bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum Decoherence in a Four-Dimensional Black Hole Background
Authors: Ellis John , Mavromatos N. E. , Winstanley Elizabeth , Nanopoulos D. V.
Published: October 2003

We display a logarithmic divergence in the density matrix of a scalar field in the presence of an Einstein–Yang–Mills black hole in four dimensions. This divergence is related to a previously-found logarithmic divergence in the entropy of the scalar field, which cannot be absorbed into a renormalization of the Hawking–Bekenstein entropy of the black hole. Motivated by the fact that the cutoff in this divergence varies as the latter decays, by an analysis of black holes in two-dimensional string models and by studies of D-brane dynamics in higher dimensions, we propose that the renormalization scale variable be identified with time. In this case, the logarithmic divergence we find induces a non-commutator term [Formula: see text] in the quantum Liouville equation for the time evolution of the density matrix ρ of the scalar field, leading to quantum decoherence. The order of magnitude of [Formula: see text] is μ2/M P , where μ is the mass of the scalar particle.
Spinons as Composite Fermions
Authors: Cabra Daniel C. , Rossini Gerardo L.
Published: October 2003

We show that gauge invariant composites in the fermionic realization of SU (N)1 conformal field theory explicitly exhibit the holomorphic factorization of the corresponding WZW primaries. In the SU (2)1 case we show that the holomorphic sector realizes the spinon Y( sl 2) algebra, thus allowing the classification of the chiral Fock space in terms of semionic quasiparticle excitations created by the composite fermions.
Gravitational Effects in a Spherical Solenoid
Authors: Ivanov B. V.
Published: October 2003

The weak field approximation is applied to the Ernst equations in the magnetovac case. The global gravitational solution induced by the magnetic field of a spherical solenoid is found. Effects like the acceleration at rest and the tension in the solenoid's shell are studied.
Chargino Production in Different Supergravity Models and the Effect of the Tadpoles
Authors: Díaz Marco Aurelio
Published: October 2003

If the lightest chargino is discovered at LEP2, the measurement of its mass and cross-section together with the mass of the lightest neutralino, enables the determination of the parameters that define the theory and the entire supersymmetric and Higgs spectrum. Within this context, we: (i) study the effect of the one-loop tadpoles in the minimization condition of the Higgs potential, by comparing the RGE-improved Higgs potential approximation with the calculation of the minimum including the effect of the one-loop tadpoles, and (ii) compare the prediction of two different supergravity models, namely, the model based on B=2m0 and motivated by the solution of the μ-problem, and the minimal supergravity model, based on A=B-m0.
Orbifolds with Continuous Wilson Lines and Soft Terms
Authors: Kim H. B. , Muñoz C.
Published: October 2003

Orbifold compactifications with continuous Wilson lines have very interesting characteristics and as a consequence they are candidates for obtaining realistic models. We perform an analysis of the soft supersymmetry-breaking terms arising in this type of compactifications. We also compare these results with those of orbifolds without including continuous Wilson lines. Their phenomenological properties turn out to be similar.
Low x Behavior of the Isovector Nucleon Polarized Structure Function and the Bjorken Sum Rule
Authors: Buccella Franco , Pisanti Ofelia , Santorelli Pietro
Published: October 2003

The combination [Formula: see text] is derived from SLAC data on polarized proton and deuteron targets, evaluated at Q2=10  GeV 2, and compared with the results of SMC experiment. The agreement is satisfactory except for the points at the three lowest x, which have an important role in the SMC evaluation on the L.H.S. of the Bjorken sum rule.
Phenomenology of a Supersymmetric Model for Fermion Mass Hierarchy
Authors: Liu Chun
Published: October 2003

Some phenomenological aspects of a supersymmetric model for fermion mass hierarchy proposed previously are discussed. It is required that the lepton universality violation is near to its current experimental bound. The lepton number violation decay modes τ→2eμ and 3μ maybe observable in the near future. The Majorana mass of electron-neutrino is predicted to be about 0.1 eV. The fine-tuning problem is discussed.
The Dirac–Hamiltonian in an Aharonov–Bohm Gauge Field and its Self-Adjoint Extensions
Authors: Odaka Kazuhiko , Satoh Kazuya
Published: October 2003

By using the spherical coordinates in (3+1) dimensions we study the self-adjointness of the Dirac–Hamiltonian in an Aharonov–Bohm gauge field of an infinitely thin magnetic fluxtube. It is shown that the angular part of the Dirac–Hamiltonian requires self-adjoint extensions. These self-adjoint extensions are parametrized by a 2×2 unitary matrix.
Fermi Excitations in Hot and Dense Quark–Gluon Plasma
Authors: Kalashnikov O. K.
Published: October 2003

The Fermi excitations in hot and dense quark–gluon plasma are studied in the Feynman gauge using the temperature Green function technique. We find four well-separated spectrum branches for all |q| in the case m=0 and establish the additional splitting between them (four different effective masses) when m≠0. The long wavelength limit of these excitations is found in the general case of the massive fermions at finite temperature and baryon densities to give the exact one-loop spectrum. This spectrum exhibits many known results as its different limits.
Large-Nc Relations Among Isgur–Wise Functions
Authors: Brahm David E. , Walden James
Published: October 2003

We investigate the relations that must hold among baryonic Isgur–Wise functions ηi in the large-Nc limit from unitarity constraints, and compare to those found by Chow using the Skyrme model [or SU(4)]. Given the exponential dropoff of the ηi away from threshold, unitarity requires only that the usual normalization conditions hold at w=1, and that η=η1 near threshold. Our results are consistent with, but less powerful than, the Skyrme model relations. This shows that large-Nc analyses comprise more than just unitarity constraints.
On Experimental Studies of Λ0 Polarization
Authors: Félix Julián
Published: October 2003

It is well known that Λ0's are created with significant polarization in pp reactions, where both the beam proton and the target proton are initially unpolarized. But then, despite the Λ0 polarization experimental studies so far performed, the source of polarization remains elusive. To provide some light on this problem, the present experimental status of Λ0 polarization produced in pp reactions is reported and discussed.
Role of Regularization in Quantum Corrections to the Scalar–Tensor Theories of Gravity
Authors: Fujii Yasunori
Published: October 2003

We show that regularizing divergent integrals is important when applied to the loop diagrams corresponding to quantum corrections to the coupling of the "gravitational" scalar field due to the interaction among matter fields. We use the method of continuous spacetime dimensions to demonstrate that WEP is a robust property of the Brans–Dicke theory beyond the classical level, hence correcting our previous assertion of the contrary. The same technique can be used to yield the violation of WEP when applied to the scale-invariant theory, thus providing another reason for expecting fifth-force-type phenomena.
The Partition Function in the Four-Dimensional Schwarz-Type Topological Half-Flat Two-Form Gravity
Authors: Abe Mitsuko
Published: October 2003

We derive the partition functions of the Schwarz-type four-dimensional topological half-flat two-form gravity model on K3-surface or T4 up to on-shell one-loop corrections. In this model the bosonic moduli spaces describe an equivalent class of a trio of the Einstein–Kähler forms (the hyper-Kähler forms). The integrand of the partition function is represented by the product of some [Formula: see text]-torsions. [Formula: see text]-torsion is the extension of R-torsion for the de Rham complex to that for the [Formula: see text]-complex of a complex analytic manifold.
Testing a Model with Additional Vector Fermions at the LEP2 Collider
Authors: Heyssler M. , Spanos V. C.
Published: October 2003

Our aim is to test a model recently presented, motivated by the reported Rb and Rc "crisis", which contains extra vector fermions. We suggest an alternative indirect test of the possible existence of new heavy quark flavors at the LEP2 collider, which turns out to give the clearest signal. We calculate [Formula: see text] cross-sections within this framework, including one-loop corrections, and find measurable differences compared to the Standard Model predictions.
A Schwinger Term in q-Deformed su(2) Algebra
Authors: Fujikawa Kazuo , Kubo Harunobu , Oh C. H.
Published: October 2003

An extra term generally appears in the q-deformed su(2) algebra for the deformation parameter q= exp 2π iθ, if one combines the Biedenharn–Macfarlane construction of q-deformed su(2), which is a generalization of Schwinger's construction of conventional su(2), with the representation of the q-deformed oscillator algebra which is manifestly free of negative norm. This extra term introduced by the requirement of positive norm is analogous to the Schwinger term in current algebra. Implications of this extra term on the Bloch electron problem analyzed by Wiegmann and Zabrodin are briefly discussed.
Curvature-Induced Phase Transition in Three-Dimensional Thirring Model
Authors: Geyer B. , Shil'nov Yu. I.
Published: October 2003

The effective potential of composite fermion fields in three-dimensional Thirring model in curved spacetime is calculated in linear curvature approximation. The phase transition accompanied by the creation of nonzero chiral invariant bifermionic vector-like condensate is shown to exist. The type of this phase transition is discussed.
Tetrahedron Reflection Equations
Authors: Isaev A. P. , Kulish P. P.
Published: October 2003

Reflection equation for the scattering of lines moving in half-plane is obtained. The corresponding geometric picture is related with configurations of half-planes touching the boundary plane in (2+1) dimensions. This equation can be obtained as an addition to the tetrahedron equation consistency condition for a modified Zamolodchikov algebra.
$Z'_8$ Orbifolds Models, Supersymmetry Breaking, and Cosmology
Authors: Frampton Paul H. , Keszthelyi Bettina , Wright Brian D. , Kephart Thomas W.
Published: October 2003

By including the effects of superstring thresholds, we consider minimal string unification together with the requirement of producing a supersymmetry breaking gluino condensate in the hidden sector. Assigning modular weights to the MSSM fields, consistent with anomaly cancellation, we generate solutions in a class of phenomenologically-viable [Formula: see text] orbifold models. In such models, a hidden photino can be a source of cosmological dark matter.
Spin-Dependent Structure Function ĝ1+ĝ2 for e++e-→B+X (Revisited)
Authors: Chen Hong
Published: October 2003

The QCD factorization expression has been revisited to the sum of two spin-dependent structure functions ĝ1 and ĝ2 for e++e-→B+X. We find that there exist some spurious quark-mass contributions in an expression derived earlier by Lu, Li and Hu. Their removal guarantees that the measurements of ĝ1 and ĝ2 indeed construct a determination of twist-three transverse spin-dependent fragmentation function, ĝT, in the case of inclusive Λ production in electron–positron annihilation.
Asymptotic States in Nonlocal Field Theories
Authors: Barci D. G. , Oxman L. E.
Published: October 2003

Asymptotic states in field theories containing nonlocal kinetic terms are analyzed using the canonical method, naturally defined in Minkowski space.

We apply our results to study the asymptotic states of a nonlocal Maxwell–Chern–Simons theory coming from bosonization in (2+1) dimensions. We show that in this case the only asymptotic state of the theory, in the trivial (non-topological) sector, is the vacuum.
W-Strings on Curved Backgrounds
Authors: Miković Aleksandar , Sazdović Branislav
Published: October 2003

We discuss a canonical formalism method for constructing actions describing propagation of W-strings on curved backgrounds. The method is based on the construction of a representation of the W-algebra in terms of currents made from the string coordinates and the canonically conjugate momenta. We construct such a representation for a W3-string propagating in the background metric with one flat direction by using a simple ansatz for the W-generators where each generator is a polynomial of the canonical currents and the vierbeins. In the case of a general background, we show that the simple polynomial ansatz fails, and terms containing the vierbein derivatives must be added.
A String-Inspired Ansatz for Quark Masses and Mixing
Authors: Kobayashi Tatsuo , Xing Zhi-Zhong
Published: October 2003

We propose a simple but realistic pattern of quark mass matrices at the string scale, which can be derived from orbifold models of superstring theory with no use of gauge symmetries. This pattern is left–right symmetric and preserves the structural parallelism between up and down quark sectors. Its phenomenological consequences on flavor mixing and CP-violation are confronted with current experiments at the weak scale by using the renormalization group equations in the framework of minimal supersymmetric standard model. We find that good agreement is achievable without fine-tuning.
On the Structure of the Early Universe
Authors: Banerjee S. N. , Chakrabarti B. , Bhattacharya A.
Published: October 2003

We have postulated that the mass of the early universe possesses a (mass) fractal dimension 'd' during the early stages of its expansion and so we have come across many interesting consequences of the early universe lying in between matter and radiation dominated limits of it.
Correlation Functions for Some Conformal Theories on Riemann Surfaces
Authors: Monastyrsky Michael , Nechaev Sergei
Published: October 2003

We discuss the geometrical connection between 2-D conformal field theories, random walks on hyperbolic Riemann surfaces and knot theory. For the wide class of CFTs with monodromies being the discrete subgroups of SL(2, ℝ), the determination of four-point correlation functions are related to construction of topological invariants for random walks on multipunctured Riemann surfaces.
Decoherence in Pre-Big-Bang Cosmology
Authors: Lukas André , Poppe Rudolf
Published: October 2003

We analyze the quantum cosmology of the simplest pre-big-bang model without dilaton potential. In addition to the minisuperspace variables we include inhomogeneous dilaton fluctuations and determine their wave function on a semiclassical background. This wave function is used to calculate the reduced density matrix and to find criteria for the loss of decoherence. It is shown that coherence between different backgrounds can always be achieved by a specific choice of vacua. Their exact expressions as functions of the wave number and the background quantities are given. Generically, however, decoherence can be expected. In particular, we discuss the implications of these results on the "exit problem" of pre-big-bang cosmology.
Extension of the Parameter Space in the Tomimatsu–Sato Solutions
Authors: Manko V. S. , Moreno C.
Published: October 2003

Extension of the parameters in the well-known Tomimatsu–Sato family of solutions is presented which makes this family simultaneously applicable for the description of the exterior fields of sub- and super-extreme spinning sources.
The Attractor Mechanism in the Minimal Tensor–Scalar Theory of Gravity
Authors: Gérard J.-M. , Mahara I.
Published: October 2003

In a previous letter, we proved that the minimal tensor–scalar theory of gravity with a spatially flat Einstein metric does not generically contain an attractor mechanism towards general relativity. Hereafter we extend our proof to the case of a spatially curved Einstein metric.
A Note on Brans–Dicke Cosmology with Axion
Authors: Mukherji Sudipta
Published: October 2003

We study the Brans–Dicke model in the presence of an axion. The dynamical equations are solved when the fields are space-independent and the metric is spatially flat. It is found that at late time the scale factor undergoes decelerated expansion but the dilaton grows large. At early time, scale factor and the dilaton approach constants.
Vacuum Fluctuations as a Source of Adiabatic Perturbations in Power-Law Inflationary Cosmology
Authors: Mijić M.
Published: October 2003

An analysis of the decoherence of quantum fluctuations shows that production of classical adiabatic density perturbations may not take place in models of power-law inflation, a(t)~tp, with 1<p≤ 3. Some consequences for models of extended inflation are pointed out. In general, the condition for decoherence places new constraint on inflationary models, which does not depend on often complicated subsequent evolution.
q2-Dependence of Heavy-to-Light Transitions
Authors: Ivanov M. A. , Valit Yu. M.
Published: October 2003

The q2-dependence of the heavy-to-light form factors in the full physical region is obtained within the relativistic quark model with heavy infrapropagators. It is shown that the behavior of the vector form factors agrees with the pole dominance hypothesis whereas the behavior of the axial form factors is rather different from the polelike function.
Perturbation Theory with Convergent Series for Arbitrary Values of Coupling Constant
Authors: Belokurov V. V. , Kamchatny V. V. , Shavgulidze E. T. , Solovyov Yu. P.
Published: October 2003

In this letter, the method of the approximative calculation of functional integrals with any given accuracy1,2 is developed. Here we use the independence of the integrals on an auxiliary regularization parameter to simplify the calculations. Also we propose a modification of the method that proves to be more convenient for calculations with large values of coupling constants.
Implications of Anomalous Gauge Boson Interactions to the Fermion Electromagnetic Moments
Authors: Bento Luís , Neves Rui
Published: October 2003

We calculate the electromagnetic form factors of the fermions induced by the anomalous gauge boson interactions contained in the operators [Formula: see text] and [Formula: see text]. The interplay between vertex corrections and gauge boson self-energies is studied in order to separate the non-universal form factors. We apply the same procedure to re-analyze previous results regarding other anomalous gauge boson interactions.
Geometric Models of the Quantum Relativistic Rotating Oscillator
Authors: Cotăescu Ion I.
Published: October 2003

A family of geometric models of quantum relativistic rotating oscillator is defined by using a set of one-parameter deformations of the static (3+1) de Sitter or anti-de Sitter metrics. It is shown that all these models lead to the usual isotropic harmonic oscillator in the nonrelativistic limit, even though their relativistic behavior is different. As in the case of the (1+1) models,1 these will have even countable energy spectra or mixed ones, with a finite discrete sequence and a continuous part. In addition, all these spectra, except that of the pure anti-de Sitter model, will have a fine-structure, given by a rotator-like term.
Baryon Number Nonconservation and the Stability of Strange Matter
Authors: Keith E. , Ma Ernest
Published: October 2003

If baryon number nonconservation exists in the form of an effective six-quark operator which also changes strangeness by four units, it could have a tremendous impact on the absolute stability of strange quark matter. We show that such an operator is negligible in the supersymmetric standard model with [Formula: see text] terms in the superpotential, but may be of importance in models with exotic particle content. From the experimental lower limit of 1025 years on the stability of nuclei, we find a model-independent lower limit of the order 105 years on the stability of strange matter against such decays.
Disappearance of Black Hole Criticality in Semiclassical General Relativity
Authors: Chiba Takeshi , Siino Masaru
Published: October 2003

We investigate the quantum effects on the so-called critical phenomena in black hole formation. Quantum effects of a scalar field are treated semiclassically via a trace anomaly method. It is found that the demand of regularity at the origin implies the disappearance of the echo. It is also found that semiclassical equations of motion do not admit continuously self-similar solutions. The quantum effects would change the critical solution from a discretely self-similar one to a solution without critical phenomena.
Proton Spin in Chiral Quark Models
Authors: Weber H. J. , Song X. , Kirchbach M.
Published: October 2003

The spin and flavor fractions of constituent quarks in the proton are obtained from their chiral fluctuations involving Goldstone bosons. SU(3) breaking suggested by the mass difference between the strange and up, down quarks is included, and this improves the agreement with the data markedly.
Dynamical Supersymmetry Breaking
Authors: Skiba Witold
Published: October 2003

We review mechanisms of dynamical supersymmetry breaking. Several observations that narrow the search for possible models of dynamical supersymmetry breaking are summarized. These observations include the necessary and sufficient conditions for supersymmetry breaking. The two conditions are based on non-rigorous arguments, and we show examples where they are too restrictive. Dynamical effects present in models with product gauge groups are given special attention.
Generalizing the Coleman–Hill Theorem
Authors: Kao Hsien-Chung
Published: October 2003

Following the work of Khare et al., we show that the generalization to systems with spontaneous symmetry breaking of the Coleman–Hill theorem to one-loop order can be extended to the case including fermions with the most general interactions. Although the correction to the parity-odd part of the vacuum polarization looks complicated in the Higgs phase, it turns out that the correction to the Chern–Simons term is identical to that in the symmetric phase, with the difference coming only from the contribution of the would be Chern–Simons term. We also discuss the implication of our result to non-Abelian systems.
WDVV Equations from Algebra of Forms
Authors: Marshakov A. , Mironov A. , Morozov A.
Published: October 2003

A class of solutions to the WDVV equations is provided by period matrices of hyperelliptic Riemann surfaces, with or without punctures. The equations themselves reflect associativity of explicitly described multiplicative algebra of (possibly meromorphic) one-differentials, which holds at least in the hyperelliptic case. This construction is direct generalization of the old one, involving the ring of polynomials factorized over an ideal, and is inspired by the study of the Seiberg–Witten theory. It has potential to be further extended to reveal algebraic structures underlying the theory of quantum cohomologies and the prepotentials in string models with N=2 supersymmetry.
String-Like Description of Gravity and Possible Applications for F-Theory
Authors: Bandos Igor A.
Published: October 2003

The Lorentz harmonic formulation of D-dimensional bosonic p-brane theory with D≥ (p+1)(p+2)/2 coupled to an antisymmetric tensor field of rank d=(p+1) provides the dynamical ground for the description of d=(p+1) dimensional gravity. Hence it realizes the idea of Regge and Teitelboim on a "string-like" description of gravity. The simplest nontrivial models of such a kind are provided by free D-dimensional p-branes in which world–volumes are embedded as minimal surfaces. Possible applications of such a model with d=2+2 and D=2+10 for studying a geometry of bosonic sector of F-theory are considered. Some speculations inspired by the proposed model are presented.
Simple Amplitudes for ϕ3 Feynman ladder graphs
Authors: Tuan R. Hong
Published: October 2003

Recently, we proposed a new approach for calculating Feynman graphs amplitude using the Gaussian representation for propagators which was proven to be exact in the limit of graphs having an infinite number of loops. Regge behavior was also found in a completely new way and the leading Regge trajectory calculated. Here we present symmetry arguments justifying the simple form used for the polynomials in the Feynman parameters [Formula: see text], where [Formula: see text] is the mean-value for these parameters, appearing in the amplitude for the ladder graphs. (Taking mean-values is equivalent to the Gaussian representation for propagators.)
q-Area Preserving Algebras SDiff(Tk) and the Matrix Algebra $\bar a_{\infty}$
Authors: Kinani E. H. El , Zakkari M.
Published: October 2003

We consider the infinite matrix Lie algebra [Formula: see text] and an infinite set of its subalgebras parametrized by an Nth root of the unity; qN=1. We obtain the embedding in [Formula: see text] of the area preserving diffeomorphism on the 2-D torus and also its one-parameter deformed version. The correspondence between the area preserving diffeomorphism on the torus Tk, k>2 and the algebra [Formula: see text] is pointed out.
Orbiting Valence Quarks and their Influence on the Structure Functions of the Nucleon
Authors: Liang Zuo-Tang , Rittel R.
Published: October 2003

It is shown that intrinsic orbital motion of the valence quarks has large influences on the spin-dependent as well as the spin-averaged nucleon structure functions. Its connection with the observed "very small contribution of quark spin to nucleon spin" and the observed violation of Gottfried sum rule is discussed.
Superalgebraic Truncations from D=10, N=2 Chiral Supergravity
Authors: Kim Chang-Ho , Park Young-Jai
Published: October 2003

We study 10-dimensional N=2 maximal chiral supergravity in the context of Lie superalgebra SU(8/1). The possible successive superalgebraic truncations from 10-dimensional N=2 chiral theory to the lower-dimensional supergravity theories are systematically realized as sub-superalgebraic chains of SU(8/1) by using the Kac–Dynkin weight techniques.
Dimensional Reduction and BRST Approach to the Description of a Regge Trajectory
Authors: Pashnev A. , Tsulaia M.
Published: October 2003

The local free field theory for Regge trajectory is described in the framework of BRST quantization method. The corresponding BRST charge is constructed using the method of dimensional reduction.
Color Effects in the Unitarization of the QCD Pomeron
Authors: Calucci Giorgio
Published: October 2003

A short discussion on the effects of the color structure in the unitarization of the BFKL–Pomeron is presented. It shows the relevance of the color in controlling the growth of the series obtained by iteration of the ladder graphs.
Induced Magnetic Field in a Finite Fermion Density Maxwell QED2+1
Authors: Zeitlin Vadim
Published: October 2003

We are studying finite fermion density states in Maxwell QED 2+1 with external magnetic field. It is shown that at any fermion density the energy of some magnetized states may be less than that of the state with the same density, but no magnetic field. Magnetized states are described by the effective Maxwell–Chern–Simons QED 2+1 Lagrangian with gauge field mass proportional to the number of filled Landau levels.
On the Origin of the Rise of F2 at Small x
Authors: Navelet H. , Peschanski R. , Wallon S. , Royon Ch. , Schoeffel L.
Published: October 2003

We have shown that, provided that the nonperturbative input is regular at the right of the ω=0 singularity of the dominant DGLAP anomalous dimension, the rise of F2 at small x, experimentally measured by the averaged observable [Formula: see text], is input-independent in the perturbative Q2 regime at small x. [Formula: see text] appears to be more input-dependent in the same range. The GRV-type parametrizations verify these properties. Other models, namely the BFKL kernel (QCD dipoles), DGLAP (with a nonperturbative input singular at the right of the ω=0) give different predictions for λ. At moderate Q2, there is a possibility of distinguishing these different perturbative QCD predictions in the near future.
On the Ultralocal and Non-Ultralocal Poisson Brackets
Authors: Pronko G. P.
Published: October 2003

We consider the classical KdV theory as an example of non-ultralocal mechanical system (i.e. where fundamental Poisson brackets contain the derivative of δ-function). We show that by an appropriate gauge transformation, the Poisson brackets of the associated monodromy matrices may be transformed into those of the classical Heisenberg magnetic.
Non-Abelian Fields in Exact String Solutions
Authors: Iofa M. Z. , Zayas L. A. Pando
Published: October 2003

Within the framework of "anomalously gauged" Wess–Zumino–Witten (WZW) models, we construct solutions which include non-Abelian fields. Both compact and noncompact groups are discussed. In the case of compact groups, as an example of background containing non-Abelian fields, we discuss conformal theory on the SO(4)/SO(3) coset, which is the natural generalization of the 2-D monopole theory corresponding to the SO(3)/SO(2) coset. In noncompact case, we consider examples with SO(2, 1)/SO(1, 1) and SO(3, 2)/SO(3, 1) cosets.
The Massive Spinning Particle Revisited
Authors: Delduc F. , Ivanov E. , Sokatchev E.
Published: October 2003

We propose a formulation of the massive spinning particle in terms of physical bosonic and fermionic fields only. We make use of neither auxiliary objects of the type of γ5 nor gauge fields. The model is to be used as a suitable starting point for a forthcoming study of the rigid superparticle.
The Longitudinal Structure Function FL as a Function of F2 and dF2/dln Q2 at Small x. The Next-to-Leading Analysis
Authors: Kotikov A. V. , Parente G.
Published: October 2003

We present a set of formulas to extract the longitudinal deep inelastic structure function FL from the transverse structure function F2 and its derivative dF2/d ln Q2 at small x. Our expressions are valid for any non-negative value of δ, with x-δ the behavior of the parton densities at low x. Using F2 HERA data we obtain FL in the range 10-4≤ x≤10-2 at Q2=20 GeV 2. Some other applications of the formulas are pointed out.
Deformations of Differential Calculi
Authors: Madore J. , Mourad J. , Sitarz A.
Published: October 2003

Two differential calculi over a two-point space have been recently introduced. The simplest is based on the algebra [Formula: see text] which is the algebra of functions on two points. The second is based on the algebra M2 of 2×2 complex matrices which can be considered as a quantized version of [Formula: see text]; only one "coordinate" can be measured at a time but a measurement always yields two values. These two calculi are compared and the first is shown, in a sense which we shall make precise, to be a singular contraction of the second.
The Superstring Propagator and the Signature of Space-Time
Authors: Pollock M. D.
Published: October 2003

The Faddeev (Newton–Wigner) propagator K for the heterotic superstring theory is derived from the Wheeler–DeWitt equation for the wave function of the Universe Ψ, obtained in the four-dimensional (mini-superspace) Friedmann space-time ds2=dt2-a2(t)dx2, after reduction from the ten-action. The effect of higher-derivative terms ℛ2 is to break the local invariance under time reparametrization to a global symmetry t→λt, and consequently there are no ghost or gauge-fixing contributions, a functional integral over the (constant) Lagrange multiplier λ being sufficient to enforce the Hamiltonian constraint implicitly. After Wick rotation of the time, [Formula: see text], the only physically acceptable solution for K decreases exponentially on the Planck time-scale ~ t P , explaining from the quantum cosmological viewpoint why the signature of space-time is Lorentzian rather than Euclidean. This is analogous to the case of the (two-dimensional) free relativistic scalar particle, discussed recently by Redmount and Suen, who found that the propagator decreases exponentially outside the light-cone on the scale of the Compton wavelength of the particle (in accordance with the Heisenberg indeterminacy principle). These two seemingly different forms of acausality are thus physically excluded in the same way.

The propagator for the Schwarzschild black hole of mass M is also obtained from the Schrödinger equation for the wave function on the apparent horizon, due to Tomimatsu, and the Hawking temperature T H =(8π M)-1 is derived from the Euclidean form of this equation.
A Lattice Test of Alternative Interpretations of "Triviality" in (λΦ4)4 Theory
Authors: Agodi A. , Andronico G. , Cea P. , Consoli M. , Cosmai L. , Fiore R. , Stevenson P. M.
Published: October 2003

There are two physically different interpretations of "triviality" in (λΦ4)4 theories. The conventional description predicts a second-order phase transition and that the Higgs mass mh must vanish in the continuum limit if v, the physical vev is held fixed. An alternative interpretation, based on the effective potential obtained in "triviality-compatible" approximations (in which the shifted "Higgs" field h(x)≡Φ(x)-<Φ> is governed by an effective quadratic Hamiltonian) predicts a phase transition that is very weakly first-order and that mh and v are both finite, cutoff-independent quantities. To test these two alternatives, we have numerically computed the effective potential on the lattice. Three different methods were used to determine the critical bare mass for the chosen bare coupling value. All give excellent agreement with the literature value. Two different methods for obtaining the effective potential were used, as a control on the results. Our lattice data are fitted very well by the predictions of the unconventional picture, but poorly by the conventional picture.
Duality in Supersymmetric SU(N) Gauge Theory with a Symmetric Tensor
Authors: Sakai Tadakatsu
Published: October 2003

Duality in supersymmetric SU(N) gauge theory with a symmetric tensor is studied using the technique of deconfining and Seiberg's duality. By construction, the gauge group of the dual theory necessarily becomes a product group. In order to check the duality, several nontrivial consistency conditions are examined. In particular we find that by deforming along a flat direction, the duality flows to the Seiberg's duality of SO(N) gauge theory.
On the Renormalization of the Chiral Fermion Meson Model: An Algebraic Approach
Authors: Franco D. H. T. , Caldas H. C. G. , Mota A. L. , Nemes M. C.
Published: October 2003

We re-investigate the problem of the renormalizability of the chiral fermion meson model on the light of the regularization-independent algebraic method. The present letter is intended as a useful application of a modern technique in theory of current interest for the description of low energy hadron phenomenology. We show that the model is stable under radiative corrections and anomaly free in a regularization-free way without having to resort to the explicit calculation of Feynman diagrams.
The Drell–Hearn–Gerasimov Sum-Rule in QCD
Authors: Bass S. D.
Published: October 2003

Photoproduction spin sum-rules offer a new window on the spin structure of the nucleon that complements the information we can learn from polarized deep inelastic scattering experiments. We review the theory and present status of the Drell–Hearn–Gerasimov sum-rule in QCD, emphasizing the possible relation between the present "discrepancy" in this sum-rule and the nucleon's strangeness magnetic moment. In the case of an elementary electron or photon target (say at the NLC) the Drell–Hearn–Gerasimov sum-rule provides a test for physics beyond the minimal Standard Model.
Cosmic Density Fluctuations, Magnetic Fields and Gravitational Waves
Authors: Pollock M. D.
Published: October 2003

It has previously been shown, for the heterotic superstring theory including higher-derivative terms ℛ2, how metric fluctuations, sufficient for galaxy formation in the Universe, arise as a consequence of the Heisenberg indeterminacy principle, applied to the dynamical auxiliary coordinate [Formula: see text] and its canonically conjugate momentum πξ, defined from the Friedmann space-time [Formula: see text]. This indeterminacy is distributed amongst the scalar, vector and tensor modes of the metric. Therefore, in addition to the fluctuations δρ/ρ in the matter, and in the cosmic microwave background radiation, there is a magnetic field, whose magnitude is estimated to agree approximately with the phenomenological value B c ~ 10-10 G required for the present-day intergalactic field (in the absence of a dynamo mechanism acting on a primordial field B s ≲ 10-17 G), and also a stochastic gravitational wave background, whose energy density must be bounded by the limit Ω gw ≲ 2.6×10-14h-2≈ 10-13 obtained by Krauss and White from the Sachs–Wolfe effect.
Generalized Gaussian Effective Potential: Second-Order Thermal Corrections
Authors: Cea Paolo , Tedesco Luigi
Published: October 2003

We discuss the finite temperature generalized Gaussian effective potential. We put out a very simple relation between the thermal corrections to the generalized Gaussian effective potential and those of the effective potential. We evaluate explicitly the second-order thermal corrections in the case of the self-interacting scalar field in one spatial dimension.
Domain Walls from M-Branes
Authors: Lü H. , Pope C. N.
Published: October 2003

We discuss the vertical dimensional reduction of M-sbranes to domain walls in D=7 and D=4, by dimensional reduction on Ricci-flat four-manifolds and seven-manifolds. In order to interpret the vertically-reduced five-brane as a domain wall solution of a dimensionally-reduced theory in D=7, it is necessary to generalize the usual Kaluza–Klein ansatz, so that the three-form potential in D=11 has an additional term that can generate the necessary cosmological term in D=7. We show how this can be done for general four-manifolds, extending previous results for toroidal compactifications. By contrast, no generalization of the Kaluza–Klein ansatz is necessary for the compactification of M-theory to a D=4 theory that admits the domain-wall solution coming from the membrane in D=11.
Equivalence of the Grand Canonical Partition Functions of Particles with Different Statistics
Authors: Chaturvedi S. , Panigrahi P. K. , Srinivasan V. , MacKenzie R.
Published: October 2003

It is shown that the grand partition function of an ideal Bose system with single particle spectrum εi=(2n+k+3/2)ℏω is identical to that of a system of particles with single particle energy εi=(n+1/2)ℏω and obeying a particular kind of statistics based on the permutation group.
Phase Transition in Gold Nuclei at 10.6A GeV
Authors: Jain P. L. , Singh G. , Gonsalves R.
Published: October 2003

The charge (Z) distribution of multifragment decays of 197 Au projectile at 10.6A GeV in nuclear emulsion is fitted with a power-law. The moments of nuclear charged fragment distribution provide strong evidence that nuclear matter possesses critical point observables. The observed values of the critical exponents γ, β and τ are very close to those for a liquid–gas system.
On the Existence of Squeezed States in an Anisotropic Universe
Authors: Pedrosa I. A. , Bezerra V. B.
Published: October 2003

We use the time-dependent invariant method in order to study the behavior of a scalar field placed in an anisotropic universe. The existence of coherent and squeezed states is discussed.
On the Vanishing of the Cosmological Vacuum Energy
Authors: Pollock M. D.
Published: October 2003

By demanding the existence of a globally invariant ground-state solution of the Wheeler–De Witt equation (Schrödinger equation) for the wave function of the Universe Ψ, obtained from the heterotic superstring theory, in the four-dimensional Friedmann space-time, we prove that the cosmological vacuum energy has to be zero.
Bender–Dunne Orthogonal Polynomials General Theory
Authors: Krajewska Agnieszka , Ushveridze Alexander , Walczak Zbigniew
Published: October 2003

A general theory of Bender–Dunne orthogonal polynomials is proposed. It is shown that these polynomials can easily be constructed for any explicitly tridiagonalizable Hamiltonians and are, in fact, the orthogonal polynomials in a discrete variable which takes its values in the set of energy levels of the corresponding quantum model. The weight functions for Bender–Dunne polynomials are explicitly constructed.
Structural Aspects of the Proton in the Chiral Quark Model
Authors: Wu Chung-Yi
Published: October 2003

We calculate with chiral symmetry the parton contents of the proton based on a two-component wave function. The results give significant sea-quark contents and, especially, the intrinsic gluon polarization is produced at a more fundamental level.
R-Deformed Heisenberg Algebra, Anyons and D=2+1 Supersymmetry
Authors: Plyushchay Mikhail S.
Published: October 2003

A universal minimal spinor set of linear differential equations describing anyons and ordinary integer and half-integer spin fields is constructed with the help of deformed Heisenberg algebra with reflection. The construction is generalized to some d=2+1 supersymmetric field systems. Quadratic and linear forms of action functionals are found for the universal minimal as well as for supersymmetric spinor sets of equations. A possibility of constructing a universal classical mechanical model for d=2+1 spin systems is discussed.
Almost Maximally Broken Permutation Symmetry for Neutrino Mass Matrix
Authors: Kang Kyungsik , Kang Sin Kyu , Kim Jihn E. , Ko Pyungwon
Published: October 2003

Assuming three light neutrinos are Majorana particles, we propose mass matrix ansatz for the charged leptons and Majorana neutrinos with family symmetry S3 broken into S1 and S2, respectively. Each matrix has three parameters, which are fixed by measured charged lepton masses, differences of squared neutrino masses relevant to the solar and the atmospheric neutrino puzzles, and the masses of three light Majorana neutrinos as a candidate for hot dark matter with ∑|mν|~ 6 eV . The resulting neutrino mixing is compatible with the data for the current upper limit,  th <0.7 eV , of neutrino-less double beta decay experiments, and the current data for various types of neutrino oscillation experiments. One solution of our model predicts that νμ→ντ oscillation probability is about < 0.008 with Δm2 ~ 10-2 eV 2, which may not be accessible at CHORUS and other on-going experiments.
Pattern Recognition in High Multiplicity Events
Authors: Astafyeva N. M. , Dremin I. M. , Kotelnikov K. A.
Published: October 2003

In very high energy collisions, many particles are produced and distributed in the available phase space volume in various ways. With new accelerator facilities (especially, for nucleus–nucleus collisions), the problem of pattern recognition in high multiplicity events becomes crucial in order to classify such events and to separate those with some special features (e.g. ring-like events, jets and other regular patterns). This letter presents the first attempt to use wavelet technique for pattern recognition in nucleus–nucleus collisions. After describing the method in general, we demonstrate its usefulness by applying it to a single event of Pb–Pb collision at 158A GeV with 1072 charged particles produced and discuss results obtained for some other events. Further extension of the method is proposed.
Oscillator Representation and Generalized van der Waals Hamiltonians
Authors: Dineykhan M.
Published: October 2003

The oscillator representation method is extended to calculate the energy spectrum of bound state systems described by axially symmetrical potentials in the parabolic system coordinates. In particular, it is applied to calculate the energy of the ground and excited states of the hydrogen atom in the uniform electric field and van der Waals field. The method gives the perturbation formulas for the analytic spectrum of the hydrogen atom in the generalized van der Waals field and defines oscillator strengths for transitions from the ground state to the perturbed manifold n=10, m=0.
Testing the Equivalence Principle Using g-2 Experiments
Authors: Mann R. B.
Published: October 2003

I discuss the utility of anomalous magnetic moments of elementary leptons as a test of the Einstein Equivalence Principle (EEP). Violations of the EEP in the leptonic sector give rise to novel effects which are manifest in qualitatively different changes in the anomalous precession frequency. The Brookhaven muon-(g-2) experiment E821 can search for such effects directly, offering us a new empirical window into the validity of the EEP.
Anti-Isospectral Transformations in Quantum Mechanics
Authors: Krajewska Agnieszka , Ushveridze Alexander , Walczak Zbigniew
Published: October 2003

In this letter we demonstrate that there exists a remarkable class of quantum models admitting Z2 anti-isospectral transformations which change the form of the potential and invert the sign of a certain finite set of energy levels. These transformations help one to construct interesting classes of non-monic polynomials which are mutually orthogonal on two different intervals with two different weight functions.
Non-Anomalous Generalized Chiral Schwinger Model
Authors: De Souza Dutra A.
Published: October 2003

Recently, Basseto and Griguolo1 did a perturbative quantization of what they called a generalized chiral Schwinger model. As a consequence of the kind of quantization adopted, some gauge-dependent masses raised in the model. On the other hand, we discussed the possibility of introducing a generalized Wess–Zumino term,2 where such gauge-dependent masses did appear. Here we intend to show that one can construct a non-anomalous version of a model which include that presented by Basseto and Griguolo as a particular case, by adding to it a generalized Wess–Zumino term, as proposed in Ref. 2. So we conclude that it is possible to construct a gauge-invariant extension of the model quoted in Ref. 1, and this can be done through a Wess–Zumino term of the type proposed in Ref. 2.
Non-Critical Open Strings Beyond the Semiclassical Approximation
Authors: Ambjørn J. , Hayasaka K. , Nakayama R.
Published: October 2003

We studied the lowest order quantum corrections to the macroscopic wave functions Γ(A,ℓ) of non-critical string theory using the semiclassical expansion of Liouville theory. By carefully taking the perimeter constraint into account we obtained a new type of boundary condition for the Liouville field which is compatible with the reparametrization invariance of the boundary and which is not only a mixture of Dirichlet and Neumann types but also involves an integral of an exponential of the Liouville field along the boundary. This condition contains an unknown function of A/ℓ2. We determined this function by computing part of the one-loop corrections to Γ(A,ℓ).
Pontryagin, Euler Forms and Chern–Simons Terms in Weyl–Cartan Space
Authors: Babourova O. V. , Frolov B. N.
Published: October 2003

The existence of the Pontryagin and Euler forms in a Weyl–Cartan space on the basis of the variational method with Lagrange multipliers are established. It is proved that these forms can be expressed via the exterior derivatives of the corresponding Chern–Simons terms in a Weyl–Cartan space with torsion and nonmetricity.
Gravitino Warm Dark Matter Motivated by Gauge-Mediated Supersymmetry Breaking Theories
Authors: Kawasaki M. , Sugiyama Naoshi , Yanagida T.
Published: October 2003

Gauge-mediated supersymmetry breaking models suggest the presence of the light gravitino with mass ~ 1 keV which can be warm dark matter in our universe. We consider large scale structure of the universe in the warm dark matter model and find that the power spectrum of the gravitino dark matter is almost the same as that of a cold dark matter at scales larger than about 1 Mpc. We also study the Ly α absorption systems which are presumed to be galaxies at high redshifts and show that the baryon density in the damped Ly α absorption systems predicted by the gravitino dark matter model is quite consistent with the present observation.