bluuebunny/crossref_metadata_2025 huggingface dataset:
HOW TO SOLVE QUANTUM NONLINEAR ABELIAN GAUGE THEORY IN TWO DIMENSIONS IN THE HEISENBERG PICTURE
Authors: IKEDA NORIAKI
Published: September 2003

The new method based on the operator formalism proposed by Abe and Nakanishi is applied to the quantum nonlinear Abelian gauge theory in two dimensions. The soluble models in this method are extended to a wider class of quantum field theories. We obtain the exact solution in the canonical-quantization operator formalism in the Heisenberg picture, so this analysis might shed some light on the analysis of gravitational theory and nonpolynomial field theories.
EXPONENTIALLY SMALL COUPLINGS BETWEEN TWISTED FIELDS OF ORBIFOLD STRING THEORIES
Authors: BRAX PH. , TUROK NEIL
Published: September 2003

We investigate the natural occurrence of exponentially small couplings in effective field theories deduced from higher-dimensional models. As a concrete example we calculate the coupling between twisted fields of the Z3 Abelian orbifold compactification of the heterotic string. These are described by an effective field theory coupling the ten-dimensional massless gauge bosons to the four-dimensional twisted fields. The propagation of massive winding modes between the fixed points of the orbifold induces exponentially small couplings between the massless twisted fields. The resulting small couplings have an exponential dependence on the mass of the intermediate states and the distance between the fixed points.
THE CLASSICAL RELATIVISTIC QUARK MODEL IN THE REST FRAME WIGNER – COVARIANT COULOMB GAUGE
Authors: ALBA DAVID , LUSANNA LUCA
Published: September 2003

The system of N scalar particles with Grassman-valued color changes plus the color SU(3) Yang–Mills field is reformulated on spacelike hypersurfaces. The Dirac observables are found and the physical invariant mass of the system in the Wigner-covariant rest frame instant form of dynamics (covariant Coulomb gauge) is given. From the reduced Hamilton equations we extract the second order equations of motion for both the reduced transverse color field and the particles. Then we study this relativistic scalar quark model, deduced from the classical QCD Lagrangian and with the color field present, in the N=2 (meson) case. A special form of the requirement of having only color singlets, suited for a field-independent quark model, produces a "pseudoclassical asymptotic freedom" and a regularization of the quark self-energy.
NONLEPTONIC DECAYS OF B MESONS AND STRONG COUPLING CONSTANTS
Authors: KRAMER GUSTAV , LÜ CAI-DIAN
Published: September 2003

Nonleptonic decays of B mesons into two mesons or meson resonances are studied on the basis of two versions of simple pole dominance models involving scalar, vector, pseudoscalar and axial vector poles. The results are compared with those obtained from the usual factorization model and are used to obtain information on strong coupling constants between the B meson and one light or one charmed meson, respectively. These coupling constants are compared to results from various QCD sum rule calculations.
THE FOUR-FERMION INTERACTION IN D = 2, 3, 4: A NONPERTURBATIVE TREATMENT
Authors: ROCHEV V. E. , SAPONOV P. A.
Published: September 2003

A new nonperturbative approach is used to investigate the Gross–Neveu model of four-fermion interaction in the space–time dimensions 2, 3 and 4, the number N of inner degrees of freedom being a fixed integer. The spontaneous symmetry breaking is shown to exist in D=2, 3 and the running coupling constant is calculated. The four-dimensional theory seems to be trivial.
FADDEEV-JACKIW APPROACH TO GAUGE THEORIES AND INEFFECTIVE CONSTRAINTS
Authors: GARCÍA J. ANTONIO , PONS JOSEP M.
Published: September 2003

The general conditions for the applicability of the Faddeev–Jackiw approach to gauge theories are studied. When the constraints are effective, a new proof in the Lagrangian framework of the equivalence between this method and the Dirac approach is given. We find, however, that the two methods may give different descriptions for the reduced phase space when ineffective constraints are present. In some cases the Faddeev–Jackiw approach may lose some constraints or some equations of motion. We believe that this inequivalence can be related to the failure of the Dirac conjecture (that says that the Dirac Hamiltonian can be enlarged to an Extended Hamiltonian including all first class constraints, without changes in the dynamics) and we suggest that when the Dirac conjecture fails, the Faddeev–Jackiw approach fails to give the correct dynamics. Finally we present some examples that illustrate this inequivalence.
THE FOURTH VIRIAL COEFFICIENT OF ANYONS
Authors: KRISTOFFERSEN ANDERS , MASHKEVICH STEFAN , MYRHEM JAN , OLAUSSEN KÅRE
Published: September 2003

We have computed by a Monte Carlo method the fourth virial coefficient of free anyons, as a function of the statistics angle θ. It can be fitted by a four term Fourier series, in which two coefficients are fixed by the known perturbative results at the boson and fermion points. We compute partition functions by means of path integrals, which we represent diagramatically in such a way that the connected diagrams give the cluster coefficients. This provides a general proof that all cluster and virial coefficients are finite. We give explicit polynomial approximations for all path integral contributions to all cluster coefficients, implying that only the second virial coefficient is statistics dependent, as is the case for two-dimensional exclusion statistics. The assumption leading to these approximations is that the tree diagrams dominate and factorize.
BPS STATES AND SUPERSYMMETRY
Authors: FERRARA SERGIO
Published: September 2003

We describe duality invariant constraints, which allow a classification of BPS states preserving different fractions of supersymmetry. We then relate this analysis to the orbits of the exceptional groups E6(6), E7(7), relevant for black holes in five and four dimensions. The orbits of O(P, Q) groups enter in the classification of BPS string in six dimensions.
CP-VIOLATING PARAMETERS IN A LEFT–RIGHT SYMMETRIC MODEL WITH AN ${\rm SU}(3)^{VL}_H$ HORIZONTAL SYMMETRY
Authors: BHOWMICK DEBASIS , RAY ASIM K. , RAYCHAUDHURI SREERUP
Published: September 2003

CP-violation can occur in the horizontal gauge boson sector of an [Formula: see text] gauge model with natural flavor conservation (NFC) in the scalar sector. We perform explicit calculations in the model of the CP-violating parameters ε and ε′/ε in the neutral kaon sector and of the electric dipole moment of the neutron (dn), along with the usual neutral meson mixings. For the full range of parameter space where the model is consistent with current experimental data on ε, one obtains very small values for the parameters ε′/ε and dn.
EXCLUSIVE SEMILEPTONIC DECAYS OF D AND B-MESONS IN A RELATIVISTIC QUARK MODEL
Authors: PANDA A. R. , SAHOO R. K.
Published: September 2003

The exclusive semileptonic decays like D0 and B0 mesons are studied in the framework of a relativistic field-theoretic quark model, where translationally invariant hadronic states are described by constituent quark field operators satisfying equal time algebra and a harmonic oscillator wave function. The present estimations to the relevant form factors and their q2 dependence, without any free parameters, show a reasonable agreement with the available experimental measurements and Heavy Quark Effective Theory (HQET) and other model calculations. Further, the calculated decay widths and their ratios, and the polarization ratios for decay processes also have a reasonable agreement with the available experiments and other model estimations.
QUANTUM MECHANICS AS A GAUGE THEORY OF METAPLECTIC SPINOR FIELDS
Authors: REUTER M.
Published: September 2003

A hidden gauge theory structure of quantum mechanics which is invisible in its conventional formulation is uncovered. Quantum mechanics is shown to be equivalent to a certain Yang–Mills theory with an infinite-dimensional gauge group and a nondynamical connection. It is defined over an arbitrary symplectic manifold which constitutes the phase space of the system under consideration. The "matter fields" are local generalizations of states and observables; they assume values in a family of local Hilbert spaces (and their tensor products) which are attached to the points of phase space. Under local frame rotations they transform in the spinor representation of the metaplectic group Mp(2N), the double covering of Sp(2N). The rules of canonical quantization are replaced by two independent postulates with a simple group-theoretical and differential-geometrical interpretation. A novel background-quantum split symmetry plays a central role.
SOLVABILITY OF THE G2 INTEGRABLE SYSTEM
Authors: ROSENBAUM MARCOS , TURBINER ALEXANDER , CAPELLA ANTONIO
Published: September 2003

It is shown that the three-body trigonometric G2 integrable system is exactly solvable. If the configuration space is parametrized by certain symmetric functions of the coordinates then, for arbitrary values of the coupling constants, the Hamiltonian can be expressed as a quadratic polynomial in the generators of some Lie algebra of differential operators in a finite-dimensional representation. Four infinite families of eigenstates, represented by polynomials, and the corresponding eigenvalues are described explicitly.
COMMENTS ON A FULL QUANTIZATION OF THE TORUS
Authors: VELHINHO J. M.
Published: September 2003

Gotay showed that a representation of the whole Poisson algebra of the torus given by geometric quantization is irreducible with respect to the most natural overcomplete set of observables. We study this representation and argue that it cannot be considered as physically acceptable. In particular, classically bounded observables are quantized by operators with unbounded spectrum. Effectively, the latter amounts to lifting the constraints that compactify both directions in the torus.
CONFORMAL MAPPING, POWER CORRECTIONS, AND THE QCD BOUND STATE SPECTRUM
Authors: JONES H. F. , RITZ A. , SOLOVTSOV I. L.
Published: September 2003

We analyze the heavy quark bound state spectrum using an order-dependent conformal mapping to re-sum the peturbative expansion for current correlators. The procedure consists of two main steps. Firstly, the Borel plane structure of the truncated perturbative expression is modified to ensure consistency with the operator product expansion. This is analogous to a resummation of infrared renormalon chains. Secondly, this perturbative expansion is conformally mapped to a new series with improved convergence properties. This approach may be shown to induce power corrections consistent with existing condensates, and the resulting expansion may be ordered in powers of an infrared-analytic effective coupling. The technique is then applied to [Formula: see text] and [Formula: see text] sum rules without any explicit introduction of vacuum condensate parameters. Ground state masses for the vector, axial–vector and A′ channels are well reproduced, while results for the scalar–pseudoscalar mass splitting are less impressive.
POLARIZATION ASYMMETRY AND THE HIGGS BOSON PRODUCTION MECHANISMS
Authors: DUBININ M. , KURIHARA Y. , SHIMIZU Y.
Published: September 2003

We calculate the cross-section of Higgs boson production in the reaction [Formula: see text] for the case of left and right longitudinally polarized initial electron beam. A complete set of signal and irreducible background diagrams is considered. It is shown that the ratio of cross-sections with left and right initial beam polarization provides a sensitive critical test since it exhibits the interplay of bremsstrahlung and fusion mechanisms of Higgs boson production inherent to the Standard Model scheme.
ON THE STRUCTURE OF QUANTUM GAUGE THEORIES WITH EXTERNAL FIELDS
Authors: FALKENBERG S. , GEYER B. , LAVROV P. , MOSHIN P.
Published: September 2003

We consider generating functionals of Green's functions with external fields in the framework of BV and BLT quantization schemes for general gauge theories. The corresponding Ward identities are obtained, and the gauge dependence is studied.
SHORT DISTANCE PROPERTIES FROM LARGE DISTANCE BEHAVIOR
Authors: MANSFIELD PAUL , SAMPAIO MARCOS , PACHOS JIANNIS
Published: September 2003

For slowly varying fields the vacuum functional of a quantum field theory may be expanded in terms of local functionals. This expansion satisfies its own form of the Schrödinger equation from which the expansion coefficients can be found. For scalar field theory in 1+1 dimensions we show that this approach correctly reproduces the short-distance properties as contained in the counterterms. We also describe an approximate simplification that occurs for the sine–Gordon and sinh–Gordon vacuum functionals.
REDUCTION OF ANYONS TO ONE DIMENSION AND CALOGERO–SUTHERLAND-TYPE MODELS
Authors: VATHSAN RADHIKA
Published: September 2003

The two-dimensional anyon system, when reduced to one dimension, yields models related to the Calogero–Sutherland model. One such reduction leads to a new model with a class of exact solutions. This model is one of a family of models obtained upon dimensional reduction of spherically symmetric models in arbitrary dimensions.
A FINITE QUANTUM SYMMETRY OF $M(3, {\Bbb C})$
Authors: DABROWSKI LUDWIK , NESTI FABRIZIO , SINISCALCO PASQUALE
Published: September 2003

The 27-dimensional Hopf algebra A(F), defined by the exact sequence of quantum groups [Formula: see text], [Formula: see text], is studied as a finite quantum group symmetry of the matrix algebra [Formula: see text], describing the color sector of Alain Connes' formulation of the Standard Model. The duality with the Hopf algebra ℋ, investigated in a recent work by Robert Coquereaux, is established and used to define a representation of ℋ on [Formula: see text] and two commuting representation of ℋ on A(F).
BOUNDARY K MATRICES AND THE LAX PAIR FOR ONE-DIMENSIONAL OPEN XYZ SPIN-CHAIN
Authors: JU GUO-XING , WANG SHI-KUN , WU KE , XIONG CHI
Published: September 2003

We analyze the symmetries of the reflection equation for open XYZ model and find their solutions K± case by case. In the general open boundary conditions, the Lax pair for open one-dimensional XYZ spin-chain is given.
AXIAL ANOMALY FROM THE BPHZ RENORMALIZED BV MASTER EQUATION
Authors: ABREU EVERTON M. C. , BRAGA NELSON R. F.
Published: September 2003

We show here that a rigid anomaly (anomalous divergence of a classically conserved Noether current) can also be calculated using the BPHZ renormalized form of the master equation of the field antifield (or BV) quantization. Considering the case of QED (where there is no gauge anomaly), the fundamental result about the anomalous contribution to the axial Ward identity is reproduced in this BPHZ regularized BV framework (originally used to compute gauge anomalies).
IRREVERSIBLE TIME FLOW IN A TWO-DIMENSIONAL DILATON BLACK HOLE WITH MATTER
Authors: DIAMANDIS G. A. , GEORGALAS B. C. , MAVROMATOS N. E. , ELLIS JOHN , NANOPOULOS D. V. , PAPANTONOPOULOS E.
Published: September 2003

We show that an exact solution of two-dimensional dilaton gravity with matter discovered previously exhibits an irreversible temporal flow towards flat space with a vanishing cosmological constant. This time flow is induced by the back reaction of matter on the space–time geometry. We demonstrate that the system is not in equilibrium if the cosmological constant is nonzero, whereas the solution with zero cosmological constant is stable. The flow of the system towards this stable end point is derived from the renormalization-group flow of the Zamolodchikov function. This behavior is interpreted in terms of noncritical Liouville string, with the Liouville field identified as the target time.
THE BOLTZMANN EQUATION IN SCALAR FIELD THEORY
Authors: BRANDT F. T. , FRENKEL J. , GUERRA A.
Published: September 2003

We derive the classical transport equation, in scalar field theory with a g2V(ϕ) interaction, from the equation of motion for the quantum field. We obtain a very simple, but iterative, expression for the effective action Γ which generates all the n-point Green functions in the high-temperature limit. An explicit and closed form is given for Γ in the static case.
BETHE ANSATZ SOLUTION OF THE ANISOTROPIC CORRELATED ELECTRON MODEL ASSOCIATED WITH THE TEMPERLEY–LIEB ALGEBRA
Authors: LIMA-SANTOS A. , RODITI I. , FOERSTER A.
Published: September 2003

A recently proposed strongly correlated electron system associated with the Temperley–Lieb algebra is solved by means of the coordinate Bethe ansatz for periodic and closed boundary conditions.
DUALITY FOR MULTIPARAMETER QUANTUM DEFORMATION OF THE SUPERGROUP GL(m/n)
Authors: DOBREV V. K. , TAHRI E. H.
Published: September 2003

We find the Hopf superalgebra [Formula: see text], which is in duality with the multiparameter quantum deformation GL u q (m/n) of the supergroup GL (m/n). Naturally [Formula: see text] is a multiparameter deformation of the superalgebra U ( gl (m/n)). We show that as a commutation algebra we have the classical structure, namely a split into two subalgebras: [Formula: see text], where [Formula: see text] is isomorphic to the standard one-parameter deformation U u( sl (m/n)), and [Formula: see text] is central in [Formula: see text] for m ≠ n. However, as a coalgebra [Formula: see text] cannot be split in this way, as only [Formula: see text] is a Hopf subalgebra, while [Formula: see text] is not a Hopf subalgebra unless m = n = 1 or some special relations between the parameters exist. These special relations are established and used to obtain explicit multiparameter Hopf superalgebra deformations of U ( sl (m/n)).
ASYMPTOTIC SEARCH FOR GROUND STATES OF SU(2) MATRIX THEORY
Authors: HALPERN M. B. , SCHWARTZ C.
Published: September 2003

We introduce a complete set of gauge-invariant variables and a generalized Born–Oppenheimer formulation to search for normalizable zero-energy asymptotic solutions of the Schrödinger equation of SU(2) matrix theory. The asymptotic method gives only ground state candidates, which must be further tested for global stability. Our results include a set of such ground state candidates, including one state which is a singlet under spin (9).
THE STATUS OF NEUTRINO MASS
Authors: CALDWELL DAVID O.
Published: September 2003

New experimental results, if correct, require at least one light sterile neutrino, in addition to the three active ones, to accommodate the mass differences required to explain the solar νe deficit, the anomalous μ/e ratio produced by atmospheric neutrinos, and either the candidate events for νμ→ νe (or [Formula: see text]) from the LSND experiment, or the possible need for a hot component of dark matter. This neutrino mass pattern can not only accommodate all these four requirements, but also provide a robust solution to a problem presently making heavy-element synthesis by supernovae impossible and resolve a possible discrepancy between big bang nucleosynthesis theory and observations.
INTERACTING INTERSECTIONS
Authors: LÜ H. , POPE C. N.
Published: September 2003

Intersecting p-branes can be viewed as higher-dimensional interpretations of multicharge extremal p-branes, where some of the individual p-branes undergo diagonal dimensional oxidation, while the others oxidize vertically. Although the naive vertical oxidation of a single p-brane gives a continuum of p-branes, a more natural description arises if one considers a periodic array of p-branes in the higher dimension, implying a dependence on the compactification coordinates. This still reduces to the single lower-dimensional p-brane when viewed at distances large compared with the period. Applying the same logic to the multicharge solutions, we are led to consider more general classes of intersecting p-brane solutions, again depending on the compactification coordinates, which turn out to be described by interacting functions rather than independent harmonic functions. These new solutions also provide a more satisfactory interpretation for the lower-dimensional multicharge p-branes, which otherwise appear to be nothing more than the improbable coincidence of charge-centres of individual constituents with zero binding energy.
On S DUALITY OF TOROIDALLY COMPACTIFIED TYPE IIB STRING EFFECTIVE ACTION
Authors: ROY SHIBAJI
Published: September 2003

It has been shown recently that the toroidally compactified type IIB string effective action possesses an SL (2, R) invariance as a consequence of the corresponding symmetry in ten dimensions when the self-dual five-form field strength is set to zero. By working in the string frame we clarify how a Z2 subgroup of this SL (2, R) group responsible for producing the strong–weak coupling duality in the ten-dimensional theory produces the same symmetry for the reduced theory. In the absence of the full covariant action of type IIB supergravity theory, we show that the T-dual version of type IIA string effective action (including the R–R terms) in D = 9 also possesses the SL (2, R) invariance, indicating that this symmetry is present for the full type IIB string effective action compactified on the torus. By making use of this symmetry we briefly indicate how, from the known classical solutions of string theory, an SL (2, Z) multiplet of solutions can be constructed. This, in turn, provides strong evidence in favor of the conjecture that SL (2, Z) is an exact symmetry group of the lower-dimensional quantum type II string theory.
THE FORM FACTORS IN THE SINH–GORDON MODEL
Authors: PILLIN MATHIAS
Published: September 2003

The most general solution to the form factor problem in the sinh–Gordon model is presented in an explicit way. The linearly independent classes of solutions correspond to powers of the elementary field. We show how the form factors of exponential operators can be obtained from the general solution by adjusting free parameters. The general formula obtained in the sinh–Gordon case reproduces the form factors of the scaling Lee–Yang model in a certain limit of the coupling constant.
THE FINITENESS OF THE FOUR-DIMENSIONAL ANTISYMMETRIC TENSOR FIELD MODEL IN A CURVED BACKGROUND
Authors: FEICHTINGER U. , MORITSCH O. , RANT J. , SCHWEDA M. , ZERROUKI H.
Published: September 2003

A renormalizable rigid supersymmetry for the four-dimensional antisymmetric tensor field model in a curved space–time background is constructed. A closed algebra between the BRS and the supersymmetry operators is only realizable if the vector parameter of the supersymmetry is a covariantly constant vector field. This also guarantees that the corresponding transformations lead to a genuine symmetry of the model. The proof of the ultraviolet finiteness to all orders of perturbation theory is performed in a pure algebraic manner by using the rigid supersymmetry.
TRIGONOMETRIC S MATRICES, AFFINE TODA SOLITONS AND SUPERSYMMETRY
Authors: GANDENBERGER GEORG M.
Published: September 2003

Using [Formula: see text]- and [Formula: see text]-invariant R matrices we construct exact S matrices in two-dimensional space–time. These are conjectured to describe the scattering of solitons in affine Toda field theories. In order to find the spectrum of soliton bound states we examine the pole structure of these S matrices in detail. We also construct the S matrices for all scattering processes involving scalar bound states. In the last part of this paper we discuss the connection of these S matrices with minimal N=1 and N = 2 super-symmetric S matrices. In particular we comment on the folding from N = 2 to N = 1 theories.
UTILITY OF GALILEAN SYMMETRY IN LIGHT-FRONT PERTURBATION THEORY: A NONTRIVIAL EXAMPLE IN QCD
Authors: HARINDRANATH A. , KUNDU RAJEN
Published: September 2003

Investigations have revealed a very complex structure for the coefficient functions accompanying the divergences for individual time(x+)-ordered diagrams in light-front perturbation theory. No guidelines seem to be available to look for possible mistakes in the structure of these coefficient functions emerging at the end of a long and tedious calculation, in contrast to covariant field theory. Since, in light-front field theory, the transverse boost generator is a kinematical operator which acts just like the two-dimensional Galilean boost generator in nonrelativistic dynamics, it may provide some constraint on the resulting structures. In this work we investigate the utility of Galilean symmetry beyond tree level in the context of coupling constant renormalization in light-front QCD using the two-component formalism. We show that for each x+-ordered diagram separately, the underlying transverse boost symmetry fixes relative signs of terms in the coefficient functions accompanying the diverging logarithms. We also summarize the results leading to coupling constant renormalization for the most general kinematics.
DIRAC'S OBSERVABLES FOR THE SU(3)×SU(2)×U(1) STANDARD MODEL
Authors: LUSANNA LUCA , VALTANCOLI PAOLO
Published: September 2003

The missing complete Hamiltonian treatment of the standard SU(3) × SU(2) × U(1) model with Grassmann-valued fermion fields in the Higgs phase is given. We bypass the complications of the Hamiltonian theory in the Higgs phase, resulting from the spontaneous symmetry breaking with the Higgs mechanism, by studying the Hamiltonian formulation of the Higgs phase for the gauge-equivalent Lagrangian in the unitary gauge. A canonical basis of Dirac's observables is found and the reduced physical Hamiltonian is evaluated. Its self-energy part is nonlocal for the electromagnetic and strong interactions, but local for the weak ones. Therefore, the Fermi four-fermion interaction reappears at the nonperturbative level.
ON THE EVALUATION OF COMPTON SCATTERING AMPLITUDES IN STRING THEORY
Authors: PASQUINUCCI ANDREA , PETRINI MICHELA
Published: September 2003

We consider the Compton amplitude for the scattering of a photon and an (massless) "electron/positron" at one loop (i.e. genus 1) in a four-dimensional fermionic heterotic string model. Starting from the bosonization of the world sheet fermions needed to explicitly construct the spin fields representing the space–time fermions, we present all the steps of the computation which leads to the explicit form of the amplitude as an integral of modular forms over the moduli space.
DYNAMICS IN A NONCOMMUTATIVE PHASE SPACE
Authors: MALIK R. P. , MISHRA A. K. , RAJASEKARAN G.
Published: September 2003

Dynamics in a noncommutative phase space is considered. The noncommuting phase space is taken to be invariant under the quantum group GLq,p(2). The q-deformed differential calculus on the phase space is formulated and using this, both the Hamiltonian and Lagrangian forms of dynamics have been constructed. In contrast to earlier forms of q-dynamics, our formalism has the advantage of preserving the conventional symmetries such as rotational or Lorentz invariance.
LOW-ENERGY QUANTUM STRING COSMOLOGY
Authors: GASPERINI MAURIZIO
Published: September 2003

We introduce a Wheeler–De Witt approach to quantum cosmology based on the low-energy string effective action, with an effective dilaton potential included to account for nonperturbative effects and, possibly, higher-order corrections. We classify, in particular, four different classes of scattering processes in minisuperspace, and discuss their relevance for the solution of the graceful exit problem.
GENERALIZED CONFORMAL SYMMETRY AND EXTENDED OBJECTS FROM THE FREE PARTICLE
Authors: CALIXTO M. , ALDAYA V. , GUERRERO J.
Published: September 2003

The algebra of linear and quadratic functions of basic observables on the phase space of either the free particle or the harmonic oscillator possesses a finite-dimensional anomaly. The quantization of these systems outside the critical values of the anomaly leads to a new degree of freedom which shares its internal character with spin, but nevertheless features an infinite number of different states. Both are associated with the transformation properties of wave functions under the Weyl-symplectic group [Formula: see text]. The physical meaning of this new degree of freedom can be established, with a major scope, only by analyzing the quantization of an infinite-dimensional algebra of diffeomorphisms generalizing string symmetry and leading to more general extended objects.
FLAVOR-CONSERVING OSCILLATIONS OF DIRAC-MAJORANA NEUTRINOS
Authors: ESPOSITO SALVATORE
Published: September 2003

We analyze both chirality-changing and chirality-preserving transitions of Dirac–Majorana neutrinos. In vacuum, the first ones are suppressed with respect to the others due to helicity conservation and the interactions with a ("normal") medium practically does not affect the expressions of the probabilities for these transitions, even if the amplitudes of oscillations change slightly. For usual situations involving relativistic neutrinos we find no resonant enhancement for all flavor-conserving transitions. However, for very light neutrinos propagating in superdense media, the pattern of oscillations [Formula: see text] is dramatically altered with respect to the vacuum case, the transition probability practically vanishing. An application of this result is envisaged.
FERMION MASSES, NEUTRINO MIXING AND CP VIOLATION FROM THE ANTI-GRAND-UNIFICATION MODEL
Authors: FROGGATT C. D. , GIBSON M. , NIELSEN H. B. , SMITH D. J.
Published: September 2003

The fermion masses and mixing angles are fitted using only three free parameters in a nonsupersymmetric extension of the Standard Model, with new, approximately conserved chiral gauge quantum numbers broken by a set of Higgs fields. The fundamental mass scale of this anti-grand-unification model is given by the Planck mass. We also calculate neutrino mixing angles and masses, as well as CP violation from the CKM matrix. A good fit to the observed fermion masses is obtained, but our predictions of the neutrino masses are too small to lead to any observable neutrino oscillation effects claimed today, without introducing another mass scale. We also give some arguments in support of this type of model based on the observed fermion masses.
D-INSTANTON CORRECTIONS AS (p, q)-STRING EFFECTS AND NONRENORMALIZATION THEOREMS
Authors: KEHAGIAS A. , PARTOUCHE H.
Published: September 2003

We discuss higher derivative interactions in the type IIB superstring in ten dimensions. From the fundamental stri ng point of view, the nonperturbative corrections are due to D-instantons. We argue that they can alternatively be understood as arising from (p, q)-strings. We derive a nonrenormalization theorem for eight-derivative bosonic interactions, which states that terms involving either NS–NS or R–R fields occur at tree-level and one-loop only. By using the SL(2, Z) symmetry of M theory on T2, we show that in order for the possible R3m+1 (m = 1, 2, …) interactions in M theory to have a consistent perturbative expansion in nine dimensions, m must be odd. Thus, only R6N+4 (N = 0,1, …) terms can be present in M theory and their string theory counterparts arise at N and 2N + 1 loops. Finally, we treat an example of fermionic term.
WORLD SHEET FORMULATION OF M THEORY
Authors: ELLIS JOHN , MAVROMATOS N. E. , NANOPOULOS D. V.
Published: September 2003

We first review the interpretation of world sheet defects as D branes described by a critical theory in 11 dimensions, that we interpret as M theory. We then show that D-brane recoil induces dynamically an anti-de Sitter (AdS) space–time background, with criticality restored by a twelfth timelike dimension described by a Liouville field. Local physics in the bulk of this AdS11 may be described by an Osp (1|32, R) ⊗ Osp (1|32, R) topological gauge theory (TGT), with nonlocal boundary states in doubleton representations. We draw analogies with structures previously exhibited in two-dimensional black hole models. Wilson loops of "matter" in the TGT may be described by an effective string action, and defect condensation may yield string tension and cause a space–time metric to appear.
EQUIVALENCE OF THE β-FUNCTION OF THE VARIATIONAL APPROACH TO THAT OF QCD
Authors: BROWN WILLIAM E.
Published: September 2003

The variational ansatz for the ground state wavefunctional of QCD is found to capture the antiscreening behaviour that contributes the dominant "-4" to the β-function and leads to asymptotic freedom. By considering an SU (N) purely gauge theory in the Hamiltonian formalism and choosing the Coulomb gauge, the origins of all screening and antiscreening contributions in gluon processes are found in terms of the physical degrees of freedom. The overwhelming antiscreening contribution of "-4" is seen to originate in the renormalisation of a Coulomb interaction by a transverse gluon. The lesser screening contribution of " [Formula: see text]" is seen to originate in processes involving transverse gluon interactions. It is thus apparent how the variational ansatz must be developed to capture the full running of the QCD coupling constant.
ADE SINGULARITY AND PREPOTENTIALS IN N=2 SUPERSYMMETRIC YANG–MILLS THEORY
Authors: ITO KATSUSHI , YANG SUNG-KIL
Published: September 2003

We calculate the instanton corrections in the effective prepotential for N=2 supersymmetric Yang–Mills theory with all ADE gauge groups from the Seiberg–Witten geometry constructed out of the spectral curves of the periodic Toda lattice. The one-instanton contribution is determined explicitly by solving the Gauss–Manin system associated with the ADE singularity. Our results are in complete agreement with the ones obtained from the microscopic instanton calculations.
PERFECT HYPERMOMENTUM FLUID: VARIATIONAL THEORY AND EQUATIONS OF MOTION
Authors: BABOUROVA O. V. , FROLOV B. N.
Published: September 2003

The variational theory of the perfect hypermomentum fluid is developed. The new type of the generalized Frenkel condition is considered. The Lagrangian density of such fluid is stated, and the equations of motion of the fluid and the Weyssenhoff-type evolution equation of the hypermomentum tensor are derived. The expressions of the matter currents of the fluid (the canonical energy–momentum three-form, the metric stress–energy four-form and the hypermomentum three-form) are obtained. The Euler-type hydrodynamic equation of motion of the perfect hypermomentum fluid is derived. It is proved that the motion of the perfect fluid without hypermomentum in a metric-affine space coincides with the motion of this fluid in a Riemann space.
SCALAR-QED β-FUNCTIONS NEAR PLANCK'S SCALE
Authors: PIRES GENTIL O.
Published: September 2003

The Renormalization Group Flow Equations of the Scalar-QED model near Planck's scale are computed within the framework of the average effective action. Exact Flow Equations, corrected by Einstein Gravity, for the running self-interacting scalar coupling parameter and for the running v.e.v. of ϕ*ϕ, are computed taking into account threshold effects. Analytic solutions are given in the infrared and ultraviolet limits.
EXCITED PIONS, ρ- AND ω-MESONS AND THEIR DECAYS IN A CHIRAL SU(2) × SU(2) LAGRANGIAN
Authors: VOLKOV M. K. , EBERT D. , NAGY M.
Published: September 2003

A chiral SU(2) × SU(2) Lagrangian containing, besides the usual meson fields, their first radial excitations is considered. The Lagrangian is derived by bosonization of the Nambu–Jona-Lasinio (NJL) quark model with separable nonlocal interactions, with form factors corresponding to three-dimensional ground and excited state wave functions. The spontaneous breaking of chiral symmetry is governed by the NJL gap equation. The first radial excitations of the pions, ρ-and ω-mesons are described with the help of two form factors. The weak decay constant Fπ′ is calculated. The values for the decay widths of the processes ρ→2π, π′→ρπ, ρ′→2π, ρ′→ωπ and ω′→ρπ are obtained in agreement with the experimental data.
ALGEBRAS, DERIVATIONS AND INTEGRALS
Authors: CASALBUONI R.
Published: September 2003

In the context of the integration over algebras introduced in a previous paper, we obtain several results for a particular class of associative algebras with identity. The algebras of this class are called self-conjugated, and they include, for instance, the para-Grassmann algebras of order p, the quaternionic algebra and the toroidal algebras. We study the relation between derivations and integration, proving a generalization of the standard result for the Riemann integral about the translational invariance of the measure and the vanishing of the integral of a total derivative (for convenient boundary conditions). We consider also the possibility, given the integration over an algebra, to define from it the integral over a subalgebra, in a way similar to the usual integration over manifolds. That is by projecting out the submanifold in the integration measure. We prove that this is possible for para-Grassmann algebras of order p, once we consider them as subalgebras of the algebra of the (p + 1) × (p + 1) matrices. We find also that the integration over the subalgebra coincides with the integral defined in the direct way. As a by-product we can define the integration over a one-dimensional Grassmann algebra as a trace over 2 × 2 matrices.
ON THE GAUGED NONCOMPACT SPIN SYSTEM
Authors: KIM SUNG-SOO , OH PHILLIAL
Published: September 2003

We examine classical and quantum aspects of the planar noncompact spin system coupled with Chern–Simons gauge field in the presence of background charge. We first define our classical spin system as nonrelativistic nonlinear sigma model in which the order parameter spin takes value in the noncompact manifold ℳ= SU(1, 1)/U(1) . Although the naive model does not allow any finite energy self-dual solitons, it is shown that the gauged system admits static Bogomol'nyi solitons with finite energy whose rotationally symmetric soliton solutions are analyzed in detail. We also discuss the large spin limit in which the self-dual equation reduces to the well-known gauged nonlinear Schrödinger model or Abelian Higgs model, depending on the choice of the background charge term. Then, we perform quantization of the model. We find that the spin algebra satisfies anomalous commutation relations, and the system is a field theoretic realization of the anyons.
NUCLEON STRUCTURE FUNCTIONS FROM A CHIRAL SOLITON IN THE INFINITE MOMENTUM FRAME
Authors: GAMBERG L. , REINHARDT H. , WEIGEL H.
Published: September 2003

We study the frame dependence of nucleon structure functions obtained within a chiral soliton model for the nucleon. Employing light cone coordinates and introducing collective coordinates together with their conjugate momenta, translational invariance of the solitonic quark fields (which describe the nucleon as a localized object) is restored. This formulation allows us to perform a Lorentz boost to the infinite momentum frame of the nucleon. The major result is that the Lorentz contraction associated with this boost causes the leading twist contribution to the structure functions to properly vanish when the Bjorken variable x exceeds unity. Furthermore we demonstrate that for structure functions calculated in the valence quark approximation to the Nambu–Jona-Lasinio chiral soliton model the Lorentz contraction also has significant effects on the structure functions for moderate values of the Bjorken variable x.
LEPTON MASS GENERATION AND FAMILY NUMBER VIOLATION MECHANISM IN THE SU(6)L⊗ U(1)Y MODEL
Authors: COTTI UMBERTO , GAITÁN RICARDO , HERNÁNDEZ-GALEANA A. , PONCE WILLIAM A. , ZEPEDA ARNULFO
Published: September 2003

Lepton family number violation processes arise in the SU(6) L⊗ U(1) Y model due to the presence of an extra neutral gauge boson, Z′, with family changing couplings, and due to the fact that this model demands the existence of heavy exotic leptons. The mixing of the standard Z with Z′ and the mixing of ordinary leptons with exotic ones induce together family changing couplings on the Z and therefore nonvanishing rates for lepton family number violation processes, such as [Formula: see text], [Formula: see text] and μ→eγ. Additional contributions to the processes μ→eγ and [Formula: see text] are induced from the mass generation mechanism. This last type of contributions may compete with the above one, depending on the masses of the scalars which participate in the diagrams which generate radiatively the masses of the charged leptons. Using the experimental data we compute some bounds for the mixings parameters and for the masses of the scalars.
NLO QCD ANALYSIS OF POLARIZED DEEP INELASTIC SCATTERING
Authors: LEADER ELLIOT , SIDOROV ALEKSANDER V. , STAMENOV DIMITER B.
Published: September 2003

We have carried out a next-to-leading order QCD analysis of the experimental data on polarized DIS in the [Formula: see text] scheme. We have studied two models of the parametrizations of the input parton densities — the first due to Brodsky, Burkhardt and Schmidt (BBS), which gives a simultaneous parametrization for the polarized and unpolarized densities and in which the counting rules are strictly imposed; in the second, the input polarized densities are written in terms of the unpolarized ones in the generic form Δq(x)=f(x)q(x), with f(x) some simple smooth function. In both cases a good fit to the polarized data is achieved. As expected, the polarized data do not allow a precise determination of the polarized gluon density. Concerning the polarized sea quark densities, these are fairly well determined in the BBS model because of the interplay of polarized and unpolarized data, whereas in the second model, where only the polarized data are relevant, the polarized sea quark densities are largely undetermined.
DILEPTON MASS FROM LEPTON DECAY
Authors: TULLY M. B. , JOSHI G. C.
Published: September 2003

Mass limits on dilepton gauge bosons are derived from limits on various muon decay parameters, and a value of 440 GeV is determined, higher than the maximum permitted value in the minimal-331 model, suggesting an enriched Higgs sector. From the decay [Formula: see text], a limit of 240 GeV is also found. The effects of possible flavor-mixing are taken into account.
MAGNETIC FIELDS AND VACUUM POLARIZATION AT THE PLANCK ERA
Authors: POLLOCK M. D.
Published: September 2003

The one-loop effective action describing polarization of the vacuum due to virtual electron-positron pairs in the Maxwell theory of electromagnetism was obtained by Heisenberg and Euler, in the limit of a background field that is constant on the scale of the electron Compton-wavelength. The case of vanishing electric field and constant, ultra-strong magnetic field B≫Bc, where [Formula: see text], yields a configuration whose energy density is less than that of the equivalent radiation field, suggesting why a magnetic field may be present in the early Universe back to the Planck era. For there is a similar but larger effect, allowing a "ferromagnetic" Yang–Mills vacuum state, in the grand-unified theory at temperatures [Formula: see text], analyzed by Skalozub. Some further aspects of ultra-strong magnetic fields are discussed vis-à-vis the origin of the Galactic field B g .
QUANTUM MECHANICS AT PLANCK'S SCALE AND DENSITY MATRIX
Authors: SHALYT-MARGOLIN A. E. , SUAREZ J. G.
Published: September 2003

In this paper Quantum Mechanics with Fundamental Length is chosen as Quantum Mechanics at Planck's scale. This is possible due to the theory of General Uncertainty Relations. Here Quantum Mechanics with Fundamental Length is obtained as a deformation of Quantum Mechanics. The distinguishing feature of the proposed approach in comparison with previous ones, lies in the fact that here the density matrix are subjected to deformation, whereas in the previous approaches only commutators are deformed. The density matrix obtained by deforming the quantum-mechanical one is named the density pro-matrix throughout this paper. Within our approach two main features of Quantum Mechanics are conserved: the probabilistic interpretation of the theory and the well-known measuring procedure corresponding to that interpretation. The proposed approach allows a description of the dynamics. In particular, the explicit form of the deformed Liouville's equation and the deformed Shrödinger's picture are given. Some implications of obtained results are discussed. In particular, the problem of singularity, the hypothesis of cosmic censorship, a possible improvement of the definition of statistical entropy and the problem of information loss in black holes are considered. It is shown that the results obtained here allow one to deduce in a simple and natural way the Bekenstein–Hawking's formula for black hole entropy in semiclassical approximation.
Circle of Willis Atherosclerosis Is a Risk Factor for Sporadic Alzheimer’s Disease
Authors: Roher Alex E. , Esh Chera , Kokjohn Tyler A. , Kalback Walter , Luehrs Dean C. , Seward James D. , Sue Lucia I. , Beach Thomas G.
Published: September 2003

Objectives—

We conducted a quantitative investigation of brain arterial atherosclerotic damage and its relationship to sporadic Alzheimer’s disease (AD).

Methods and Results—

Fifty-four consecutive autopsy cases, 32 AD and 22 nondemented control subjects, were examined to establish the degree of arterial stenosis. Vessel external and lumenal area measurements were taken from 3-mm arterial cross-sections to calculate a stenosis index. AD patient circle of Willis arteries possessed a significant degree of stenosis as a consequence of multiple and severe atherosclerotic lesions. These lesions were significantly more severe in AD cases than in age-matched controls (
P
<0.0001), and the number of stenoses and the index of occlusion (
R
=0.67;
P
<0.00001) were positively correlated. In addition, the index of stenosis significantly correlated with the following measures of AD neuropathological lesions: total plaque score, neuritic plaque score, neurofibrillary tangle score, Braak stage score, and white matter rarefaction score.

Conclusions—

Our study reveals an association between severe circle of Willis atherosclerosis and sporadic AD that should be considered a risk factor for this dementia. These observations strongly suggest that atherosclerosis-induced brain hypoperfusion contributes to the clinical and pathological manifestations of AD.
Enhanced Thrombosis in Atherosclerosis-Prone Mice Is Associated With Increased Arterial Expression of Plasminogen Activator Inhibitor-1
Authors: Schäfer Katrin , Müller Katja , Hecke Anneke , Mounier Emmanuelle , Goebel Julia , Loskutoff David J. , Konstantinides Stavros
Published: September 2003

Objectives—

This study was undertaken to investigate the origin and pathophysiological importance of plasminogen activator inhibitor (PAI-1) in atherosclerosis.

Methods and Results—

We used the ferric chloride model to induce carotid artery injury in apolipoprotein E knockout (apoE
−/−
) and wild-type (WT) mice. ApoE
−/−
mice fed high-fat diet for 4 months developed severe hypercholesterolemia and had significantly elevated plasma PAI-1 levels (2.3±0.3 versus 0.6±0.1 ng/mL in WT mice;
P
<0.05). These mice exhibited a prothrombotic phenotype with shortened times to thrombotic arterial occlusion (8.6 versus 11.5 minutes;
P
<0.001) and reduced recanalization rates (12% versus 51%;
P
<0.0001) compared with WT mice. In situ hybridization, reverse transcriptase–polymerase chain reaction, and immunohistochemistry showed a significantly upregulated PAI-1 expression in P-selectin–positive (activated) endothelial cells lining normal-appearing arterial segments and within the advanced atherosclerotic lesions of apoE
−/−
mice. No significant upregulation of PAI-1 expression was found in the other organs studied, and only trace amounts of PAI-1 mRNA were detected in murine platelets. Importantly, deletion of the PAI-1 gene reversed the prothrombotic tendency and reduced neointimal growth after injury in apoE
−/−
mice despite the persistence of excessive hypercholesterolemia.

Conclusions—

These results suggest that increased vascular expression of PAI-1 may contribute to the elevated circulating levels of the inhibitor and be responsible, at least in part, for the prothrombotic phenotype in apoE
−/−
mice.