on the choice of parton distributions and renormalization/factorization scales is investigated.
GEOMETRICAL CONSTRUCTION OF THE HIROTA BILINEAR FORM OF THE MODIFIED KORTEWEG-DE VRIES EQUATION ON A THIN ELASTIC ROD: BOSONIC CLASSICAL THEORY
Authors: MATSUTANI SHIGEKI
Published: November 2004

Recently there have been several studies of a nonrelativistic elastic rod in R2 whose dynamics is governed by the modified Korteweg-de Vries (MKdV) equation. Goldstein and Petrich found the MKdV hierarchy through its dynamics [Phys. Rev. Lett. 69, 555 (1992).] In this article, we will show the physical meaning of the Hirota bilinear form along the lines of the elastica problem after we formally complexify its arc length.
TESTING THE VECTOR BOSON DOMINANCE OF ELECTROWEAK INTERACTIONS VIA $e^ + e^ - \to \bar ff$
Authors: KABACHENKO V.V. , PIROGOV YU. F.
Published: November 2004

Restrictions on the universal four-fermion contact interactions are investigated in the framework of the vector boson dominance (VBD) of electroweak interactions for composite leptons, quarks and Higgs bosons. Manifestations of the VBD via these interactions at the 2 TeV e+e− linear collider are studied. Definite signatures of the VBD are exposed. It is shown that the VBD could be tested at the collider for the unified substructure scale up to O(50 TeV), which lies well in the naturally preferred deca-TeV region.
PION LOOP CONTRIBUTION TO THE ELECTROMAGNETIC PION CHARGE RADIUS
Authors: ALKOFER REINHARD , BENDER AXEL , ROBERTS CRAIG D.
Published: November 2004

A phenomenological Dyson-Schwinger equation approach to QCD, formalized in terms of a QCD-based model field theory, is used to calculate the electromagnetic charge radius of the pion. The contributions from the core of dressed quarks and the pion loop are identified and compared. It is shown explicitly that the divergence of the charge radius in the chiral limit is due to the pion loop but that at mπ=0.14 GeV this loop contributes less than 15% to [Formula: see text], i.e. the dressed quark core is the dominant determining characteristic for the pion.
RATIONAL HOPF ALGEBRAS: POLYNOMIAL EQUATIONS, GAUGE FIXING, AND LOW-DIMENSIONAL EXAMPLES
Authors: FUCHS JÜRGEN , GANCHEV ALEXANDER , VECSERNYÉS PETER
Published: November 2004

Rational Hopf algebras, i.e. certain quasitriangular weak quasi-Hopf algebras whose representations form a tortile modular C* category, are expected to describe the quantum symmetry of rational field theories. In this paper the essential structure (hidden by a large gauge freedom) of rational Hopf algebras is revealed. This allows one to construct examples of rational Hopf algebras starting only from the corresponding fusion ring. In particular we classify all solutions for fusion rules with not more than three sectors, as well as for the level 3 affine [Formula: see text] fusion rules.