bluuebunny/crossref_metadata_2025 huggingface dataset:
A Finite-Size Magnetic Monopole in Double-Potential Formalism
Authors: Lebedev Oleg
Published: October 2003

Using the double-potential formalism developed by Zwanziger, it is possible to construct nonsingular four-potentials corresponding to a given distribution of magnetic charge without violating the Bianchi identity. In this letter, we study a ball-like monopole with uniform distribution of magnetic charge. The corresponding four-potentials are found explicitly. We also construct the angular momentum operator of an electron in the field of such a monopole, which can be used to investigate the problem of electron-monopole scattering and to rectify Kazama–Yang–Goldhaber singularity.
On the Possible Detection of Massive Stable Exotic Particles at the LHC
Authors: Nisati Aleandro , Petrarca Silvano , Salvini Giorgio
Published: October 2003

The possible detection of massive quasi-stable exotic particles at the high luminosity hadronic colliders is discussed. In this decade, the LHC, now under preparation, has the best opportunity to observe them at the TeV scale. The present design of the ATLAS detector, that has been almost irreversibly decided, may turn out to be flexible enough to allow the detection of this interesting class of exotic particles. The trigger acceptance, the track reconstruction and the particle identification are studied. The necessity of a good measurement of the ionization loss in the muon sector of the detectors is recommended.
On the Description of Hadron Multiplicities Associated with Heavy Flavours
Authors: Kisselev A. V. , Petrov V. A.
Published: October 2003

We make some critical remarks concerning the recent statements from Ref. 1 about QCD tests in multihadron e+e- events induced by heavy quarks.
Charged Higgs Boson Mass in the Gauge-Mediated Supersymmetry Breaking Model
Authors: Kang Sin Kyu
Published: October 2003

We compute the charged Higgs boson mass in the minimal GMSB model. We find that the present experimental bounds on Br (b→ sγ) lead to mH±≳ 445 (686) GeV for tan β=3 (40) and Mt=175 GeV. The predictions of mH± imply that the decay mode t→ H+b is closed in the minimal GMSB model.
Testing Cosmic Censorship in Kerr-Like Collapse Situations
Authors: Rudnicki Wiesław
Published: October 2003

According to the cosmic censorship hypothesis of Penrose, naked singularities should never occur in realistic collapse situations. One of the major open problems in this context is the existence of a naked singularity in the Kerr solution with |a|>m; this singularity can be interpreted as the final product of collapse of a rapidly rotating object. Assuming that certain very general and physically reasonable conditions hold, we show here, using the global techniques, that a realistic gravitational collapse of any rotating object, which develops from a regular initial state, cannot lead to the formation of a final state resembling the Kerr solution with a naked singularity. This result supports the validity of the cosmic censorship hypothesis.
Solitons in Chern–Simons Theories of Nonrelativistic CPN-1 Models: Spin Textures in the Quantum Hall Effect
Authors: Ichinose Ikuo , Sekiguchi Akira
Published: October 2003

Topological solitons in CP N-1 models coupled with a Chern–Simons gauge field and a Hopf term are studied both analytically and numerically. These models are low-energy effective theories for the quantum Hall effect (QHE) with internal degrees of freedom, like the QHE in double-layer electron systems. These solitons correspond to skyrmions and merons which are charged quasi-excitations in the QHE. We explicitly show that the CP N-1 models can be used to represent (pseudo-)spin textures in the original Chern–Simons theory of bosonized electrons.
Sub-Millisecond Absolute Timing: Toward an Actual Gravitational Observatory
Authors: Cerdonio M. , Visconti V. Crivelli , Ortolan A. , Prodi G. , Taffarello L. , Vedovato G. , Vitale S.
Published: October 2003

In this letter we report the results we obtained experimentally demonstrating the feasibility of absolute timing of impulsive gravitational wave signals by means of a resonant bar detector. We reached a resolution of less than 20 μs for SNR ≥ 10. We also discuss the important prospects this result opens for the present and for the future, as a necessary condition for the implementation of a global network of gravitational wave detectors.
Observables of the Generalized 2D Yang–Mills Theories on Arbitrary Surfaces: A Path Integral Approach
Authors: Khorrami M. , Alimohammadi M.
Published: October 2003

Using the path integral method, we calculate the partition function and the generating functional (of the field strengths) of the generalized 2-D Yang–Mills theories in the Schwinger–Fock gauge. Our calculation is done for arbitrary 2-D orientable, and also nonorientable surfaces.
Supersymmetric Nambu–Jona-Lasinio Model in an External Gravitational Field
Authors: Buchbinder I. L. , Inagaki T. , Odintsov S. D.
Published: October 2003

We investigate the effect of an external gravitational fields to the chiral symmetry breaking in the supersymmetric (SUSY) Nambu–Jona-Lasinio (NJL) model coupled to gravity in a non-supersymmetric way. Evaluating the effective potential in the leading order of the 1/Nc-expansion and in the linear curvature approximation, it is possible to have the chiral symmetry breaking in the SUSY NJL model in an external gravitational fields. In the broken phase the dynamically generated mass is analytically and numerically calculated.
Excited States of 71Ge above the Neutron Emission Threshold and Solar Neutrino Capture Rates for Ga Detectors
Authors: Kar Kamales , Sarkar Sukhendusekhar , Goswami Srubabati , Raychaudhuri Amitava
Published: October 2003

In Gallium detectors for solar neutrinos, the capture rate due to Gamow–Teller transitions to excited states of 71Ge beyond the neutron emission threshold is usually neglected. We make a model calculation to estimate its effect and find that this yields an additional contribution which may be as much as 0.4 SNU, even larger than that from the Isobaric Analog State in 71 Ge reached by Fermi transitions, which is normally included in the standard predictions.
Nonperturbative Analysis of the Coleman–Weinberg Phase Transition
Authors: Litim D. F. , Wetterich C. , Tetradis N.
Published: October 2003

We study the coarse grained free energy for the Coleman–Weinberg phase transition in four-dimensional scalar QED (as a function of the mass term). Our method is based on the solution of a nonperturbative flow equation. This permits a consistent treatment of the effective potential near the origin, a region not accessible to standard perturbation theory. Our results confirm the first-order character of the phase transition for arbitrary values of the scalar coupling. They demonstrate how flow equations can be used for a description of first-order phase transitions.
The (Im)possibility of Detecting a Fifth Dimension
Authors: Wesson P. S. , Mashhoon B. , Liu H.
Published: October 2003

We show that it is impossible to rule out the existence of a fifth dimension using the classical tests of relativity in the solar system. A similar impasse occurs in certain cosmologies. However, it might be possible to detect a fifth dimension indirectly, via its effects on vacuum energy, thermodynamics or spin.
Derivation of Squeezed States Via Weyl Ordering Approach
Authors: Fan Hong-Yi , Fan Yue
Published: October 2003

By virtue of the invariance of Weyl ordering under similar transformations we find a new approach to derive explicit forms of squeezed states. The technique of integration within an ordered product of operators is fully used in our discussions.
Effective Action and Measure in Matrix Model of IIB Superstrings
Authors: Chekhov L. , Zarembo K.
Published: October 2003

We calculate an effective action and measure induced by the integration over the auxiliary field in the matrix model recently proposed to describe IIB superstrings. It is shown that the measure of integration over the auxiliary matrix is uniquely determined by locality and reparametrization invariance of the resulting effective action. The large-N limit of the induced measure for string coordinates is discussed in detail. It is found to be ultralocal and, thus, is possibly irrelevant in the continuum limit. The model of the GKM type is considered in relation to the effective action problem.
Canonical Equivalence of a Generic 2-D Dilaton Gravity Model and a Free Field Theory
Authors: Cruz J. , Navarro-Salas J.
Published: October 2003

We show that a canonical transformation converts, up to a boundary term, a generic 2-D dilaton gravity model into a free field theory with a Minkowskian target space.
Renormalization Transformations of the 4-D BFYM Theory
Authors: Accardi Alberto , Belli Andrea
Published: October 2003

We study the most general renormalization transformations for the first-order formulation of the Yang–Mills theory. We analyze, in particular, the trivial sector of the BRST cohomology of two possible formulations of the model: the standard one and the extended one. The latter is a promising starting point for the interpretation of the Yang–Mills theory as a deformation of the topological BF theory. This work is a necessary preliminary step towards any perturbative calculation, and completes some recently obtained results.
Rapidity Gap of Weakly Coupled Leptoquark Production in ep Collider
Authors: Kuo T. K. , Lee Taekoon
Published: October 2003

We show that the current bounds on the leptoquark couplings imply that if leptoquarks are produced in ep collisions, a significant fraction of them could form a leptoquark–quark bound state. The decay of the bound state has a distinct event shape with rapidity gap. A possible application of this observation in the leptoquark search at HERA is discussed.
On the Parity Degeneracy of Baryons
Authors: Kirchbach M.
Published: October 2003

The gross features of the observed baryon excitation spectrum below 2 GeV are well explained if the spectrum generating algebra of its intrinsic orbital angular momentum states is o (4) ⊗ su (2)I. The spins of the resonances are obtained through the coupling of a Lorentz bi-spinor {1/2,0} ⊕ {0,1/2} to a multiplet of the type {j,j} in its O(4)/O(3) reduction. The parities of the resonances follow from those of the O(3) members of the {j,j} multiplets. In this way relativistic SL (2,C) representations are constructed. For example, the first S11, P11, and D13 states with masses around 1500 MeV fit into the {1/2,1/2} ⊗ [{1/2,0} ⊕ {0,1/2}] representation. The observed parities of the resonances correspond to natural parities of the {1/2,1/2} states. The second P11, S11, D13 — together with the first P13, F15, D15, and (a predicted) F17-resonances, centered around 1700 MeV, are organized into the {3/2,3/2} ⊗ [{1/2,0} ⊕ {0,1/2}] representation. We argue that the members of the {3/2,3/2} multiplet carry unnatural parities and that in this region chiral symmetry is restored. In the N(939)→ N(1650) transition the chiral symmetry mode is changed, and therefore, a chiral phase transition is predicted to take place.
Geometric Foundation of the Magnetic Dipole Moment
Authors: Hammond Richard T.
Published: October 2003

The observed value of the magnetic dipole moment of the electron is much larger than that allowed by electromagnetic theory. In particular, Maxwell's equations, together with the known upper bound on the size of the electron predict a magnetic moment much smaller than the observed one, even if the particle is rotating at the speed of light! In gravitation with an asymmetric connection, the intrinsic spin of an elementary particle gives rise to torsion. It is shown here that this source, spin, can also give rise to the observed magnetic dipole moment of the electron, and do so with no moving parts.
MSW-Like Enhancements Without Matter
Authors: Stephenson G. J. , Goldman T. , McKellar B. H. J.
Published: October 2003

We study the effects of a scalar field, coupled only to neutrinos, on oscillations among weak interaction current eigenstates. The effect of a real scalar field appears as effective masses for the neutrino mass eigenstates, the same for [Formula: see text] as for ν. Under some conditions, this can lead to a vanishing of δ m2, which maximizes mixing independently of the vacuum mixing angles, as in the MSW effect. We discuss some examples and show that it is possible to resolve an apparent discrepancy in spectra required by r-process nucleosynthesis in the mantles of supernovae and by solar neutrino solutions.
Perturbation Expansion: Is it Asymptotic?
Authors: Yamamoto Kunio
Published: October 2003

It is pointed out that, for any model with bound state, contrary to the case of nonrelativistic quantum mechanics, perturbation expansion based on Feynman rules in relativistic quantum field theory is not asymptotic of physical amplitude in which the effects of bound state are considered.
Are Naked Singularities Forbidden by the Second Law of Thermodynamics?
Authors: Barve Sukratu , Singh T. P.
Published: October 2003

By now, many examples of naked singularities in classical general relativity are known. It may, however, be that a physical principle over and above the general theory prevents the occurrence of such singularities in nature. Assuming the validity of the Weyl curvature hypothesis, we propose that naked singularities are forbidden by the second law of thermodynamics.
Gravitational Theory Without the Cosmological Constant Problem
Authors: Guendelman E. I. , Kaganovich A. B.
Published: October 2003

We develop a gravitational theory where the measure of integration in the action principle is not necessarily [Formula: see text] but it is determined dynamically through additional degrees of freedom. This theory is based on the demand that such measure respects the principle of "non-gravitating vacuum energy" which states that the Lagrangian density L can be changed to L + const. without affecting the dynamics. Formulating the theory in the first-order formalism we get as a consequence of the variational principle a constraint that enforces the vanishing of the cosmological constant. The most realistic model that implements these ideas is realized in a six or higher dimensional space–time. The compactification of extra dimensions into a sphere gives the possibility of generating scalar masses and potentials, gauge fields and fermionic masses. It turns out that the remaining four-dimensional space–time must have effective zero cosmological constant.
Multiple Gluon Effects in $q+\bar{q}\rightarrow t+\bar{t}+X$ at FNAL Energies: Semi-Analytical Results
Authors: Delaney D. , Jadach S. , Kim S. M. , Shio Ch. , Siopsis G. , Ward B. F. L.
Published: October 2003

We apply our Yennie–Frautschi–Suura exponentiated cross-section formulas for the parton process [Formula: see text] to the process [Formula: see text] at FNAL energies, where G is a QCD gluon. We use semi-analytical methods to compute the ratio [Formula: see text], where [Formula: see text] is our soft gluon YFS exponentiated cross-section and [Formula: see text] is the Born cross-section. For mt=0.176(0.199) TeV, we get r expt =1.65(1.48), respectively, for q=u for example. We show that these parton level results, when properly synthesized with the DGLAP structure function evolution, lead to the conclusion that the YFS exponentiated hadron level cross-section for [Formula: see text] is increased by ~0.6–0.8% beyond the Born cross-section due to the re-summation of soft gluon effects beyond those in the exact [Formula: see text] correction when mt=176 GeV. These results are not inconsistent with the recent observations by CDF and D0.
Semiclassical Form of the Relativistic Particle Propagator
Authors: Gitman Dmitri M. , Zlatev Stoian I.
Published: October 2003

A detailed derivation of the semiclassical form for the relativistic particle propagator in arbitrary external electromagnetic field is presented. To this end a path-integral representation is used. The final formula is a generalization of the Van Vleck–Pauli–Morette semiclassical representation in the nonrelativistic quantum mechanics. We demonstrate the efficiency of the former in the case of an arbitrary constant electromagnetic field.
Testing the Vector Condensate Model of Electroweak Interactions at High Energy Hadron Colliders
Authors: Cynolter G. , Lendvai E. , Pócsik G.
Published: October 2003

In the vector condensate model a doublet of vector fields plays the role of the Higgs doublet of the standard model and the gauge symmetry is broken dynamically. This results in a theory surviving the test of radiative corrections provided that the new charged and neutral vector particles B+,0 have masses of at least several hundred GeVs. In this note we show that while at the Tevatron the heavy B-particle production is too low, at LHC the yield is large and, for instance, the inclusive cross-section of B+B- pairs is 33.0 (8.5) fb at [Formula: see text] and mB=400 (500) GeV.
On Finite-Temperature and Finite-Density Radiative Corrections to the Neutrino Effective Potential in the Early Universe
Authors: Horvat R.
Published: October 2003

Finite-temperature and finite-density radiative corrections to the neutrino effective potential in the otherwise CP-symmetric early Universe are considered in the real-time approach of thermal field theory. A consistent perturbation theory endowed with the hard thermal loop resummation techniques developed by Braaten and Pisarski is applied. Special attention is focused on the question whether such corrections can generate any nonzero contribution to the CP-symmetric part of the neutrino potential, if the contact approximation for the W-propagator is used.
Quarks or Leptons?
Authors: Sidharth B. G.
Published: October 2003

In this letter, using the recent model of quantum mechanical black holes, it is shown how the proton can be considered consistently to be made up of two positrons and an electron, and how this is consistent with deep inelastic scattering data. It is indicated how particle multiplets can then be constructed.
On the Cosmic Rotation Axis
Authors: Kühne Rainer W.
Published: October 2003

Recently, Nodland and Ralston reported to have discovered a cosmic axis. We argue that their axis is supported by an earlier independent observation on the spin axes of galaxies in the Perseus–Pisces supercluster and explainable within the framework of Gödel's cosmology.
Energy Spectrum of Anyon in the Coulomb Field
Authors: Kruglov S. I. , Sergeenko M. N.
Published: October 2003

Anyonic atom is considered as a two-dimensional system. Using some approximations we find the energy spectrum of the anyon in the Coulomb field. It is shown that the anyonic atom is stable.
Cutting Rules at Finite Temperature
Authors: Bedaque Paulo F. , Das Ashok , Naik Satchidananda
Published: October 2003

We discuss the cutting rules in the real-time approach to finite temperature field theory and show the existence of cancellations among classes of cut graphs which allows a physical interpretation of the imaginary part of the relevant amplitude in terms of the underlying microscopic processes. Furthermore, with these cancellations, any calculation of the imaginary part of an amplitude becomes much easier and completely parallel to the zero temperature case.
Neutrino Oscillations from Cosmic Sources: A Nu Window to Cosmology
Authors: Wagner D. J. , Weiler Thomas J.
Published: October 2003

Neutrino astrophysics promises a wealth of information about neutrinos and the history of the universe through which they have traveled. In this letter, we extend the standard neutrino qoscillation discussion to neutrinos propagating through expanding curved space. This extension introduces a new cosmological parameter in the oscillation phase. The new parameter ℐ records cosmic history in much the same manner as the redshift variable z or the apparent luminosity distance DL. Measuring ℐ through neutrino oscillations may help to determine cosmological parameters and distinguish between different cosmologies.
Exact Finite Size Corrections for the Ising Model on Planar Random Surfaces
Authors: Hanlon B. E.
Published: October 2003

The exact form of finite size corrections is determined for the Ising model on 2-D planar random surfaces for any Ising temperature. The behaviour of these in the context of reliably extracting meaningful values for observables from numerical studies is investigated. In particular, it is noted that the leading order correction need not dominate.
Fixed Points and Vacuum Energy of Dynamically Broken Gauge Theories
Authors: Natale A. A. , Da Silva P. S. Rodrigues
Published: October 2003

We show that if a gauge theory with dynamical symmetry breaking has nontrivial fixed points, they will correspond to extrema of the vacuum energy. This relationship provides a different method to determine fixed points.
Feynman's Proof of the Lorentz Force Equations with Dissipation Linear in the Velocity
Authors: Soni S. K. , Singh Simmi
Published: October 2003

We present the Feynman proof of the Lorentz force law plus dissipative terms with a linear dependence on the velocity vector. In addition, we discuss in this context the inverse problem of the calculus of variations and the inverse problem for the Poisson dynamics. Given the equations of motion, the Helmholtz conditions for the inverse problem of the calculus of variations are solved and the Lagrangian is shown to have the nonsingular gauge type form.
Asymmetry Measurements at LEP/SLC Revisited
Authors: Aziz Tariq
Published: October 2003

We examine the fermion asymmetry measurements at LEP and SLC leading to effective weak mixing angle, sin 2θ eff . We notice very interesting regularity in these measurements. All asymmetry measurements fall into two classes. Class A measurements where hadronisation effects are not relevant for the final result and class B measurements where hadronisation effects cannot be avoided and can only be corrected with whatever understanding of these phenomena we have. In each of these classes there is excellent agreement between LEP and SLC results. However the two classes are distinctly apart by more than 3σ. We suggest that for precision test of the Standard Model the class A measurements should be preferred.
Form Factors of Exponential Fields in the Sine–Gordon Model
Authors: Lukyanov Sergei
Published: October 2003

An integral representation for form factors of exponential fields eiaφ in the sine–Gordon model is proposed.
A Study of Fermionic Three-Point Vertex with Gluon Condensate
Authors: Yang J. J. , Chen H. , Li G. L. , Shen H. Q.
Published: October 2003

We derive the dimension-four gluon condensate contributions to the fermionic three-point vertex with different forms of the gluon condensate component of the nonlocal two-gluon vacuum expectation value (vev). We find that the result with the non-covariant form of nonlocal two-gluon vev in the fixed-point gauge depends on whether the zero-point is set on the fermionic- or gluonic-line. But this uncertainty can be avoided by using the covariant form of the nonlocal two-gluon vev.
General Static N=2 Black Holes
Authors: Sabra W. A.
Published: October 2003

We find general static BPS black hole solutions for general N=2, d=4 supergravity theories with an arbitrary number of vector multiplets. These solutions are completely specified by the Kähler potential of the underlying special Kähler geometry and a set of constrained harmonic functions.
Factorization of Multiparticle Scattering in the Heisenberg Spin Chain
Authors: Doikou Anastasia , Mezincescu Luca , Nepomechie Rafael I.
Published: October 2003

We give an explicit proof within the framework of the Bethe ansatz/string hypothesis of the factorization of multiparticle scattering in the antiferromagnetic spin-1/2 Heisenberg spin chain, for the case of three particles.
Chiral Symmetry Breaking in Quantum R2-Gravity
Authors: Shil'nov Yu. I. , Chitov V. V. , Kotwicki A. T.
Published: October 2003

Schwinger–Dyson equations have been used to investigate the dynamical breaking of chiral symmetry in quantum R2-gravity on the flat background. The dynamical mass generation has been shown to exist in both 2-D and 4-D cases. This phenomenon has been noted to take place in a different gauge in spite of the gauge dependence of the qualitative values caused by using the ladder approximation. The numerical analysis of the model phase structure has been done in details.
Casimir Force Between a Flat Plate and a Spherical Lens: Application to the Results of a New Experiment
Authors: Bezerra V. B. , Klimchitskaya G. L. , Romero C.
Published: October 2003

The Casimir force is calculated in a configuration consisting of a lens placed above a flat plate of arbitrary size used in recent experiment. The corrections due to the finite size of the plate are shown to be negligible. On the other hand, corrections due to the small distortions of interacting surfaces, their deviation from the perfect geometrical shape and due to the finite metal conductivity were found to be several times larger than the relative experimental error. It is shown that the corrections due to distortions and finite conductivity have opposite signs and may compensate each other.
Boundaries of 11-Dimensional Membranes
Authors: Cederwall Martin
Published: October 2003

The action for an 11-dimensional supermembrane contains a chiral Wess–Zumino–Witten model coupling to the E8 super-Yang–Mills theory on the end-of-the-world nine-brane. It is demonstrated that this boundary string theory is dictated both by gauge invariance and by κ-symmetry.
M-Theory Inspired No-Scale Supergravity
Authors: Li Tianjun , Nanopoulos D. V. , Lopez Jorge L.
Published: October 2003

We propose a supergravity model that contains elements recently shown to arise in the strongly-coupled limit of the E8 × E8 heterotic string (M-theory), including a no-scale-like Kähler potential, the identification of the string scale with the gauge coupling unification scale, and the onset of supersymmetry breaking at an intermediate scale determined by the size of the 11th dimension of M-theory. We also study the phenomenological consequences of such scenario, which include a rather constrained sparticle spectrum within the reach of present-generation particle accelerators.
NNI-Form Quark Mass Matrix Expressed by the Observable Quantities
Authors: Koide Yoshio
Published: October 2003

It is pointed out that the phase convention of the CKM matrix V affects texture analysis of the quark mass matrices (Mu,Md) when we try to describe (Mu,Md) by the observable quantities (quark masses and CKM matrix parameters) only. This is demonstrated for a case of non-Hermitian Fritzsch-type mass matrix [Formula: see text], which is a general expression of quark mass matrix (Mu,Md) and is described by 12 parameters. We find that we can always choose a phase convention of V which yields [Formula: see text], so that the remaining ten parameters in [Formula: see text], can be completely expressed by the ten observable quantities.
Hawking Radiation for Non-Minimally Coupled Matter from Generalized 2-D Black Hole Models
Authors: Kummer W. , Liebl H. , Vassilevich D. V.
Published: October 2003

It is well known that spherically symmetric reduction of general relativity (SSG) leads to non-minimally coupled scalar matter. We generalize (and correct) recent results to Hawking radiation for a class of dilaton models which share with the Schwarzschild black hole non-minimal coupling of scalar fields and the basic global structure. An inherent ambiguity of such models (if they differ from SSG) is discussed. However, for SSG we obtain the rather disquieting result of a negative Hawking flux at infinity, if the usual recipe for such calculations is applied.
Maxwell–Chern–Simons Gauged Nonrelativistic O(3) Model with Self-Dual Vortices
Authors: Tchrakian D. H. , Tomaras T. N.
Published: October 2003

A nonrelativistic version of the (2+1)-dimensional gauged Chern–Simons O(3) sigma model, augmented by a Maxwell term, is presented and shown to support topologically stable static self-dual vortices. Same as their counterparts of the ungauged model, these vortices are shown to exhibit Hall behavior in their dynamics.
Vector–Tensor Duality
Authors: Lahiri Amitabha
Published: October 2003

A dynamical non-Abelian two-form potential gives masses to vector bosons via a topological coupling.1 Unlike in the Abelian case, the two-form cannot be dualized to Goldstone bosons. Duality is restored by coupling a flat connection to the theory in a particular way, and the new action is then dualized to a nonlinear sigma model. The presence of the flat connection is crucial, which saves the original mechanism of Higgs-free topological mass generation from being dualized to a sigma model.
Duality between Topologically Massive and Self-Dual Models
Authors: Guillou J. C. Le , Moreno E. F. , Núñez C. , Schaposnik F. A.
Published: October 2003

We show that, with the help of a general BRST symmetry, different theories in three dimensions can be connected through a fundamental topological field theory related to the classical limit of the Chern–Simons model.
Sudakov Form Factors in Leptoproduction of Vector Mesons
Authors: Dremin I. M.
Published: October 2003

It is shown that Sudakov form factors for a color dipole in a QCD-inspired model of leptoproduction of vector mesons reduce the value of the cross-section of the process by an order of magnitude. They suppress the large size quark–antiquark pairs and unequal sharing of energy among the components of the dipole. Some freedom in the choice of the model parameters is also discussed.
Different Quantum Field Constructions in the (1/2,0) ⊕ (0,1/2) Representation
Authors: Dvoeglazov Valeri V.
Published: October 2003

We present another concrete realization of a quantum field theory, envisaged many years ago by Bargmann, Wightman and Wigner. Considering the special case of the (1/2,0)⊕ (0,1/2) field and developing the Majorana–McLennan–Case–Ahluwalia construction for neutrino, we show that fermion and its antifermion can have the same intrinsic parity. The construction can be applied to explain the present situation in neutrino physics.
Study of Radiative B Decay
Authors: Routh H. , Gautam V. P.
Published: October 2003

Radiative B decays provide valuable information on some poorly known CKM matrix elements |Vtb| and |Vts|. So in our letter we propose to study the flavor changing radiative B decays corresponding to the inclusive b→ sγ and b→dγ decays. In this letter we discuss the radiative flavor changing B→ K**γ, Bs→ϕ;γ and the rare Bc→D*γ decays taking into account both the Penguin as well as weak annihilation contribution and it is found that weak annihilation contribution is negligible in case of decay of mesons consisting of light spectator, i.e. for B→K**γ and Bs→ϕ;γ but in case of decay of Bc→D*γ, weak annihilation contribution is the most dominating factor. It is also interesting to note that all the B→ K**γ, Bs→ϕ;γ and Bc→ D*γ decays have almost the same decay width because they have the same type of inclusive decay process b→ s(d)γ.
Higher-Dimensional WZW Model on Kähler Manifold and Toroidal Lie Algebra
Authors: Inami Takeo , Ueno Tatsuya , Kanno Hiroaki
Published: October 2003

We construct a generalization of the two-dimensional Wess–Zumino–Witten model on a 2n-dimensional Kähler manifold as a group-valued nonlinear sigma model with an anomaly term containing the Kähler form. The model is shown to have an infinite-dimensional symmetry which generates an n-toroidal Lie algebra. The classical equation of motion turns out to be the Donaldson–Uhlenbeck–Yau equation, which is a 2n-dimensional generalization of the self-dual Yang–Mills equation.
Renormalization of the Topological Charge in Yang–Mills Theory
Authors: Reuter M.
Published: October 2003

The conditions leading to a nontrivial renormalization of the topological charge in four-dimensional Yang–Mills theory are discussed. It is shown that if the topological term is regarded as the limit of a certain nontopological interaction, quantum effects due to the gauge bosons lead to a finite multiplicative renormalization of the θ-parameter while fermions give rise to an additional shift of θ. A truncated form of an exact renormalization group equation is used to study the scale dependence of the θ-parameter. Possible implications for the strong CP-problem of QCD are discussed.
New Precision Electroweak Tests in Supergravity Models
Authors: Park Gye T. , Lee Kang Young
Published: October 2003

We update the analysis of the precision electroweak tests in terms of four epsilon parameters, ε1,2,3,b, to obtain more accurate experimental values of them by taking into account the new LEP data released at the 28th ICHEP (Poland, 1996). We also compute ε1 and εb in the context of the no-scale SU (5)× U (1) supergravity model to obtain the updated constraints by imposing the correlated constraints in terms of the experimental ellipses in the ε1–εb plane and also by imposing the new conservative bound on the lightest chargino mass, [Formula: see text]. Upon imposing these new experimental results, we find that the situations in the no-scale model are much more favorable than those in the standard model, and if mt≳ 170 GeV, then the allowed regions at the 95% C.L. in the no-scale model are tan β≳ 4 and [Formula: see text] for μ>0 (μ< 0), which are in fact much more stringent than in our previous analysis. Therefore, assuming that mt≳ 170 GeV, if the lightest chargino mass bound were to be pushed up to 82 GeV, the sign on the Higgs mixing term μ in the no-scale model could well be determined from the ε1–εb constraint to be positive at the 95% C.L. At any rate, better accuracy in the measured mt from the Tevatron in the near future combined with the LEP data is most likely to provide a decisive test of the no-scale SU (5)× U (1) supergravity model.
Estimate of the Long-Distance Contribution Through b→ sψ to the Bs→γγ Decay Rate
Authors: Hiller G. , Iltan E. O.
Published: October 2003

The Bs→ϕψ decay is modeled through the inclusive b→ sψ decay. Using the vector meson dominance model, the amplitude for the chain process Bs→ϕ;ψ→ϕγ→γγ is estimated and it is found to be at most 4% of the corresponding amplitude from the O7 type LD contribution. The intermediate amplitude for the process Bs→ϕγ is compared with the corresponding one obtained by a different approach based on the interaction of the virtual charm quark loop with soft gluons.7 Both amplitudes are found to agree within 10%. Further the influence on the branching ratio B (Bs→γγ) SD + LD O7 from inclusive b→ sψ is estimated to be less than 1%.
Evaluation of Periods via Fibrations in Seiberg–Witten Theories and in Type-II String
Authors: Suzuki Hisao
Published: October 2003

We show how the periods can be evaluated in Seiberg–Witten theories and in K3-fibered Calabi–Yau manifolds by using fibrations of the theories. In the Seiberg–Witten theories, it is shown that the dual pair of fields can be constructed from the classical fields in a simple form.

As for Calabi–Yau manifolds which are fibrations of K3 surface, we obtain the solutions of the Picard–Fuchs equations from the periods of K3 surface. By utilizing the expression of periods for two-parameter models of type-II string, we derive the solutions of the Picard–Fuchs equations around the points of enhanced gauge symmetry and show a simple connection to the SU(2) Seiberg–Witten theory.
Relativistic Semiclassical Wave Equation and its Solution
Authors: Sergeenko M. N.
Published: October 2003

The properties of relativistic particles in the quasiclassical region are investigated. The relativistic semiclassical wave equation appropriate in the quasiclassical region is derived. It is shown that the leading-order WKB quantization rule is the appropriate method to solve the equation obtained.
A BCS-Like Approach to the Excited State in 11Li
Authors: Kyotoku M. , Lima C. L. , Neto E. Baldini , Teruya N.
Published: October 2003

A modified BCS approach is used to interpret the first excited state of 11 Li halo nuclei. In this scheme, a simple two-level model calculation is performed leading to results in good agreement with the experimental results for 11 Li for both ground and first excited states. A comparison with exact and QRPA calculations is also presented.
On Convergence of the Schwinger–De Witt Expansion
Authors: Slobodenyuk V. A.
Published: October 2003

The Schwinger–De Witt expansion for the evolution operator kernel of the Schrödinger equation is studied for convergence. It is established that divergence of this expansion which is usually implied for all continuous potentials, excluding those of the form V(q)=aq2+bq+c, takes place only if the coupling constant g is treated as an independent variable. But the expansion may be convergent for some kinds of potentials and for some discrete values of charge, if the latter is considered as fixed parameter. Class of such potentials is interesting because inside it the property of discreteness of the charge in nature is reproduced in theory in the natural way.
Geometric and Kinematic Dimensional Reduction in Quantum Field Theory
Authors: Stephens C. R.
Published: October 2003

Dimensional reduction in quantum field theory is discussed with emphasis on the difference between "geometric" versus "kinematic" dimensional reduction. It is shown how environmentally friendly renormalization can also be applied to the latter case. As concrete examples, finite temperature λϕ4 theory and the Regge limit of ϕ2ψ are considered. In the latter, crossover between large and small energies at fixed momentum transfer is considered and asymptotic forms of the crossover scaling functions are exhibited for all two-particle scattering processes in this channel.
Possible Effects of Non-Vanishing Particle Sizes in the Early Universe
Authors: Terazawa Hidezumi
Published: October 2003

Possible effects of the non-vanishing sizes of particles (atoms, nuclei, nucleons, quarks, and leptons) in the early universe (the temperature T) are discussed in an extended Friedmann model of the universe (the scale a). In particular we point out the following possibilities: (a) if rq>(2NB/π)-1/3a, most of the proposed scenarios for T>103 TeV including the inflationary universe are unrealistic, (b) rq<(2NB/π)-1/3a due to the smallness of rq(≲ 10-27 cm ), (c) rq<(2NB/π)-1/3a due to the smallness of NB in which the baryon number (or quark number) must be generated at T≲03 TeV if rq≳ 10-17 cm (where rq and NB are the effective radius of quarks and the baryon number in the universe, respectively), and (d) for T≳ 103 TeV , the universe was filled not with quark–gluon plasma but with "subquark plasma".
Emergence of Spinless and Spin-1/2 Particles from Higher-Dimensional Gravity with D-Dimensional Torus as a Compact Manifold
Authors: Srivastava S. K. , Sinha K. P.
Published: October 2003

Using gravitational action for four-dimensional theory of R2-gravity, it has been shown earlier that, at high energy level, Ricci scalar R behaves like a physical field in addition to its usual nature as a geometrical field. The physical aspect of R is represented by spinless particles, called riccions. It is shown here that riccions can also be obtained from multi-dimensional R2-gravity. Further it is shown that these riccions disintegrate into fermion and anti-fermion pairs under certain conditions. Some physical properties of these fermions (here called riccinos) are discussed. On the basis of the results obtained here, one is tempted to speculate that our physical universe might have emerged through decay of riccions and riccinos.
The Variational Theory of the Perfect Dilaton-Spin Fluid in a Weyl–Cartan Space
Authors: Babourova O. V. , Frolov B. N.
Published: October 2003

The variational theory of the perfect fluid with intrinsic spin and dilatonic charge (dilaton-spin fluid) is developed. The spin tensor obeys the classical Frenkel condition. The Lagrangian density of such fluid is stated, and the equations of motion of the fluid, the Weyssenhoff-type evolution equation of the spin tensor and the conservation law of the dilatonic charge are derived. The expressions of the matter currents of the fluid (the canonical energy-momentum three-form, the metric stress-energy four-form and the dilaton-spin momentum three-form) are obtained.
Perturbation Method for Boundary S-Matrix in 2D Quantum Field Theory
Authors: Topor Nadia
Published: October 2003

We develop a perturbation theory for evaluating the boundary S-matrix in 2D quantum field theory. We apply this approach to calculate the one-loop boundary S-matrix for the elementary particle of the sine–Gordon model with a boundary interaction. Our perturbative result agrees with the exact expression of the S-matrix conjectured by Goshal; it also allows us to derive the perturbative relation between the parameter ϑ in the S-matrix and the free parameter M in the boundary action, in the particular case in which its other free parameter φ0 is zero.
Quantum Homomorphisms of Associative Algebras
Authors: Djemai A. E. F.
Published: October 2003

Given an associative algebra A generated by {ek, k=1, 2,…} and with an internal law of type: [Formula: see text], we first show that it is possible to construct a quantum bi-algebra [Formula: see text] with unit and generated by (non-necessarily commutative) elements [Formula: see text] satisfying the relations: [Formula: see text]. This leads one to define a quantum homomorphism[Formula: see text]. We then treat the example of the algebra of functions on a set of N elements and we show, for the case N=2, that the resulting bihyphen;algebra is an inhomogeneous quantum group. We think that this method can be used to construct quantum inhomogeneous groups.
Some Analytical Results of Bunching Parameters for Multiplicity Fluctuations in High Energy Collisions
Authors: Huang Ding-Wei
Published: October 2003

A few analytical results are presented for the bunching parameters analysis applied to study the fluctuations of hadron multiplicity density in high energy collisions. The behaviors of bunching parameters are analyzed in the cases of concatenate and partitioning fluctuations. The effect of pairing in partition is also studied. As the phase-space decreases, the concatenation can be observed as the divergence of one of the bunching parameters, which also implies a strong short range correlation. In the case of a weak short range correlation, both types of binomial partitions lead to saturation for all the bunching parameters. As the phase-space increases, the effects of pair production can be observed as the oscillatory bunching parameters ηq — a function of order q. The characteristics of the observed features are discussed. Comparisons to experimental data are also presented.
Finite Temperature SU(2) LMG Model: Mean-Field Versus Exact Calculation
Authors: Brito L. , Da Providência C. , Da Providência J.
Published: October 2003

A variational approach is applied to the description of temperature effects in an N-particle exactly solvable schematic model, with SU(2) symmetry. The ground-state energy and the strength distribution for different couplings and temperatures are compared with the exact results.
Primordial Torsion Fields as an Explanation of the Anisotropy in Cosmological Electromagnetic Propagation
Authors: Dobado Antonio , Maroto Antonio L.
Published: October 2003

In this letter we provide a simple explanation of the recent finding of anisotropy in electromagnetic (EM) propagation claimed by Nodland and Ralston. We consider, as a possible origin of such effect, the effective coupling between EM fields and some tiny background torsion field. The coupling is obtained after integrating out charged fermions, it is gauge-invariant and does not require the introduction of any new physics.
Can a Gravitational Wave and a Magnetic Monopole Coexist?
Authors: Abe Osamu , Tabata Osamu
Published: October 2003

We investigate the behavior of small perturbations around the Kaluza–Klein monopole in the five-dimensional space–time. We find that the even parity gravitational wave does not propagate in the five-dimensional space–time with Kaluza–Klein monopole provided that the gravitational wave is constant in the fifth direction. We conclude that a gravitational wave and a U(1) magnetic monopole do not coexist in five-dimensional Kaluza–Klein space–time.
An Associated Metric for a Particle in a Quantum Energy Level
Authors: Atzmon E.
Published: October 2003

We show that the quantum probabilistic distribution over the space in the spectator world can be associated to a metric in which the particle lives. According to this geometrical view, the metric in the particle world is "contracted" or "stretched" in an inverse proportion to the probability distribution.
D*→ Dγ and B*→ Bγ as Derived from QCD Sum Rules
Authors: Zhu Shi-Lin , Yang Ze-Sen , Hwang W.-Y. P.
Published: October 2003

We use the method of QCD sum rules in the presence of the external electromagnetic Fμν field to analyze radiative decays of charmed or bottomed mesons such as D*→ Dγ and B*→ Bγ, in a model-independent manner upon making use of the susceptibilities obtained previously from the study of baryon magnetic moments. Our predictions on D* decays agree very well with the experimental data. There are differences among the various theoretical predictions on B* decays and future experimental data should help to discriminate among the various predictions.
Hamiltonian Structure and Coset Construction of the Supersymmetric Extensions of N=2 KdV Hierarchy
Authors: Bonora L. , Krivonos S.
Published: October 2003

A manifestly N=2 supersymmetric coset formalism is applied to analyze the "fermionic" extensions of N=2, a=4 and a=-2 KdV hierarchies. Both hierarchies can be obtained from a manifest N=2 coset construction. This coset is defined as the quotient of some local but nonlinear superalgebra by a Û (1) subalgebra. Three superextensions of N=2 KdV hierarchy are proposed, among which one seems to be entirely new.
Nontrivial Extensions of the 3D-Poincaré Algebra and Fractional Supersymmetry for Anyons
Authors: Traubenberg M. Rausch de , Slupinski M. J.
Published: October 2003

Nontrivial extensions of three-dimensional Poincaré algebra, beyond the supersymmetric one, are explicitly constructed. These algebraic structures are the natural three-dimensional generalizations of fractional supersymmetry of order F already considered in one and two dimensions. Representations of these algebras are exhibited, and unitarity is explicitly checked. It is then shown that these extensions generate symmetries which connect fractional spin states or anyons. Finally, a natural classification arises according to the decomposition of F into its product of prime numbers leading to subsystems with smaller symmetries.
A Geometric Representation for the Proca Model
Authors: Camacaro Jaime , Gaitán Rolando , Leal Lorenzo
Published: October 2003

The Proca model is quantized in an open-path dependent representation that generalizes the loop representation of gauge theories. The starting point is a gauge-invariant Lagrangian that reduces to the Proca Lagrangian when certain gauge is selected.
Gravitationally Dressed Parke–Taylor Amplitudes
Authors: Selivanov K. G.
Published: October 2003

A generating function for the Parke–Taylor amplitudes with any number of positive helicity gravitons in addition to the positive helicity gluons is obtained using the recently constructed self-dual classical solution of the type of perturbiner in Yang–Mills theory interacting with gravity.
Poisson–Lie T-Duality and N=2 Superconformal WZNW Models on Compact Groups
Authors: Parkhomenko S. E.
Published: October 2003

The supersymmetric generalization of Poisson–Lie T-duality in the N=2 superconformal WZNW models on the compact groups is considered. It is shown that the role of Drinfeld's doubles play the complexifications of the corresponding compact groups. These complex doubles are used to define the natural actions of the isotropic subgroups forming the doubles on the group manifolds of the N=2 superconformal WZNW models. The Poisson–Lie T-duality in N=2 superconformal U(2)-WZNW model is considered in details. It is shown that this model admits Poisson–Lie symmetries with respect to the isotropic subgroups forming Drinfeld's double Gl (2,C). Poisson–Lie T-duality transformation maps this model into itself but acts nontrivially on the space of classical solutions. Supersymmetric generalization of Poisson–Lie T-duality in N=2 superconformal WZNW models on the compact groups of higher dimensions is proposed.