bluuebunny/crossref_metadata_2025 huggingface dataset:
SYMPLECTIC REDUCTION AND SYMMETRY ALGEBRA IN BOUNDARY CHERN–SIMONS THEORY
Authors: OH PHILLIAL , PARK MU-IN
Published: May 2003

We derive the Kac–Moody algebra and Virasoro algebra in Chern–Simons theory with boundary by using the symplectic reduction method and the Noether procedures.
THE QUANTUM CORRECTIONS TO THE ENTROPY OF ROTATING U(1) ⊗ U(1)-DILATON BLACK HOLES
Authors: SHEN YOU-GEN , CHEN DA-MING
Published: May 2003

By using 't Hooft's brick wall model, the corrections for a massless quantum scalar field to the black hole entropy are studied in rotating U (1) ⊗ U (1)-dilaton black hole space–time. The free energy and entropy for this case are calculated, and in Hartle–Hawking states, the derived quantum entropy is composed of the geometric part and the non-geometric part which is logrithmically divergent. It turns out that the logrithmic part is related to the characteristic quantities of a black hole.
KINKS STABILITY IN TWO-HIGGS MODELS
Authors: BRIHAYE Y. , KOSINSKI P.
Published: May 2003

We analyze the stability of two kink-type classical solutions available in a model describing two scalar Higgs fields in (1+1) dimensions. It is shown that one of these solutions is stable while the other is sphaleron. A few algebraic eigenmodes of the problem are exhibited.
NEUTRINO OSCILLATION IN A SPACE–TIME WITH TORSION
Authors: ALIMOHAMMADI M. , SHARIATI A.
Published: May 2003

Using Einstein–Cartan–Dirac theory, we study the effect of torsion on neutrino oscillation. We see that torsion cannot induce neutrino oscillation, but affects it whenever oscillation exists for other reasons. We show that the torsion effect on neutrino oscillation is as important as the neutrino mass effect, whenever the ratio of neutrino number density to neutrino energy is ~ 1069 cm -3/ eV , or the number density of the matter is ~ 1069 cm -3.
ON A QUANTUM EQUIVALENCE PRINCIPLE
Authors: CAMACHO A.
Published: May 2003

The logical consistency of a description of quantum theory in the context of general relativity, which includes minimal coupling principle, is analyzed from the point of view of Feynman's formulation in terms of path integrals. We will argue from this standpoint and use an argument that claims the incompleteness of the general relativistic description of gravitation, which emerges as a consequence of the gravitationally induced phases of the so-called flavor-oscillation clocks, that the postulates of quantum theory are logically incompatible with the usual minimal coupling principle. It will be shown that this inconsistency could emerge from the fact that the required geometrical information to calculate the probability of finding a particle at any point of the respective manifold does not lie in a region with finite volume. Then we put forth a new quantum minimal coupling principle in terms of a restricted path integral, and along the ideas of this model not only the propagator of a free particle is calculated but also the conditions under which we recover Feynman's case for a free particle are deduced. The effect on diatomic interstellar molecules is also calculated. The already existing relation between restricted path integral formalism and decoherence model will enable us to connect the issue of a quantum minimal coupling principle with the collapse of the wave function. From this last remark we will claim that the geometrical structure of the involved manifold acts as, always present, a measuring device on a quantum particle. In other words, in this proposal we connect the issue of a quantum minimal coupling principle with a claim which states that gravity could be one of the physical entities which results in the collapse of the wave function.
NUCLEON SIGMA TERM AND IN-MEDIUM QUARK CONDENSATE IN THE MODIFIED Quark–MESON COUPLING MODEL
Authors: JIN XUEMIN , MALHEIRO MANUEL
Published: May 2003

We evaluate the nucleon sigma term and in-medium quark condensate in the modified quark–meson coupling model which features a density-dependent bag constant. We obtain a nucleon sigma term consistent with its empirical value, which requires a significant reduction of the bag constant in the nuclear medium similar to those found in the previous works. The resulting in-medium quark condensate at low densities agrees well with the model-independent linear order result. At higher densities, the magnitude of the in-medium quark condensate tends to increase, indicating no tendency towards chiral symmetry restoration.
SELF-DUALITY OF SUPER D3-BRANE ACTION ON AdS5×S5 BACKGROUND
Authors: KIMURA T.
Published: May 2003

We show that the super D3-brane action on AdS5×S5 background recently constructed by Metsaev and Tseytlin is exactly invariant under the combination of the electric–magnetic duality transformation of the world-volume gauge field and the SO(2) rotation of N=2 spinor coordinates. The action is shown to satisfy the Gaillard–Zumino duality condition, which is a necessary and sufficient condition for an action to be self-dual. Our proof needs no gauge fixing for the κ-symmetry.
ALL ROADS LEAD TO ROME: SUPERSOLVABLES AND SUPERCOSETS
Authors: PESANDO I.
Published: May 2003

We show explicitly that the two recently proposed actions for the type IIB superstring propagating on AdS5×S5 agree completely.
IMPACT OF THE SUSY DECAYS ON THE SEARCH FOR THE MSSM HIGGS BOSONS AT THE LHC
Authors: DJOUADI A.
Published: May 2003

In the context of the minimal supersymmetric extension of the Standard Model, we discuss the impact of the decays of the neutral Higgs bosons into supersymmetric particles, charginos/neutralinos and sfermions. We show that these decay modes could be dominant, when they are kinematically accessible, thus strongly suppressing the branching ratios for the decay channels which are used to detect the Higgs bosons at hadron colliders. These SUSY decay modes should therefore not be overlooked in the search for the Higgs particles at the LHC.
THE LARGE-N LIMIT OF $\mathcal{N} = 1$ FIELD THEORIES FROM F THEORY
Authors: AHN CHANGHYUN , OH KYUNGHO , TATAR RADU
Published: May 2003

We study AdS/CFT correspondence in four-dimensional [Formula: see text] field theories realized on the world-volume of D3 branes near the intersections between D7 and D 7′ branes in F theory studied by Aharony et al. We consider the compactification of F theory on elliptically fibered Calabi–Yau threefolds corresponding to two sets of parallel D7 branes sharing six space–time directions. This can be viewed as orbifolds of six torus T6 by Zp × Zq(p,q = 2,3,4,6). We find the large-N spectrum of chiral primary operators by exploiting the property of AdS/CFT correspondence. Moreover, we discuss super gravity solutions for D3 branes in D7 and D 7′ branes background.
A NOTE ON "QUARKS OR LEPTONS?"
Authors: SIDHARTH B. G.
Published: May 2003

In the context of a recent description of fermions as Kerr–Newman type black holes with quantum mechanical inputs, it is shown how the quark picture can be recovered. The advantage is that in the process we obtain a rationale for such features as the puzzling fractional charges of the quarks, their masses, confinement and handedness in a unified scheme.
NONLINEAR VECTOR SUSY FOR THE THREE-DIMENSIONAL TOPOLOGICAL MASSIVE YANG–MILLS THEORY
Authors: SASAKI C. A. G. , SASAKI D. G. G. , SORELLA S. P.
Published: May 2003

A nonlinear vector supersymmetry for three-dimensional topological massive Yang–Mills is obtained by making use of a nonlinear but local and covariant redefinition of the gauge field.
CONSTRAINTS ON ELECTROWEAK CONTACT INTERACTIONS FROM LEP AND TEVATRON DATA
Authors: BELYAEV ALEXANDER , ROSENFELD ROGERIO
Published: May 2003

A complete set of dimension-six effective contact interactions involving Higgs, gauge bosons and quarks is studied. Limits on the coefficients of these new operators are obtained from the experimental values of the Z and W gauge bosons widths.
EFFECT OF STRONG MAGNETIC FIELD ON THE FIRST-ORDER ELECTROWEAK PHASE TRANSITION
Authors: FIORE R. , TIESI A. , MASPERI L. , MÉGEVAND A.
Published: May 2003

The broken-symmetry electroweak vacuum is destabilized in the presence of a magnetic field stronger than a critical value. Such magnetic field may be generated in the phase transition and restore the symmetry inside the bubbles. A numerical calculation indicates that the first-order phase transition is delayed but may be completed for a sufficient low value of the Higgs mass unless the magnetic field is extremely high.
CONSTRAINTS OF MIXING ANGLES FROM LEPTON NUMBER VIOLATING PROCESSES
Authors: NISHIURA HIROYUKI , MATSUDA KOUICHI , FUKUYAMA TAKESHI
Published: May 2003

We discuss the constraints of lepton mixing angles from lepton number violating processes such as neutrinoless double beta decay, μ--e+ conversion and K decay, K-→π+μ-μ- which are allowed only if neutrinos are Majorana particles. The rates of these processes are proportional to the averaged neutrino mass defined by [Formula: see text] in the absence of right-handed weak coupling. Here a, b(j) are flavor(mass) eigenstates and Uaj is the left-handed lepton mixing matrix. We give general conditions imposed on ab in terms of mi, lepton mixing angles and CP violating phases (three phases in Majorana neutrinos). These conditions are reduced to the constraints among mi, lepton mixing angles and ab which are irrelevant to the concrete values of CP phases. Given a ab experimentally, these conditions constrain mi and the lepton mixing angles. Though these constraints are still loose except for neutrinoless double beta decay, they will become helpful through rapid improvements of experiments. By using these constraints we also derive the limits on averaged neutrino masses for μ--e+ conversion and K decay, K-→π+μ-μ-, respectively. We also present the bounds for CP phases in terms of mi, mixing angles and ab.
THE CONFINEMENT MECHANISM IN YANG–MILLS THEORY?
Authors: MAGPANTAY JOSE A.
Published: May 2003

Using the recently proposed nonlinear gauge condition [Formula: see text] we show the area law behavior of the Wilson loop and the linear dependence of the instantaneous gluon propagator. The field configurations responsible for confinement are those in the nonlinear sector of the gauge-fixing condition (the linear sector being the Coulomb gauge). The nonlinear sector is actually composed of "Gribov horizons" on the parallel surfaces ∂ · Aa=fa≠0. In this sector, the gauge field [Formula: see text] can be expressed in terms of fa and a new vector field [Formula: see text]. The effective dynamics of fa suggests nonperturbative effects. This was confirmed by showing that all spherically symmetric (in 4-D Euclidean) fa(x) are classical solutions and averaging these solutions using a Gaussian distribution (thereby treating these fields as random) lead to confinement. In essence the confinement mechanism is not quantum mechanical in nature but simply a statistical treatment of classical spherically symmetric fields on the "horizons" of ∂ · Aa=fa(x) surfaces.
INFLUENCE OF THE SOURCE EVOLUTION ON PARTICLE CORRELATIONS
Authors: ANDREEV I. V.
Published: May 2003

Modification of the particles in the course of the source evolution is considered. Influence of this effect on multiplicities and correlations of the particles is displayed, including an enhancement of the production rates and identical particle correlations and also back-to-back particle–antiparticle correlations.
MIURA-LIKE FREE FIELD REALIZATION OF FERMIONIC CASIMIR $\mathcal{WB}_3$ ALGEBRAS
Authors: ÖZER H. T.
Published: May 2003

Starting from the well-known quantum Miura-like transformation for the non-simply-laced Lie algebras ℬN, we give an explicit construction of the Casimir WB3 algebras. We reserve the notation [Formula: see text] for the Casimir [Formula: see text] algebras of type [Formula: see text] which contains one fermionic field. It is seen that WB3 algebra is closed and associative for all values of the central charge c.
EXPERIMENTAL TEST OF A QUANTUM-LIKE THEORY: MOTION OF ELECTRONS IN A UNIFORM MAGNETIC FIELD, IN A VARIABLE POTENTIAL WELL
Authors: UNNIKRISHNAN C. S. , SAFVAN C. P.
Published: May 2003

We describe an experiment to test a quantum-like theory which predicts quantum-like behavior for an ensemble of electrons in a classical configuration with static magnetic and electric fields. Some of the earlier experiments had supporting evidence for anomalous, quantum-like effects in such a situation showing systematic modulations of electron current when a retarding potential is varied, even though the quantum wavelength of the electrons in such a configuration was less than a billionth of the spatial width of the potential well. Our experiment conclusively rules out any nonclassical, quantum-like behavior in electron transmission through simple electric barriers, when magnetic fields are present. We identify secondary electrons generated at various electrodes as the main source of apparent anomalous behavior. We also present a classical derivation of the quantum-like equation describing the modulations.
DOKSHITZER–GRIBOV–LIPATOV–ALTARELLI–PARISI EVOLUTION AND THE RENORMALIZATION GROUP IMPROVED YENNIE–FRAUTSCHI–SUURA THEORY IN QCD
Authors: WARD B. F. L. , JADACH S.
Published: May 2003

We show that the recently derived renormalization group improved Yennie–Frautschi–Suura (YFS) exponentiation of soft (k0→0) gluons in QCD is fully compatible with the usual Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) evolution of the structure functions of hadrons in the respective hadron–hadron hard interactions. We show how to implement the YFS exponentiation without double or over counting effects already implied by the DGLAP equation. In this way, we arrive at a theory which allows for the development of realistic, multiple gluon Monte–Carlo event generators for hard hadron–hadron scattering processes in which the DGLAP evolved structure functions are correctly synthesized with the respective YFS exponentiated soft gluon effects in a rigorous way.
A MANIFESTLY N=2 SUPERSYMMETRIC BORN–INFELD ACTION
Authors: KETOV SERGEI V.
Published: May 2003

A manifestly N=2 supersymmetric completion of the four-dimensional Nambu–Goto–Born–Infeld action, which is self-dual with respect to electric–magnetic duality, is constructed in terms of an Abelian N=2 superfield strength W in the conventional N=2 superspace. A relation to the known N=1 supersymmetric Born–Infeld action in N=1 superspace is established. The action found can be considered either as the Goldstone action associated with a partial breaking of N=4 supersymmetry down to N=2, with the N=2 vector superfield being a Goldstone field, or, equivalently, as the gauge-fixed superfield action of a (D-3)-brane in flat six-dimensional ambient space–time.
SOLAR SYSTEM EXPERIMENTS AND THE INTERPRETATION OF THE TRANSPOSED EQUI-AFFINE THEORY OF GRAVITY AS A THEORY WITH A VARIABLE PLANCK "CONSTANT"
Authors: FIZIEV P. , YAZADJIEV S.
Published: May 2003

It is shown that the recently proposed interpretation of the transposed equi-affine theory of gravity as a theory with a variable Planck "constant" is inconsistent with basic solar system gravitational experiments.
SYMMETRIC SUBGROUPS OF GAUGED SUPERGRAVITIES AND AdS STRING THEORY VERTEX OPERATORS
Authors: DOLAN L. , LANGHAM M.
Published: May 2003

We show how the gauge symmetry representations of the massless particle content of gauged supergravities that arise in the AdS/CFT correspondences can be derived from symmetric subgroups to be carried by string theory vertex operators, although explicit vertex operator constructions of the IIB string on AdS remain elusive. Our symmetry mechanism parallels the construction of representations of the Monster group and affine algebras in terms of twisted conformal field theories, and may serve as a guide to a perturbative description of the IIB string on AdS.
DUALITY IN SU(N) × SU(N′) PRODUCT GROUP FROM M THEORY
Authors: LEE JULIAN , SIN SANG-JIN
Published: May 2003

We generalize the M-theoretic duality of Schmaltz and Sundrum to the product group SU (N) × SU (N′) case. We show that the type IIA brane configurations for dual gauge theories are in fact two special limits of the same M-theory five-brane, just as in the case of the simple SU (N) group.
FROM CLASSICAL CHAOS TO DECOHERENCE IN ROBERTSON–WALKER COSMOLOGY
Authors: LOMBARDO FERNANDO C. , CASTAGNINO MARIO A. , BOMBELLI LUCA
Published: May 2003

We analyze the relationship between classical chaos and particle creation in Robertson–Walker cosmological models with gravity coupled with a scalar field. Within our class of models chaos and particle production are seen to arise in the same cases. Particle production is viewed as the seed of decoherence, which enables the quantum to classical transition and ensures that the correspondence between the quantum and classically chaotic models will be valid.
A q-DEFORMATION OF VIRASORO AND U(1) KAC–MOODY ALGEBRAS WITH HOPF STRUCTURE
Authors: MANSOUR M. , TAHRI E. H.
Published: May 2003

Using a general formalism of a q-deformation of an arbitrary Lie algebra, new kinds of q-deformed centerless Virasoro and U(1) Kac–Moody algebras are found. This q-deformation is associated to an R-matrix of unit square satisfying the quantum Yang–Baxter equation and allows a nontrivial Hopf structure. The central extension is also incorporated in this formalism.
TWO-DIMENSIONAL BOSONIZATION FROM VARIABLE SHIFTS IN THE PATH INTEGRAL
Authors: THOMASSEN JAN B.
Published: May 2003

A method to perform bosonization of a fermionic theory in (1+1) dimensions in a path integral framework is developed. The method relies exclusively on the path integral property of allowing variable shifts, and does not depend on the explicit form of Green's functions. Two examples, the Schwinger model and the massless Thirring model, are worked out.
UNIQUENESS OF THE MINIMUM OF THE FREE ENERGY OF THE 2-D YANG–MILLS THEORY AT LARGE N
Authors: AGHAMOHAMMADI A. , ALIMOHAMMADI M. , KHORRAMI M.
Published: May 2003

There have been some controversies about the large N behaviour of the 2-D Yang–Mills and chiral 2-D Yang–Mills theories. To be more specific, is there a one-parameter family of minima of the free energy in the strong region, or is the minimum unique? We show that by adding an equation (which was missing) to the known equations, the minimum becomes unique.
ON GRAVITO-ELECTROMAGNETIC DUALITY IN GENERAL RELATIVITY
Authors: DADHICH NARESH
Published: May 2003

In analogy with the electromagnetic theory, we resolve the Riemann curvature into electric and magnetic parts and consider the analogous duality transformation which keeps the Einstein action for vacuum invariant. It is remarkable that the duality symmetry of the action also leads to the vacuum field equation without cosmological constant. Further invariance of the vacuum equation and the action under the gravito-electric duality require gravitational constant to change sign.
MAPS AND TWISTS RELATING U(sl(2)) AND THE NONSTANDARD Uh(sl(2)): UNIFIED CONSTRUCTION
Authors: ABDESSELAM B. , CHAKRABARTI A. , CHAKRABARTI R. , SEGAR J.
Published: May 2003

A general construction is given for a class of invertible maps between the classical U ( sl (2)) and the Jordanian U h( sl (2)) algebras. Here the role of the maps is studied in the context of construction of twist operators relating the cocommutative and non-cocommutative coproducts of the U(sl(2)) and U h( sl (2)) algebras respectively. It is shown that a particular map called the "minimal twist map" implements the simplest twist given directly by the factorized form of the ℛh matrix of Ballesteros–Herranz. For a "non-minimal" map the twist has an additional factor obtainable in terms of the similarity transformation relating the map in question to the minimal one. Our general prescription may be used to evaluate the series expansion in powers of h of the twist operator corresponding to an arbitrary "non-minimal" map. The classical and the Jordanian antipode maps may also be interrelated by suitable similarity transformations.
A RELATIVISTIC DESCRIPTION OF GENTRY'S NEW REDSHIFT INTERPRETATION
Authors: SHIMIZU T. , WATANABE K.
Published: May 2003

We obtain a new expression of the Friedmann–Robertson–Walker metric, which is an analogue of a static chart of the de Sitter space–time. The reduced metric contains two functions, M(T, R) and Ψ(T, R), which are interpreted as, respectively, the mass function and the gravitational potential. We find that, near the coordinate origin, the reduced metric can be approximated in a static form and that the approximated metric function, Ψ(R) satisfies the Poisson equation. Moreover, when the model parameters of the Friedmann–Robertson–Walker metric are suitably chosen, the approximated metric coincides with exact solutions of the Einstein equation with the perfect fluid matter. We then solve the radial geodesics on the approximated space–time to obtain the distance-redshift relation of geodesic sources observed by the comoving observer at the origin. We find that the redshift is expressed in terms of a peculiar velocity of the source and the metric function, Ψ(R), evaluated at the source position, and one may think that this is a new interpretation of Gentry's new redshift interpretation.
IN SEARCH FOR NATURAL WORMHOLES
Authors: ANCHORDOQUI LUIS A. , TORRES DIEGO F. , ROMERO GUSTAVO E. , ANDRUCHOW I.
Published: May 2003

We have investigated 631 time profiles of gamma ray bursts from the BATSE database searching for observable signatures produced by microlensing events related to natural wormholes. The results of this first search of topologically nontrivial objects in the Universe can be used to constrain their number and mass.
CONSISTENT OFF-SHELL TREE STRING AMPLITUDES
Authors: LICCARDO ANTONELLA , PEZZELLA FRANCO , MAROTTA RAFFAELE
Published: May 2003

We construct off-shell tree bosonic string amplitudes, based on the operatorial formalism of the N-string vertex, with three external massless states both for open and closed strings by requiring them to be projective invariant. In particular our prescription leads, in the low-energy limit, to the three-gluon amplitude in the usual covariant gauge.
NON-ABELIAN DUAL MAPS IN PATH SPACE
Authors: MARTÍN ISBELIA
Published: May 2003

We study an extension of the procedure to construct duality transformations among Abelian gauge theories to the non-Abelian case using a path space formulation. We define a pre-dual functional in path space and introduce a particular nonlocal map among Lie algebra valued one-form functionals which reduces to the ordinary Hodge-⋆ duality map of the Abelian theories. Further, we establish a full set of equations on path space representing the ordinary Yang–Mills equations and Bianchi identities of non-Abelian gauge theories of four-dimensional Euclidean space.
RE-ASSESSING THE ANOMALOUS J/ψ-SUPPRESSION IN THE CERN NA50 DATA
Authors: GAVAI RAJIV V.
Published: May 2003

A systematic analysis of the L-dependence of the J/ψ-suppression in the data of the CERN NA38 and NA50 experiments shows that the anomalous suppression in the 1995 Pb–Pb data is at best a 4σ effect at any of the L-values for the Pb–Pb data, where L is the geometrical mean path length of the J/ψ in the colliding nuclei. Possible implications for the 1996 data are discussed.
ON THEORETICAL STUDIES OF Λ0 POLARIZATION
Authors: FÉLIX JULIÁN
Published: May 2003

The Λ0 polarization, in pp reactions, and from an experimental point of view, is a simple and well characterized phenomenon as function of both xF and PT; contrasting such simplicity, an accurate theoretical explanation so far is not available. This letter briefly presents and discusses the proposed theoretical ideas on Λ0 polarization, for Λ0's produced in pp collisions.
NONEXISTENCE THEOREMS FOR TRAVERSABLE WORMHOLES
Authors: SAA ALBERTO
Published: May 2003

Gauss–Bonnet formula is used to derive a new and simple theorem of nonexistence of vacuum static nonsingular Lorentzian wormholes. We also derive simple proofs for the nonexistence of Lorentzian wormhole solutions for some classes of static matter such as, for instance, real scalar fields with a generic potential obeying ϕV′(ϕ)≥0 and massless fermion fields.
CPT- AND B-VIOLATION: THE $p -\bar p$ SECTOR
Authors: KENNEDY DALLAS C.
Published: May 2003

The CPT symmetry of relativistic quantum field theory requires the total lifetimes of particles and antiparticles to be equal. Detection of [Formula: see text] lifetime shorter than [Formula: see text] yr would signal the breakdown of CPT invariance, in combination with B-violation. The best current limit on [Formula: see text], inferred from cosmic ray measurements, is about one Myr, placing lower limits on CPT-violating scales that depend on the exact mechanism. Paths to CPT breakdown within and outside ordinary quantum mechanics are sketched. Many of the limiting CPT-violating scales in [Formula: see text] decay lie within the weak-to-Planck range.
DYNAMICAL HAMILTONIAN FOR PREASSIGNED TIME-EVOLUTION OF FERMIONIC SQUEEZING
Authors: FAN HONG-YI , LIN JING-XIAN
Published: May 2003

We derive the general form of dynamical Hamiltonian generating the preassigned time-evolution of multimode fermionic squeezing. The fermionic squeezing is a quantum-mechanical image in fermionic Hilbert space corresponding to an orthogonal transformation in pseudo-classical Grassmann number space. The derivation is mainly based on the orthogonal properties of the transformation matrices. It is shown that some new fermionic operator realization of SO (2n) group and some new Hamiltonians can be obtained via this approach.
ELEMENTARY DOUBLETS OF BOUND STATES OF THE RADIAL DIRAC EQUATION
Authors: ZNOJIL MILOSLAV
Published: May 2003

For non-relativistic Schrödinger equations the lowering of their degree by substitution Ψ(r)→F(r)=Ψ′(r)/Ψ(r) is known to facilitate our understanding and use of their (incomplete, so-called quasi-exact) solvability. We show that and how the radial Dirac relativistic equation may quasi-exactly be solved in similar spirit.
SELF-ENERGIES AND VERTEX CORRECTIONS WITH TWO FACTORIZING LOOPS
Authors: BRÜCHER L. , FRANZKOWSKI J.
Published: May 2003

A complete set of factorizing two-loop self-energies and vertex corrections is calculated analytically for arbitrary masses and momenta — including the case of collinear singularities — within the ℛ-functions approach.
SKYRME MODEL ON S3 AND HARMONIC MAPS
Authors: BRIHAYE Y. , GABRIEL C.
Published: May 2003

A nonlinear sigma model mimicking the Skyrme model on S3 is proposed and a family of classical solutions to the equations are constructed numerically. The solutions terminate into catastrophic-like spikes at critical values of the Skyrme coupling constant and, when this constant is zero, they coincide with the series of harmonic maps on S3 constructed some years ago by P. Bizon.
NEUTRINO OSCILLATIONS AND FLAVOR STRUCTURE OF SUPERSYMMETRY WITHOUT R-PARITY
Authors: KONG OTTO C. W.
Published: May 2003

Focusing on a simple three neutrino oscillation scenario motivated by the recent super-Kamiokande result, we discuss both tree-level and one-loop contributions to neutrino masses in supersymmetry without R-parity, aiming at discerning the flavor structure issues of the theory. The single-vev parametrization framework, which allows the first consistent treatment of the bilinear and trilinear R-parity violating terms, and hence the tree and one-loop contributions, without any assumption on the nature of R-parity violation. Though the very small neutrino masses imply stringent suppressions of the relevant R-parity violating couplings, we show that there is still room for understanding the suppressions as a simple consequence of the general flavor hierarchy.
SUBMODELS OF NONLINEAR GRASSMANN SIGMA MODELS IN ANY DIMENSION AND CONSERVED CURRENTS, EXACT SOLUTIONS
Authors: FUJII KAZUYUKI , HOMMA YASUSHI , SUZUKI TATSUO
Published: May 2003

In the preceding paper,1 we constructed submodels of nonlinear Grassmann sigma models in any dimensions and, moreover, an infinite number of conserved currents and a wide class of exact solutions.

In this letter, we first construct almost all conserved currents for the submodels and all those for CP1-model. We next review the Smirnov and Sobolev construction for the equations of CP1-submodel and extend the equations, the S-S construction and conserved currents to higher order ones.
CONTRIBUTION OF A NEUTRINO ANAPOLE MOMENT TO THE MUON ANOMALOUS MAGNETIC MOMENT
Authors: ROSADO A.
Published: May 2003

We consider a Dirac neutrino and compute the contribution of its anapole moment κ anap to the anomalous magnetic moment of the muon using an unsubtracted dispersion relation and assuming a small neutrino structure. We find that this contribution could be important and may allow us to put a bound on κ anap .
THE CONSTRUCTION OF TRIGONOMETRIC INVARIANTS FOR WEYL GROUPS AND THE DERIVATION OF THE CORRESPONDING EXACTLY SOLVABLE SUTHERLAND MODELS
Authors: HASCHKE O. , RÜHL W.
Published: May 2003

Trigonometric invariants are defined for each Weyl group orbit on the root lattice. They are real and periodic on the co-root lattice. Their polynomial algebra is spanned by a basis which is calculated by means of an algorithm. The invariants of the basis can be used as coordinates in any cell of the co-root space and lead to an exactly solvable model of Sutherland type. We apply this construction to the F4 case.
ON SOME CHARACTERISTIC FEATURES OF THE PHASE TRANSITION IN A FRACTAL UNIVERSE
Authors: BHATTACHARYA A. , BANERJEE S. N. , CHAKRABORTI B.
Published: May 2003

The scaling properties of the early universe during its evolution have been studied in terms of the mass fractal dimension, "d". The speed of sound in the mixed phase of radiation and matter dominated era has been investigated and the possibility of a first-order phase transition between the two eras has been explored.
POSSIBLE EXPLANATION FOR THE SUPERFICIALLY NEGATIVE ELECTRON-NEUTRINO-MASS-SQUARE OBSERVED IN NUCLEAR β-DECAYS
Authors: TERAZAWA HIDEZUMI
Published: May 2003

The superficially negative mass square of the electron neutrino recently reported in several tritium β-decay experiments can be explained by a possible effect of the weak neutral current interaction of the produced neutrino with quarks in the nucleus, which has previously been predicted. The effect may present a serious obstacle to precise measurements of the neutrino mass within the accuracy of a few eV but, once established experimentally, it may be very useful to measure the weak mixing angle and the quark density in various nuclei.
A FERMIONIC HODGE STAR OPERATOR
Authors: DAVIS ALFRED , HÜBSCH TRISTAN
Published: May 2003

A fermionic analogue of the Hodge star operation is shown to have an explicit operator representation in models with fermions, in space–times of any dimension. This operator realizes a conjugation (pairing) not used explicitly in field theory, and induces a metric in the space of wave function(al)s just as in exterior calculus. If made real (hermitian), this induced metric turns out to be identical to the standard one constructed using hermitian conjugation; the utility of the induced complex bilinear form remains unclear.
GLUON-W-MESON SCATTERING VIA DIFFERENT RENORMALIZATION SCHEMES
Authors: DEMINOV M. M. , SLAVNOV A. A.
Published: May 2003

The one-loop gluon-W-meson amplitude is calculated by means of the gauge-invariant generalized Pauli–Villars regularization and with the help of dimensional regularization. It is shown that in the former case the amplitude satisfies generalized Ward identities, whereas in the latter case the amplitude differs from the former by the constant.
STELLAR FOOTPRINTS OF A VARIABLE G
Authors: TORRES DIEGO F.
Published: May 2003

Theories with varying gravitational constant G have been studied long time ago. Among them, the most promising candidates as alternatives of the standard general relativity are known as scalar–tensor theories. They provide consistent descriptions of the observed universe and arise as the low energy limit of several pictures of unified interactions. Therefore, an increasing interest on the astrophysical consequences of such theories has been sparked over the last few years. In this letter we comment on two methodological approaches to study evolution of astrophysical objects within a varying-G theory, and the particular results we have obtained for boson and white dwarf stars.
BEYOND THE HORIZON TO UNKNOWN TERRITORIES: THE SINGULARITY INSIDE BLACK HOLES
Authors: BURKO LIOR M.
Published: May 2003

We study the Cauchy horizon singularity inside a spherical charged black hole, coupled to a self-gravitating scalar field. We show that all the radial causal geodesics terminate at a weak singularity according to the Tipler classification. Our result is valid anywhere along the singularity, in particular in the regime where nonlinear effects are crucial.
PATH-INTEGRAL FORMULATION OF CASIMIR EFFECTS IN SUPERSYMMETRIC QUANTUM ELECTRODYNAMICS
Authors: ABE HIROYUKI , HASHIDA JUNYA , MUTA TAIZO , PURWANTO AGUS
Published: May 2003

The path-integral method of calculating the Casimir energy between two parallel conducting plates is developed within the framework of supersymmetric quantum electrodynamics at vanishing temperature as well as at finite temperature. The choice of the suitable boundary condition for the photino on the plates is argued and the physically acceptable condition is adopted which eventually breaks the supersymmetry. The photino mass term is introduced in the Lagrangian and the photino mass dependence of the Casimir energy and pressure is fully investigated.
SCALE INVARIANCE, NEW INFLATION AND DECAYING Λ-TERMS
Authors: GUENDELMAN E. I.
Published: May 2003

Realizations of scale invariance are studied in the context of a gravitational theory where the action (in the first-order formalism) is of the form [Formula: see text] where Φ is a density built out of degrees of freedom, the "measure fields" independent of gμν and matter fields appearing in L1, L2. If L1 contains the curvature, scalar potential V(ϕ) and kinetic term for ϕ, L2 another potential for ϕ, U(ϕ), then the true vacuum state has zero energy density, when theory is analyzed in the conformal Einstein frame (CEF), where the equations assume the Einstein form. Global scale invariance is realized when V(ϕ)=f1eαϕ and U(ϕ)=f2e2αϕ. In the CEF the scalar field potential energy V eff (ϕ) has, in addition to a minimum at zero, a flat region for αϕ→∞, with nonzero vacuum energy, which is suitable for either a new inflationary scenario for the early universe or for a slowly rolling decaying Λ-scenario for the late universe, where the smallness of the vacuum energy can be understood as a kind of seesaw mechanism.
THE COUPLING OF GRAVITY TO SPIN AND ELECTROMAGNETISM
Authors: FINSTER FELIX , SMOLLER JOEL , YAU SHING-TUNG
Published: May 2003

The coupled Einstein–Dirac–Maxwell equations are considered for a static, spherically symmetric system of two fermions in a singlet spinor state. Stable soliton-like solutions are shown to exist, and we discuss the regularizing effect of gravity from a Feynman diagram point of view.
AN ENTROPIC COSMOLOGICAL PRINCIPLE
Authors: BARROW JOHN D.
Published: May 2003

We show why there is a huge disparity between the radiation and Bekenstein–Hawking entropies of the universe today. We explain why this disparity does not tell us that the universe is in a highly improbable state. The coincidence of the classical and quantum entropies for black holes with Hawking lifetime equal to the age of the universe, and hence of radius equal to the proton size, is shown to a consequence of observing the universe at the main-sequence lifetime.
A SIMPLE METHOD OF DETERMINING THE HUBBLE CONSTANT
Authors: QIN YI-PING
Published: May 2003

Bidirectional relativistic proper motions of radio components of nearby extragalactic sources give a strong constraint on the determination of the Hubble constant H0. Under the assumption that the real velocity of radio components of extragalactic sources is not less than that of Galactic sources, the value of H0 can be estimated at a high level of accuracy. The assumption is reasonable due to the general belief that the activity in the core of galaxies must be more powerful than that of stars. This method is simple and with only one uncertainty — the real velocity of components. This uncertainty is related to the value of the real velocity of components of Galactic sources and the latter is always well-determined (note that the determination is independent of H0 and the distance of Galactic sources can be directly measured at a rather high level of accuracy). Hopefully the method will play an important role in future research to fix the value of H0. With the data of the three sources available so far and the assumption that the real velocity of components of at least one of the sources is not less than a known velocity of components of a Galactic source, the constant is estimated to be within 27.08 kms -1 Mpc -1<H0≤ 53.15 kms -1 Mpc -1 with this method.
PHASE TRANSITION IN QUANTUM GRAVITY?
Authors: HUSAIN VIQAR , JAIMUNGAL SEBASTIAN
Published: May 2003

A fundamental problem with attempting to quantize general relativity is its perturbative non-renormalizability. However, this fact does not rule out the possibility that nonperturbative effects can be computed, at least in some approximation. We outline a quantum field theory calculation, based on general relativity as the classical theory, which implies a phase transition in quantum gravity. The order parameters are composite fields derived from space–time metric functions. These are massless below a critical energy scale and become massive above it. There is a corresponding breaking of classical symmetry.
ORIGIN OF THE INFLATIONARY UNIVERSE
Authors: BARVINSKY ANDREI O. , YU. KAMENSHCHIK ALEXANDER , KIEFER CLAUS
Published: May 2003

We give a consistent description of how the inflationary universe emerges in quantum cosmology. This involves two steps: (a) it is shown that a sensible probability peak can be obtained from the cosmological wave function. This is achieved by going beyond the tree level of the semiclassical expansion. (b) Due to decoherence interference terms between different semiclassical branches are negligibly small. The results give constraints on the particle content of a unified theory.
CHARGED DILATONIC BLACK HOLES: STRING FRAME VERSUS EINSTEIN FRAME
Authors: CASADIO ROBERTO , HARMS BENJAMIN
Published: May 2003

The descriptions of Reissner–Nordström and Kerr–Newman dilatonic black holes in the Einstein frame are compared to those in the string frame. We describe various physical measurements in the two frames and show which experiments can distinguish between the two frames. In particular we discuss the gyromagnetic ratios of black holes, the decay law via Hawking radiation and the propagation of light on black hole backgrounds.
CYLINDRICALLY SYMMETRIC SPINNING BRANS–DICKE SPACE–TIMES WITH CLOSED TIMELIKE CURVES
Authors: ANCHORDOQUI LUIS A. , BERGLIAFFA SANTIAGO E. PEREZ , TROBO MARTA L. , BIRMAN GRACIELA S.
Published: May 2003

We present here three new exact solutions of Brans–Dicke theory for a stationary geometry with cylindrical symmetry in the presence of matter in rigid rotation with [Formula: see text]. All the solutions have eternal closed timelike curves in some region of space–time which has a size that depends on ω. Moreover, two of them do not go over a solution of general relativity in the limit ω→∞.
DIFFERENCE ANALOGUES OF THE FREE SCHRÖDINGER EQUATION
Authors: DOBREV V. K. , DOEBNER H.-D. , MRUGALLA C.
Published: May 2003

We propose an infinite family of difference equations, which are derived from the first principle that they are invariant with respect to the Schrödinger algebra. The first member of this family is a difference analogue of the free Schrödinger equation. These equations are obtained via a purely algebraic construction from a corresponding family of singular vectors in Verma modules over the Schrödinger algebra. The crucial moment in the construction is the realization of the Schrödinger algebra through additive difference vector fields, i.e. vector fields with difference operators instead of differential operators. Our method produces also differential-difference equations in which only space- or time-differentiation is replaced with the corresponding difference operators.
DEFORMATION OF SCHILD STRING
Authors: KURIKI R. , OGUSHI S. , SUGAMOTO A.
Published: May 2003

We attempt to construct new superstring actions with a D-plet of Majorana fermions [Formula: see text], where ℬ is the D-dimensional space–time index and A is the two-dimensional spinor index, by deforming the Schild action. As a result, we propose three kinds of actions: the first is invariant under N=1 (the worldsheet) supersymmetry transformation and the area-preserving diffeomorphism. The second contains the Yukawa type interaction. The last possesses some nonlocality because of bilinear terms of [Formula: see text]. The reasons why completing a Schild type superstring action with [Formula: see text] is difficult are finally discussed.
CHARGE QUANTIZATION IN THE LARGEST LEPTOQUARK–BILEPTON CHIRAL ELECTROWEAK SCHEME
Authors: DOFF A. , PISANO F.
Published: May 2003

The uniqueness of the hypercharge assignments in the three-fermion families leptoquark–bilepton SU (3)C× SU (4)L× U (1)N model is established. Although the gauge group contains an explicit U(1) factor, freedom from triangle anomalies combined with the requirement of nonvanishing charged fermion masses uniquely fix the electric charges of all fermions independently of the neutrinos being massless or not. The electric-charge quantization, flavor family replication, and the existence of three colors are interwoven.
ANTI-DE SITTER GRAVITY ASSOCIATED WITH THE SUPERGROUP SU(1,1|2) × SU(1,1|2)
Authors: DAVID JUSTIN R.
Published: May 2003

We construct the anti-de Sitter supergravity in three dimensions associated with the supergroup SU (1,1|2)× SU (1,1|2). The field content and the action are inferred using the fact that AdS supergravity theories in three dimensions are Chern–Simons theories.
SUPERSYMMETRY OF MULTI-BOSON HAMILTONIANS
Authors: BECKERS J. , BRIHAYE Y. , DEBERGH N.
Published: May 2003

Supersymmetry in quantum optical models is pointed out here by dealing with differential realizations of the generators of the nonlinear Higgs algebra, when this algebra is seen as the spectrum generating algebra subtending the multi-boson Hamiltonians of such models.
COSMOLOGICAL CONSEQUENCES OF A MODEL WITH A GENERALIZED COSMOLOGICAL CONSTANT
Authors: AL-RAWAF A. S.
Published: May 2003

Here, we discuss the cosmological consequences of a previous suggested model for the case K = ±1. It is shown that the model covers the whole observed ranges for the Hubble's constant, the age of the universe and the density parameter.
DETERMINATIONS OF |Vub| AND |Vcb| FROM MEASUREMENTS OF B→ Xu,cℓν DIFFERENTIAL DECAY RATES
Authors: JIN CHANGHAO
Published: May 2003

Methods are described in the framework of light-cone expansion which allow one to determine the Cabibbo–Kobayashi–Maskawa matrix elements |Vub| and |Vcb| from measurements of the differential decay rates as a function of the scaling variables in the inclusive semileptonic decays of B mesons. By these model-independent methods the dominant hadronic uncertainties can be avoided and the B→ Xuℓν decay can be very efficiently differentiated from the B→ Xcℓν decay, which may lead to precise determinations of |Vub| and |Vcb|.
PAIR PRODUCTION IN A TIME-DEPENDENT MAGNETIC FIELD
Authors: CALUCCI GIORGIO
Published: May 2003

The production of electron–positron pairs in a time-dependent magnetic field is estimated in the hypotheses that the magnetic field is uniform over large distances with respect to the pair localization and it is so strong that the spacing of the Landau levels is larger than the rest mass of the particles. This calculation is presented since it has been suggested that extremely intense and varying magnetic fields may be found around some astrophysical objects.
A POSSIBLE ANISOTROPY IN BLACK BODY RADIATION VIEWED THROUGH NON-UNIFORM GASEOUS MATTER
Authors: RAI DASTIDAR T. K.
Published: May 2003

A nonlocal gauge symmetry of a complex scalar field, which can be trivially extended to spinor fields, was demonstrated in a recent paper (Mod. Phys. Lett.A13, 1265 (1998), hep-th/9902020). The corresponding covariant Lagrangian density yielded a new, nonlocal quantum electrodynamics. In this letter we show that as a consequence of this new QED, a black body radiation viewed through gaseous matter appears to show a slight deviation from the Planck formula, and propose an experimental test to check this effect. We also show that a non-uniformity in this gaseous matter distribution leads to an (apparent) spatial anisotropy of the black body radiation.
NON-UNIVERSAL GRAVITATIONAL COUPLINGS OF NEUTRINOS IN MATTER
Authors: NIEVES JOSÉ F. , PAL PALASH B.
Published: May 2003

When neutrinos travel through a normal matter medium, the electron neutrinos couple differently to gravity compared to the other neutrinos, due to the presence of electrons in the medium and the absence of the other charged leptons. The matter-induced gravitational couplings of the neutrinos under such conditions are calculated and their contribution to the neutrino index of refraction in the presence of a gravitational potential is determined.
SPONTANEOUS BREAKING OF SUPERSYMMETRY IN COSMOLOGICAL MODELS AND SUPERGRAVITY THEORIES
Authors: TKACH V. I. , ROSALES J. J. , SOCORRO J.
Published: May 2003

In this work we have constructed the most general action for a set of complex homogeneous scalar supermultiplets interacting with the scale factor in the supersymmetric FRW model. It is shown that the local conformal time supersymmetry leads to a scalar field potential defined in terms of the Kähler potential and superpotential in the same combination as in supergravity (or effective superstring) theories. This scalar field potential depends on an arbitrary parameter α which is not fixed by conformal time supersymmetry and induces the spontaneous breaking of supersymmetry in supergravity theories.
GENERALIZED PARTITION FUNCTIONS, INTERPOLATING STATISTICS AND HIGHER VIRIAL COEFFICIENTS
Authors: BORGES P. F. , BOSCHI-FILHO H. , FARINA C.
Published: May 2003

Starting from determinants at finite temperature obeying an intermediate boundary condition between the periodic (bosonic) and antiperiodic (fermionic) cases, we find results which can be mapped onto those obtained from anyons for the second virial coefficient. Using this approach, we calculate the corresponding higher virial coefficients and compare them with the results in the literature.
RENORMALIZATION OF GAUGE THEORIES AND MASTER EQUATION
Authors: ZINN-JUSTIN J.
Published: May 2003

The evolution of ideas which has led from the first proofs of the renormalizability of non-Abelian gauge theories, based on Slavnov–Taylor identities, to the modern proof based on the BRS symmetry and the master equation is recalled. This lecture has been delivered at the Symposium in Honour of Professor C. N. Yang, Stony Brook, May 21, 22, 1999.
QUANTIZATION CONDITION FOR HIGHLY EXCITED STATES
Authors: FERNÁNDEZ FRANCISCO M. , GUARDIOLA RAFAEL
Published: May 2003

We develop a quantization condition for the excited states of simple quantum-mechanical models. The approach combines perturbation theory for the oscillatory part of the eigenfunction with a rational approximation to the logarithmic derivative of the nodeless part of it. We choose one-dimensional anharmonic oscillators as illustrative examples.
OCTONIONIC MÖBIUS TRANSFORMATIONS
Authors: MANOGUE CORINNE A. , DRAY TEVIAN
Published: May 2003

A vexing problem involving nonassociativity is resolved, allowing a generalization of the usual complex Möbius transformations to the octonions. This is accomplished by relating the octonionic Möbius transformations to the Lorentz group in ten space–time dimensions. The result will be of particular interest to physicists working with lightlike objects in ten dimensions.