bluuebunny/crossref_metadata_2025 huggingface dataset:
MASSIVE YANG-MILLS THEORY: RENORMALIZABILITY VERSUS UNITARITY
Authors: DELBOURGO R. , TWISK S. , THOMPSON G.
Published: November 2004

Various massive Yang-Mills theories not based on the Higgs mechanism are investigated. They are subject to conflicting demands in the twin requirements of unitarity and perturbative renormalizability. Either one or other of these requirements is violated. Unitarity is considered in some detail.
LEVELS IN ${}_{38}^{80}{\rm Sr}$, ${}_{39}^{83}{\rm Y}$ AND ${}_{40}^{83}{\rm Zr}$ AND THE NEW REGION OF STRONG DEFORMATION AROUND N=Z≈38
Authors: RAMAYYA A.V. , HERATH-BANDA M.A. , BARCLAY M. , HAMILTON J.H. , MA W.C. , SOUNDRANAYAGAM R. , PANCHOLI S.C. , YAMADA H. , CLEEMANN L. , SCHMAL N. , EBERTH J. , HECK T. , ROTH J. , KOENIG W. , MARTIN B.
Published: November 2004

The energy levels in [Formula: see text] and [Formula: see text] were identified and investigated along with 80 Sr via in-beam γ-ray spectroscopy to explore the new region of strong deformation centered around N=Z=38. The reaction 51 V (32 S , p2n)80 Sr was studied at the Holifield Heavy Ion Research Facility and reactions 54 Fe (32 S , α2p)80 Sr ; 54 Fe (32 S , 3p)83 Y and 54 Fe (32 S , 2pn)83 Zr at the Max Planck Tandem. The deformation in the ground state band in 80 Sr observed to 12+ shows a significant increase as N decreases toward 38. A 9/2+ ground state band in [Formula: see text] observed to (29/2+) exhibits larger deformation than an excited (9/2+) band in [Formula: see text] as expected as Z moves away from 38. These nuclei support the proposal that the large deformation observed in this region arises from the reinforcing of the proton and neutron shape driving force as both N and Z approach shell gaps at large deformation for N and Z of 38.
THE MODELS OF TWO-DIMENSIONAL CONFORMAL QUANTUM FIELD THEORY WITH Zn SYMMETRY
Authors: FATEEV V.A. , LYKYANOV S.L.
Published: November 2004

An infinite set of conformally invariant solutions of the two-dimensional quantum field theory, possessing a global symmetry Zn is constructed. These solutions can describe the critical behavior of Zn symmetric statistical systems.
EQUIVALENCE OF THE LAGRANGIAN AND HAMILTONIAN BRST CHARGES FOR THE BOSONIC STRING IN THE HARMONIC AND CONFORMAL GAUGES
Authors: DEL DUCA V. , MAGNEA L. , VAN NIEUWENHUIZEN P.
Published: November 2004

We consider the BRST formalism for the bosonic string in arbitrary gauges, both from the Hamiltonian and from the Lagrangian point of view. In the Hamiltonian formulation we construct the BRST charge Q(H) following the Batalin-Fradkin-Fradkina-Vilkovisky (BFFV) formalism in phase space. In the Lagrangian formalism, we use the Noether procedure to construct the BRST charge Q(L) in configuration space. We then discuss how to go from configuration to phase space and demonstrate that the dependence of Q(L) on the gauge fixing disappears and that both charges become equal. We work through two gauges in detail: the conformal gauge and the de Donder (harmonic) gauge. In the conformal gauge one must use equations of motion, and a simple canonical transformation is found which exhibits the equivalence. In the de Donder gauge, nontrivial canonical transformations are needed. Our results overlap with work by Beaulieu, Siegel and Zwiebach on the de Donder gauge, but since we only require BRST invariance and not anti-BRST invariance, we need simpler field redefinitions; moreover, we stay off-shell.
RENORMALIZATION GROUP IN MODERN PHYSICS
Authors: SHIRKOV D.V.
Published: November 2004

Renormalization groups used in diverse fields of theoretical physics are considered. The discussion is based upon functional formulation of group transformations. This attitude enables development of a general method by using the notion of functional self-similarity which generalizes the usual self-similarity connected with power similarity laws.

From this point of view we present a simple derivation of the renorm-group (RG) in QFT “liberated” from ultra-violet divergences philosophy, discuss the RG approach in other fields of physics and compare “different” RG’s.
SUPERGRAV—A REDUCE PACKAGE FOR BOSE-FERMI EXTERIOR CALCULUS AND THE CONSTRUCTION OF SUPERGRAVITY ACTIONS
Authors: CASTELLANI L.
Published: November 2004

We describe the use of a symbolic manipulation package, written in REDUCE 3.2, for the construction of supergravity actions. As illustrative examples, some calculations in D=10, N=1 supergravity are performed.
A BOSE-FERMI MAP IN THE SU(3) LIMIT OF THE IBA
Authors: WOOD L.D. , MORRISON I.
Published: November 2004

We investigate a way of mapping bose-fermi systems within the framework of the fermion SU(3) model, using sdg-bosons with intrinsic spin and isospin. Consequences of the formalism chosen are discussed, particularly with respect to a choice of single particle transfer operator for supersymmetry models.
STUDY OF Z(N) GAUGE THEORIES ON A THREE-DIMENSIONAL PSEUDORANDOM LATTICE
Authors: PERTERMANN D. , RANFT J.
Published: November 2004

Using the simplicial pseudorandom version of lattice gauge theory we study simple Z(n) gauge models in D=3 dimensions. In this formulation it is possible to interpolate continuously between a regular simplicial lattice and a pseudorandom lattice. Calculating average plaquette expectation values we look for the phase transitions of the Z(n) gauge models with n=2 and 3. We find all the phase transitions to be of first order, also in the case of the Z(2) model. The critical couplings increase with the irregularity of the lattice.
THE CRITERION FOR NONTRIVIALITY OF λϕ4 MODEL AND ITS ULTRAVIOLET STABLE FIXED POINT
Authors: NI GUANG-JIONG , LOU SEN-YUE , CHEN SU-QING
Published: November 2004

Using the Gaussian effective potential (GEP) method, we examine the quantized λϕ4 model in detail. The criterion for existence of either a symmetric phase or a broken phase is shown to be related to the bare parameters σ0 and λ0 in [Formula: see text]. A running coupling parameter λ with its associated B(λ) function are introduced and numerically calculated for both phases. In either case, a finite λ0 exhibits as an ultraviolet stable fixed point.
HIGGS BOSON PRODUCTION VIA Z, W BOSONS AND TOPONIUM IN THE E6 SUPERSTRING MODEL
Authors: BARGER V. , WHISNANT K.
Published: November 2004

We examine the production of light Higgs bosons associated with electroweak symmetry-breaking in an E6 superstring model in Z→HZ* decays, in e+e− annihilation and in toponium decays. We find that the couplings of the lightest scalar Higgs boson [Formula: see text] in these models are very similar to those of the standard Higgs boson unless the pseudoscalar P0 in the model has mass ≤Mz. Possible new modes for Higgs boson production not found in the standard model include [Formula: see text] or [Formula: see text] and [Formula: see text] or (H+H−), where [Formula: see text] is the second lightest scalar. We give simple analytic expressions for the Higgs boson masses and mixing angles in the limit that the extra Z′ gauge boson is heavy which clearly shows the production mechanisms that are favored for a given set of model parameters. The lower bound on the mass of the charged Higgs boson associated with the electroweak symmetry breaking is 53 GeV, independent of the Z′ boson mass or mixing; this bound is realized only for very small [Formula: see text] and P0 masses. Toponium decays to [Formula: see text] and H+H− may exist at up to the per cent level for some model parameters. The dominant decay mode for [Formula: see text] could be [Formula: see text], if kinematically allowed, while the principal decays for [Formula: see text] could be [Formula: see text] or [Formula: see text] .
ON MASS SHELL RENORMALIZATION OF ONE LOOP RADIATIVE CORRECTIONS IN e+e−→W+W−
Authors: KALYNIAK P. , SUNDARESAN M.K.
Published: November 2004

In this paper, the one loop radiative corrections for the process e+e−→W+W− are re-examined adopting the on-mass shell subtraction scheme. The main purpose of the paper is to present the details of this procedure. A complete computer program for the calculation of the radiative corrections in e+e−→W+H− based on this scheme is being developed to analyze the experimental data when they become available from LEP II.
ACCELERATOR PHYSICS ISSUES AT THE SSC
Authors: JOHNSON D.E.
Published: November 2004

The proposed Superconducting Super Collider (SSC) is a high-luminosity proton-proton colliding-beam accelerator, unique in the world, providing access to particle collision energies at least an order of magnitude greater than are available at existing facilities. The design of the SSC has been previously described in the Conceptual Design Report.1 Although not the final SSC design, this paper updates the previous design to include the changes due to the change in cell phase advance from 60 to 90 degrees, and particularly emphasizes the underlying accelerator physics issues which are involved in the SSC. A brief history of the SSC program is given followed by detailed design considerations.
THEORY OF WEAK INTERACTIONS: RECENT DEVELOPMENT AND PROBLEMS
Authors: SHIFMAN M.A.
Published: November 2004

Accumulation of theoretical experience, on one hand, and experimental data, on the other, resulted in a considerable progress in weak interactions. The current literature concentrates mainly on such issues as the study of the Kobayashi-Maskawa matrix and the application of quantum chromodynamics to concrete processes. Here I discuss the most interesting developing fields referring both to old (light) and new (heavy) hadrons. The first part is devoted to [Formula: see text] oscillations and other processes of the second order yielding information on Vbu and the t quark mass. The second and the largest part describes the modern QCD-based approaches in the traditional problems (K meson and hyperon physics) and in new problems associated with heavy quarks.
SUPER YANG-MILLS THEORIES COUPLED TO SUPERGRAVTTY: TANGENT BUNDLE TO A SUPERGROUP MANIFOLD APPROACH
Authors: FOUSSATS A. , ZANDRON O.
Published: November 2004

Supersymmetric Yang-Mills theories coupled to supergravity are analyzed by using the tangent bundle to a supergroup manifold as geometrical framework. The factorization condition imposed on these theories is considered from this point of view. The so-called H-gauge transformation for both, the super Yang-Mills and supergravity one-forms gauge fields are obtained as a consequence of a change of trivialization in the corresponding coset manifold. Also, we briefly point out the existence of factorized solutions not diffeomorphically equivalent for the set of pseudo-connections one-forms or gauge fields.
ON TOLMAN'S MASS-ENERGY RELATION AND A NEW TOLMAN-TYPE RELATION
Authors: BARKER B. M. , O'CONNELL R. F.
Published: November 2004

Tolman derived the mass-energy relation [Formula: see text] using a particular choice of coordinates, viz. the Schwarzschild solution for the metric tensor in isotropic coordinates for a body of mass m at rest at the origin. Here we show that this relation retains the same form for the case of a very general coordinate system. The latter includes the Schwarzschild and harmonic coordinates as special cases. In addition, we give a new Tolman-type relation [Formula: see text]. The quantities [Formula: see text] and [Formula: see text] are the energy-momentum densities for matter and the gravitational field, respectively.
REALISTIC HIERARCHIES FROM THE SUPERSTRING
Authors: COUGHLAN G. D.
Published: November 2004

A simple phenomenological parametrization of the four-dimensional field theory arising from compactification of the ten-dimensional heterotic string is considered. Possible vacuum states of the four-dimensional theory are examined in the context of the "model" low-energy Lagrangian proposed by Witten. A large hierarchy between MP and m3/2 arises naturally for a large region of parameter space, with the compactification scale typically 0(1 − 10−2)and a vanishing cosmological constant. The presence of E6 singlet superfields with large nonperturbative masses (coming from world-sheet instantons) can drastically alter the hierarchy in certain cases, but nonetheless leads to acceptable low-energy phenomenology.
SOLITON EQUATIONS AND THE VIRASORO ALGEBRA
Authors: SEMIKHATOV A. M.
Published: November 2004

Starting in the Grassmannian set-up with a Fock space representation of the Virasoro algebra related by the Krichever map to the action of Diff S1 on J differentials on a Riemann surface, we proceed to the Kadomtsev-Petviashvily (KP) equations and show the Diff S1 generators to become certain vector fields on a manifold [Formula: see text] of pseudodifferential operators arising in the KP theory. These vector fields furnish a representations with c = 0. We conjecture that constructing its central extension may involve the Gelfand-Dikii symplectic structures on [Formula: see text].
INDUCED QUANTUM NUMBERS IN SOME 2 + 1 DIMENSIONAL MODELS
Authors: CHEN YI-HONG , WILCZEK FRANK
Published: November 2004

The fermion current induced by slow variations in background scalar and gauge fields are computed for a class of 2 + 1 dimensional σ-like models. Local current densities proportional to topological currents in the background fields are found. The coefficient depends discontinuously on certain field ratios. The induced fermion numbers we find, mesh nicely with recent results on induced angular momentum and induced statistics. In particular, the spin and statistics is intimately related to the global parity anomaly. Lattice realizations are suggested.
ACTION PRINCIPLE FOR OVERDETERMINED SYSTEMS OF NONLINEAR FIELD EQUATIONS
Authors: NISSIMOV E. , PACHEVA S. , SOLOMON S.
Published: November 2004

We propose a general scheme for constructing an action principle for arbitrary consistent overdetermined systems of nonlinear field equations. The principal tool is the BFV-BRST formalism. There is no need for star-product nor Chern-Simons forms. The main application of this general construction is the derivation of a superspace action in terms of unconstrained superfields for the D = 10N = 1 Super-Yang-Mills theory. The latter contains cubic as well as quartic interactions.
MEASURING THE CHARGINO MIXING PARAMETERS OF THE MINIMAL SUSY EXTENSION OF THE STANDARD MODEL AT e+e− COLLIDERS IN THE TEV REGION
Authors: LEIKE A.
Published: November 2004

It is proposed to measure the parameters of the chargino mixing of the minimal supersymmetric extension of the standard model by chargino pair production at e+e− colliders with TeV energies. Some information about the lightest SUSY particle and its mass can be gained. With a polarized beam the minimal SUSY extension of the Standard model could be ruled out.
NEW CLASSES OF D = 4, N = 2 SUPERSYMMETRIC NONLINEAR σ MODELS
Authors: SAĬDI E. H.
Published: November 2004

We show that there exists three independent N = 2, harmonic superspaces denoted as [Formula: see text]; [Formula: see text] and (2, 2)+−. These superspaces are in one-to-one correspondence with the three complex structures of the quaternionic body. The underlying supersymmetric nonlinear σ models preserving the SU(2) symmetry are developed. Two of them are described by a neutral hyperkahler potential. New results are obtained.
RELATIVISTIC HEAVY ION REACTIONS
Authors: BARTKE JERZY
Published: November 2004

A review of relativistic heavy ion reactions is presented, including results of the new generation of high energy experiments at CERN and Brookhaven. Data on cross sections, secondary particle multiplicities and spectra are discussed, together with the question of applicability of the superposition model and other theoretical models. Some place is also devoted to fragmentation processes (electromagnetic and nuclear) and to hypernuclei which can be effectively studied using relativistic heavy ion beams. The problem of estimation of energy density attained in relativistic heavy ion collisions is treated in more detail in connection with the search for a phase transition to quark-gluon plasma.
A CHIRALLY SYMMETRIC EFFECTIVE ACTION FOR VECTOR AND AXIAL VECTOR FIELDS IN A GLOBAL COLOR SYMMETRY MODEL OF QCD
Authors: ROBERTS C. D. , PRASCHIFKA J. , CAHILL R. T.
Published: November 2004

We consider the quantum field theory of a model of an extended Nambu-Jona-Lasinio type with a QCD based nonlocal fermion current-current interaction which has global SU(Nc) symmetry. We obtain an exact bosonization of this model in four Euclidean dimensions using auxiliary bilocal fields and discuss the dynamical breakdown of chiral symmetry in the massless fermion limit. A local field bosonization is obtained by decomposing the bilocal fields in terms of complete orthonormal sets of functions with the expansion coefficients, which are local functions, identified as the local meson fields. Retaining the ground state pseudoscalar, vector and pseudovector local fields we obtain a local effective action for this sector of the theory. The derivative expansion of the fermionic determinant necessary to obtain this local action is self-regularizing because of the bilocal substructure present in the model which is manifest in the form factors that are associated with the local fields. In our local action the value of each coefficient depends critically on the underlying fermionic dynamics through these form factors and the vacuum functions. As a consequence of this the vector and pseudovector fields in the theory are best interpreted as simple fermion-antifermion bound states rather than as massive Yang-Mills fields or exotic composites of the pseudoscalars; interpretations that we find are not in general admitted when models such as the GCM are treated correctly. Identifying then the physical vector and pseudovector fields with the linearly transforming chiral partners introduced by the bosonization, we obtain an effective action for this sector of the meson spectrum which predicts values for the kinematic and dynamic quantities associated with these fields.
MICROSCOPIC SELF-CONSISTENT AND COLLECTIVE MODEL DESCRIPTION OF LOW-ENERGY NUCLEAR STRUCTURE
Authors: HEYDE K.
Published: November 2004

In the present review, an attempt is made to approach the different facets of the nucleus at low excitation energy from both a microscopic, self-consistent and a collective model approach. Some attention is given on how to relate the two “opposite” approaches to nuclear structure. In a final chapter, we discuss some newly appreciated modes in the nucleus that are specific to the proton and neutron degrees of freedom e.g. the study of intruder states near closed shells and the presence of proton-neutron mixed-symmetry collective motion.
A PLACE FOR TECHNICOLOR IN GUT
Authors: GRECH DARIUSZ K.
Published: November 2004

A possibility of incorporation of the extra QCD-like forces into the unified models of interactions is analysed. It is shown that this is possible only for models with the naive number of fermion generations gN=0, but thanks to the new QCD-like symmetry, the observable number of them can be as large as gR=8. All such models are listed. Then the asymptotic behavior of such theories including the effects of decoupling is investigated. It is found that in none of the unified models the additional strong forces are asymptotically free. This excludes them as possible candidates for technicolor interactions causing dynamical breaking of the standard SU(3)c× SU(2)L×U(1)y model.
NUMERICAL REEXAMINATION OF SUPERSYMMETRIC AND NONSUPERSYMMETRIC SU(5)-LIKE GRAND UNIFIED MODELS
Authors: GRECH DARIUSZ K.
Published: November 2004

The significance of numerical analysis in both nonsupersymmetric and supersymmetric Grand Unified Theories is pointed out. The exact analytical and numerical analysis we present shows a need of larger corrections to the values of unifying parameters, i.e. sin 2 θw, Mx, τp than those often quoted in literature. When an unmodified nonsupersymmetric version of SU(5) is considered we show that numerical computation allows some of the models still to be experimentally admissible. The difference between analytical and numerical results for the supersymmetric SU(5) model is also stressed. In particular, corrections due to the mass threshold of additional generations or supersymmetric particles are calculated both analytically and numerically at the two-loop level. We found them far more important for the final values of sin 2 θw, Mx and τp than the effects of Higgs-Yukawa couplings between scalars and fermions.
TOPONIUM DECAY TO A HIGGS BOSON AND BOTTOM QUARKS
Authors: BARGER V. , HAN T. , KEUNG W.-Y.
Published: November 2004

The pseudoscalar (ηt) and vector (θt) toponium states may decay to a neutral Higgs boson and a [Formula: see text] pair. For mH≲30 GeV we find branching fractions of a few times 10−4 for Mηt ≳ 130 GeV or Mθt ≳ MZ. We also present the dynamical distributions of the decay products. We find that [Formula: see text] may be observable for Mθt ~ 120-160 GeV and mH ≲ 30 GeV .
EFFECTIVE CHIRAL LAGRANGIANS, THE QUARK MODEL OF SUPERCONDUCTIVITY TYPE AND THE PROBLEM OF P-A DIAGONALIZATION
Authors: VOLKOV M.K. , IVANOV A.N. , TROITSKAYA N. , NAGY M.
Published: November 2004

The vertices appearing after the inclusion of P-A transitions and a subsequent diagonalization of the chiral Lagrangian are analyzed in the quark model of superconductivity type. These vertices can conditionally be divided into physical and nonphysical ones. It is shown that if the Pauli-Villars regularization is used, the contribution of the latter can be eliminated from the description of the physical processes. This is in full agreement with the experimental data.
SUPERSYMMETRIC QUANTUM MECHANICS AND PARTIAL ALGEBRAIZATION OF THE SPECTRAL PROBLEM
Authors: SHIFMAN M.A.
Published: November 2004

It is shown how Witten’s supersymmetric quantum mechanics can be used to expand the class of quasi-exactly-solvable problems discovered recently.
SUPERSYMMETRIC MODELS WITH EXTENDED HIGGS SECTOR
Authors: DREES MANUEL
Published: November 2004

The Higgs sector of supersymmetric models with an additional SU (2)× U (1)Y singlet or an additional pair of Higgs doublet superfields is investigated. It is shown that in the model with a Higgs singlet bounds on Higgs boson masses are considerably weaker than in the minimal supersymmetric model; in particular, all neutral scalars can be heavier than about 150 GeV or lighter than [Formula: see text], whereas the mass of the charged Higgs boson is essentially unconstrained. The four doublet model resembles the minimal model more closely; in particular, the bounds for the heaviest and lightest neutral scalar and the heaviest charged Higgs boson are unaltered. In this model, many relations between masses of different Higgs bosons can be found; 44 of the 66 possible decays of one Higgs boson into another Higgs boson plus a real W or Z boson are kinematically forbidden. It is also shown that in both models, the lightest neutral scalar becomes indistinguishable from the standard model Higgs boson if all other Higgs bosons of the model are much heavier than Mw.
HOLOMORPHIC QUANTUM MECHANICS, CONFORMAL REFLECTION AND THE INTERNAL SYMMETRY OF HADRONS
Authors: BANDYOPADHYAY PRATUL
Published: November 2004

It is shown here that the holomorphic quantum mechanics in a complexified Minkowski space-time helps us to study the geometrical feature of the internal space of a particle and its relevance with conformal geometry. It is noted that the conformal reflection can be depicted in the formalism of an internal helicity which takes the value [Formula: see text] and [Formula: see text] for the particle and antiparticle state. This again can be described in the framework of holomorphic quantum mechanics in terms of the half-orbital angular momentum of a constituent in an anisotropic space in the sense of Minkowski space-time with a fixed lz value for the particle and antiparticle configuration when a composite system is considered. A massive or massless spinor moving with such characteristic in the configuration of a composite system can be depicted as a Cartan semispinor and behaves as a twistor. The doublet of such spinors with opposite helicities represent an eight-component conformal spinor. The internal symmetry group SU(3) for a composite system of hadrons can then be realized from the reflection group. This formalism reveals the microlocal region of a complexified Minkowski space-time as a twistor space.
ASYMPTOTIC SCALING IN QUARK AND GLUON JET MULTIPLICITY DISTRIBUTIONS IN NEXT-TO-LEADING ORDER QCD
Authors: MALAZA E. D.
Published: November 2004

We study asymptotic scaling in quark and gluon jets in QCD beyond the leading most singular contributions of the double logarithmic approximation. We work to [Formula: see text] of perturbative QCD.
COLLECTIVE SPIN FROM THE LINEARIZATION OF THE SCHRÖDINGER EQUATION IN MULTIDIMENSIONAL RIEMANNIAN SPACES USED IN COLLECTIVE NUCLEAR MODELS
Authors: HERRMANN RICHARD , PLUNIEN GÜNTER , GREINER MARTIN , SCHEID WERNER
Published: November 2004

The free Schrödinger equation in Riemannian collective spaces with an arbitrary number of dimensions is linearized. The coupling of external fields is discussed. The operators to classify collective spin states are introduced and the collective Pauli equation is derived.
SOLUTION OF THE BCS MODEL
Authors: IZMAILOV ALEXANDER F. , KESSEL ALEXANDER R.
Published: November 2004

The exact calculation of the reduced BCS model quantum partition function in the region of temperatures T > Tc was carried out by the path integration method. The partition function demonstrates the critical behavior at some temperature Tc. It turns out that this temperature is larger than the critical temperature T'c obtained in the traditional theories which are valid in the temperature region T < T'c.
THERMAL MASS SHIFTS IN OPEN SUPERSTRING MODELS
Authors: CLAVELLI L. , ELMFORS P. , HARMS B. , SKAGERSTAM B.-S. , STERN A.
Published: November 2004

We investigate some thermodynamical properties of an open type I superstring model in six space-time dimensions. The model is free of tachyons at the tree level but acquires a tachyonic one-loop mass shift at zero-temperature. Even though the space-time supersymmetry is spontaneously broken, the asymptotic form of the fermionic and bosonic level densities are the same, i.e. there is a unique Hagedorn temperature TH. As expected, TH is a limiting temperature, i.e. the energy density of the string gas diverges at T=TH. The finite temperature one-loop correction to the mass of the scalar mesons, which are massless at three level, is calculated and is found to be finite for all temperatures. It is found that thermal corrections do not stabilize the zero-temperature one-loop tachyonic mass shift of the model.
PURE WESS-ZUMINO ACTIONS IN 1+1 DIMENSIONAL NONLINEAR σ-MODELS
Authors: STERN A.
Published: November 2004

We examine the Hamiltonian formulation for a 1+1 dimensional nonlinear σ-model where the action is given solely by a Wess-Zumino term. The theory corresponds to the Wess-Zumino-Witten model where the standard nonlinear chiral model action is absent. We find that the Poisson bracket algebra for the currents corresponds to a Kac-Moody algebra. The system, however, contains second class constraints which we eliminate via the construction of Dirac brackets. The Kac-Moody algebra is then not realized by the Dirac brackets. Instead, new (nonlocal) terms appear in the algebra of the conserved currents which appear to obstruct quantization.
ON THE VACUUM STABILITY IN THE SUPERRENORMALIZED YUKAWA-TYPE THEORY
Authors: EFIMOV G.V. , GANBOLD G.
Published: November 2004

The stability of the ground state and the possibility of the appearance of a phase transition in the superrenormalizable nonlocal Yukawa-type field theory are investigated.

A variational estimation of the upper bound for the effective potential is obtained.

It is shown that there exists a finite critical value for the boson-fermion coupling constant.

The initial vacuum becomes unstable when this coupling constant exceeds the critical value. As a result, the system under consideration goes into the phase with nonvanishing expectation value of the field.
FOUR DIMENSIONAL FERMIONIC STRING THEORIES AND SYMMETRIC ORBIFOLDS
Authors: BAILIN DAVID , DUNBAR DAVID C. , LOVE ALEX
Published: November 2004

Aspects of the connection between the free fermion formulation of four dimensional string theories and orbifolds are explored, and the ideas are illustrated by reference to simple models obtained by realizing the internal degrees of freedom of a bosonic string as free fermions.
CONFORMAL FIELD THEORY AND PURELY ELASTIC S-MATRICES
Authors: FATEEV V.A. , ZAMOLODCHIKOV A.B.
Published: November 2004

Particular perturbations of a 2D Conformal Field Theory leading to Integrable massive Quantum Field Theories are examined. The mass spectra and S-matrices for some models, including the field theory of the Ising Model with magnetic field and “thermal” deformations of the tricritical Ising and 3-state Potts models, are proposed. The hidden Lie-algebraic structures of these spectra and their relation to the Toda systems are discussed.
QCD SUM RULE APPROACH TO THE K→VACUUM WEAK AMPLITUDE
Authors: AHMED M.A. , RASHEED M.S.
Published: November 2004

We study the kaon-to-vaccum weak matrix element using the method of the QCD duality finite energy sum rules. It is found that the matrix element in question can be expressed as a sum of two terms: one behaving like ms−md and the other like [Formula: see text]. Detailed numerical estimates are also given.
REFLECTION ASYMMETRIC SHAPE IN 221Ra
Authors: LIANG C.F. , PARIS P. , BRIANÇON CH. , SHELINE R.K.
Published: November 2004

Mass separated sources of 225Th were used to study the level structure of 221Ra following alpha decay. Fluorination techniques were used to obtain the selectivity in atomic number. The low lying levels in 221Ra are interpreted in terms of K=5/2± and 3/2± parity doublet bands which occur naturally from reflection asymmetric models. The anomalous spin sequences in the K= 3/2± bands of 221Ra are interpreted in terms of their Coriolis coupling with K=1/2± bands with large decoupling parameters. The low-lying parity doublet bands in 221Ra, 223Ra and 225Ra, and particularly the Coriolis coupling of their K=3/2± bands, are compared and contrasted.
FACE ALGEBRAS AND EXACT BETHE ANSATZ SOLUTIONS FOR SOS MODELS
Authors: VEGA H.J. DE
Published: November 2004

An analog of the Yang-Baxter Algebra (YBA) is defined in face language. The operators tαα′,ββ′(θ) introduced here enjoy all essential properties of the vertex language YBA. Using this face YBA an algebraic Bethe Ansatz (BA) is constructed for SOS models (unrestricted IRF models). The face dual of the six-vertex model and the critical ABF model are worked out explicitly. Eigenvectors and eigenvalues of the transfer matrix are found and the corresponding BA equations derived and compared with the six vertex BAE.
THE LINEAR σ-MODEL AND FINITE TEMPERATURE EFFECTS
Authors: CONTRERAS C. , LOEWE M.
Published: November 2004

We discuss the temperature effects on the masses and couplings constants in the linear σ-model including the effective pion decay constant fπ(T). We analyze in detail the region where our discussion is valid. The temperature effects on masses include an explicit discussion concerning the role of the thermal tadpoles as a mass contribution due to the vacuum.
VERTEX OPERATORS FOR THE CLOSED BOSONIC STRING THEORY AT ARBITRARY GENUS IN THE OPERATOR FORMALISM
Authors: LUGO ADRIAN R.
Published: November 2004

A systematic procedure for constructing vertex operators for the physical states of the closed bosonic string theory at genus g in the operator formalism is presented. The method is based on imposing suitable commutation relations with the generators of the conformal transformations required by unitarity of scattering amplitudes. An Arakelov-type metric on the Riemann surface naturally arises in the case of the tachyon, which allows to define vertex operators at higher levels via covariant derivatives. They involve covariant derivatives of the curvature with respect to this metric as it happens in the path integral approach. As a particular result, the Fradkin-Tseytlin dilaton coupling is obtained.
FUSION MATRICES AND C<1 (QUASI) LOCAL CONFORMAL THEORIES
Authors: FURLAN P. , GANCHEV A. CH. , PETKOVA V.B.
Published: November 2004

General properties of the fusion matrices and their explicit expression given by the Uq( sl (2)) quantum 6j-symbols are exploited to analyze some two dimensional c<1 conformal theories. The primary fields structure constants of the local theory, corresponding to the (A10, E6) modular invariant, and of the Z2 quasilocal analogs of the (A, D) and (A10, E6) series, are computed. The list of the Γ0(2) submodular invariant partition functions on the torus is extended.
EXACTLY SOLVABLE CONFORMALLY INVARIANT QUANTUM FIELD MODELS IN D DIMENSIONS
Authors: FRADKIN E.S. , PALCHIK M. Ya.
Published: November 2004

A class of exactly solvable models of the conformally invariant quantum field theory in D dimensions is proposed. It is shown that in any conformal theory of the field φ(x) with the scale dimension d there exists an infinite collection of the tensor fields Ps of the ranks and the dimensions ds=d+s independently of the type of interaction. These tensor fields appear in the product Tµν(x1)φ(x2) operator expansion where Tµν is the energy-momentum tensor. The fields Ps are analogues to the certain superpositions of the secondary fields of D=2 models. The existence of the fields Ps follows from the structure of the Ward identities for the energy-momentum tensor conformally invariant Green functions.

Each model of the above-mentioned class is defined by the operator equation Ps(x)=0. The method of solving these models is proposed. Some of the models coincide with the certain lagrangian models. The method allows us to obtain closed differential equations for each Green function of fundamental and composite fields, and also algebraic equations for scale dimensions of the fields. The derivation of all these equations is based on the energy momentum conformal Ward identities’ specific property. Detailed analysis of the Ward identities is given in the paper.

It is shown that each D>2-model involves a special scalar field PD−2 with the scale dimension dP=D−2. This field is an analogue of the central charge of D=2 models and becomes the constant coinciding with the central charge when D=2.

A new class of D=2 models with broken infinite parametric symmetry is obtained. In each model the closed differential equations for the highest Green functions are derived and the central charge is calculated. The general method of solving the D≥2 models is illustrated on examples of Thirring and Wess-Zumino-Witten models and on a trivial model in four-dimension space.
QCD JET MULTIPLICITIES AT THE SSC
Authors: ODORICO R.
Published: November 2004

Jet multiplicity distributions and corresponding cross sections are calculated at the energy of the SSC collider. Their impact on the level of the 4-jet background to the WW, WZ and ZZ signals is discussed.
ON THE NECKING-IN PROCESS IN CLUSTER DECAYS
Authors: DEPTA K. , MARUHN J. A. , WANG HOU-JI , SĂNDULESCU A. , GREINER W. , HERRMANN R.
Published: November 2004

Two new macroscopic models (liquid drop and Yukawa-plus-exponential) describing the decays with emission of large fragments including alpha decay are developed. The proposed shape parametrization consists of two intersecting spheres smoothly joined by a third "rolling sphere". The first two spheres describe asymptotically the charge and mass asymmetries and the third one the necking-in process. It is shown that the potential energy surfaces in the neck and the relative distance between the centers of the spheres (for a given mass and charge fragmentation) lead to different dynamical paths depending on the mass and charge of the emitted fragment. Along the path a phenomenological shell correction term and a zero point vibrational energy are introduced. It is shown that this model gives an excellent description of the present experimental data.
THE METHOD OF COADJOINT ORBITS: AN ALGORITHM FOR THE CONSTRUCTION OF INVARIANT ACTIONS
Authors: DELIUS GUSTAV W. , VAN NIEUWENHUIZEN PETER , RODGERS V. G. J.
Published: November 2004

The method of coadjoint orbits produces for any infinite dimensional Lie (super) algebra A with nontrivial central charge an action for scalar (super) fields which has at least the symmetry A. In this article, we try to make this method accessible to a larger audience by analyzing several examples in more detail than in the literature. After working through the Kac-Moody and Virasoro cases, we apply the method to the super Virasoro algebra and reobtain the supersymmetric extension of Polyakov's local nonpolynomial action for two-dimensional quantum gravity. As in the Virasoro case this action corresponds to the coadjoint orbit of a pure central extension. We further consider the actions corresponding to the other orbits of the super Virasoro algebra. As a new result we construct the actions for the N = 2 super Virasoro algebra.
RAPIDITY DEPENDENCE OF MULTIPLICITY DISTRIBUTIONS IN ALPHA-EMULSION INTERACTIONS AT 12.4A GEV
Authors: AGGARWAL M. M. , ARORA R. , BERI S. B. , BHATIA V. S. , KAUR M. , MITTRA I. S. , KUMAR V. , PALSANIA H. S. , LAL P. , SHUKLA V. S. , GILL A. , BHALLA K. B. , LOKANATHAN S. , BADYAL S. K. , BHASIN A. , GUPTA V. K. , KITROO S. , MANGOTRA L. K. , RAO N. K. , CLAESSON G. , GARPMAN S. , LUND I. , OTTERLUND I. , STENLUND E. , SODERSTROM K.
Published: November 2004

We present results based on an analysis of alpha-emulsion interactions at 12.4A GeV. The multiplicity distributions of shower particles in the restricted rapidity intervals are well described by negative binomial distributions (NBD). The behaviour of parameters [Formula: see text] and 1/k of the NBD with increasing Δy in the backward hemisphere is quite different from that found in elementary collisions. Star size dependence is also investigated. An attempt has been made to interpret the results in the framework of a clan model. In the forward hemisphere the average decay multiplicity of clans is small [Formula: see text] and seems to be target-independent, whereas bigger clans are produced in the backward hemisphere and their sizes seem to depend on the target size. Also the average number of clans in the backward hemisphere is less than that in the forward hemisphere and shows target size dependence. Clans seem to be produced independently and their extent in rapidity seems to be target-independent.
ROLE OF GLUON FRAGMENTATION IN THE LEPTONIC BACKGROUND AT THE SSC
Authors: ODORICO R.
Published: November 2004

Inclusive charged lepton yields from the decays of hadronically produced charm and bottom particles at the energy of the SSC collider are presented. The gluon fragmentation contribution is found to dominate at small and moderate pτ.
EVOLUTION EQUATION IN THE FIELD THEORY OF STRINGS
Authors: MARUI MIHO , SUGAMOTO AKIO , ODA ICHIRO
Published: November 2004

A stringy version of the Altarelli-Parisi equation is given within the field theory of bosonic strings formulated in the light-cone gauge. Using this equation, we study the behavior of the decay function of strings under the change of reference scale, especially imposing an assumption of large transverse momentum. In some cases the n-th moment of the decay function behaves very differently from QCD.
SCHWINGER α-PARAMETRIC REPRESENTATION OF FINITE TEMPERATURE FIELD THEORIES: RENORMALIZATION
Authors: BENHAMOU M. , KASSOU-OU-ALI A.
Published: November 2004

We present the extension of the zero temperature Schwinger α-representation to the finite temperature scalar field theories. We give, in a compact form, the α-integrand of Feynman amplitudes of these theories. Using this representation, we analyze short-range divergences, and recover in a simple way the known result that the counterterms are temperature-independent.
EUCLIDEAN WILSON LOOP AND AXIAL GAUGE
Authors: NARDELLI G. , SOLDATI R.
Published: November 2004

A critical analysis is given in order to set up a well-defined perturbative expansion for Yang-Mills Euclidean theories within the axial gauge choice, using Cauchy principal value prescription to handle the spurious singularities. It is shown that, following a mathematically meaningful and unambiguous procedure, the exponential behavior of the Euclidean Wilson loop does not occur at variance with the covariant and planar gauge choices. A comparison with previous similar approaches and results is worked out in order to clearly understand the reasons for the breakdown of gauge invariance in the present case. In particular we can conclude that the so far proposed alternative prescriptions, which have been claimed to restore gauge invariance, should be carefully reexamined, at least for the Euclidean formulation.
Processing, Structure, and High-Temperature Superconductivity
Authors: Engler E.M. , Beyers R.B. , Lee V.Y. , Nazzal A. , Lim G. , Parkin S.S.P. , Grant P.M. , Vazquez J.E. , Ramirez M.L. , Jacowitz R.
Published: November 2004

The superconducting behavior in oxygen defect perovskite oxides is found to depend on the amount and order of oxygen in the structure. In the case of Y 1 Ba 2 Cu 3 O 9−y, the highest and sharpest transitions are related to ordering of one-dimensional Cu-O ribbons in the structure which are in turn coupled to a network of adjacent 2-dimensional Cu-O sheets. The isostructural rare earth derivatives of Y 1 Ba 2 Cu 3 O 9−y are found to display similar behavior.
A NEW AVENUE OF IMPROVING THE BEHAVIORS OF Y-Ba-Cu-O SUPERCONDUCTING CERAMICS
Authors: Yin Fuchang , Chen Shoutian , Liu Jianmin , Liu Fuyi , Sun Hongtao , Wu Xiaoqing , Yang Baitun , Yao Xi
Published: November 2004

Based on systematic investigation of Y 1−x Ba x CuO 3 high Tc superconducting materials, a further study on the effects of various ion additives on their conduction behaviors has been carried out. It has been found that types and amount of ions as well as sintering temperature exhibit remarkable influence on Tc of the materials. A small amount of cobalt ion additive can significantly increase the zero resistance temperature of the materials. A Y-Ba-Cu-O superconducting ceramic with a given amount of cobalt ion additive having zero resistance temperature of 110K and transition width of 1.5K has been achieved.
A SDUTY OF SUPERCONDUCTING OXIDE Y-Ba-Cu-Sn-O
Authors: Jin Xin , Shao Huimin , Wang Guiqin , Lu Mu , Zhang Hanhe , Lin Chengyi , Chen Wuming , Ji Jiaben , Zhang Jiamei , Zhao Jiwan
Published: November 2004

A high-Tc superconductor YBa2Cu3 Snx07+z was characterized. We observed the existence about 90K superconductivity in variety of compositions. The samples were examined by x-ray diffraction , Mössbauer, SEM and EDS. Their structure are still ABO3 perovskite but part of Cu atoms are displaced by Sn. It was observed that when the x increased the critical current density were increased based on the measurements of magnetic hysteresis.
SUPERCONDUCTIVITY IN Y-Ba-Cu(Cr)-O SYSTEM
Authors: Xianyu Z. , Li R.J. , Zhao Q.H. , Liu L.Q. , Wang Q.T. , He Y.F. , Xiu Z.M. , Li D.X. , Shao Z.B. , Chen T.G. , Gao R.P. , Tu Y , Li Y. , Jin H.Y. , Li D.J. , Hong J.E. , Liu F. , Liu Z.J. , Jia Y.Q. , Sun J.Q.
Published: November 2004

We report the superconductor of Y-Ba-Cu-O system, with Tci= 100K , Tc=95K , Tcf=94.1K and Δ Tc=1K . The structural analysis by X-ray diffraction shows that single phase superconductor has order-disorder transformation around 220K and phase transformation takes place in the multiphase sample in the range of (123–173K). This indicates that the phase transformation related to the high Tci.

With the substitution of Cr for Cu, with Cu:Cr=2:1 we have also obtained the superconductor with Tci=95.5 , Tc=91K , Tcf=86.3K and Tc=1K X-ray structural analysis shows that the major superconducting phase of this system is hexagonal phase.
HREM STUDY ON THE DEFECTS OF Y-Ba-Cu-O SUPERCONDUCTORS
Authors: Liang Yuehai , Chen Jun , Wang Luchun , Yian Yong , Pan Xiaoqing , Wei Ming , Jin Xing , Wang Guiqing , Feng Duan
Published: November 2004

HREM study on the defects in high Tc superconductor YBaCuO discovered recently was reported. It was found that there are large amounts of local lattice distortions, point defects and misarrangements of Y or Ba atoms within the specimens observed. HREM images of grain boundaries and interfaces between the crystal state and so-called intermediate ordered state have been obtained. The tripled period lattice image has local distortion, especially near the interfaces.
PHASE RELATION,CRYSTAL STRUCTURE AND SUPERCONDUCTIVITY IN Ba-La-Cu-O SYSTEM
Authors: Dong Cheng , Liang Jinkui , Che Guangcan , Xie Sishen , Zhao Zhongxian , Yang Qiansheng , Ni Yomgmin , Liu Guirong
Published: November 2004

Great efforts have been made to study the copper-containing oxide system since the discovery of superconductivity in Ba-La-Cu-O sestem was reported by Bednorz and Müller(1). In order to identify the reasons of superconductivity and explore new supurconductive material, it is crucial to determine the phase relations and crystal structures of the superducting compounds. The compound with Tc about 40K has been revealed to have the K2N1F4 type structure. The phase diagram of Ba-La-Cu-O system was studied by Che et al. in our laboratory,and another superconducting compound with Tc about 15K was discovered (2). The present study are concentrated on the superconductivity of the materials with nominal compositions La1−xBaxCuO3−y and the phase relation in this system.
SUBSOLIDUS PHASE RELATIONSHIPS AND SUPERCONDUCTIVITY IN Gd2O3-BaO-CuO SYSTEM
Authors: LIANG Jingkui , Xu Xianting , RAO Guanghui , XIE Sishen , SHAO Xiuyu , DUAN Zhanguo
Published: November 2004

The 960°C subsolidus phase relationships in the Gd2O3-BaO-CuO system were determined by means of X-ray diffraction as well as superconductive properties measurements. In the measured partial diagram, two ternary compounds occur: GdBa2Cu3O9−y and Gd2BaCuO5 The relationships between composition and superconductivity were also reported in this paper.

Since superconductivity in Ba-Y-Cu-O system was reported(1, 2), many authors have measured the phase diagram for this system (3, 4). In a recent communication we reported superconductivity existing in Ba-Gd-Cu-O system(5). Now we present the results of partial subsolidus phase relationships sintered at 960°C in air, which in turn provide a basis for the sample preparetion technology. We also discussed the effect of compositions on the sintering temperature in this paper.
DYNAMICS OF TWIN BOUNDARIES AND HIGH Tc SUPERCONDUCTORS
Authors: Horovitz B. , Barsch G.R. , Krumhansl J.A.
Published: November 2004

The formation of coherent arrays of twins in a tetragonal to orthorhombic transition and its effects on electronic properties are studied. The twin boundary oscillations (“dyadons”) have an anisotropic dispersion with frequencies typically ≲1010 sec −1 for wavevectors perpendicular to the boundaries. This results in a ~T2 contribution to the specific heat for T≳ 1° K and a linear temperature dependence of the resistivity. The unusual anisotropy yields vertex corrections which diverge at high temperatures and can enhance T c.
POSSIBLE RESONATING VALENCE BOND TRAPPING BY IMPURITIES IN HIGH TEMPERATURE SUPERCONDUCTORS, OBSERVED BY MÖSSBAUER SPECTROSCOPY
Authors: Tihov J. , Vasilev P. , Kostadinov I. , Mateev M. , Rusanov V. , Ivanov Ts.
Published: November 2004

Ytrium-based high temperature superconductor (HTS) YBa2Cu3O7−y was studied electrically, by Mössbauer spectroscopy and also structurally. The anomaly in the 90 K region of the Mössbauer spectra and resistivity suggests strongly trapping of the resonating valence bond (RVB) of oxigen vacancies on the base of the orthorombic cell.
Anomalous Resistance Behaviour in Non-Superconducting Y–Ba–Cu–O at High Pressures.
Authors: Sastry V. Sankara , Kalavathi S. , Guha B.K. , Baskaran R. , De U. , Janaki J. , Radhakrishnan T.S. , Thomas K.A. , Rao G.V. Subba
Published: November 2004

Electrical resistance measurements at low temperatures and high quasihydrostatic pressures on superconducting and non-superconducting varieties of Y0.8Ba1.2Cu2O5 (obtained by annealing in oxygen. and air respectively) show striking anomalies in the vicinity of 100K and 40K. Arguments are presented to show that these anomalies as also the occurrence of Tc’s in the oxide superconductors in the vicinity of 100K or of 40K are connected with their layered structure containing planes of Cu–O octahedral complexes.