bluuebunny/crossref_metadata_2025 huggingface dataset:
CAN THE NEUTRINOS FROM Z0-DECAY OSCILLATE?
Authors: YU. SMIRNOV A. , ZATSEPIN G. T.
Published: November 2004

A common prejudice is that neutrinos produced by the decays of real or virtual Z0-bosons do not oscillate. We will show that this is incorrect even in case of the universality of interactions and of the absence of sterile neutrinos. In Z0-decay the coherent state of neutrino pairs is produced. The oscillation picture can be observed in principle by measuring the flavors of both neutrinos from the same Z0-decay.
CURRENT ALGEBRA OF WZNW MODELS AT AND AWAY FROM CRITICALITY
Authors: ABDALLA E. , FORGER M.
Published: November 2004

We derive the current algebra of principal chiral models with a Wess-Zumino term. At the critical coupling where the model becomes conformally invariant (Wess-Zumino-Novikov-Witten theory), this algebra reduces to two commuting Kac-Moody algebras, while in the limit where the coupling constant is taken to zero (ordinary chiral model), we recover the current algebra of that model. In this way, the latter is explicitly realized as a deformation of the former, with the coupling constant as the deformation parameter.
ONE-LOOP TOPOLOGICAL MASS IN QED2+1 WITHIN A BROAD CLASS OF GAUGE INVARIANT REGULARIZATION SCHEMES
Authors: NOVOTNÝ J.
Published: November 2004

An explicit calculation of the one-loop topological mass term within a broad class of gauge invariant regularization schemes developed recently is presented for (2+1)-dimensional QED. This provides an uniform description of the results obtained recently in the literature and an explanation of their regularization scheme dependence. The Pauli-Villars and dimensional regularization are discussed in more detail in this context and an alternative formulation of dimensional regularization in (2+1) dimensions is described.
RADIATIVE CORRECTION PARAMETER S IN BEYOND-THE-STANDARD MODELS
Authors: INAMI T. , LIM C. S. , YAMADA A.
Published: November 2004

The electroweak parameter S, one of the three parameters describing the oblique radiative corrections due to heavy particles, is estimated in three types of beyond-the-standard models: multi-doublet Higgs model, technicolor-like model and minimal SUSY model. We show that the global chiral symmetry SU (2)L or SU (2)R plays a useful role in analyzing S.
STRONG COUPLING QED BREAKS CHIRAL SYMMETRY
Authors: SEMENOFF GORDON W.
Published: November 2004

We show that the strong coupling limit of d-dimensional quantum electrodynamics with 2d/2[d/2] flavors of fermions can be mapped onto the s=1/2 quantum Heisenberg antiferromagnet in d–1 space dimensions. We use this mapping to prove that the strong coupling limit of QED breaks chiral symmetry. The staggered Néel order parameter of the antiferromagnet is the expectation value of a mass operator in QED and the spin-waves are pions. We speculate that the chiral symmetry breaking phase transition corresponds to a transition between the flux phase and the conventional Néel ordered phase of an antiferromagnetic t-J model.
COPRODUCT OF VECTOR FIELDS ON THE QUANTUM LORENTZ GROUP
Authors: CHRYSSOMALAKOS C.
Published: November 2004

We use properties of the L± matrices, specific to the case of the q-deformed Lorentz group, to derive expressions for the coproduct of its bicovariant vector fields.
QUANTIZATION OF REDUCED CHERN–SIMONS GRAVITY WITH A SOURCE
Authors: NAZARENKO A. V.
Published: November 2004

Using the Dirac's theory of constraints, procedure of reduction of field degrees of freedom, whose number is restricted by equations of motion and topological conditions, is proposed. Such a procedure is applied in the case of space with the topology of a torus to the Chern–Simons gravity generalized by inclusion of a source. It is shown that in this system some modular transformations preserving the volume do not lead to physically equivalent states. Such a breaking of modular symmetry reduces the degeneration of quantum states with preservation of continuous spectrum of the volume operator. Probability of transition between spaces of different volumes is computed.
SUPERCONDUCTIVITY AND SUPERSYMMETRIC QED3
Authors: CARENA M. , CLARK T.E. , WAGNER C.E.M.
Published: November 2004

Current theories of high temperature superconductivity are based on the behavior of the ideal (2+1)-dimensional anyon gas at finite density. The anyon gas can be described using fundamental fermionic or bosonic matter in interaction with a topologically massive statistical gauge field. If the renormalized Chern-Simons coefficient at zero density takes the values γR(0)=N/2π, the anyon gas is a superfluid, and if the fundamental matter is electrically charged, it behaves like a superconductor. In this article we analyze an ideal anyon gas composed of two anyonic species, each associated with fundamental matter that has different (fermionic and bosonic) statistics. For supersymmetric values of the masses and couplings, no exotic statistics can occur when the system is in a superconducting state at finite density. However, semionic superconductivity can be achieved when the supersymmetry is very softly broken by a fundamental boson-fermion mass splitting.
NEW SCALING VARIABLE FROM LIGHT-CONE PERTURBATION THEORY
Authors: MA BO-QIANG , SUN JI
Published: November 2004

We argue from both the quark language and the free field light-cone expansion in light-cone perturbation theory that the constraint of overall “energy” conservation in deep inelastic lepton-nucleon scattering yields a similar new scaling variable xp, which reduces to the Weizmann variable, the Bloom-Gilman variable and the Bjorken variable at some approximations. The xp rescaling is expected to be a good scaling variable, and hence gives strong power-law type corrections to the deviations of Bjorken scaling. An understanding of this xp rescaling from both the free field operator product expansion (OPE) and the ordinary OPE is also given, indicating it is likely a higher order effect in the coefficient functions, i.e. it does not belong to the higher twist effect. Therefore this xp rescaling is likely a new effect contributing to the power-law type corrections.
CHERN-SIMONS QUANTUM MECHANICS, SUPERSYMMETRY, AND SYMPLECTIC INVARIANTS
Authors: BLAU MATTHIAS
Published: November 2004

We explain the relation between supersymmetry and equivariant cohomology, combining recent investigations of Chern-Simons quantum mechanics and path integrals on coadjoint orbits. We then construct a supersymmetric (topological) quantum mechanics model whose partition function — probing the cohomology of the symplectomorphism group — yields a symplectic invariant introduced by Weinstein.

We demonstrate by explicit calculation that this provides another example where the Duistermaat-Heckman theorem (exactness of the semi-classical approximation) appears to hold in infinite dimensions, and make some suggestions concerning its role in (conformal) field theory.
CALCULATION OF EXPONENT η TO O(1/N2) IN THE O(N) GROSS NEVEU MODEL
Authors: GRACEY J.A.
Published: November 2004

The critical exponent η is calculated in the Gross Neveu model in arbitrary dimensions to next to leading order within the 1/N expansion, by computing the skeleton equations for the propagators near the critical region. The exponent ν is also computed and the next to leading order structure of the β-function deduced. Consequently, the four-loop term of the anomalous dimension is determined.
SYMPLECTIC STRUCTURE ON THE SET OF GEODESICS OF A RIEMANNIAN MANIFOLD
Authors: CARIÑENA JOSÉ F. , LÓPEZ CARLOS
Published: November 2004

A natural symplectic structure is defined on the set of oriented geodesics of a Riemannian or pseudo-Riemannian manifold. Particular examples—the set of straightlines of a plane and the set of light rays of an optical system—are developed.
DILEPTONS AND PHOTONS IN HIGH ENERGY HEAVY ION REACTIONS: A REVIEW
Authors: RAHA SIBAJI , SINHA BIKASH
Published: November 2004

We review the production of dilepton pairs, direct photons and diphoton pairs in ultrarelativistic heavy ion collisions, with special attention to the applicability of these particles as the signal for a new state of matter—the quark-gluon plasma.
COVARIANTLY QUANTIZED D=4, N=1 GREEN-SCHWARZ SIGMA MODELS
Authors: MAJUMDAR PARTHASARATHI
Published: November 2004

The Batalin-Vilkovisky quantization technique is used to provide a manifestly Lorentz covariant quantization of the σ-model describing the D=4 heterotic Green-Schwarz superstring propagating in a background superpsace consisting of minimal supergravity “entangled” with a tensor multiplet. The ultraviolet finiteness properties of the one-loop effective action are shown to be identical to those obtained earlier using a manifestly non-covariant gauge-fixing condition.
ANALOG OF THE “EMC EFFECT” IN NEUTRINO-NUCLEUS INTERACTIONS
Authors: LASSILA K.E. , SUKHATME U.P.
Published: November 2004

We have recently demonstrated that the main features of the EMC effect at all x follow straightforwardly if multiquark clusters exist in nuclei with physically reasonable probabilities. Here, we examine neutrino and antineutrino reactions as possible ways to explore multiquark clusters and other sources of the EMC effect. We find that the neutrino and antineutrino probes are able to emphasize different momentum fraction regions and allow discriminating experiments to be done.
LOW-LYING MESON SPECTROSCOPY AND CONFINEMENT
Authors: ANISOVICH V.V. , GERASYUTA S.M. , SARANTSEV A.V.
Published: November 2004

The paper is devoted to the construction of low-energy quark-scattering amplitudes. The amplitudes of dressed quarks qq→qq and [Formula: see text] are calculated in the framework of the dispersion N/D method with the help of the iteration bootstrap procedure including two types of point-like input interactions, namely the four-fermion interaction with quantum numbers of the gluon and four-fermion interaction induced by instantons (the exchanges of white states with JP=0±). The mass values of the lowest mesons (JP=0−, 1−, 0+) and their quark content are obtained. In the colour meson channel a bound state was found which corresponds to the constituent gluon with the mass MG=0.67 GeV . The qq-amplitudes in the colour state [Formula: see text] have the diquark levels with JP=0+ and the masses mud=0.72 GeV and mus=mds=0.86 GeV . The interaction of dressed quarks appeared to be an effectively short-range one. The calculated amplitudes satisfy the Okubo-Zweig-Iisuka rule. The creation of mesons (pion included) is mainly due to the gluon exchange. The mesons with heavy quarks (c and b) are considered also, using the calculated forces. We discuss the possibility of constructing the amplitudes which take into account the quark confinement.
HIGHER SPIN ALGEBRAS AND QUANTIZATION ON THE SPHERE AND HYPERBOLOID
Authors: VASILIEV M.A.
Published: November 2004

The oscillator-type realization is proposed for the continuous set of infinite-dimensional algebras of quantum operators on the two-dimensional sphere and hyperboloid. This realization is typical for infinite-dimensional higher spin algebras related to higher spin gauge theories. It involves the Klein-type operator that emerges nontrivially in the Heisenberg-type commutation relations for the oscillators. The invariant trace and bilinear form are constructed. The latter is shown to degenerate for all odd-integer values of the continuous parameter ν, which parametrizes the class of algebras under investigation. The degeneration points are shown to correspond to ordinary finite-dimensional matrix algebras and superalgebras. Possible applications of these results to higher spin gauge theories are discussed. In particular, it is noted that the deformation parameter ν can be interpreted as a vacuum value of some auxiliary scalar field in an appropriate higher spin gauge theory.
A NON-PERTURBATIVE APPROACH TO SYMMETRY BEHAVIOUR IN THE OPEN EINSTEIN UNIVERSE
Authors: ROY BARNANA
Published: November 2004

We use the Schrödinger formulation of quantum field theory to study symmetry behaviour in the static open Einstein universe.
STATE SPACE IN BRST-QUANTIZATION AND KUGO-OJIMA QUARTETS
Authors: RYBKIN G.N.
Published: November 2004

The structure of the state space in the BRST-quantization is considered and the connection between different approaches to the proof of the positive-definiteness of the metric on the physical state space is established. The correspondence between different expressions for the BRST-charge, quadratic in fields, is obtained. The relation between different representations of the BRST-algebra is found.
CHERN-SIMONS THEORY, MODULAR FUNCTIONS AND QUANTUM MECHANICS IN AN ALCOVE
Authors: MAJID SHAHN , SOIBELMAN YA. S.
Published: November 2004

We show how the vacuum expectation value of the Wilson loop of the trivial knot in the left-regular representation in a Chern-Simons theory is basically the partition function for a quantum particle confined to a certain bounded region (namely, an alcove of the gauge group Lie algebra). For example, for su(3) the particle is confined to an equilateral triangle. The result follows from mathematical work on the category-theoretic rank of quantum groups obtained in a previous paper. In the present paper we give the details of the physical interpretation and discuss the implications. In particular, both these physical systems are connected with number theory.
QUADRONIUM: UNRAVELLING THE e+e− PUZZLE
Authors: GRIFFIN JAMES J.
Published: November 2004

The development of the Quadronium scenario for the e+e− puzzle is reviewed. The Quadronium (strong binding) hypothesis leads to a two-stage (spontaneous creation)/(energy inflation) production process for Q0, which can yield decay lines as narrow in energy as those observed, and which suggests that Q0 may either be created free, or bound to an outgoing heavy ion. In turn, this bound/free dichotomy provides a template for analyzing the experimental facts, which yields a good semiquantitative description of the EPOS data. Remarkably, this description of the later stages of the process is independent of the internal structure of the decaying object, and yet provides predictions for much of the available data.

Finally, the bound decays imply a new (and so far never studied) process of sharp annihilative positron emission (SAPosE), in which the electron is captured into a Bohr — Dirac orbit of the nuclear ion, and the positron emerges with a total energy equal to the energy of the decaying Q0 state plus the binding energy of the electron. These successes focus the attention on the underlying hypothesis: How can one prove definitively either that Q0 is or is not strongly bound?
TOWERS OF ALGEBRAS IN RATIONAL CONFORMAL FIELD THEORIES
Authors: GOMEZ CÉSAR , SIERRA GERMAN
Published: November 2004

Jones fundamental construction is applied to rational conformal field theories. The Jones algebra which emerges in this application is realized in terms of duality operations. The generators of the algebra are an open version of Verlinde’s operators. The polynomial equations appear in this context as sufficient conditions for the existence of Jones algebra. The ADE classification of modular invariant partition functions is put in correspondence with Jones classification of subfactors.
A GAUGE-INVARIANT FLUID DESCRIPTION OF PRIMORDIAL DENSITY FLUCTUATIONS OF COLLISIONLESS PARTICLES
Authors: SCHAEFER ROBERT K.
Published: November 2004

Formulas are derived for describing the evolution of fluctuations in the density of collisionless particles in the expanding universe using the gauge-invariant fluid description. The formulas use the “gauge-invariant” variables proposed by Bardeen to describe cosmological perturbations. These variables are hydrodynamic in nature and we show the behavior of the equations when the particles have streaming lengths large compared to the scales of interest. We also show how these equations couple gravitationally when other species of matter are present in significant densities. Using the “fourteen moment” approximation for the particle distribution function, we get a simple set of ordinary differential equations which are much easier to use than a direct integration of the Boltzmann equation. This formulation is especially useful when we are considering universes with more than one cosmologically significant component of matter density. An example of a numerical integration of the evolution equations is presented for comparison of this method to other work. A formula for calculating fluctuations in the cosmic microwave background radiation is also given.
DYNAMICS OF AND SUPERSELECTION RULES ON ONE-DIMENSIONAL MULTIPLY CONNECTED SYSTEMS
Authors: ANEZIRIS CHARILAOS N.
Published: November 2004

In this paper we study the dynamics of one-dimensional multiply connected systems, or networks, and find under what conditions the Hamiltonian is self-adjoint. These conditions give the spectrum, and impose superselection rules in the “non-Abelian” case. We discuss the spectrum and superselection rules for some special cases.
A STATISTICAL ANALYSIS OF THE CHLORINE SOLAR NEUTRINO EXPERIMENT
Authors: NUNOKAWA HIROSHI , MINAKATA HISAKAZU
Published: November 2004

A detailed analysis is performed so as to reveal the statistical significance of the possible anticorrelation between the solar neutrino flux, measured by the 37 Cl experiment, and the sunspot activity. We find that the new data added since 1986 do contribute to improving the significance of the anticorrelation. However, we also observe that the statistical significance depends upon the treatment of errors rather sensitively. Therefore, we conclude that the anticorrelation is not definitively established at the present stage of the experiment. We also point out the possibility of a new type of correlation.
CONSTRAINTS ON HEAVY NEUTRINO DECAYS IN THE EARLY UNIVERSE
Authors: GRANEK HENRY , McKELLAR BRUCE H.J.
Published: November 2004

A numerical model of interactions of photons with the electron-proton plasma in the early universe at temperatures below the electron rest mass is used to constrain the branching ratio for massive neutrinos and photons. The model includes the double Compton process, which was shown49, 80 to be more important than bremsstrahlung at the relatively low densities of electrons and protons encountered. A generalised kinetic equation for interactions of electromagnetic radiation with matter in an expanding universe is derived.
OPERATOR QUANTIZATION OF THE MASSLESS SUPERPARTICLE
Authors: PLYUSHCHAY M.S.
Published: November 2004

The quantization of the massless Brink-Schwarz superparticle in four-dimensional space-time in terms of independent variables and by the Gupta-Bleuler method is developed. The connection between these two approaches to quantization of the model is retraced and covariantization of the latter one is realized. The properties of the system under spatial inversion are explored and the quantum theory which is invariant with respect to it is constructed.
NOVEL STATISTICS FOR STRINGS AND STRING “CHERN-SIMON” TERMS
Authors: ANEZIRIS C. , BALACHANDRAN A.P. , KAUFFMAN L. , SRIVASTAVA A.M.
Published: November 2004

We study the statistics of identical strings in R3. Novel possibilities for string statistics are shown to exist at least in the absence of physical inputs such as the possibility of string pair creation. There are for instance strings which do not obey Bose, Fermi or parastatistics. There are also strings which violate the standard spin-statistics relation. The Abelian Chern-Simons Lagrangian which leads to anyons is generalized to strings. It leads to exotic phase changes of wave functions when strings are moved in homotopically nontrivial loops in the N-string configuration space. Non-Abelian generalizations of this Abelian string Lagrangian are also proposed.
HEAVY-ION COLLISION PHENOMENOLOGY
Authors: JACOB M.
Published: November 2004

This review is the full version of an invited contribution to the session on heavy-ion collisions at the Singapore Conference, where several topical points were discussed in detail, through a series of talks.
SEARCHING FOR AN OPTIMAL LATTICE COLOUR DIELECTRIC THEORY
Authors: GROSSMANN B. , PIRNER H.J. , SIGNAL A.I. , BAIER R. , WROLDSEN J.
Published: November 2004

We investigate the use of renormalization group transformations (RGTs) to define an effective colour dielectric theory on the lattice. Starting from the pure gauge sector of SU(2), we try to find an optimal RGT which leads to an effective action with few parameters. We test this effective action by simulating the colour dielectric theory on the lattice and checking for operator matching.
STRANGE BARYON SPECTRA IN A BETHE-SALPETER DYNAMICAL MODEL
Authors: LONDERGAN J.T. , MITRA A.N.
Published: November 2004

A Bethe-Salpeter equation (BSE) has been derived using a covariant confining interaction motivated from QCD. Recently, this interaction has been applied to a qqq system under the null plane ansatz (NPA), which reduces the resulting equations to three-dimensional form. For equal mass quarks, encouraging results were obtained for baryon masses and quantum numbers. In the present paper, this formalism is generalized to unequal mass kinematics and applied to the spectroscopy of strange baryons (Λ, Σ, Ξ, Ω). All input parameters are fixed from previous calculations. The reduced qqq equation in the NPA is solved algebraically in a six-dimensional harmonic oscillator basis, on lines analogous to the corresponding techniques developed for the equal mass qqq problem. The results on the Λ, Σ spectra are in good agreement with data, where available, up to levels N=5. Our results are compared with those from another relativized potential of baryon masses.
STOCHASTIC INFLATION AND QUANTUM COSMOLOGY
Authors: MIJIĆ MILAN
Published: November 2004

We review stochastic inflation and its consequences for the interpretation of wave functions in quantum cosmology.
A MODEL OF QUANTUM GRAVITATIONAL COLLAPSE
Authors: GREENSITE J.
Published: November 2004

Some issues in the quantum mechanics of gravitational collapse are discussed in the framework of a simple minisuperspace model, consisting of a Friedman metric coupled to a massless scalar field. The model illustrates the role of intrinsic time coordinates in parametrizing gravitational collapse through a singularity, and the relevance of quantizing the metric scale factor over an infinite, rather than half-infinite, range.
TRANSVERSE POLARIZATION AT e+e− COLLIDERS AND CP VIOLATION FROM NEW PHYSICS
Authors: BURGESS C.P. , ROBINSON J.A.
Published: November 2004

We investigate the implications of CP violation from new physics for the process [Formula: see text] using transversely polarized electrons at SLC and LEP. We define an asymmetry whose nonzero value signals the time reversal violation of the underlying interactions. Using a general effective Lagrangian we analyse the signal expected from any new physics. We show that for a large class of theories this observable is exclusively sensitive to a single CP-violating electron gauge boson dimension six interaction. Experiments at LEP can probe such CP violation from new physics at scales up to several TeV.
A COMPACT BOSON COUPLED TO TWO-DIMENSIONAL GRAVITY
Authors: SAKAI NORISUKE , TANII YOSHIAKI
Published: November 2004

The radius dependence of partition functions is explicitly evaluated in the continuum field theory of a compactified boson, interacting with two-dimensional quantum gravity (noncritical string) on Riemann surfaces for the first few genera. The partition function for the torus is found to be a sum of terms proportional to R and 1/R. This is in agreement with the result of a discretized version (matrix models), but is quite different from the critical string. The supersymmetric case is also explicitly evaluated.
The geometry of the KdV equation
Authors: Segal Graeme
Published: November 2004

In this talk I shall give a fairly geometrical account of the main facts about the KdV equation on the circle, explaining in particular how it is related to the group Diff(S1), and why it is a completely integrable Hamiltonian system. In §4 I shall describe the theorem of Drinfeld and Sokolov [1] which shows that the KdV system can be regarded as a symplectic quotient of a coadjoint orbit of the loop group of SL2(R). Finally, in §5 I shall explain how the theory generalizes from second-order equations and SL2 to nth-order equations and SLn: the resulting classical system is the one whose quantization leads to the Zamolodchikov algebra Wn. My aim is purely expository: all the material is well known.
Properties of covariant W gravity
Authors: Schoutens K. , Sevrin A. , Nieuwenhuizen P. van
Published: November 2004

We present the beginnings of a new consistent gauge theory with spin 2 and spin 3 gauge fields in two dimensions. It is based on a nonlinear Lie algebra, whose “gauging” is discussed in detail. (The present treatment of the gauge sector is expanded as compared to [3]). For the coupling to matter, we introduce the concept of a “nested covariant derivative”, and we obtain an invariant action by solving a functional integrability condition. It reads
GALILEI-INVARIANT QUANTUM FIELD THEORIES WITH PAIR INTERACTIONS: A REVIEW
Authors: NARNHOFER HEiDE , THIRRING WALTER
Published: November 2004

We exhibit a class of quantum field theories where particles interact with pair potentials and for which the time evolution exists in the Heisenberg representation. The essential condition for existence is stability in the thermodynamic sense and this is achieved by having the interaction fall off with the relative momenta of the particles. This can be done in a Galilei-invariant manner. We show that these systems have some mixing properties which one postulates in ergodic theory but which are difficult to prove for classical systems.
INTEGRAL REPRESENTATION OF THE N=4 CONFORMAL ANOMALY
Authors: SAIDI E.H. , ZAKKARI M.
Published: November 2004

Extended super-Riemann surfaces are studied and their underlying superconformal properties are derived as solutions of an operator equation. Superconformal tensors and differential forms are discussed in detail and are shown to be classified by means of a triplet of integers or half-integers. The integration on super-Riemann surfaces is developed. Finally, we derive the solution of the N=4 anomaly compatible with the non-locality feature and discuss the necessary conditions for its vanishing. A heuristic geometrical interpretation of these conditions is also given.
CORRELATIONS AND INTERMITTENCY IN HIGH ENERGY MULTIHADRON DISTRIBUTIONS
Authors: CARRUTHERS P. , EGGERS H.C. , GAO QIANG , SARCEVIC INA
Published: November 2004

The linked-pair approximation to the hierarchy of cumulant correlation functions is tested in the central rapidity domain, where approximate translation invariance is appropriate. The bin-averaged factorial moments up to the fifth order are well described in terms of the second-order experimental moment for final states created in hadronic collisions. Given the two-particle correlation function, the only constants appearing in the higher moments are very close to those-appropriate to the negative binomial distribution, as pointed out recently by De Wolf. The close correspondence of the linked-pair decomposition to the same structure occurring in galaxy correlations (with slightly different coefficients) is noted, as is the apparently negative binomial character of the number distribution of galaxies in clusters. Preliminary results are discussed for the rapidity distributions arising in proton-nucleus and nucleus-nucleus collisions. We present a variety of fits to correlation functions and also discuss bin-bin correlations deriving from our model.
SUPERCONFORMAL GEOMETRY FROM THE GRASSMANN AND HARMONIC ANALYTICITIES II: THE N=4 SU(2) CONFORMAL CASE
Authors: SAIDI E.H. , ZAKKARI M.
Published: November 2004

N=4 SU(2) conformal invariance is studied in the harmonic superspace. It is shown that the N=4 SU(2) conformal structure is equivalent to the harmonic analyticity. The solutions to the superconformal constraints are worked out in detail and the conformal properties of all objects of interest are given. A realization of the N=4 current in terms of the free (F.S.) hypermultiplet is obtained.
AXIAL ANOMALIES AND FOUR-DIMENSIONAL COUNTERPARTS OF DIMENSIONAL REGULARIZATION
Authors: NOVOTNÝ J.
Published: November 2004

A regularization of the fermion determinant is discussed within a four-dimensional counterpart of the canonical dimensional regularization developed recently. The γ5 anomaly is obtained and compared with those obtained within other regularization schemes. The equivalence with the ζ function regularization as well as the Fujikawa regularizations is shown. As a byproduct a Fujikawa regulator for the canonical dimensional regularization is constructed.
CORRELATION FUNCTIONS OF INTEGRABLE 2D MODELS OF THE RELATIVISTIC FIELD THEORY: ISING MODEL
Authors: YUROV V.P. , ZAMOLODCHIKOV AL. B.
Published: November 2004

A program is proposed to study numerically the correlation functions in massive integrable 2D relativistic field theories. It relies crucially on the exact form factors of fields which can be reconstructed from the factorized scattering data. The correlation functions are expressible as infinite sums over intermediate asymptotic states. We suggest using computer power to perform the summation numerically. The convergence of the sum is tested for the simplest example of the scaling Ising spin-spin correlations (without magnetic field).
CAUSALITY PRINCIPLE AND RETRODICTION IN QUANTUM PHYSICS
Authors: SHIROKOV M.I.
Published: November 2004

The causality principle (CP) states that the cause can only be inside the past light cone of an effect. The principle is used in choosing retarded solutions to field equations and also in the Bogoliubov derivation of dispersion relations. However, using CP leads to the following problem: CP determines a “time arrow” in microphysics and shuts out other ways of explaining time irreversibility in Nature (based on statistical physics, cosmology, etc). It is shown that CP can be replaced by the condition that we consider only prediction problems, sometimes together with the use of a principle which is weaker than CP: the cause cannot be outside an effect’s light cones. The retrodiction problem and verification of CP in quantum mechanics are discussed.
FROM PARTONS TO CONSTITUENT QUARKS
Authors: INDUMATHI D. , MURTHY M.V.N. , RAVINDRAN V.
Published: November 2004

We discuss the moments of the proton structure functions F2(x) and g1(x) via the operator-product formalism. We introduce an effective mass for the quarks through an equation of motion. Making use of this, we show that successive moments of a structure function are related to one another in a simple manner. Specifically, the ratios of successive moments depend only on the square of the mass parameter so introduced, and not on the explicit operator matrix elements themselves. Experimental data on the moments indicate that this mass is around 300 MeV, of the order of the constituent quark mass. We strengthen our results by evaluating the moments in a bag model with massive nonstrange quarks.
BOUNDARY CONDITIONS IN FIRST QUANTIZATION
Authors: SIEGEL W.
Published: November 2004

In the BRST approach to first quantization, bosonic ghosts can cause ambiguities in the cohomology (and thus in second quantization). We show how nonminimal terms give a general solution to this problem, avoiding the need for “picture-changing operators.” As examples, we consider spinning particles, superparticles, covariantized light cone bosonic string field theory, and NSR superstring field theory.
PHASE TRANSITIONS IN THE ABELIAN HIGGS MODEL AT FINITE DENSITIES
Authors: PETER V.J. , SABIR M.
Published: November 2004

We study the U(1)-invariant Abelian Higgs model at a finite temperature and a finite chemical potential, at the one-loop level of approximation, and show the existence of chemical-potential-induced multiple-phase transitions at finite temperatures. The temperature and density dependence of the coupling constants is also analyzed. The gauge invariance of the results obtained is demonstrated.
EXCLUSIVE PHOTON-PROTON REACTIONS AT MODERATELY LARGE MOMENTUM TRANSFER
Authors: KROLL P. , SCHÜRMANN M. , SCHWEIGER W.
Published: November 2004

The diquark model in which protons are viewed as being built up by quarks and diquarks (the latter are treated as quasi-elementary constituents at moderately large momentum transfer) is applied to Compton scattering off protons and combined with similar studies of the electromagnetic form factors of nucleons and of [Formula: see text]. It is demonstrated that the model is able to describe very well the data for these reactions at moderately large values of the momentum transfer with a common set of parameters. We also investigate the helicity dependence of the amplitudes. Very interesting and characteristic predictions for various observables are given. In particular a sizeable transversal polarization of the proton is obtained for Compton scattering.
DYNAMICS OF EUCLIDEANIZED EINSTEIN-YANG-MILLS SYSTEMS WITH ARBITRARY GAUGE GROUPS
Authors: BERTOLAMI O. , MOURÃO J.M. , PICKEN R.F. , VOLOBUJEV I.P.
Published: November 2004

We describe the dynamics of euclideanized SO(4)-symmetric Einstein-Yang-Mills (EYM) systems with arbitrary compact gauge groups [Formula: see text]. For the case of SO(n) and SU(n) gauge groups and simple embeddings of the isotropy group in [Formula: see text], we show that in the resulting dynamical system, the Friedmann equation decouples from the Yang-Mills equations. Furthermore, the latter can be reduced to a system of two second-order differential equations. This allows us to find a broad class of instanton (wormhole) solutions of the EYM equations. These solutions are not afflicted by the giant-wormhole catastrophe.
THE WAVE FUNCTION OF THE UNIVERSE AND p-ADIC GRAVITY
Authors: AREF’EVA I. YA. , DRAGOVICH B. , FRAMPTON P.H. , VOLOVICH I.V.
Published: November 2004

A new approach to the wave function of the universe is suggested. The key idea is to take into account fluctuating number fields and present the wave function in the form of a Euler product. For this purpose we define a p-adic generalization of both classical and quantum gravitational theory. Elements of p-adic differential geometry are described. The action and gravitation field equations over the p-adic number field are investigated. p-adic analogs of some known solutions to the Einstein equations are presented. It follows that in quantum cosmology one should consider summation only over algebraic manifolds. The correspondence principle with the standard approach is considered.
A FUNCTIONAL FORMALISM FOR MULTIPARTON INTERACTIONS IN HIGH ENERGY COLLISIONS
Authors: CALUCCI G. , TRELEANI D.
Published: November 2004

We present a generating functional formalism suited to the treatment of multiple partonic interactions in high energy hadronic and nuclear collisions. In simple nontrivial cases closed expressions for the semihard cross section are obtained and partonic correlations in the multiparton distributions are explicitly taken into account.
QUANTUM EFFECTS IN A COMBINATION OF A CONSTANT UNIFORM FIELD AND A PLANE WAVE FIELD
Authors: GITMAN D.M. , NOSKOV M.D. , SHVARTSMAN SH. M.
Published: November 2004

Quantum effects are considered in the external field, which is a superposition of a constant uniform electromagnetic field and a plane wave field. The complete and orthonormal sets of solutions to the Klein-Gordon and Dirac equations are constructed for this field. The probabilities of scattering and pair creation are calculated. The representations of various Green functions, which are used in quantum electrodynamics with unstable vacuum, are obtained. The radiative processes are explored for the field under consideration.
PHASE DIAGRAM AND ORTHOGONAL POLYNOMIALS IN MULTIPLE-WELL MATRIX MODELS
Authors: LECHTENFELD OLAF , RAY RASHMI , RAY ARUP
Published: November 2004

We investigate a zero-dimensional Hermitian one-matrix model in a triple-well potential. Its tree-level phase structure is analyzed semiclassically as well as in the framework of orthogonal polynomials. Some multiple-arc eigenvalue distributions in the first method correspond to quasiperiodic large-N behavior of recursion coefficients for the second. We further establish this connection between the two approaches by finding three-arc saddle points from orthogonal polynomials. The latter require a modification for nondegenerate potential minima; we propose weighing the average over potential wells.
THE GAUSSIAN APPROXIMATION FOR THE λφ4THEORY AT FINITE TEMPERATURE REVISITED
Authors: GRASSI FRÉDÉRIQUE , HAKIM RÉMI , SIVAK HORACIO D.
Published: November 2004

This paper is devoted to a systematic study of the λφ4 theory in the Gaussian approximation and at finite temperature. Although our results can be extended in a straightforward manner to other dimensions, only the case of four (1+3) dimensions is dealt with here. The Gaussian approximation is implemented via the moments of the field φ, a method somewhat simpler than the Gaussian functional approach. Furthermore, the effective potential (equivalently, the free energy) is calculated through the evaluation of the energy-momentum tensor of quasiparticles endowed with an effective mass. This effective mass generally obeys a gap equation, which is analyzed and solved. Besides the “precarious” solution of Stevenson or the “autonomous” one of Stevenson and Tarrach, which are recovered and rediscussed, several nonperturbative solutions, either exhibiting “spontaneous symmetry breaking” or not, are obtained with the help of systematic expansions of various physical quantities in powers of ε, the parameter occurring in the dimensional regularization scheme used throughout this paper. The effects of temperature are discussed in detail: phase transitions in the precarious or autonomous solutions occur. Other simple Gaussian (but not minimal) solutions for the effective potential (free energy) are also obtained.
NONLINEAR SCHRÖDINGER EQUATIONS ON SUPER SYMMETRIC SPACES RELATED TO LIE SUPERALGEBRAS A(m, n)
Authors: CANOḠLU AHMET , GÜLDOḠAN BAHRİ , SALİHOḠLU SELÂMİ
Published: November 2004

We obtain new integrable coupled nonlinear partial differential equations by assuming that the soliton connection has values in the Lie superalgebras A(m, n). These equations are coupled nonlinear Schrödinger equations on various super symmetric spaces.
STATISTICS IN ONE DIMENSION
Authors: ANEZIRIS C. , BALACHANDRAN A.P. , SEN DIPTIMAN
Published: November 2004

We show that there are novel generalizations of statistics for identical particles in one dimension. These arise due to possible boundary conditions on wave functions, or equivalently due to δ-function interactions, at points of coincidence of particle coordinates. Special choices of these boundary conditions describe bosons, fermions or paraparticles. The general solution for the boundary conditions involves vector-valued wave functions and statistics with non-Abelian features, even though the classical configuration space has an Abelian fundamental group. Physical models leading to such non-Abelian statistics, involving for example δ-function interactions of spins, are constructed. Properties under parity and time reversal of the new boundary conditions are studied. It is shown that the Bethe ansatz does not always give eigenstates of energy. When it does, the wave numbers in the ansatz for three or more particles must satisfy a weaker form of the Yang-Baxter equations and certain additional equations. The energy spectrum and wave functions for identical particles on R1 or S1 are discussed in some simple cases. Our work generalizes the previous work of Lieb and Liniger, Lieb, Yang and Leinaas and Myrheim.
SU(2)k MODULAR-INVARIANT PARTITION FUNCTIONS FROM ORBIFOLDS
Authors: ARDALAN F. , ARFAEI H. , ROUHANI S.
Published: November 2004

We present a method which generates the modular-invariant partition functions of the ADE series of SU(2)k. Dividing the diagonal theory by discrete subgroups of the conformal group, we construct all the modular-invariant partition functions, thus proving that orbifold construction generates all the partition functions of SU(2)k.
STRANGE-PULSAR MODELS
Authors: BENVENUTO O.G. , HORVATH J.E. , VUCETICH H.
Published: November 2004

v1.6 We review the theory and observational status of strange-pulsar models. After introduction of the subject, a summary of observational facts about pulsars is presented. The theory of quark matter and strange matter relevant to astrophysical applications is briefly discussed, and applied afterwards to type-II supernova theory and to pulsar models. A discussion of the comparison with observation shows the viability of strange-pulsar models.
GENERALIZED VOLKOV PROBLEM
Authors: SHISHKIN GERMAN V. , YASIN MOHAMMED A.
Published: November 2004

We consider the Dirac equation in Minkowski space-time in Cartesian coordinates with external wave fields of different tensor structures, namely in the presence of scalar, vector, pseudoscalar, pseudovector, coupled vector and tensor, and coupled vector and pseudovector waves, i.e. we consider the generalized Volkov problem. The solution of the Dirac equation is reduced to that of a system of four equations, two of which are first-order ordinary differential equations and two are algebraic ones. Series of new solutions of the Dirac equation are obtained.
STRESS TENSOR PERTURBATIONS IN CONFORMAL FIELD THEORY
Authors: CAMPBELL MARC , NELSON PHILIP , WONG EUGENE
Published: November 2004

We reconsider the problem of deforming a conformal field theory to a neighboring theory which is again critical. An invariant formulation of this problem is important for understanding the underlying symmetry of string theory. We give a simple derivation of A. Sen’s recent formula for the change in the stress tensor and show that, when correctly interpreted, it is coordinate-invariant. We give the corresponding superconformal perturbation for superfield backgrounds and explain why it has no direct analog for spin-field backgrounds.
SYSTEMATICS OF SUPERDEFORMATION FROM A~8 TO A~248
Authors: SHELINE R.K. , SOOD P.C. , RAGNARSSON INGEMAR
Published: November 2004

The systematics of superdeformation (∈≈0.6) is studied throughout the mass regions from A~8 to the fission isomers with A~242, including the recently observed superdeformed nuclei with A~152 and ~192. Strong shell effects are calculated which are described in a shell energy landscape in terms of valleys of stability which proceed from oblate through spherical to normal-deformed (∈≈0.25–0.3) and on to superdeformed and hyperdeformed (∈≈0.86) shapes with increasing nucleon number. Local minima in these valleys are calculated for prolate nuclei with 4, 10, 16, 28–32, 40–44, 60–66, 80–86, 110–116 and 140–150 neutrons and/or protons when the ratio of the major to minor axes is ≈ 2:1 and the deformation ∈≈0.6. Although the local minima represent the regions of greatest stability, the shell energy valleys should be viewed as more or less continuous structures in which a variety of different deformations can occur. Other local minima in the valleys of the shell energy landscape are observed for oblate (∈≈−0.75) and hyperdeformed nuclei. When shell effects are added to the liquid-drop potential in the Nilsson-Strutinsky formalism, spherical and normal deformation shapes tend to predominate. However, superdeformed, oblate and hyperdeformed shapes are also predicted. In the case of superdeformed nuclei, shell effects predominate over the liquid-drop potential for the light nuclei creating superdeformed ground states. In intermediate-mass nuclei, the liquid-drop potential predominates and superdeformation is only observed at fairly high energy and at high spins where the superdeformation is stabilized. In the heaviest nuclei, the combined effect of the Coulomb potential and the fissionability of the liquid drop causes the potential to reach a maximum at ∈≈0.6. The shell effect then produces a second minimum 2–3 MeV above the ground state with its coexisting spectroscopy. Existing experimental data throughout the nuclear periodic table are shown to be in remarkable agreement with theoretical expectations. Predictions of new regions of superdeformation are presented.
ANALYTIC RESULTS FOR THE EFFECTIVE ACTION
Authors: BLAU STEVEN K. , VISSER MATT , WIPF ANDREAS
Published: November 2004

Motivated by the seminal work of Schwinger, we obtain explicit closed-form expressions for the one-loop effective action in a constant electromagnetic field. We discuss both massive and massless charged scalars and spinors in two, three and four dimensions. Both strong-field and weak-field limits are calculable. The latter limit results in an asymptotic expansion whose first term reproduces the Euler-Heinsenberg effective Lagrangian. We use the prescription of zeta-function renormalization, and indicate its relationship to Schwinger’s renormalized effective action.
ON THE INTERPRETATION OF HIGHER-DIMENSIONAL TERMS IN QCD-INSPIRED LAGRANGIANS
Authors: ANDRIANOV A.A. , ANDRIANOV V.A. , MANASHOV A.N.
Published: November 2004

Using a method of double chiral bosonization for π, π′ and σ mesons we clarify the origin of some vertices in the effective chiral Lagrangian. The coupling and decay constants, masses, are calculated for π′ and σ mesons.
THE HUBBARD U=∞ MODEL IN ONE DIMENSION - THE SLAVE BOSON METHOD AS ALTERNATIVE BOSONIZATION SCHEME
Authors: Schmeltzer D.
Published: November 2004

The Hubbard U=∞ in one dimension is equivalent to a non-interacting spinless fermion in a gauge field. The gauge field induced by spin fluctuations is described by a gas of instantons. This gas is in the plasma phase which leads to the decoupling of spin and charge at large distances.
CORRELATED FERMIONS IN ONE DIMENSION
Authors: SCHULZ H.J.
Published: November 2004

A brief introduction to the bosonization method for interacting one-dimensional fermion systems is given. Using these results, the long-distance decay of correlation functions in the one-dimensional Hubbard model is determined exactly for arbitrary bandfilling and correlation strength, using the exact solution of Lieb and Wu. For infinite U the results are generalized to the case of nonzero nearest-neighbour interaction. The behaviour of thermodynamic quantities, of the frequency-dependent conductivity, and of the thermopower is also discussed, in particular in the proximity of the metal-insulator transitions occurring for half- and quarter-filling. The one-dimensional Luttinger liquid is shown to be unstable in the presence of interchain hopping. The results for the metal-insulator transition are compared with other scenarios developed in higher dimensions.
HOLE-HOLE CORRELATIONS IN THE 2D HUBBARD MODEL
Authors: Sorella S. , Parola A. , Tosatti E.
Published: November 2004

The hole-hole correlation function in the 2D Hubbard model is investigated in the low doping regime both via Monte Carlo simulations for U=4 and Lanczos diagonalization on a 16 site cluster for very large U. The results are compared with available theoretical predictions for the strong coupling limit. There is a clear short range repulsion, but no signature of hole-hole attraction is found in either case. At U=4 correlations are still remarkably weak-coupling-like. For large U, they become rather similar to those of hard core bosons.
Questions, Controversies and Frustration in Quantum Antiferromagnetism
Authors: Chandra P. , Coleman P. , Ritchey I.
Published: November 2004

The search for a gapless spin liquid phase has raised many issues in quantum antiferromagnetism. Here we review recent developments in this field, and in particular address questions and controversies surrounding a proposed “spin nematic” state.