bluuebunny/crossref_metadata_2025 huggingface dataset:
NONEXISTENCE OF QUANTUM NAMBU MECHANICS
Authors: SAHOO DEBENDRANATH , VALSAKUMAR M. C.
Published: November 2004

We investigate the problem of quantization of Nambu mechanics — a problem posed by Nambu [Phys. Rev.D7, 2405 (1973)] — along the line of Wigner–Weyl–Moyal (WWM) phase-space quantization of classical mechanics and show that the quantum analog of Nambu mechanics does not exist.
SIGNATURES OF SINGLE QUARK LINE WEAK TRANSITIONS
Authors: KARLSEN R. E. , SCADRON M. D.
Published: November 2004

We study the ΔI = 1/2 single quark line transition that occurs in p-wave baryon B → B′π, in radiative Ξ− → Σ−γ, in decuplet Ω− → Ξπ and in kaon K° → ππ weak decays. This leads to five empirical signatures of the single quark line scale. This scale is also predicted from a quark loop model.
SOME ASPECTS OF PION PHYSICS IN A DYNAMICALLY BROKEN ABELIAN GAUGE THEORY
Authors: MACHET B.
Published: November 2004

We show how an Abelian spontaneously broken gauge theory of fermions endowed with a composite scalar multiplet becomes naturally anomaly-free, and yet correctly describes the couplings of a neutral isoscalar pion to two gauge fields and to leptons: the first coupling is the same as that computed from the chiral anomaly, and the second is identical with that obtained from the 'Partially Conserved Axial Current' hypothesis. The general (non-Abelian) case of the standard model is only mentioned and will be the subject of another work.
POISSON STRUCTURE INDUCED (TOPOLOGICAL) FIELD THEORIES
Authors: SCHALLER PETER , STROBL THOMAS
Published: November 2004

A class of two-dimensional field theories, based on (generically degenerate) Poisson structures and generalizing gravity-Yang–Mills systems, is presented. Locally, the solutions of the classical equations of motions are given. A general scheme for the quantization of the models in a Hamiltonian formulation is found. A BRS-formulation is outlined briefly.
SL(2, R) YANG-MILLS THEORY ON A CIRCLE
Authors: BENGTSSON INGEMAR , HALLIN JOAKIM
Published: November 2004

The kinematic of SL (2, ℝ) Yang-Mills theory on a circle is considered, for reasons that are spelt out. The gauge transformations exhibit hyperbolic fixed points, and this results in a physical configuration space with a non-Hausdorff “network” topology. The ambiguity encountered in canonical quantization is then much more pronounced than in the compact case and cannot be resolved through the kind of appeal made to group theory in that case.
A CRITICAL LOOK AT PRECISION ELECTROWEAK DATA AT HIGH ENERGY—A HINT FOR PHYSICS BEYOND THE STANDARD MODEL?
Authors: GURTU A.
Published: November 2004

High energy electroweak data, including the recent measurement of M top is analyzed within the basic framework of the standard model. While the experimentally measured value of [Formula: see text] implies a low value of M top , the rest of the data demands a much higher value. Estimates of M Higgs within the SM framework including and excluding this Rb measurement are given. Next this discrepancy is expressed in terms of a new parameter, [Formula: see text], the excess[Formula: see text] production compared to that expected from a SM fit. This parameter is determined to be (9.4 to 12.8) ± 5.0 MeV, implying an excess of over 10 000 [Formula: see text] events in each LEP experiment after the 1993 data is fully analyzed. The origin of these events could be non-minimal Higgs pair production which should be thoroughly searched for in the full data sample of ~2×106 events per LEP experiment. Unless this discrepancy eventually turns out to be a fluctuation one may be witnessing at LEP the advent of physics beyond the standard model.
NONLOCAL MATRIX GENERALIZATIONS OF N=2 SUPER VIRASORO ALGEBRA
Authors: HUANG WEN-JUI
Published: November 2004

We study the generalization of the second Gelfand-Dickey bracket to the superdifferential operators with matrix-valued coefficients. The associated matrix Miura transformation is derived. Using this bracket we work out a nonlocal and nonlinear N=2 superalgebra which contains the N=2 super Virasoro algebra as a subalgebra. The bosonic limit of this superalgebra is considered. We show that when the spin-1 fields in this bosonic algebra are set to zero the resulting Dirac bracket gives precisely the recently derived V2,2 algebra.
A UNIFIED VIEW OF MULTIPLICITY DISTRIBUTIONS BASED ON A PURE BIRTH PROCESS
Authors: CHATURVEDI S. , GUPTA V. , SONI S.K.
Published: November 2004

Various probability distributions which have been proposed to explain the charged particle multiplicity distributions in high energy collisions are shown to arise from the evolution equation of a pure birth process subject to appropriate initial conditions. For example, both the negative binomial distribution (NBD) as well as the partially coherent laser distribution (PCLD) can be obtained in this way. New interrelations between some of these probability distributions are also brought out.
FOCK BUNDLES AND QUANTIZATION OF SYSTEMS WITH FIRST CLASS CONSTRAINTS
Authors: POPOV A.D.
Published: November 2004

The flat phase space (R2n, ω) with a symmetry group G generated by quadratic first class constraints is considered. We analyze the quantization of this constrained system in terms of the Fock bundle [Formula: see text], where S=Sp(2n, R)/U(n) is the space of positive translationally invariant complex structures J on (R2n, ω) and fibers HJ are the Hilbert spaces of quantization associated with the space (R2n, ω, J).
HEAVY-NEUTRINO EFFECTS ON τ-LEPTON DECAYS
Authors: PILAFTSIS A.
Published: November 2004

Minimal extensions of the standard model that are motivated by grand unified theories or superstring models with an E6 symmetry can naturally predict heavy neutrinos of Dirac or Majorana nature. Such heavy neutral leptons violate the decoupling theorem at the one-loop electroweak order and hence offer a unique chance for possible lepton-flavor decays of the τ-lepton, e.g. τ→eee or τ→μμμ, to be seen in LEP experiments. We analyze such decays in models with three and four generations.
ANALYSIS OF THE NONSINGULAR WYMAN-SCHWARZSCHILD METRIC
Authors: CORNISH NEIL J.
Published: November 2004

The analog of the Schwarzschild metric is explored in the context of nonsingular gravity. Analytic results are developed describing redshifts, curvatures and topological features of the space-time.
THE HIGGS BOSON MASS IN SUPERSYMMETRIC WEINBERG-SALAM MODEL BROKEN AT HIGH SCALE
Authors: KRASNIKOV N.V. , KREYERHOFF G. , RODENBERG R.
Published: November 2004

We study the dependence of the Higgs boson mass on the scale of supersymmetry breaking in the minimal supersymmetric extension of the standard Weinberg-Salam model.
ON BOGOLIUBOV TRANSFORMATION OF SCALAR WAVE FUNCTIONS IN DE SITTER SPACE
Authors: SATO HARU-TADA , SUZUKI HISAO
Published: November 2004

We discuss the Bogoliubov transformation of the scalar wave functions caused by the change of coordinates in four-dimensional de Sitter space. It is shown that the exact Bogoliubov coefficients can be obtained from the global coordinates to the static coordinates where there exists manifest horizon. We consider two types of global coordinates. In one global coordinates, it is shown that the Bogoliubov transformation to the static coordinates can be expressed by the discontinuous integral of Weber and Schafheitlin. The positive and negative energy states in the global coordinates degenerate in the static coordinates. In the other global coordinates, we obtain the Bogoliubov coefficients by using the analytic continuation of the hypergeometric functions in two variables.

We also discuss the relation between two types of global coordinates and find an integral relation between the mode functions.
INDUCED VIOLATION OF WEAK EQUIVALENCE PRINCIPLE IN THE BRANS-DICKE THEORY
Authors: FUJII YASUNORI
Published: November 2004

A quantum correction to the Brans-Dicke theory due to interactions among matter fields is calculated, resulting in violation of WEP, hence giving a constraint on the parameter ω far more stringent than accepted so far. The tentative estimate gives the lower bounds ≳106 and ≳108 for the assumed force-range ≳1 m and ≳1 AU , respectively.
THE NEUTRALINO SECTOR IN STRONGLY INTERACTING SUPERSYMMETRIC MODELS
Authors: VELDHUIS W.T.A. TER
Published: November 2004

The neutralino sector is analyzed for a supersymmetric nonlinear sigma model. This model describes the low energy physics of strongly interacting theories in which super-symmetry is softly broken at scales below the electroweak symmetry breaking scale. The measured width of the Z boson constrains the allowed range of parameters. In case the lightest neutralino is stable, limits on additional contributions to the invisible width of the Z boson and on the relic neutralino density further restrict parameter space. As a consequence, the lightest neutralino in the considered class of theories is required to have a mass above 15 GeV, but below MZ.
WEYL EQUATION IN GÖDEL TYPE UNIVERSES
Authors: PIMENTEL LUIS O. , CAMACHO ABEL , MACIAS ALFREDO
Published: November 2004

The Weyl equation (massless Dirac equation) is studied in a family of metrics of the Gödel type. The field equation is solved exactly for one member of the family.
FERMIONS IN THE BACKGROUND OF DILATONIC SPHALERONS
Authors: LAVRELASHVILI GEORGE
Published: November 2004

We discuss the properties and interpretation of a discrete sequence of a static spherically symmetric solutions of the Yang-Mills dilaton theory. This sequence is parametrized by the number of zeros, n, of a component of the gauge field potential. It is demonstrated that solutions with odd n possess all the properties of the sphaleron. It is shown that there are normalizable fermion zero modes in the background of these solutions. The question of instability is critically analyzed.
VECTOR-CHIRAL EQUIVALENCE IN NULL GAUGED WZNW THEORY
Authors: ARDALAN FARHAD , GHEZELBASH AMIR MASOUD
Published: November 2004

We consider the standard vector and chiral gauged WZNW models gauged by their maximal null subgroups and show that they can be mapped to each other by a special transformation. We give an explicit expression for the map in the case of the classical Lie groups AN, BN, CN, DN, and note its connection with the duality map for the Riemannian globally symmetric spaces.
THE ETA FUNCTION IN BF TOPOLOGICAL FIELD THEORY
Authors: GIBBS RICHARD , MOKHTARI SOUSSAN
Published: November 2004

The eta function in BF topological field theory is computed in a gauge which is both non-local and non-covariant. As expected, the result differs from that obtained when a covariant gauge is used. An explicit calculation of the Vilkovisky-DeWitt correction term is then presented which allows one to recover the covariant gauge result, which is proportional to the Chern-Simons term.
COVARIANT QUANTIZATION OF CHIRAL BOSON IN BATALIN-FRADKIN-VILKOVISKY SCHEME
Authors: GHOSH SUBIR
Published: November 2004

The scheme developed by Batalin, Fradkin and Vilkovisky (BFV) to convert a second class constrained system to that of a first class (having gauge invariance) is used in the Floreanini-Jackiw formulation of the chiral boson. Explicit expressions of the BRS charge and the unitarizing Hamiltonian are provided. The equivalence between the BFV quantized system and its gauge fixed counterpart representing the original chiral boson is discussed.
W∞-ALGEBRA FOR FERMIONS IN THE LOWEST LANDAU LEVEL
Authors: MYUNG YUN SOO
Published: November 2004

We derive the W∞-algebra directly from the cocycle (translational) transformation of fermions in the lowest Landau level. This happens whenever the translational symmetry is unbroken in the ground state. Under the cocycle transformations, the lowest Landau level condition and fermion number are preserved. In the droplet approximation, the algebra of this system is reduced to the classical w∞-algebra (area-preserving deformations) and is related to condensed matter physics. This describes the edge modes of the fractional quantum Hall effect.
BRST COHOMOLOGY RING IN 2D GRAVITY COUPLED TO MINIMAL MODELS
Authors: KANNO H. , SARMADI M.H.
Published: November 2004

The ring structure of Lian-Zuckerman states for (q, p) minimal models coupled to gravity is shown to be ℛ=ℛ0⊗ C[w, w−1], where ℛ0 is the ring of ghost number zero operators generated by two elements and w is an operator of ghost number −1. Some examples are discussed in detail. For these models the currents are also discussed and their algebra is shown to contain the Virasoro algebra.
POINCARÉ ZERO-MASS REPRESENTATIONS
Authors: MIRMAN R.
Published: November 2004

The zero-mass, discrete-spin, finite-dimensional representations of the proper Poincaré group are discussed, using the nondecomposable — and so nonunitary — representations of the little group, SE(2); matrix elements are thus arbitrary functions. The physical meaning and significance of the results are emphasized. Matrices are not decomposable, so the bases are connections, not tensors, giving gauge invariance — a partial statement of Poincaré invariance for zero mass only. Gravitation, a zero-mass spin-2 field, obeys a nonlinear condition (unlike the zero-mass spin-1 electromagnetic A), the Bianchi identity, which follows from the nature of Γ, and its integrated form, the Einstein equations, resulting in a curvature of space. Gravitation must be and is nonlinear, and electromagnetism linear, because of restrictions on which massless objects can interact with massive ones, these resulting from the differences in their little groups. The nonlinear representation is equivalent to a curvature of space — which thus can be considered a consequence of nonlinearity.
MULTIVALUED FIELDS ON THE COMPLEX PLANE AND BRAID GROUP STATISTICS
Authors: FERRARI FRANCO
Published: November 2004

In this paper we study a class of theories of free particles on the complex plane satisfying a non-Abelian statistics. This kind of particles are generalizations of the anyons and are sometimes called plectons. The peculiarity of these theories is that they are associated to free conformal field theories defined on Riemann surfaces with a discrete and non-Abelian group of authomorphisms Dm. More explicitly, the plectons appear here as “induced vertex operators” that simulate, on the complex plane, the nontrivial topology of the Riemann surface. In order to express the local exchange algebra of the particles, one is led to introduce an R matrix satisfying a multiparameter generalization of the usual Yang-Baxter equations. It is interesting that analogous generalizations have already been investigated in connection with integrable models, in which the spectral parameter takes its values on a Riemann surface that is in many respects similar to the Riemann surfaces we are studying here. The explicit form of the R matrices mentioned above can be also used to define a multiparameter version of the quantum complex hyperplane.
HAMILTONIAN FORMALISM OF TWO-LOOP WZNW MODEL
Authors: DING XIANG-MAO , HOU BO-YU , YANG HUAN-XIONG
Published: November 2004

The Hamiltonian canonical formalism of two-dimensional WZNW model based on an arbitrary affine Lie algebra is given under the Chevalley basis. The Poisson brackets of conserved chiral currents are calculated, which turn out to be the classical two-loop Kac-Moody current algebras.
WHERE IS TOP?
Authors: DALITZ R.H. , GOLDSTEIN GARY R.
Published: November 2004

Possibilities are discussed for determining the top-quark mass mt from observations on the decay processes for top-antitop pairs produced in antiproton-proton collisions at Tevatron energies, assuming that the t→bW+ decay channel is dominant and much faster than hadronization. The final states [Formula: see text] provide the most striking signal, with little background, but they are rare (≈2/81). If all three candidate events prove to be from [Formula: see text], an estimate follows for P(mt| rate ), the probability distribution for mt. The one reported configuration allows an independent estimate for P (mt|μ± e∓ 2 jets ). These two distributions are compatible and can be combined to give an mt estimate of about 122 GeV.

Decay events “1 energetic lepton(ℓ)+4 jets” should appear 12 times as often as “ μ± e∓ 2 jets ” events and can be analyzed to give estimates for P(mt|ℓ 4 jets ); this is illustrated for a fictitious event. There may be background from nontop events but suitable cuts on the data and our analysis procedure together reduce this to a low level. The rate observed for these events does not appear to be as large as the factor 12.

Identification of either or both of the [Formula: see text] jets would be a great step forward, separating out the “[Formula: see text]” and “[Formula: see text]” events of importance with little background. We advocate an energetic approach to the analysis of individual events [whether 2, 1 or no (b or [Formula: see text]) jets identified] on an event-by-event basis, with the hope of finding a subgroup of events with a common mass estimate.
TOWARDS FINITENESS WITHOUT SUPERSYMMETRY
Authors: SKARKE HARALD
Published: November 2004

Some aspects of finite quantum field theories in 3+1 dimensions are discussed. A model with nonsupersymmetric particle content and vanishing one- and two-loop beta functions for the gauge coupling and one-loop beta functions for Yukawa couplings is presented.
FERMIONS, ANOMALY AND UNITARITY IN HIGH ENERGY ELECTROWEAK INTERACTIONS
Authors: GUIDA R. , KONISHI K. , MAGNOLI N.
Published: November 2004

We report on the "state of the art" of the problem of B + L violation in high energy electroweak scatterings. Results of various analyses point to (but do not prove rigorously yet) "half-suppression," i.e. the (B + L)-violating cross section remains suppressed at least by the negative exponent of the single instanton action, at all energies. The most interesting techniques developed in this field are reviewed. Particular attention is paid to unitarity constraints on the anomalous cross section, and to some conceptual problems involving the use of the optical theorem in the presence of instantons.
THE RENORMALIZATION STRUCTURE AND QUANTUM EQUIVALENCE OF 2D DILATON GRAVITIES
Authors: ELIZALDE E. , ODINTSOV S. D. , NAFTULIN S.
Published: November 2004

The one-loop effective action corresponding to the general model of dilaton gravity given by the Lagrangian [Formula: see text], where Z (Φ), C (Φ) and V (Φ) are arbitrary functions of the dilaton field, is found. The question of the quantum equivalence of classically equivalent dilaton gravities is studied. By specific calculation of explicit examples, it is shown that classically equivalent quantum gravities are also perturbatively equivalent at the quantum level, but only on-shell. The renormalization group equations for the generalized effective couplings Z (Φ), C (Φ) and V (Φ) are written. An analysis of the equations shows, in particular, that the gravitational sector of the Callan–Giddings–Harvey–Strominger model is not a fixed point of these equations.
SQUEEZED VACUA AND THE QUANTUM STATISTICS OF COSMOLOGICAL PARTICLE CREATION
Authors: HU B. L. , KANG G. , MATACZ A.
Published: November 2004

We use the language of squeezed states to give a systematic description of two issues in cosmological particle creation: (a) Dependence of particle creation on the initial state specified; we consider in particular the number state, the coherent state and the squeezed state; (b) the relation of spontaneous and stimulated particle creation and their dependence on the initial state. We also present results for the fluctuations in particle number in anticipation of its relevance to defining noise in quantum fields and the vacuum susceptibility of space–time.
PATH SPACES AND $\mathcal W$ FUSION IN MINIMAL MODELS
Authors: KELLENDONK JOHANNES , RÖSGEN MICHAEL , VARNHAGEN RAIMUND
Published: November 2004

Product forms of characters of Virasoro minimal models are obtained which factorize into (2, odd) × (3, even) characters. These are related by generalized Rogers–Ramanujan identities to sum forms, allowing for a quasiparticle interpretation. The corresponding dilogarithm identities are given and the factorization is used to analyze the related path space structure as well as the fusion of the maximally extended chiral algebra.
CP-ODD NEUTRAL HIGGS EFFECTS IN $t\bar t$ PRODUCTION
Authors: PILAFTSIS A. , NOWAKOWSKI M.
Published: November 2004

We study CP violation in the process [Formula: see text] at an e+e− TeV collider. As the source of CP violation we assume a two-Higgs doublet model with an explicitly CP- noninvariant Higgs potential. The finite width effects of the neutral Higgs boson in the subprocess reaction, [Formula: see text], give rise to CP-odd observables which can have sizeable values. CPT constraints due to final (initial) state interactions are also taken into account. Numerical estimates of the expected CP asymmetry are given.
COORDINATE-INDEPENDENT DEFINITION OF TIME AND VACUUM IN CURVED SPACE–TIME
Authors: CAPRI A. Z. , ROY S. M.
Published: November 2004

We propose a definition of time and of the vacuum such that they are intrinsic to a given globally hyperbolic 1 + (n − 1)-dimensional space–time geometry and independent of the choice of coordinates. To arrive at this definition we use the new physical principle that a 1 + 1-dimensional Poincaré algebra, including Killing conditions on the generators, should be valid on the hypersurface of instantaneity. Given a timelike vector at a point (an observer's velocity) we define "an instant of time" to be the spacelike surface of geodesics which pass through that point and are orthogonal to that timelike vector. Gaussian coordinates erected on this surface yield 1 + 1-dimensional subspaces with Poincaré symmetry valid on that surface. The generator associated with time translation now uniquely picks out the direction of time on that surface. This fact permits unambiguous quantization on the surface of a field evolving in this background metric. For flat space–time the corresponding vacuum is always the Minkowski vacuum. We also consider in detail the case of static and Robertson–Walker metrics in 1 + 1 dimensions and find our vacuum to be different from those given before. The vacuum for the de Sitter metric in 1 + 1 dimensions is compared with the results in the literature and found to be different. Our definition of particles, and hence particle production, is consequently different also.
CHIRAL GAUGE E6 AS A BINDING GROUP FOR COMPOSITE LEPTONS, QUARKS AND HIGGS BOSONS
Authors: PIROGOV YU. F.
Published: November 2004

The uniqueness of the chiral gauge E6 symmetry in providing the mechanism of binding for composite models is stressed. A maximally symmetric pattern of chiral symmetry breaking, consistent with dynamical mass generation along with preservation of the strongly coupled E6 gauge symmetry, is considered. Chiral anomaly matching conditions for the residual chiral symmetry are studied and likely massless composite fermions are found. The possibility for these fermions as well as Goldstone bosons to be treated eventually as leptons, quarks and Higgs bosons is discussed. The scheme possesses the generic realistic-like features and could serve as a prototype for a realistic composite model.
ALGEBRAIC ASPECTS OF ORBIFOLD MODELS
Authors: BANTAY P.
Published: November 2004

Algebraic properties of orbifold models on arbitrary Riemann surfaces are investigated. The action of mapping class group transformations and of standard geometric operations is given explicitly. An infinite-dimensional extension of the quantum group is presented.
SPINORS, VECTORS AND SCALARS IN GRASSMANN SPACE AND CANONICAL QUANTIZATION FOR FERMIONS AND BOSONS
Authors: MANKOČ-BORŠTNIK NORMA
Published: November 2004

A point particle which lives in a d-dimensional ordinary and a d-dimensional Grassmann space (d ≥ 5) manifests itself in an ordinary four-dimensional subspace as a spinor, a scalar or a vector. The canonical quantization of fields leads to either fermions or bosons. Fermions as well as bosons have either positive or negative internal parity according to discrete symmetries in the Grassmann space.
THE SUPER W3 CONFORMAL ALGEBRA AND THE BOUSSINESQ HIERARCHY
Authors: POPOWICZ ZIEMOWIT
Published: November 2004

The bi-Hamiltonian structure of the N=2 supersymmetric Boussinesq equation is found. It is not reduced to the corresponding classical structure and hence it describes the pure supersymmetric effect. For the supersymmetric Boussinesq equation which contains the classical partner the Lax pair is given explicitly. Thus we prove the integrability of this equation.
BRST EXACTNESS OF STRESS-ENERGY TENSORS
Authors: MIYATA HIDEO , SUGIMOTO HIROSHI
Published: November 2004

BRST commutators in the topological conformal field theories obtained by twisting N=2 theories are evaluated explicitly. By our systematic calculations of the multiple integrals which contain screening operators, the BRST exactness of the twisted stress-energy tensors is deduced for classical simple Lie algebras and general level k. We can see that the paths of integrations do not affect the result, and further, the N=2 coset theories are obtained by deleting two simple roots with Kac-label 1 from the extended Dynkin diagram; in other words, by not performing the integrations over the variables corresponding to the two simple roots of Kac-Moody algebras. It is also shown that a series of N=1 theories are generated in the same way by deleting one simple root with Kac-label 2.
GENERALIZED SKLYANIN ALGEBRA AND INTEGRABLE LATTICE MODELS
Authors: QUANO YAS-HIRO
Published: November 2004

We study three properties of the ℤn⊗ℤn-symmetric lattice model; i.e. the initial condition, the unitarity and the crossing symmetry. The scalar factors appearing in the unitarity and the crossing symmetry are explicitly obtained. The [Formula: see text]-Sklyanin algebra is introduced in the natural framework of the inverse problem for this model. We build both finite- and infinite-dimensional representations of the [Formula: see text]-Sklyanin algebra, and construct an [Formula: see text] generalization of the broken ℤN model. Furthermore, the Yang-Baxter equation for this new model is proved.
THE EXACT RENORMALIZATION GROUP AND APPROXIMATE SOLUTIONS
Authors: MORRIS TIM R.
Published: November 2004

We investigate the structure of Polchinski’s formulation of the flow equations for the continuum Wilson effective action. Reinterpretations in terms of I.R. cutoff Green’s functions are given. A promising nonperturbative approximation scheme is derived by carefully taking the sharp cutoff limit and expanding in “irrelevancy” of operators. We illustrate with two simple models of four-dimensional λφ4 theory: the cactus approximation, and a model incorporating the first irrelevant correction to the renormalized coupling. The qualitative and quantitative behaviour give confidence in a fuller use of this method for obtaining accurate results.
LINEARIZED FORM OF THE GENERIC AFFINE-VIRASORO ACTION
Authors: BOER J. DE , CLUBOK K. , HALPERN M.B.
Published: November 2004

Halpern and Yamron have given a Lorentz, conformal, and Diff S2-invariant world-sheet action for the generic irrational conformal field theory, but the action is highly nonlinear. In this paper, we introduce auxiliary fields to find an equivalent linearized form of the action, which shows in a very clear way that the generic affine-Virasoro action is a Diff S2-gauged WZW model. In particular, the auxiliary fields transform under Diff S2 as local Lie g× Lie g connections, so that the linearized affine-Virasoro action bears an intriguing resemblance to the usual (Lie algebra) gauged WZW model.
FERMIONS IN THE INSTANTON-ANTI-INSTANTON VALLEY AND HIGH-ENERGY ELECTROWEAK INTERACTIONS
Authors: GUIDA RICCARDO , KONISHI KENICHI
Published: November 2004

We consider the behavior of fermions in the background of instanton-anti-instanton valley fields. Several different physics problems, from the high-energy electroweak interactions to the study of vacuum structure of QCD and of large orders of perturbation theory, are related to this problem. The spectrum of the Dirac operator in such a background is studied in detail. We present an approximation for the fermion correlation function when the instanton-anti-instanton separation (R) is large compared to their sizes (ρ). The situation where the instanton-anti-instanton overlap and melt is studied through the behavior of the Chern-Simons number as a function of R/ρ and x4. Applying our results to widely discussed cases of fermion-number violation in the electroweak theory, we conclude that there is no theoretical basis for expecting anomalous cross-sections to become observable at energies in the 10 TeV region.
RECENT DEVELOPMENTS IN D=2 STRING FIELD THEORY
Authors: KAKU MICHIO
Published: November 2004

We review the recent developments in the construction of string field theory in two dimensions. We analyze the bewildering number of string field theories that have been proposed, all of which correctly reproduce the correlation functions of two-dimensional string theory. These include (1) free fermion field theory, (2) collective string field theory, (3) temporal gauge string field theory and (4) nonpolynomial string field theory. We will analyze discrete states, the ω(∞) symmetry, and correlation functions in terms of these different string field theories. We will also comment on the relationship between these field theories, which is still not well understood.
THE FERMION-FERMION EFFECTIVE ACTION FOR THE THREE-DIMENSIONAL MASSIVE THIRRING MODEL
Authors: RIBEIRO R.F. , MELLO E.R. BEZERRA DE
Published: November 2004

In this paper a nonrelativistic fermion-fermion effective potential for a three-dimensional massive Thirring model is obtained in a 1/N expansion. We show, by analyzing the Schrödinger equation in the presence of this potential, that the system presents a fermion-fermion bound state for a positive value of the coupling constant g.
A NEW FORMULATION OF QUANTUM FIELD THEORY ON S4
Authors: HARRIS B.A. , JOSHI G.C.
Published: November 2004

Recent developments in quantum gravity suggest that wormholes may influence the observed values of the constants of nature. The Euclidean formulation of quantum gravity predicts that wormholes induce a probability distribution in the space of possible fundamental constants. In particular, the effective action on a large spherical space may lead to the vanishing of the cosmological constant and possibly determine the values of other constants of nature. The ability to perform calculations involving interacting quantum fields, particularly non-Abelian models, on a four-sphere is vital if one is to investigate this possibility. In this paper we present a new formulation of field theory on a four-sphere using the angular momentum space representation of SO(5). We give a review of field theory on a sphere and then show how a matrix element prescription in angular momentum space and a new summation technique based on the complex l plane, overcome previous limitations in calculational techniques. The standard one-loop graphs of QED are given as examples.
SOLUTION OF MATRIX MODELS IN THE D III GENERATOR ENSEMBLE
Authors: ROUSSEL HAROLD
Published: November 2004

In this work we solve two new matrix models using standard and new techniques. The two models are based on matrix ensembles not previously considered, namely the D III generator ensemble. It is shown that, in the double scaling limit, their free energy has the same behavior as previous models describing oriented and unoriented surfaces. We also found an additional solution for one of the models.
SKYRME MODEL OF BARYONS AND WEAK RADIATIVE DECAYS
Authors: MAITY ARUN
Published: November 2004

We study the weak radiative decays of baryons when these are considered to be composed of baby Skyrmions. Weak interaction gauge bosons take a prominent role when a baby Skyrmion interacting with such a boson governs the main dynamics. This mechanism effectively gives rise to the pole model where the parity-conserving and parity-violating poles are not arbitrary but are dictated by the mechanism itself.
EXACT RENORMALIZATION GROUP EQUATIONS FOR THE AVERAGE ACTION AND SYSTEMATIC EXPANSIONS
Authors: WETTERICH C.
Published: November 2004

We derive exact equations describing the dependence of the average action on the scale k characteristic for the averaging. Such an equation is a differential equation with infinitely many variables. We reformulate it as a system of infinitely many differential equations for infinitely many couplings and sketch systematic expansions for this system. We also establish the connection between these equations and other formulations of exact renormalization group equations.
MEASUREMENT, IRREVERSIBILITY AND DECOHERENCE IN QUANTUM MECHANICS
Authors: BAAQUIE BELAL E.
Published: November 2004

We review Prigogine's model of quantum measurement. The measuring apparatus is considered to be an unstable quantum system with its state vector belonging to a rigged Hilbert space. Time irreversibility arises due to the dissipative nature of the measuring apparatus (an unstable quantum system) which induces decoherence in the system being measured. Friedrichs' model is used to concretely illustrate these ideas.
HIGH TEMPERATURE PHASE TRANSITIONS WITHOUT INFRARED DIVERGENCES
Authors: TETRADIS N. , WETTERICH C.
Published: November 2004

The most commonly used method for the study of high temperature phase transitions is based on the perturbative evaluation of the temperature-dependent effective potential. This method becomes unreliable in the case of a second order or weakly first order phase transition, due to the appearance of infrared divergences. These divergences can be controlled through the method of the effective average action, which employs renormalization group ideas. We report on the study of the high temperature phase transition for the N-component ϕ4 theory. A detailed quantitative picture of the second order phase transition is presented, including the critical exponents for the behavior in the vicinity of the critical temperature. An independent check of the results is obtained in the large N limit, and contact with the perturbative approach is established through the study of the Schwinger–Dyson equations.
EXACT COSMIC STRING SOLUTIONS BASED ON THE CONTINUUM THEORY OF DISLOCATIONS
Authors: FUJISHIRO TAKEHIKO T. , HAYASHI MITSUO J. , TAKESHITA SHOJI
Published: November 2004

The effective action from the string compactification is studied on the manifolds with absolute parallelism. The cosmic strings can be described naturally by torsion formalism which has a direct analogy with dislocations in three-dimensional crystalline solids. We have found a stringy solution in a six-dimensional model on M4 × T2 which is compatible with that of Greene et al. and a cylindrically symmetric exact solution is obtained, which are different from the exact cosmic string solutions of the Einstein theory ever proposed. We have also obtained an exact solution in a four-dimensional model on M2 × T2 which can be considered as an example of the compactification on the noncompact manifold and may be expected to describe a space–time structure of our universe. The relation between the mass per unit length and the deficit angle is different from but can be consistent with that of the Einstein theory, since our solution could reproduce its prediction with a condition. We could also obtain the maximum value of the mass per unit length μ ~ 10−6 (~ 1022 g/cm ) by fine-tuning a parameter, which is consistent with recent observations. We have discussed the cosmic strings with the deficit angle larger than 2π.
CHIRAL QUANTIZATION ON A GROUP MANIFOLD
Authors: HASIEWICZ ZBIGNIEW , SIEMION PRZEMYSLAW , TROOST WALTER
Published: November 2004

The phase space of a particle on a group manifold can be split into left and right sectors, in close analogy with the chiral sectors in Wess–Zumino–Witten models. We perform a classical analysis of the sectors, and geometric quantization in the case of SU(2). The quadratic relation, classically identifying SU(2) as the sphere S3, is replaced quantum-mechanically by a similar condition on noncommutative operators ("quantum sphere"). The resulting quantum exchange algebra of the chiral group variables is quartic, not quadratic. The fusion of the sectors leads to a Hilbert space that is subtly different from the one obtained through a more direct (unsplit) quantization.
B PHYSICS AND CP VIOLATION STUDIES WITH THE CMS DETECTOR AT LHC
Authors: DENEGRI D. , LEMOIGNE Y. , FRIDMAN A. , HASSARD J. , MARGETIDES S. , VIRDEE T. S. , KARIMÄKI V. , KINNUNEN R. , PIMIÄ M. , KHARCHILAVA A. , KONECKI M. , NEUMEISTER N. , SINANIS N. J. , RACCA C. , RUBBIA A. , WROCHNA G. , STARODUMOV A.
Published: November 2004

In this paper we evaluate the potential of the CMS detector for the measurement of CP violation in the B system at the initial low luminosity of LHC (~1033 cm −2 s −1). The sensitivity to the unitarity triangle angle β obtained from the [Formula: see text] channel is given by δ ( sin 2β) = 0.046, whilst the sensitivity to a from the [Formula: see text] channel is given by δ ( sin 2α) = 0.082. We also discuss the possibilities of observing semi-inclusive B → μ + D(s) final states, to measure [Formula: see text] oscillations and to observe some B baryon modes.
FERMION MASS IN THE WILSON-YUKAWA APPROACH FOR CHIRAL YUKAWA THEORY
Authors: AOKI SINYA , KIKUKAWA YOSHIO
Published: November 2004

We consider a modification of the Wilson-Yukawa model to overcome the difficulty that the fermion mass is not proportional to the Higgs vacuum expectation value. In the modification scalar and fermionic regulator fields are introduced so that all the physical fermion fields possess shift symmetry when the Yukawa coupling vanishes. With the fermionic hopping parameter expansion it is shown that the fermion mass is proportional to the Higgs vacuum expectation value. We find, however, that the coupling of fermion to the external gauge field is always vectorlike in the continuum limit and that further modifications to the scalar action cannot change this undesirable conclusion.
GAUGE INVARIANCE OF THE GLUON FIELD CONDENSATION PHENOMENON IN FINITE TEMPERATURE QCD
Authors: SKALOZUB V.V.
Published: November 2004

It is shown that in finite temperature QCD the two-loop effective action of the gauge field zero component condensate W(A0, ξ), calculated in the background [Formula: see text] gauge, satisfies the Nielsen identity and has a nontrivial minimum. In this way the gauge invariance of the gluon condensation phenomenon is proved. The role of quarks and a comparison with results of other authors are briefly discussed.
EXACT STRING BACKGROUNDS FROM WZW MODELS BASED ON NON-SEMISIMPLE GROUPS
Authors: SFETSOS KONSTADINOS
Published: November 2004

We formulate WZW models based on a centrally extended version of the Euclidean group in d dimensions. We obtain string backgrounds corresponding to conformal σ models in D=d2 space-time dimensions with exact central charge c=d2 and d(d−1)/2 null Killing vectors. By identifying the corresponding conformal field theory we show that the one-loop results coincide with the exact ones up to a shifting of a parameter.
STANDARD-MODEL PREDICTIONS FOR W-PAIR PRODUCTION IN ELECTRON-POSITRON COLLISIONS
Authors: BEENAKKER WIM , DENNER ANSGAR
Published: November 2004

We review the status of the theoretical predictions for W-pair production in e+e− collisions within the electroweak standard model (SM). We first consider for on-shell W bosons the lowest-order cross-section within the SM, the general effects of anomalous couplings, the radiative corrections within the SM, and approximations for them. Then we discuss the inclusion of finite-width effects in the lowest order and the existing results for radiative corrections to off-shell W-pair production, and we outline the general strategy for calculating radiative corrections within the pole scheme. We summarize the theoretical predictions for the total and partial W-boson widths including radiative corrections and discuss the quality of an improved Born approximation. Finally, we provide a general discussion on the structure-function method for calculating large-logarithmic higher-order corrections associated with collinear photon radiation.
QUARK MODEL FOR SEMILEPTONIC DECAYS B→D(*)eν
Authors: KISELEV V.V.
Published: November 2004

A model of the heavy meson, composed of constituent quarks, is considered. It allows one to calculate the semileptonic decay widths of B→D(*)eν and to extract the Kobayashi—Maskawa matrix element |Vbc|=0.033±0.003 from experimental data. The infinitely heavy quark limit is discussed.
C2 TODA THEORY IN THE REDUCED WZNW FRAMEWORK
Authors: BAJNOK Z.
Published: November 2004

We consider the C2 Toda theory in the reduced WZNW framework. Analyzing the classical representation space of the symmetry algebra (which is the corresponding C2W algebra), we determine its classical highest weight representations. We quantize the model, promoting only the relevant quantities to operators. Using the quantized equation of motion we determine the selection rules for the u field, which corresponds to one of the Toda fields, and we give restrictions for its amplitude functions and for the structure of the Hilbert space of the model.
SUPERGRAVITY IN 2+∊ DIMENSIONS
Authors: KOJIMA SHIN-ICHI , SAKAI NORISUKE , TANII YOSHIAKI
Published: November 2004

Supergravity theory in 2+∊ dimensions is studied. It is invariant under supertransformations in two and three dimensions. One-loop divergence is explicitly computed by the background field method and a nontrivial fixed point is found. In quantizing the supergravity, a gauge-fixing condition is devised which explicitly isolates conformal and superconformal modes. The renormalization of the gravitationally dressed operators is studied and their anomalous dimensions are computed. Problems in using the dimensional reduction are also examined.
TWISTOR-LIKE APPROACH TO SUPERSYMMETRIC GAUGE THEORIES
Authors: YAMASHITA HIROYUKI
Published: November 2004

We consider the constraint conditions on the supersymmetric Yang-Mills theories in D=6, N=1, which are gauge- and super-covariant. These constraint conditions have been introduced to remove superfluous fields. We present a method to tell how and to what degree the constraint restricts the theory in the D=6, N=1 Abelian case by analogy with the twistor method for self-dual equations. The constraint is transformed into an infinite series of constraint equations. We find that a previously known theory in D=6, N=1 corresponds to a special case which is chosen so that the series is finite.
THE GENERALIZED HARTREE-FOCK METHOD IN THE GROSS-NEVEU MODEL
Authors: YAMADA HIROFUMI
Published: November 2004

In the generalized Hartree-Fock scheme one can incorporate nonperturbative effects from the beginning of a diagrammatic expansion. In order to make a detailed analysis of the method, we apply it to the Gross-Neveu model as an example and calculate the chiral condensate at large N by using a direct diagrammatic expansion. The unperturbed Gaussian kernel is adjusted to be massive by adding fermion mass terms and the mass terms are subtracted from the interaction part, thus not changing the full Lagrangian. The chiral condensate  is expanded in powers of the renormalized coupling constant and then improved by the method of effective charges. We find that our diagrammatic expansion is compatible with renormalization. By using the principle of minimal sensitivity, we evaluate  and show that the exact broken and unbroken solutions for the discrete γ5 symmetry are obtained at each order of the expansion.
CRYSTAL GROWTH OF OXIDE THIN FILMS USING MASS-SEPARATED LOW-ENERGY O+ ION BEAMS
Authors: KITA RYUSUKE
Published: November 2004

A new technique developed for growing high-quality oxide thin films by molecular beam epitaxy (MBE) is described. The technique uses low-energy and high density O + ion beams mass-separated from an oxygen plasma, as an oxidation source. Since O + ion beams have great oxidation ability and kinetic energy, the technique enables us to grow oxide films by MBE not only under ultrahigh vacuum comparable to the environment where semiconductors are prepared, but also at low temperatures. The application of the technique to the MBE growth of CuO, BaO, SrO and Sr–Cu–O thin films is also described.
FRACTAL AND DYNAMICAL PROPERTIES OF THE KICKED HARPER MODEL
Authors: ARTUSO R. , CASATI G. , BORGONOVI F. , REBUZZINI L. , GUARNERI I.
Published: November 2004

We review recent work on the so-called kicked Harper model, which can be viewed either as a model system in the framework of quantum chaos, or as a pulsed version of the Harper model, which has been thoroughly investigated in the context of magnetic field effects in solid state physics. In particular we describe its rich phase diagram, by means of both dynamical methods and multifractal analysis of the spectrum.
ELASTIC PROPERTIES OF La-BASED AND Y-BASED OXIDE SUPERCONDUCTIVE MATERIALS
Authors: TING WU , FOSSHEIM K.
Published: November 2004

Elastic measurements on La-based and Y-based bulk oxide superconductive materials in the temperature range 4.2–350 K are reviewed. Emphasis is placed on the elastic behavior near the superconducting transition temperature Tc and at higher temperatures where phase transitions or structural instabilities may occur. Possible mechanisms responsible for the observed elastic anomalies are discussed.
FINITE TEMPERATURE RESULTS FROM CONSTRAINED FERMIONIZATION IN THE 2-D SPIN 1/2 HEISENBERG ANTIFERROMAGNET II: FLUCTUATIONS IN THE DIMER PHASES
Authors: DI STASIO M. , TAGLIACOZZO A. , ERCOLESSI E. , MORANDI G.
Published: November 2004

The constraint of single-site occupancy is implemented in the fermionization of the model, within the saddle point approximation. The columnar and the staggered dimer phases are studied and the contribution of the fluctuations to the zero point energy and the specific heat is analyzed.
HOPPING TRANSPORT IN GALLIUM ANTIMONIDE
Authors: Demishev S.V.
Published: November 2004

This report summarizes a study of hopping transport in doped crystalline and amorphous gallium antimonide. The experimental results demonstrate the importance of short-range correlations rather than Coulomb ones. Anomalous behaviour of the Hall coefficient and the thermoelectric power is described.
EFFECTIVE ACTION AND ADIABATIC EXPANSIONS FOR THE 1-D AND 2-D HUBBARD MODELS AT HALF-FILLING
Authors: DI STASIO M. , ERCOLESSI E. , MORANDI G. , RIGHI R. , TAGLIACOZZO A. , ZUCCHELLI G.P.
Published: November 2004

We analyze here the occurrence of antiferromagnetic (AFM) correlations in the half-filled Hubbard model in one and two space dimensions using a natural fermionic representation of the model and a newly proposed way of implementing the half-filling constraint. We find that our way of implementing the constraint is capable of enforcing it exactly already at the lowest levels of approximation. We discuss how to develop a systematic adiabatic expansion for the model and how Berry’s phase contributions arise quite naturally from the adiabatic expansion. At low temperatures and in the continuum limit the model gets mapped onto an O(3) nonlinear sigma model (NLσ). A topological, Wess-Zumino term is present in the effective action of the 1D NLσ as expected, while no topological terms are present in 2D. Some specific difficulties that arise in connection with the implementation of an adiabatic expansion scheme within a thermodynamic context are also discussed, and we hint at possible solutions.