bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Similarity of YbeD Protein from
Escherichia coli
to Allosteric Regulatory Domains
Authors: Kozlov Guennadi , Elias Demetra , Semesi Anthony , Yee Adelinda , Cygler Miroslaw , Gehring Kalle
Published: November 2004

Lipoic acid is an essential prosthetic group in several metabolic pathways. The biosynthetic pathway of protein lipoylation in
Escherichia coli
involves gene products of the
lip
operon. YbeD is a conserved bacterial protein located in the
dacA
-
lipB
intergenic region. Here, we report the nuclear magnetic resonance structure of YbeD from
E. coli
. The structure includes a βαββαβ fold with two α-helices on one side of a four-strand antiparallel β-sheet. The β2-β3 loop shows the highest sequence conservation and is likely functionally important. The β-sheet surface contains a patch of conserved hydrophobic residues, suggesting a role in protein-protein interactions. YbeD shows striking structural homology to the regulatory domain from
d
-3-phosphoglycerate dehydrogenase, hinting at a role in the allosteric regulation of lipoic acid biosynthesis or the glycine cleavage system.
RULE EXTRACTION WITH FUZZY NEURAL NETWORK
Authors: D’ALCHÉ-BUC FLORENCE , ANDRÈS VINCENT , NADAL JEAN-PIERRE
Published: November 2004

This paper deals with the learning of understandable decision rules with connectionist systems. Our approach consists of extracting fuzzy control rules with a new fuzzy neural network. Whereas many other works on this area propose to use combinations of nonlinear neurons to approximate fuzzy operations, we use a fuzzy neuron that computes max-min operations. Thus, this neuron can be interpreted as a possibility estimator, just as sigma-pi neurons can support a probabilistic interpretation. Within this context, possibilistic inferences can be drawn through the multi-layered network, using a distributed representation of the information. A new learning procedure has been developed in order that each part of the network can be learnt sequentially, while other parts are frozen. Each step of the procedure is based on the same kind of learning scheme: the backpropagation of a well-chosen cost function with appropriate derivatives of max-min function. An appealing result of the learning phase is the ability of the network to automatically reduce the number of the condition-parts of the rules, if needed. The network has been successfully tested on the learning of a control rule base for an inverted pendulum.
A CONSTRUCTIVE ALGORITHM THAT CONVERGES FOR REAL-VALUED INPUT PATTERNS
Authors: BURGESS NEIL
Published: November 2004

A constructive algorithm is presented which combines the architecture of Cascade Correlation and the training of perceptron-like hidden units with the specific error-correcting roles of Upstart. Convergence to zero errors is proved for any consistent classification of real-valued pattern vectors. Addition of one extra element to each pattern allows hyper-spherical decision regions and enables convergence on real-valued inputs for existing constructive algorithms. Simulations demonstrate robust convergence and economical construction of hidden units in the benchmark “N-bit parity” and “twin spirals” problems.
ACCELERATED LEARNING BY ACTIVE EXAMPLE SELECTION
Authors: ZHANG BYOUNG-TAK
Published: November 2004

Much previous work on training multilayer neural networks has attempted to speed up the backpropagation algorithm using more sophisticated weight modification rules, whereby all the given training examples are used in a random or predetermined sequence. In this paper we investigate an alternative approach in which the learning proceeds on an increasing number of selected training examples, starting with a small training set. We derive a measure of criticality of examples and present an incremental learning algorithm that uses this measure to select a critical subset of given examples for solving the particular task. Our experimental results suggest that the method can significantly improve training speed and generalization performance in many real applications of neural networks. This method can be used in conjunction with other variations of gradient descent algorithms.
MAP FORMATION IN PROPRIOCEPTIVE CORTEX
Authors: CHO SUNGZOON , REGGIA JAMES A.
Published: November 2004

Current understanding of feature maps in proprioceptive cortex is quite limited. To complement experimental studies, we developed a computational model of map formation in proprioceptive cortex. Muscle length and tension from six muscle groups controlling the position of a model arm in three-dimensional space served as input to the simulated cortex. The resultant feature map consisted of regularly spaced clusters of cortical columns representing individual muscle lengths and tensions. Cortical units became tuned to plausible combinations of tension and length, and multiple representations of each muscle group were present. The map was organized such that compact regions within which all muscle group lengths and tensions are represented could be identified. Most striking was the observation that, although not explicitly present in the input, the cortical map developed a representation of the three-dimensional space in which the arm moved. These findings represent testable predictions about proprioceptive cortex, and may also help clarify some organizational issues concerning primary motor cortex.
AVERAGE CASE ANALYSIS OF AN HEBB-TYPE RULE THAT FINDS THE NETWORK CONNECTIVITY
Authors: GOLEA MOSTEFA
Published: November 2004

We describe an Hebb-type algorithm for learning unions of nonoverlapping perceptrons with binary weights. Two perceptrons are said to be nonoverlapping if they do not share any input variables. The learning algorithm is able to find both the network architecture and the weight values necessary to represent the target function. Moreover, the algorithm is local, homogeneous, and simple enough to be biologically plausible. We investigate the average behavior of this algorithm as a function of the size of the training set. We find that, as the size of the training set increases, the hypothesis network built by the algorithm “converges” to the target network, both in terms of the number of perceptrons and the connectivity. Moreover, the generalization rate converges exponentially to perfect generalization as a function of the number of training examples. The analytic expressions are in excellent agreement with the numerical simulations. To our knowledge, this is the first average case analysis of an algorithm that finds both the weight values and the network connectivity.
NEUTRINO OSCILLATIONS AND THE EXACT PARITY MODEL
Authors: FOOT R.
Published: November 2004

We re-examine neutrino oscillations in exact parity models. Previously it was shown in a specific model that large neutrino mixing angles result. We show here that this is a general result of neutrino mixing in exact parity models provided that the neutrino mass matrix is real. In this case, the effects of neutrino mixing in exact parity models is such that the probability of a given weak eigenstate remaining in that eigenstate averages to less than half when averaged over many oscillations. This result is interesting in view of the accumulating evidence for a significant deficit in the number of solar neutrinos. It may also be of relevance to the atmospheric neutrino anomaly.
FLAVOR GAUGE THEORY, AND MASSES OF TOP AND NEUTRINO
Authors: CVETIČ G. , KIM C.S.
Published: November 2004

We assume that the standard model (SM) breaks down around some energy Λ, and is replaced by a new (Higgsless) flavor gauge theory (FGT). We investigate this possibility by studying the renormalization group equations for the Yukawa couplings of SM with two Higgs doublets for various mt and υU/υD. With appropriate flavor democratic boundary conditions at Λ FGT , we derive the bounds on masses of top and tau-neutrino, which are compatible with experimental bounds.
b→sγ AND εb CONSTRAINTS ON TWO-HIGGS DOUBLET MODEL
Authors: PARK GYE T.
Published: November 2004

We perform a combined analysis of two stringent constraints on the two-Higgs doublet model, one coming from the recently announced CLEO II bound on B (b→sγ) and the other from the recent LEP data on εb. We have included one-loop vertex corrections to [Formula: see text] through εb in the model. We find that the new εb constraint excludes most of the less appealing window tan β≲1 at 90% C.L. for mt=150 GeV. We also find that although b→sγ constraint is stronger for tan β>1, εb constraint is stronger for tan β≲1, and therefore these two are the strongest and complimentary constraints present in the charged Higgs sector of the model.
WILSON LOOP ON A SPHERE
Authors: BOULATOV D.V.
Published: November 2004

We give the formula for a simple Wilson loop on a sphere which is valid for an arbitrary QCD2 saddle point [Formula: see text]. The strong coupling phase solution is investigated.
REMARKS ON ENTROPY-AREA PROPORTIONALITY FOR A REDUCED SYSTEM
Authors: WOO C.H.
Published: November 2004

A plausible physical reason is given for the entropy-area proportionality that was discussed recently by Srednicki. Such a proportionality is not a general feature when the degrees of freedom within a certain volume are traced out of a pure state.
LANDAU LEVELS AND QUANTUM GROUP
Authors: SATO HARU-TADA
Published: November 2004

We find a quantum group structure in two-dimensional motions of a nonrelativistic electron in a uniform magnetic field and in a periodic potential. The representation basis of the quantum algebra is composed of wave functions of the system. The quantum group symmetry commutes with the Hamiltonian and is relevant to the Landau level degeneracy. The deformation parameter q of the quantum algebra turns out to be given by the fractional filling factor v=1/m (m odd integer).
RECENT RESULTS ON SEMIMUONIC DECAYS OF CHARM MESONS FROM FERMILAB EXPERIMENT E653
Authors: GIBAUT D. B. , POTTER D. M.
Published: November 2004

Fermilab experiment E653 has recently reported several results on the semimuonic decays of charm mesons. In this paper we review these results, which include the measurement of form factor ratios in [Formula: see text], the first measurement of form factor ratios in [Formula: see text], the first observations of [Formula: see text], and of the Cabibbo disfavored channel D+ → ρ0μ+ν, and an upper limit for rare D0 decays.
ON FERMION ZERO MODES IN INSTANTON V - A MODELS WITH SPONTANEOUS SYMMETRY BREAKING
Authors: SARIRIAN KAMRAN
Published: November 2004

The left- and right-handed fermion zero modes are examined. Their behavior under the variation of the size of the instanton, ρ I , and the size of the Higgs core, ρ H , for a range of Yukawa couplings corresponding to the fermion masses in the electroweak theory are studied. It is shown that the characteristic radii of the zero modes, in particular those of the left-handed fermions, are locked to the instanton size, and are not affected by the variation of ρ H , except for fermion masses much larger than those in the standard electroweak theory.
NOTE ON N = 0 STRING AS N = 1 STRING
Authors: ISHIKAWA HIROSHI , KATO MITSUHIRO
Published: November 2004

A similarity transformation, which brings a particular class of N = 1 strings to those with N = 0, is explicitly constructed. It enables us to give a simple proof for the argument recently proposed by Berkovits and Vafa. The N = 1 BRST operator is turned into the direct sum of the corresponding N = 0 BRST operator and that for an additional topological sector. As a result, the physical spectrum of these N = 1 vacua is shown to be isomorphic to the tensor product of the N = 0 spectrum and the topological sector which consists of only the vacuum. This transformation manifestly keeps the operator algebra.
ON DUBROVIN TOPOLOGICAL FIELD THEORIES
Authors: ZUBER J.-B.
Published: November 2004

I show that the new topological field theories recently associated by Dubrovin with each Coxeter group may all be obtained in a simple way by a "restriction" of the standard ADE solutions. I then study the Chebyshev specializations of these topological algebras, examine how the Coxeter graphs and matrices reappear in the dual algebra and mention the intriguing connection with the operator product algebra of conformal field theories. A direct understanding of the occurrence of Coxeter groups in that context is highly desirable.
POSSIBLE DYNAMICAL ORIGINS OF INTERMITTENCY IN HIGH ENERGY COLLISIONS
Authors: HWA RUDOLPH C.
Published: November 2004

This is a brief review of the dynamical origins of intermittency. For elementary processes involving leptons and hadrons, we discuss toy models, perturbative QCD, Monte-Carlo and other models. For complex processes involving nuclear collisions we review theoretical ideas on hadronic fluctuations as consequences of phase transition.
NON-LEPTONIC WEAK TRANSITIONS WITH ΔI = 1/2 RULE IN DIQUARK-QUARK MODEL USING THE PAULI-GÜRSEY SYMMETRY
Authors: SUZUKI K. , TOKI H.
Published: November 2004

We study the non-leptonic weak transitions of ground state baryons in diquark-quark model. These weak transitions exhibit the ΔI = 1/2 rule, which is hard to account for in the standard weak process. If the diquark correlations are strong among flavor-antitriplet and spin-singlet pairs, we can make the weak transitions among diquarks followed by pion emission much stronger than the standard process. We estimate all the non-leptonic weak transitions of ground state baryons by assuming the Pauli-Gürsey symmetry together with the SU(6) wave functions. We can account for all the P-wave transition strengths quantitatively and hence the ΔI = 1/2 rule.
QCD CORRECTIONS TO TWO-PHOTON DECAY OF THE HIGGS BOSON AND ITS REVERSE PROCESS
Authors: INOUE M. , NAJIMA R. , OKA T. , SAITO J.
Published: November 2004

Two-photon decay of the Higgs boson H→γγ and its reverse process γγ→H are important processes in detecting Higgs boson which plays a fundamental role in the Standard Model of electroweak interaction. We calculate the QCD corrections to these processes for all mass ranges of the Higgs boson without any constraint for the top quark mass. For a heavy Higgs boson (mH≫mt), the QCD corrections become very large (50–100%), while for a lighter one (mH≤mt), the corrections are negligible.
THE FOUR-POINT FUNCTION ON A SURFACE OF INFINITE GENUS
Authors: DAVIS SIMON
Published: November 2004

The four-point function arising in the scattering of closed bosonic strings in their tachyonic ground state is evaluated on a surface of infinite genus. The amplitude has poles corresponding to physical intermediate states and divergences at the boundary of moduli space, but no new types of divergences result from the infinite number of handles. The implications for the universal moduli space approach to string theory are briefly discussed.
A MODEL OF THE DEUTERON BASED ON A BREIT TYPE EQUATION
Authors: FERREIRA P. LEAL , ALCARÁS J.A. CASTILHO , GALEĀO A.P.
Published: November 2004

A relativistic treatment of the deuteron and its observables based on a two-body Dirac (Breit) equation, with phenomenological interactions, associated to one-boson exchanges with cutoff masses, is presented. The 16-component wave function for the deuteron (Jπ=1+) solution contains four independent radial functions which obey a system of four coupled differential equations of first order. This radial system is numerically integrated, from infinity to the origin, by fixing the value of the deuteron binding energy and using appropriate boundary conditions at infinity. Specific examples of mixtures containing scalar, pseudoscalar and vector like terms are discussed in some detail and several observables of the deuteron are calculated. Our treatment differs from more conventional ones in that nonrelativistic reductions of the order c−2 are not used.
NON-EINSTEINIAN GRAVITY IN d=2: SYMMETRY AND CURRENT ALGEBRA
Authors: KUMMER W. , WIDERIN P.
Published: November 2004

For a geometric theory with dynamical torsion an absolutely conserved quantity can be related to a Noether current for a peculiar field dependent off-shell (global) symmetry. Moreover the nonlinear deformed iso(2,1) symmetry in phase space discovered previously, for which that conserved quantity is one element of the center, can be reinterpreted as a current algebra.
QUANTUM POTENTIAL INTERPRETATION OF THE WHEELER-DeWITT EQUATION
Authors: HORIGUCHI TSUTOMU
Published: November 2004

We apply Bohm’s quantum potential interpretation to quantum cosmology. We study closed, flat and open minisuperspace models by introducing “extended” Robertson-Walker time which exists not only in classically allowed region but also in classically forbidden region. It is shown that how the classical universe emerges from the quantum area. We also discuss briefly quantum potential interpretation of quantum geometrodynamics based on the Arnowitt-Deser-Misner canonical formalism.
SQUEEZE-OUT OF PION EMISSION IN RELATIVISTIC HEAVY-ION COLLISIONS
Authors: JAIN P.L. , SINGH G.
Published: November 2004

The azimuthal angle distributions of charged pions with respect to the reaction plane determined by projectile heavy fragments is presented for 32S at 200A GeV. The squeezeout of pions perpendicular to the reaction plane for 28Si at 14.5A GeV and 197Au at 10.6A GeV is observed as a function of impact parameter (b) and the target mass.
EXAMPLE OF FRACTAL DIFFERENCE EQUATIONS
Authors: MIYAKE MEGUMU
Published: November 2004

Fractal is undifferentiable almost everywhere. When considered only from the condition to be undifferentiable, there is a possibility that a wider horizon of fractal may be opened. Therefore, let us consider a certain equation and the condition to be undifferentiable almost everywhere. The difference equation under the conditions will be an example of fractal equations.
ARE p-BRANES ASYMPTOTICALLY BLACK HOLES?
Authors: BYTSENKO ANDREI , KIRSTEN KLAUS , ZERBINI SERGIO
Published: November 2004

An attempt is made to compare the asymptotic state density of twisted p-branes and the related state density of mass level M of a D-dimensional neutral black holes. To this aim, the explicit form of the twisted p-brane total level degeneracy is calculated. The prefactor of the degeneracy, in contrast to the leading behavior, is found to depend on the winding number of the p-brane.
PROBING THE FROISSART BOUND FOR MODELS WITH CHARGED VECTOR FIELDS IN D=3
Authors: DEL CIMA O.M.
Published: November 2004

One discusses the tree-level unitarity and presents asymptotic behavior of scattering amplitudes for three-dimensional gauge-invariant models where complex Chern- Simons-Maxwell fields (with and without a Proca-like mass) are coupled to an Abelian gauge field.
QUANTUM GROUP SYMMETRY AND QUANTUM HALL WAVE FUNCTIONS ON A TORUS
Authors: SATO HARU-TADA
Published: November 2004

We generalize the quantum group structure of two-dimensional nonrelativistic electron in a uniform magnetic field into the case of a many-particle system on a torus. We verify the conjecture that the deformation parameter of the quantum algebra is given by the filling factor ν=1/p (p odd) on the basis of the Haldane-Rezayi’s wave functions.
NEUTRINO MASSES AND MIXINGS IN FLIPPED SU(5)
Authors: TANIMOTO MORIMITSU
Published: November 2004

We study the neutrino masses and mixings in the flipped SU(5) model assuming the Dimopoulos-Hall-Raby type mass matrices. The neutrino masses are evolved down to low energies by using the renormalization group equation of the effective seesaw mass operator. The ντ mass and the νµ−ντ mixing are predicted by using the solar neutrino data. The predicted mass is consistent with the condition of the hot dark matter expected from COBE results. Our results are also compared with the ones in SO(10). Although the large νµ−ντ mixing could be obtained in our model, the ντ mass is too small to be consistent with the atmospheric muon neutrino deficit from KAMIOKA and IMB.
OFF-SHELL BETHE ANSATZ EQUATION FOR GAUDIN MAGNETS AND SOLUTIONS OF KNIZHNIK-ZAMOLODCHIKOV EQUATIONS
Authors: BABUJIAN H.M. , FLUME R.
Published: November 2004

We generalize the previously established connection between the off-shell Bethe ansatz equation for inhomogeneous SU(2) lattice vertex models in the quasiclassical limit and the solutions of the SU(2) Knizhnik-Zamolodchikov equations to the case of simple Lie algebras of higher rank.
GELFAND-DIKII BRACKETS FOR NONSTANDARD LAX EQUATIONS
Authors: BRUNELLI J.C. , DAS ASHOK , HUANG WEN-JUI
Published: November 2004

We generalize the construction of Gelfand-Dikii brackets to the case of nonstandard Lax equations. We also discuss the possible origin of Kac-Moody algebras present in such systems.
AN EXHAUSTIVE LIST OF COMPLETE INTERSECTION CALABI-YAU MANIFOLDS
Authors: GAGNON M. , HO-KIM Q.
Published: November 2004

We have obtained a new list of Calabi-Yau manifolds realized as complete intersections of polynomials in Cartesian products of complex projective spaces. It contains 97,360 configurations with Euler numbers ranging from 0 to −200. A remarkable structure emerges from this compilation.
A SIMPLE METHOD FOR COMPUTING SOLITON STATISTICS
Authors: SPECTOR DONALD
Published: November 2004

I propose a simple method for identifying the statistics of kink-type solitons in a large class of theories. The method is based on the Witten index, but can in fact be used to determine soliton statistics in non-supersymmetric theories as well.
SCHIZOSYMMETRY: A NEW PARADIGM FOR SUPERFIELD EXPANSIONS
Authors: DELBOURGO R. , JARVIS P.D. , WARNER ROLAND C.
Published: November 2004

A new principle of ‘schizosymmetry’ is proposed for interpreting superfield expansions over Grassmann parameters in quantum field theory. Symmetry generators T phys , determining component field transformation properties, are allowed to depend on the grading via T phys =Tℙ e +T′ℙ o , where ℙ e and ℙ o are the projections onto even and odd components in the Grassmann coordinates, respectively, and T and T′ correspond to different representations. Examples are given for both internal and space-time schizosymmetry. In the latter case, superfield expansions have components with both integer and half-integer spin. A program for the Lagrangian realization of schizosymmetry, including unified model building, is outlined.
DIRAC OPERATORS ON QUANTUM-TWO SPHERES
Authors: OHTA KAZUTOSHI , SUZUKI HISAO
Published: November 2004

We investigate the spin-1/2 fermions on quantum-two spheres. It is shown that the wave functions of fermions and a Dirac operator on quantum-two spheres can be constructed in a manifestly covariant way under the quantum group SU (2)q. The concept of total angular momentum and chirality can be expressed by using q-analog of Pauli-matrices and appropriate commutation relations.
“CHARGE-DYON” SYSTEM AS THE REDUCED OSCILLATOR
Authors: NERSESSIAN A. , TER-ANTONIAN V.
Published: November 2004

It is shown that in general the Kustaanheimo-Stiefel transformation (reduction of 4-D oscillator on the twistor space by the Hamiltonian action of U(1) with further timereparametrization) leads to the integrable system, describing the motion of a spinless electrically charged particle in the dyon field.
TOWARDS A CLASSIFICATION OF FINITE FIELD THEORIES
Authors: GRANDITS PETER
Published: November 2004

We consider the finiteness conditions on the Yukawa couplings of a general quantum field theory for gauge groups SU (n)(n>6) and a rather general particle content. It is shown that in the class of theories considered (149 different particle contents), only two models are able to fulfill the finiteness conditions. Only one of these is supersymmetric. For the nonsupersymmetric one the appropriate Yukawa couplings are constructed explicitly.
FIRST EVIDENCE FOR ELECTROWEAK RADIATIVE CORRECTIONS FROM THE NEW PRECISION DATA
Authors: NOVIKOV V.A. , OKUN L.B. , ROZANOV A.N. , VYSOTSKY M.I.
Published: November 2004

The analysis of the newest data on the leptonic Z-decays and mW appears to reveal the first manifestations of electroweak radiative corrections. In fact, these data differ, at the level of 2σ, from their electroweak Born values, while they agree, to within 1σ, with the theoretical values which take the electroweak radiative corrections into account. Previous data were within 1σ in agreement with both sets of values.
REALIZATION OF FRT ALGEBRA RELATED TO A COLORED BRAID GROUP REPRESENTATION
Authors: BASU-MALLICK B.
Published: November 2004

A colored braid group representation (CBGR) is constructed by using some modified universal ℛ-matrix associated with U q( gl (2)) quantized algebra. Explicit realization of Faddeev–Reshetikhin–Takhtajan (FRT) algebra, involving color parameter dependent upper and lower triangular matrices, is built up for this CBGR and subsequently applied to generate nonadditive type solutions of quantum Yang–Baxter equation. Rational limit of such solutions interestingly yields 'colored' extension of known Lax operators associated with lattice nonlinear Schrödinger model and Toda chain.
THE CONSERVED CHARGES AND INTEGRABILITY OF THE CONFORMAL AFFINE TODA MODELS
Authors: ARATYN H. , FERREIRA L. A. , GOMES J. F. , ZIMERMAN A. H.
Published: November 2004

We construct infinite sets of local conserved charges for the conformal affine Toda model. The technique involves the abelianization of the two-dimensional gauge potentials satisfying the zero-curvature form of the equations of motion. We find two infinite sets of chiral charges and apart from two lowest spin charges, all the remaining ones do not possess chiral densities. Charges of different chiralities Poisson commute among themselves. We discuss the algebraic properties of these charges and use the fundamental Poisson bracket relation to show that the charges conserved in time are in involution. Connections to other Toda models are established by taking particular limits.
ON EXACT INTEGRABILITY OF 2-D POINCARÉ GRAVITY
Authors: SOLODUKHIN SERGEY
Published: November 2004

We consider the 2-D Poincaré gravity and show its exact integrability. The choice of the gauge is discussed. The Euclidean solutions on compact closed differential manifolds are studied.
Uq(N) GAUGE THEORIES
Authors: CASTELLANI LEONARDO
Published: November 2004

Improving on an earlier proposal, we construct the gauge theories of the quantum groups U q(N). We find that these theories are also consistent with an ordinary (commuting) space-time. The bicovariance conditions of the quantum differential calculus are essential in our construction. The gauge potentials and the field strengths are q-commuting "fields," and satisfy q-commutation relations with the gauge parameters. The transformation rules of the potentials generalize the ordinary infinitesimal gauge variations. For particular deformations of U (N) ("minimal deformations"), the algebra of quantum gauge variations is shown to close, provided the gauge parameters satisfy appropriate q-commutations. The q-Lagrangian invariant under the U q(N) variations has the Yang–Mills form [Formula: see text], the "quantum metric" gij being a generalization of the Killing metric.
THE CANONICAL ALGEBRA OF SYMMETRIES FOR GAUGE THEORIES: THE EXAMPLE OF ANYONS
Authors: PONS J. M.
Published: November 2004

Some special features of the algebra of continuous symmetries for constrained systems are illustrated through the example of the nonrelativistic ideal gas of anyons. The relation between constants of motion and symmetry generators for this gauge system is completely worked out. The generators of both its rigid and gauge continuous symmetries are explicitly given in the canonical formalism. Also the interplay between these two types of symmetries within the symmetry algebra is exhibited.
GENERALIZED QCD2 VIA THE BILOCAL METHOD
Authors: PESANDO IGOR
Published: November 2004

We use the bilocal method to derive the large-N solution of the most general QCD 2.
INTERMITTENCY IN THE FIRST- AND SECOND-ORDER PHASE TRANSITION THEORY
Authors: LEBEDEV I. A. , NAZIROV M. T.
Published: November 2004

The study of the multiplicity fluctuations of hadrons in a small bin at high-energy nuclear collisions using an analogy with usual phase transition of first and second orders is suggested. It is shown that the experiment cannot discriminate between them.
LEPTOQUARK PAIR PRODUCTION AT ep COLLIDERS
Authors: BLÜMLEIN JOHANNES , BOOS EDWARD , PUKHOV ALEXANDER
Published: November 2004

The pair production cross-section for scalar and vector leptoquarks at ep colliders is calculated for the case of photon-gluon fusion. In a model independent analysis we consider the most general C and P conserving couplings of gluons and photons to both scalar and vector leptoquarks described by an effective low-energy Lagrangian which obeys U (1) em × SU (3)c invariance. Numerical predictions are given for the kinematical regime at HERA and LEP ⊗ LHC .
LIE SUPERALGEBRA AND EXTENDED TOPOLOGICAL CONFORMAL SYMMETRY IN NON-CRITICAL W3-STRINGS
Authors: ITO KATSUSHI , KANNO HIROAKI
Published: November 2004

We obtain a new free field realization of N = 2 super W3-algebra using the technique of quantum Hamiltonian reduction. The construction is based on a particular choice of the simple root system of the affine Lie superalgebra sl (3|2)(1) associated with a non-standard sl (2) embedding. After twisting and a similarity transformation, this W-algebra can be identified as the extended topological conformal algebra of non-critical W3 string theory.
THE BOSONIC STRUCTURE OF FERMIONS
Authors: RUAN J. , CREWTHER R. J.
Published: November 2004

We bosonize fermions by identifying their occupation numbers as the binary digits of a Bose occupation number. Unlike other schemes, our method allows infinitely many fermionic oscillators to be constructed from just one bosonic oscillator.
HYPER-KÄHLER METRICS BUILDING AND INTEGRABLE MODELS
Authors: SAIDI E.H. , SEDRA M.B.
Published: November 2004

Methods developed for the analysis of integrable systems are used to study the problem of hyper-Kähler metrics building as formulated in D=2, N=4 supersymmetric harmonic superspace. We show in particular that the constraint equation [Formula: see text] and its Toda-like generalizations are integrable. Explicit solutions together with the conserved currents generating the symmetry responsible for the integrability of these equations are given. Other features are also discussed.
CHIRALITY OF KNOTS 942 AND 1071 AND CHERN-SIMONS THEORY
Authors: RAMADEVI P. , GOVINDARAJAN T.R. , KAUL R.K.
Published: November 2004

Up to 10 crossing numbers, there are two knots, 942 and 1071 whose chirality is not detected by any of the known polynomials, namely, Jones invariants and their two variable generalizations, HOMFLY and Kauffman invariants. We show that the generalized knot invariants, obtained through SU(2) Chern-Simons topological field theory, which give the known polynomials as special cases, are indeed sensitive to the chirality of these knots.
GENERALIZED QUON STATISTICS
Authors: MELJANAC STJEPAN , PERICA ANTE
Published: November 2004

Generalized quons interpolating between Bose, Fermi, para-Bose, para-Fermi and anyonic statistics are proposed. They follow from the R-matrix approach to deformed associative algebras. It is proved that generalized quons have the same main properties as quons. A new result for the number operator is presented and some physical features of generalized quons are discussed in the limit [Formula: see text].
CLASSICAL YANG-MILLS-DIRAC SYSTEM WITH CONFORMAL SYMMETRY: A GEOMETRICAL ANALYSIS
Authors: ANTOINE J.-P. , DABROWSKI L. , MAHARA I.
Published: November 2004

We consider classical Yang-Mills-Dirac equations on Minkowski space, with gauge group SU(2), and look for solutions invariant (up to a gauge transformation) under a four-dimensional subgroup of the conformal group. In each of the four different cases that we analyze, the equations admit non-Abelian solutions, but these cannot be obtained analytically. In addition, some cases admit solutions with chiral spinors that may be physically relevant. All these solutions are singular.
A THERMODYNAMICAL BAG MODEL FOR NUCLEON STRUCTURE FUNCTIONS
Authors: DEVANATHAN V. , KARTHIYAYINI S. , GANESAMURTHY K.
Published: November 2004

A thermodynamical bag model is proposed to study the parton distribution functions and nucleon structure functions in the deep inelastic scattering (DIS) of leptons on nucleons. Equations of state for the thermodynamical bag are deduced and solved self-consistently. The theory explains all the observed features in DIS and gives a good fit to the experimental data.
ON THE BETHE ANSATZ FOR A FERMIONIC CHAIN WITH LONG RANGE INTERACTION
Authors: CHOUDHURY A.G. , CHOWDHURY A. ROY
Published: November 2004

Using the methodology of Wadati et al. and de Vega we have constructed a fermionic chain with long range interaction. The Bethe states are explicitly constructed and the energy and momentum eigenvalues of excited states are determined.
A NOTE ON ABELIAN CONVERSION OF CONSTRAINTS
Authors: AMORIM RICARDO , DAS ASHOK
Published: November 2004

We show that for a system containing a set of general second class constraints which are linear in the phase space variables, the Abelian conversion can be obtained in a closed form and that the first class constraints generate a generalized shift symmetry. We study in detail the example of a general first order Lagrangian and show how the shift symmetry noted in the context of BV quantization arises.
GRAVITATIONAL COLLAPSE OF THICK DOMAIN WALLS: AN ANALYTIC MODEL
Authors: WANG ANZHONG
Published: November 2004

An exact solution to the Einstein field equations is found, which represents the gravitational collapse of a thick domain wall. During the collapse, the wall emits gravitational radiation, which can be measured as a gravitational pp wave at the spacelike infinity. The time-reversed solution represents an expanding universe, in which a domain wall resides. It is shown explicitly that such a wall can be inflated away.
SOME APPLICATIONS OF A SIMPLE STATIONARY LINE ELEMENT FOR THE SCHWARZSCHILD GEOMETRY
Authors: KRAUS PER , WILCZEK FRANK
Published: November 2004

Guided by a Hamiltonian treatment of spherically symmetric geometry, we are led to a remarkably simple—stationary, but not static—form for the line element of Schwarzschild (and Reissner-Nordstrom) geometry. The line element continues smoothly through the horizon; by exploiting this feature we are able to give a very simple and physically transparent derivation of the Hawking radiance. We construct the complete Penrose diagram by enforcing time-reversal symmetry. Finally we outline how an improved treatment of the radiance, including effects of self-gravitation, can be obtained.
THE WAVE EQUATIONS FOR THE LANCZOS TENSOR/SPINOR, AND A NEW TENSOR IDENTITY
Authors: BRIAN EDGAR S.
Published: November 2004

The apparent discrepancy between the vacuum wave equations obtained for the Lanczos potential respectively by spinor and tensor methods is explained; it is shown that the additional expression in the tensor version is actually identically zero in four dimensions.
ON A QUANTUM MINIUNIVERSE FILLED WITH YANG-MILLS RADIATION
Authors: CAVAGLIÀ MARCO , DE ALFARO VITTORIO
Published: November 2004

The Wheeler-DeWitt equation for a Robertson-Walker closed universe filled with an SU(2) Yang-Mills spatially uniform field is separable; we are then led to impose on the wave function the usual rules for a quantum bound system: square integrability and orthogonality. We investigate the correspondence principle for large gravitational quantum numbers. The classical probability depends on the gauge chosen for the time, and we examine lapse functions of the form N=N(a) (having in mind cosmic time and conformal time). The correspondence principle holds for these gauges if the differential representation of the momentum is gauge-dependent. This gives a prescription for the ordering of operators in the Wheeler-DeWitt equation. We also discuss the measure in the minisuperspace needed to ensure invariance of matrix elements of gauge-invariant operators.
QUANTUM FUNCTIONAL INTEGRATION OF NON-EINSTEINIAN GRAVITY IN d=2
Authors: HAIDER FLORIAN , KUMMER WOLFGANG
Published: November 2004

Complete integrability of R2 gravity with dynamical torsion in d=2 is also found in the quantum case, provided the light cone gauge is chosen. In our present work the path integral is derived from a covariant canonical and a canonical BRS approach. In the latter case and in that particular gauge all quantum effects — including Faddeev-Popov ghosts — vanish within the most simple topological setting which emphasizes local properties only. In the covariant canonical approach and with respect to a previous all-order perturbative analysis, the results are found to differ only by a counterterm.
CLASSICAL N=1 and N=2 SUPER W ALGEBRAS FROM A ZERO-CURVATURE CONDITION
Authors: GIERES FRANÇOIS , THEISEN STEFAN
Published: November 2004

Starting from superdifferential operators in an N=1 superfield formulation, we present a systematic prescription for the derivation of classical N=1 and N=2 super W algebras by imposing a zero-curvature condition on the connection of the corresponding first-order system. We illustrate the procedure on the first nontrivial example (beyond the N=1 superconformal algebra) and also comment on the relation with the Gelfand-Dickey construction of W algebras.
CALCULATION OF EXCITATION SPECTRA OF THE SPIN MODEL RELATED WITH THE VECTOR REPRESENTATION OF THE QUANTIZED AFFINE ALGEBRA OF TYPE $A_n^{(1)} $
Authors: DATE ETSURO , OKADO MASATO
Published: November 2004

The energy and momentum of the spin model related to the vector representation of the quantized affine algebra of type [Formula: see text] are computed in the framework of Davies et al. Commutation relations among creation and annihilation operators are also derived.
RELATIVISTIC QED IN (2+1)-DIMENSIONAL SPACE: THE INTEGER AND FRACTIONAL QUANTIZED HALL EFFECTS
Authors: ACHARYA R. , SWAMY P. NARAYANA
Published: November 2004

A unified theory of the phenomena of the integer and the fractional quantized Hall effects (FQHE) is presented within the framework of quantum electrodynamics in 2+1 dimensions. It is demonstrated that FQHE emerges naturally from a nonperturbative, weak coupling (ladder approximation) solution of a linearized Dyson–Schwinger equation for massive electrons interacting with massless photons. The Chern–Simons term plays no role in this analysis.
ELECTROMAGNETIC INTERACTION OF ANYONS IN NONRELATIVISTIC QUANTUM FIELD THEORY
Authors: CORTÉS J. L. , GAMBOA J. , VELÁZQUEZ L.
Published: November 2004

The nonrelativistic quantum-field-theoretic Lagrangian which describes an anyon system in the presence of an electromagnetic field is identified. A nonminimal magnetic coupling to the Chern–Simons statistical field as well as to the electromagnetic field together with a direct coupling between both fields are the nontrivial ingredients of the Lagrangian obtained from the nonrelativistic limit of the fermionic relativistic formulation. The results, an electromagnetic gyromagnetic ratio 2 for any spin together with a nontrivial dynamical spin-dependent contact interaction between anyons as well as the spin dependence of the electromagnetic effective action, agree with the quantum-mechanical formulation.
LOOP EQUATION AND AREA LAW IN TURBULENCE
Authors: MIGDAL A. A.
Published: November 2004

This is an extended version of the preprint,4 based on the lectures given at Cargese Summer School and Chernogolovka Summer School in 1993. The incompressible fluid dynamics is reformulated as dynamics of closed loops C in coordinate space. We derive explicit functional equation for the pdf of the circulation PC (Γ) which allows the scaling solutions in the inertial range of spatial scales. The pdf decays as exponential of some power of Γ3/A2, where A is the minimal area inside the loop.
A GEOMETRICAL INTERPRETATION OF RENORMALIZATION GROUP FLOW
Authors: DOLAN BRIAN P.
Published: November 2004

The renormalization group (RG) equation in D-dimensional Euclidean space, RD, is analyzed from a geometrical point of view. A general form of the RG equation is derived which is applicable to composite operators as well as tensor operators (on RD) which may depend on the Euclidean metric. It is argued that physical N-point amplitudes should be interpreted as rank N covariant tensors on the space of couplings, [Formula: see text], and that the RG equation can be viewed as an equation for Lie transport on [Formula: see text] with respect to the vector field generated by the β functions of the theory. In one sense it is nothing more than the definition of a Lie derivative. The source of the anomalous dimensions can be interpreted as being due to the change of the basis vectors on [Formula: see text] under Lie transport. The RG equation acts as a bridge between Euclidean space and coupling constant space in that the effect on amplitudes of a diffeomorphism of RD (that of dilations) is completely equivalent to a diffeomorphism of [Formula: see text] generated by the β functions of the theory. A form of the RG equation for operators is also given. These ideas are developed in detail for the example of massive λφ4 theory in four dimensions.
RENORMALIZATION GROUP ANALYSIS OF YUKAWA PARAMETERS WITH ONE AND TWO HIGGS DOUBLETS, AND FLAVOR GAUGE THEORY
Authors: CVETIČ G. , KIM C. S.
Published: November 2004

We assume that the standard model (SM) breaks down around some energy Λ and is replaced there by a new (Higgsless) flavor gauge theory (FGT) with fewer input parameters in the interactions corresponding to the Yukawa sector of SM. This would imply more symmetry for the values of the Yukawa (running) parameters of SM at E ~ Λ, possibly by a (approximate) flavor democracy (for the quark mass sector). We investigate this possibility by studying the renormalization group equations (RGE's) for the quark Yukawa couplings of SM with one and two Higgs doublets, by running them from the known physical values at low energies (E ~ 1 GeV ) to Λ (> 1 TeV ) and comparing the resulting quark masses mq (E ~ Λ) for various mt and υU/υD. Unlike previous investigations of these RGE's, we do not implement the requirement mt(Λ pole ) = ∞. We found that SM with two Higgs doublets (type 2) is most likely to experience a gradual transition to FGT. Our results also shed more light on the adequacy and deficiencies of the usual RGE approaches within TMSM and related models. We also found that, independent of the assumption of a transition mechanism to FGT, [Formula: see text] for Λ pole ≪ Λ Planck in most cases of SM with two Higgs doublets.
ON HIGHER-SPIN GENERALIZATIONS OF STRING THEORY
Authors: LU H. , POPE C. N. , WANG X. J.
Published: November 2004

We construct BRST operators for certain higher-spin extensions of the Virasoro algebra, in which there is a spin-s gauge field on the world sheet, as well as the spin-2 gauge field corrresponding to the two-dimensional metric. We use these BRST operators to study the physical states of the associated string theories, and show how they are related to certain minimal models.
VERTEX OPERATORS FOR THE BF SYSTEM AND ITS SPIN–STATISTICS THEOREMS
Authors: BALACHANDRAN A. P. , TEOTONIO-SOBRINHO P.
Published: November 2004

Let B and [Formula: see text] be two-forms, Fµν being the field strength of an Abelian connection A. The topological BF system is given by the integral of B ∧ F. With "kinetic energy" terms added for B and A, it generates a mass for A, thereby suggesting an alternative to the Higgs mechanism, and also gives the London equations. The BF action, being the large length and time scale limit of this augmented action, is thus of physical interest. In earlier work, it has been studied on spatial manifolds Σ with boundaries ∂Σ, and the existence of edge states localized at ∂Σ has been established. They are analogous to the conformal family of edge states to be found in a Chern–Simons theory in a disc. Here we introduce charges and vortices (thin flux tubes) as sources in the BF system and show that they acquire an infinite number of spin excitations due to renormalization, just as a charge coupled to a Chern–Simons potential acquires a conformal family of spin excitations. For a vortex, these spins are transverse and attached to each of its points, so that it resembles a ribbon. Vertex operators for the creation of these sources are constructed and interpreted in terms of a Wilson integral involving A and a similar integral involving B. The standard spin–statistics theorem is proved for these sources. A new spin–statistics theorem, showing the equality of the "interchange" of two identical vortex loops and 2π rotation of the transverse spins of a constituent vortex, is established. Aharonov–Bohm interactions of charges and vortices are studied. The existence of topologically nontrivial vortex spins is pointed out and their vertex operators are also discussed.
COMPLEX MASS FERMIONIC FIELDS
Authors: BARCI D.G. , OXMAN L.E.
Published: November 2004

We consider a fermionic field obeying a second order equation containing a pair of complex conjugate mass parameters.

After obtaining a natural representation for the different degrees of freedom, we are able to construct a unique vacuum as the more symmetric state (zero energy-momentum, charge and spin). This representation, unlike the real mass case, is not holomorphic in the Grassmann variables.

The vacuum eigenstate allows the calculation of the field propagator which turns out to be half advanced plus half retarded.
ELECTROWEAK EFFECTIVE LAGRANGIANS
Authors: WUDKA JOSÉ
Published: November 2004

In this paper I review several aspects of the use of effective Lagrangians in (mainly) electroweak physics. The conditions under which this approach is reliable and useful, as well as the limitations of the formalism, are detailed. Various applications are also presented.
FRACTIONAL STATISTICS IN ONE DIMENSION: MODELING BY MEANS OF 1/x2 INTERACTION AND STATISTICAL MECHANICS
Authors: ISAKOV SERGEI B.
Published: November 2004

The equivalence of a quantum system of particles interacting with a two-body inverse square potential to a system of noninteracting particles obeying 1D fractional statistics (1D anyons), stated by Polychronakos for particles on a line, is studied for the cases where the interacting system is placed (i) into a harmonic potential on a line, and (ii) on a ring, with imposing periodic boundary conditions. In the first case, reducibility of the interacting system to the Calogero system is used to explore the statistical distribution for free 1D anyons. On a ring, the thermodynamic limit is discussed in terms of the thermodynamic (asymptotic) Bethe ansatz. Yang and Yang’s integral equation is treated in this case as describing the statistical mechanics of free 1D anyons. It gives a functional equation for the statistical distribution of 1D anyons consistent with the harmonic potential approach. We show that on a ring of a finite circumference, a system of two free 1D anyons is equivalent to a system of two particles interacting with an inverse sine square potential (the Sutherland system). We also discuss the relation to the statistical mechanics of free anyons in 2+1 dimensions.
NEUTRAL EXOTICS IN THE COMPOSITE MODEL — ISOSINGLET WEAK BOSON
Authors: AKAMA KEIICHI , HATTORI TAKASHI
Published: November 2004

We investigate properties of the isosinglet partner (WS boson) of the composite weak boson in the dynamical subquark model of the Nambu-Jona-Lasinio (NJL) type. The WS boson is assumed to be made up of the isospin-carrying subquark w, and to be subject to the NJL type dynamics. We derive the following properties of the WS boson. It couples to the quarks and leptons with the equal strength g0 (before mixing), and to the weak bosons only through mixing. We find that the current mixing parameter with photon is proportional to the average of the charges of the subquark w, and inversely proportional to the coupling constant g0. The compositeness conditions almost fix g0 in terms of the weak coupling constant g. We see how the present experimental results restrict the mass and the coupling strength of the diagonalized WS boson (called the X boson). We calculate the decay widths of the X boson and the forward-backward asymmetry in [Formula: see text] scattering.