bluuebunny/crossref_metadata_2025 huggingface dataset:
Geochemistry and petrogenesis of Ordovician arc-related mafic volcanic rocks in the Popelogan Inlier, northern New Brunswick
Authors: Wilson Reginald A
Published: September 2003

The Popelogan Inlier consists mainly of mafic volcanic rocks (lapilli tuffs and massive to amygdaloidal, plagioclase-phyric flows) of the Middle Ordovician Goulette Brook Formation. Pyroclastic rocks include high-MgOCrNi picritic tuffs (type I) containing, in some cases, >20% MgO, and related high-MgO andesitic tuff (type II). High-MgO rocks were generated by 3040% partial melting of an enriched mantle source; type II is descended from type I mainly by fractionation of olivine. Mafic flows comprise basaltic andesites (type III) with low trace-element abundances and strongly fractionated, trace-element-enriched andesites (type IV). Types III and IV represent ~20 and ~10% partial melts, respectively, of a mantle source similar to that of the pyroclastic rocks, based on similar ratios of high field strength elements (HFSE). Unlike types I and II, petrogenesis of mafic flows involved fractionation of plagioclase and possibly amphibole. Volcanic arc signatures include negative Nb and Ti anomalies in all basalt types, along with low abundances of HFSE. Trace-element abundances are inconsistent with prior depletion in the back arc and require involvement of a mantle plume or subcontinental lithosphere. The highly magnesian composition of the picrites demands high melting temperatures and rapid transit through the crust, both of which suggest extension of the arc-bearing plate. Compositionally similar rocks in the South Pacific are associated with unusual tectono-magmatic settings involving ridge subduction, which may have established the necessary extensional environment. It is proposed that subduction of a plume-influenced ridge segment could explain the chemistry of the Goulette Brook volcanic rocks.
Structure of the crust and upper mantle of the Great Slave Lake shear zone, northwestern Canada, from teleseismic analysis and gravity modelling
Authors: Eaton David W , Hope Jacqueline
Published: September 2003

The Great Slave Lake shear zone (GSLsz) exposes lower crustal rocks analogous to deep-seated segments of modern strike-slip fault zones, such as the San Andreas fault. Extending for 1300 km beneath the Western Canada Sedimentary Basin to the southern margin of the Slave Province, the GSLsz produces one of the most prominent linear magnetic anomalies in Canada. From May to October 1999, 13 three-component portable broadband seismograph stations were deployed in a 150-km profile across a buried segment of the shear zone to investigate its lithospheric structure. Splitting analysis of core-refracted teleseismic shear waves reveals an average fast-polarization direction (N49°E ± 19°) that is approximately parallel to the shear zone. Individual stations near the axis of the shear zone show more northerly splitting directions, which we attribute to interference between regional anisotropy in the upper mantle (fast axis ~N60°E) and crustal anisotropy within the shear zone (fast axis ~N30°E). At the location of our profile, the shear zone is characterized by a 10-mGal axial gravity high with a wavelength of 30 km, superimposed on a longer wavelength 12-mGal low. This gravity signature is consistent with the basic features of the crustal model derived from receiver-function analysis: a Moho that dips inward toward the shear-zone axis and a mid-crustal zone with high S-wave velocity (ΔVs = 0.6 ± 0.2 km/s). The axial gravity high may be related to uplift of deeper crustal material within the shear zone, or protolith-dependent compositional differences between the shear zone and surrounding wall rocks.
Paleotopographic reconstructions of the eastern outlets of glacial Lake Agassiz
Authors: Leverington David W , Teller James T
Published: September 2003

Paleotopographic reconstructions of the eastern outlets of glacial Lake Agassiz provide a foundation for understanding the complex manner in which terrain morphology controlled the routing of overflow through the eastern outlets during the lake's Nipigon Phase (ca. 94008000 14C years BP) and for understanding the causes of outlet-driven declines in lake level during that period. Although flow paths across the divide between the Agassiz and Nipigon basins were numerous, eastward releases from Lake Agassiz to glacial Lake Kelvin (modern Lake Nipigon) were channeled downslope into a relatively small number of major channels that included the valleys of modern Kopka River, Ottertooth Creek, Vale Creek, Whitesand River, Pikitigushi River, and Little Jackfish River. From Lake Kelvin, these waters overflowed into the Superior basin. The numerous lowerings in lake level between stages of the Nipigon Phase, controlled by topography and the position of the retreating southern margin of the Laurentide Ice Sheet, had magnitudes of between 8 and 58 m, although some of these drawdowns may have occurred as multiple individual events that could have been as small as several metres. The total volumes of water released in association with these drops were as great as 8100 km3, and for all Nipigon stages were probably between about 140 and 250 km3 per metre of lowering. The topographic reconstructions demonstrate that Lake Agassiz occupied the area of glacial Lake Nakina (located northeast of modern Lake Nipigon) by the The Pas stage (ca. 8000 14C years BP) and that Lake Agassiz drainage through the Nipigon basin to the Great Lakes ended before the succeeding Gimli stage.
Pleistocene magmatism in a lithospheric transition area: petrogenesis of alkaline and peralkaline lavas from the BaringoBogoria Basin, central Kenya Rift
Authors: Clément Jean-Philippe , Caroff Martial , Hémond Christophe , Tiercelin Jean-Jacques , Bollinger Claire , Guillou Hervé , Cotten Joseph
Published: September 2003

New petrological, geochronological, and geochemical data on basalts, mugearites, peralkaline trachytes, and phonolites from the BaringoBogoria Basin, central Kenya Rift, are presented. KAr dating indicates that the volcanic rocks were emplaced between 894 ± 13 and 92 ± 5 ka. 87Sr/86Sr ranges from 0.70304 to 0.70692, 143Nd/144Nd from 0.51237 to 0.51295, 206Pb/204Pb from 18.4 to 19.8, 207Pb/204Pb from 15.46 to 15.70, and 208Pb/204Pb from 38.2 to 40.5. Despite a rather restricted sampling area and a relatively short time span ([Formula: see text]820 ka), the mineralogical and geochemical variations are not consistent with a simple cogenetic link between the lavas. The studied area is located in a transition zone between two different lithospheric domains (Tanzanian Craton and Panafrican Mobile Belt). We propose that the petrological and geochemical variations of the studied lavas are essentially linked to the nature of the underlying lithosphere. Some basaltic products underwent carbonate contamination, possibly within the crust. Trachytes and phonolites are derived from different basaltic parents through crustal assimilation coupled with fractional crystallization. One phonolite sample contains primary calcite-rich veinlets. Textural relations and geochemical evidence suggest that there is a direct cogenetic link between these carbonate and phonolite melts. The veinlets are the modal expression of a carbonate component included in all the phonolites from the BaringoBogoria Basin.
PERFECT FLUID AND TEST PARTICLE WITH SPIN AND DILATONIC CHARGE IN A WEYL–CARTAN SPACE
Authors: BABOUROVA O. V. , FROLOV B. N.
Published: September 2003

The equation of perfect dilaton-spin fluid motion in the form of generalized hydrodynamic Euler-type equation in a Weyl–Cartan space is derived. The isoentropic character of perfect dilaton-spin fluid motion is established. The equation of motion of a test particle with spin and dilatonic charge in the Weyl–Cartan geomtry background is obtained. The peculiarities of test particle motion in a Weyl–Cartan space are discussed.
TWO-BODY NONLEPTONIC Λb DECAYS WITH 1/mQ CORRECTIONS
Authors: GIRI A. K. , MAHARANA L. , MOHANTA R.
Published: September 2003

The two-body nonleptonic Λb decays are considered in the HQET with 1/mQ corrections and factorization approximation. The Isgur–Wise function is evaluated in the bound state soliton picture. The results obtained remain well below their previously predicted upper limit.
N = 2 SUPERCONFORMAL FIELD THEORY ON THE BASIS OF osp(2|2)
Authors: SHAFIEKHANI A. , CHUNG W.-S.
Published: September 2003

Using a unified and systematic scheme, the free field realization of irreducible representations of osp(2|2) is constructed. By using these realizations, the correlation functions of N = 2 superconformal model based on osp(2|2) symmetry and free field representation of [Formula: see text] generators are calculated. Free field representation of currents are used to determine the stress-energy tensor and the central charge of the model.
SYSTEMATIC THEORETICAL SEARCH FOR DIBARYONS IN A RELATIVISTIC MODEL
Authors: GOLDMAN T. , MALTMAN K. , STEPHENSON G. J. , PING JIA-LUN , WANG FAN
Published: September 2003

A relativistic quark potential model is used to do a systematic search for quasi-stable dibaryon states in the u, d and s three-flavor world. Flavor symmetry breaking and channel coupling effects are included and an adiabatic method and fractional parentage expansion technique are used in the calculations. The relativistic model predicts dibaryon candidates completely consistent with the nonrelativistic model.
AN APPLICATION OF THE TOPOLOGICAL DEGREE TO GRAVITATIONAL LENSES
Authors: LOMBARDI MARCO
Published: September 2003

In this letter we provide a new proof of a general theorem on gravitational lenses, first proven by Burke (1981) for the special case of thin lenses. The theorem states that a transparent gravitational lens with non-singular mass distribution produces an odd number of images of a point source. Our general proof shows that the topological degree finds natural and interesting applications in the theory of gravitational lenses.
CONFORMAL SYMMETRY AND HIGGS EFFECT IN QUANTUM COSMOLOGY
Authors: PERVUSHIN V. N. , SMIRICHINSKI V. I.
Published: September 2003

We point out an important role of conformal invariant observables in the formulation of quantum cosmology with a normalizable wave function which bears a direct relationship to the Friedmann observational evolution of the Universe (with redshift and Hubble law). Conformal invariant field variables allow us to establish relation between standard cosmological models and quantum field theory actions. The conformal symmetry principle excludes the Higgs potential from the Weinberg–Salam model and includes the Penrose–Chernikov–Tagirov term. In the conformal version of the standard model for electroweak interaction unified with the Einstein gravity, the Higgs field is absorbed by the space metric so that the elementary particle masses and the evolution of the Universe have one and the same origin. In the flat-space limit we got the σ-version of the Weinberg–Salam model without the Higgs particle-like excitations.
A POLYMER GAS ON A RANDOM SURFACE
Authors: DURHUUS BERGFINNUR , JONSSON THORDUR
Published: September 2003

Using the observation that configurations of N polymers with hard core interactions on a closed random surface correspond to random surfaces with N boundary components, we calculate the free energy of a gas of polymers interacting with fully quantized two-dimensioanal gravity. We derive the equation of state for the polymer gas and find that all the virial coefficients beyond the second one vanish identically.
SPACE–TIME FOAM, CASIMIR ENERGY AND BLACK HOLE PAIR CREATION
Authors: GARATTINI REMO
Published: September 2003

We conjecture that the neutral black hole pair production is related to the vacuum fluctuation of pure gravity via the Casimir-like energy. Implications on the foam-like structure of space–time are discussed.
FERMI–BOSE CANCELLATION IN TOPOLOGICALLY NONTRIVIAL BACKGROUNDS
Authors: HLOUSEK ZVONIMIR , SPECTOR DONALD
Published: September 2003

We show in a model-independent way that, in the background of a topological soliton or instanton that saturates a Bogomol'nyi bound, the fermion and boson excitation spectra of nonzero modes cancel at the one-loop level. This generalizes D'Adda and DiVecchia's result for some specific instanton models. Our method also establishes, again in a model-independent way, the generality of the connection between zero-modes in topologically nontrivial backgrounds and index theorems.
SPACE–TIME UNCERTAINTY PRINCIPLE FROM BREAKDOWN OF TOPOLOGICAL SYMMETRY
Authors: ODA ICHIRO
Published: September 2003

Starting from topological quantum field theory, we derive space–time uncertainty relation with respect to the time interval and the spatial length proposed by Yoneya through breakdown of topological symmetry in the large-N matrix model. This work suggests that the topological symmetry might be an underlying higher symmetry behind the space–time uncertainty principle of string theory.
BPS SOLUTIONS IN D=5 DILATON–AXION GRAVITY
Authors: KECHKIN OLEG , YUROVA MARIA
Published: September 2003

We show that the D=5 dilaton–axion gravity compactified on a two-torus possesses the SL(4,R)/SO(4) matrix formulation. It is used to construct the SO(2,2)-invariant BPS solution depending on a single harmonic function.
MIRROR FERMIONS IN NONCOMMUTATIVE GEOMETRY
Authors: LIZZI F. , MANGANO G. , MIELE G. , SPARANO G.
Published: September 2003

In a recent paper we pointed out the presence of extra fermionic degrees of freedom in a chiral gauge theory based on Connes' noncommutative geometry. Here we propose a mechanism which provides a high mass to these mirror states, so that they decouple from low energy physics.
GENERAL BPS BLACK HOLES IN FIVE DIMENSIONS
Authors: SABRA W. A.
Published: September 2003

An algorithm for constructing general static black hole configuration for the theory of N=2, d= 5 supergravity coupled to an arbitrary number of Abelain vector multiplets is given. The underlying very special geometry structure plays a major role in this construction. From the viewpoint of M-theory compactified on a Calabi–Yau threefold, these black holes are identified with BPS winding states of the membrane around two-cycles of the Calabi–Yau threefold, and thus are of importance in the probing of the phase transitions in the moduli space of M-theory compactified on a Calabi–Yau threefold.
MOYAL BRACKETS IN M-THEORY
Authors: FAIRLIE DAVID B.
Published: September 2003

The infinite limit of matrix theory in four and 10 dimensions is described in terms of Moyal brackets. In those dimensions there exists a Bogomol'nyi bound to the Euclideanized version of these equations, which guarantees that solutions of the first-order equations also solve the second-order matrix theory equations. A general construction of such solutions in terms of a representation of the target space coordinates as nonlocal spinor bilinears, which are generalisations of the standard Wigner functions on phase space, is given.
ACTINIDE SUB-ACTINIDE FLUX RATIO ESTIMATED FROM NASA CHALLENGER SPACE SHUTTLE BORNE PASSIVE DETECTOR EXPERIMENT
Authors: BASU BASUDHARA , BHATTACHARYYA D. P. , BISWAS S. , O'SULLIVAN D. , THOMPSON A.
Published: September 2003

A video trace analysis of 117 ultra heavy cosmic nuclei detected by NASA space shuttle borne lexan detectors has been presented here. The major axes of the elliptical track etch pits in the long hour etched detectors have been measured using a Hund microscope computerized for the measurements using a Pentium. The major axes distribution exhibits the existence of ultra heavy nuclei of charges of Z ranging from 72 to 96 compatible with the expected results from restricted energy loss calculations. The estimated actinide sub-actinide flux ratio has been found to be 0.0636±0.0248 which is comparable to the earlier observations by Fowler et al., Thompson et al. and O'Sullivan.
QUASI-EXACTLY SOLVABLE DEFORMATIONS OF GAUDIN MODELS AND "QUASI-GAUDIN ALGEBRAS"
Authors: USHVERIDZE A. G.
Published: September 2003

A new class of completely integrable models is constructed. These models are deformations of the famous integrable and exactly solvable Gaudin models. In contrast with the latter, they are quasi-exactly solvable, i.e. admit the algebraic Bethe ansatz solution only for some limited parts of the spectrum. An underlying algebra responsible for both the phenomena of complete integrability and quasi-exact solvability is constructed. We call it "quasi-Gaudin algebra" and demonstrate that it is a special non-Lie-algebraic deformation of the ordinary Gaudin algebra.
A PROOF OF BRANE CREATION VIA M-THEORY
Authors: NAKATSU TOSHIO , OHTA KAZUTOSHI , YOKONO TAKASHI , YOSHIDA YUHSUKE
Published: September 2003

We study configurations of a single M five-brane in the geometry R7× Q where Q is the Taub–NUT space. Taking the IIA limit at each value of their modulus, two possible IIA configurations are revealed.
DECOHERENT SCATTERING OF LIGHT PARTICLES IN A D-BRANE BACKGROUND
Authors: ELLIS JOHN , KANTI P. , MAVROMATOS N. E. , WINSTANLEY ELIZABETH , NANOPOULOS D. V.
Published: September 2003

We discuss the scattering of two light particles in a D-brane background. It is known that, if one light particle strikes the D-brane at small impact parameter, quantum recoil effects induce entanglement entropy in both the excited D-brane and the scattered particle. In this letter we compute the asymptotic "out" state of a second light particle scattering off the D-brane at large impact parameter, showing that it also becomes mixed as a consequence of quantum D-brane recoil effects. We interpret this as a non-factorizing contribution to the superscattering operator $ for the two light particles in a Liouville D-brane background, that appears when quantum D-brane excitations are taken into account.
a→e+e- DECAY IN A MODEL WITH INDUCED COUPLING TO LEPTONS
Authors: MIKHEEV N. V. , OVCHINNIKOV O. S. , VASSILEVSKAYA L. A.
Published: September 2003

The process of electron–positron pair production by axion propagating in an external magnetic field is investigated in a model with only induced axion coupling to leptons. Contributions of the lowest and higher Landau levels are analyzed. The results we have obtained demonstrate a strong catalyzing influence of the field.
ORIGIN, PROBLEMATIC ASPECTS AND INVARIANT FORMULATION OF q-, k- AND OTHER QUANTUM DEFORMATIONS
Authors: SANTILLI RUGGERO MARIA
Published: September 2003

In this letter we indicate some of the first references on quantum deformations, we point out their physical problematic aspects and outline their invariant formulation which appears to be unknown in the rather vast literature in the field.
IMPLICATIONS OF A QUANTUM MECHANICAL TREATMENT OF THE UNIVERSE
Authors: ÖZER MURAT
Published: September 2003

We attempt to treat the very early Universe according to quantum mechanics. Identifying the scale factor of the Universe with the width of the wave packet associated with it, we show that there cannot be an initial singularity and that the Universe expands. Invoking the correspondence principle, we obtain the scale factor of the Universe and demonstrate that the causality problem of the standard model is solved.
THE CASIMIR–AHARONOV–BOHM EFFECT?
Authors: SITENKO YU. A. , YU. BABANSKY A.
Published: September 2003

The combined effect of the magnetic field background in the form of a singular vortex and the Dirichlet boundary condition at the location of the vortex on the vacuum of quantized scalar field is studied. We find the induced vacuum energy density and current to be periodic functions of the vortex flux and holomorphic functions of the space dimension.
Λb→Λc+a1 IN HQET WITH FACTORIZATION
Authors: SINHA SONALI , KHANNA M. P.
Published: September 2003

Recently an event of the decay [Formula: see text] has been reported. In this letter we have computed the rate for this decay in the heavy quark effective theory with the additional assumption of factorization.
DYNAMICAL COSMOLOGICAL CONSTANT AND RELATIONS AMONG PSEUDO-GOLDSTONE BOSONS
Authors: VIGIL JUAN ESTRADA , MASPERI LUIS
Published: September 2003

The present apparent cosmological constant is interpreted as the potential of the lightest pseudo-Goldstone boson. Some numerical relations among cosmological parameters and particle masses are shown to arise from the mixture of this very light particle, whose interaction is of the gravitational order, with other pseudo-Goldstone bosons like the pion and the axion which feel the strong interaction.
WEYL CORRESPONDENCE AND PATH INTEGRAL FOR TWO-MODE CORRELATED SYSTEM
Authors: FAN HONG-YI , FAN YUE
Published: September 2003

The Weyl correspondence and Wigner operator theory for two-mode correlated system is developed on the common eigenstate basis <η| of two particles' total momentum and relative position. The development brings much convenience for calculating the Wigner functions of some two-mode correlated states and makes some Weyl correspondence derivation possible. Correspondingly, the path integral with midpoint prescription in <η| representation is also formulated.
NUCLEAR SHADOWING EFFECTS ON CHARMONIUM PRODUCTION IN QCD
Authors: PAJARES C. , SALGADO C. A. , SHABELSKI Yu. M.
Published: September 2003

It is shown that the effects on charmonium production of the modification of nucleon parton distributions inside nuclei are similar in the factorization approach based on nonrelativistic QCD and in the color evaporation model. In the first model, a separate study of the color octet and color singlet contributions to the yields of the various charmonium states as well as the contributions of these states to the total J/ψ production is performed. It is found that a clear xF dependence of these contributions which, together with an overall normalization given by absorption of the pre-resonant [Formula: see text] state inside the nuclear medium, can reproduce experimental data a for moderate xF. However, at large xF, there is bigger suppression that cannot be fit by this overall normalization together with the shadowing of structure functions.
A NEW FAMILY OF INTEGRABLE EXTENDED MULTI-BAND HUBBARD HAMILTONIANS
Authors: AMBJØRN J. , SEDRAKYAN A. , AVAKYAN A. , HAKOBYAN T.
Published: September 2003

We consider exactly solvable 1D multi-band fermionic Hamiltonians, which have affine quantum group symmetry for all values of the deformation. The simplest Hamiltonian is a multi-band t-J model with vanishing spin–spin interaction, which is the affinization of an underlying XXZ model. We also find a multi-band generalization of standard t-J model Hamiltonian.
STUDY OF ELECTRIC AND MAGNETIC SCREENING MASSES IN THE QUARK–GLUON PLASMA
Authors: CHEN HONG , ZHENG RENRONG
Published: September 2003

We calculate the electric and magnetic screening masses to leading order QCD by thermo field dynamics including baryon density and dynamical quark mass. We show that the magnetic screening is sensitive to the baryon density, and the electric screening mass is enhanced by the baryon density only in the low temperatures.
RENORMALIZATION AMBIGUITIES AND GAUGE SYMMETRY IN CHERN–SIMONS THEORIES
Authors: LÓPEZ J. L.
Published: September 2003

The universality of radiative corrections to the gauge coupling constant k of the Chern–Simons theory is studied in a very general regularization scheme in the background gauge formalism. The effective constant k eff induced by radiative corrections can be any real number depending on the balance between the ultraviolet behavior of scalar and pseudoscalar terms in the regularized action. This ambiguity of the effective action is related to the ambiguity in the parity anomaly of three-dimensional Dirac fermions. The effective action also contains a non-analytic term in the gauge field with the same coefficient and opposite gauge transformation in such a way that the effective action is gauge-invariant. The results open the possibility of a connection with non-rational two-dimensional conformal theories for non-integer values of k eff .
ON THE PICARD–FUCHS EQUATIONS OF N= 2 SUPERSYMMETRIC E6 YANG–MILLS THEORY
Authors: GHEZELBASH A. M. , SHAFIEKHANI A. , ABOLHASANI M. R.
Published: September 2003

We obtain the Picard–Fuchs equations of N=2 supersymmetric Yang–Mills theory with the exceptional gauge group E6. Such equations are based on E6 spectral curve.
CP-VIOLATION IN EPR-LIKE NEUTRINO OSCILLATIONS
Authors: SAMAL M. K.
Published: September 2003

After reviewing the general framework to study EPR-like neutrino oscillations, we derive expressions for the oscillation probabilities and a direct measure of CP-violation. We compare the possibility of studying CP-violation in this case with that of baseline accelerator experiments and conclude that it is possible to study CP-violation in experiments with length scales comparable to that of short baseline accelerator experiments.
COMMUTING CHARGES OF THE QUANTUM KORTEWEG-DE VRIES AND BOUSSINESQ THEORIES FROM THE REDUCTION OF W∞ AND W1+∞ ALGEBRAS
Authors: BORDNER ANDREW J.
Published: September 2003

Integrability of the quantum Boussinesq equation for c=-2 is demonstrated by giving a recursive algorithm for generating explicit expressions for the infinite number of commuting charges based on a reduction of the W∞-algebra. These charges exist for all spins s≥2. Likewise, reductions of the W∞/2- and W(1+∞)/2-algebras yield the commuting quantum charges for the quantum KdV equation at c= -2 and c=1/2, respectively.
SPONTANEOUS DECAY OF THE EFFECTIVE COSMOLOGICAL CONSTANT
Authors: ÖZER MURAT , TAHA M. O.
Published: September 2003

We discuss the notion that quantum fields may induce an effective time-dependent cosmological constant which decays from a large initial value. It is shown that such cosmological models are viable in a non-de Sitter space–time.
FLUCTUATING STRINGS IN THE UNIVERSAL CONFINING STRING THEORY AND GLUODYNAMICS
Authors: ANTONOV D. V.
Published: September 2003

An effective string theory emerging from the bilocal approximation to the method of vacuum correlators in gluodynamics is shown to be well-described by the 4D theory of the massive Abelian Kalb–Ramond field interacting with the string, which is known to be the low energy limit of the universal confining string theory. This correspondence follows from the agreement of the behavior of the coefficient functions, which parametrize the gauge-invariant correlator of two gluonic field strength tensors, known from the lattice data, with their values obtained from the propagator of the Kalb–Ramond field. We discuss this correspondence in several aspects and demonstrate that the mass of the Kalb–Ramond field in this approach plays the role of the inverse correlation length of the vacuum, so that in the massless limit string picture disappears. Next, we apply the background field method, known in the theory of nonlinear sigma models, to obtain the action, which is quadratic in quantum fluctuations around a given (e.g. minimal) string worldsheet. Several nontrivial types of couplings of these fluctuations with the background worldsheet are obtained and discussed.
QUASI-EXACT SOLVABILITY IN LOCAL FIELD THEORY
Authors: USHVERIDZE A. G.
Published: September 2003

The quantum mechanical concept of quasi-exact solvability is based on the idea of partial algebraizability of spectral problem. This concept cannot be used directly on the systems with infinte number of degrees of freedom. For such systems a new concept based on the partial Bethe ansatz solvability is proposed. In this letter we demonstrate the constructivity of this concept and formulate a simple method for building quasi-exactly solvable field theoretical models on a one-dimensional lattice. The method automatically leads to local models described by Hermitian Hamiltonians.
GROUND STATE ENERGY OF THE MODIFIED NAMBU–GOTO STRING
Authors: HADASZ LESZEK
Published: September 2003

We calculate, using zeta function regularization method, semiclassical energy of the Nambu–Goto string supplemented with the boundary, Gauss–Bonnet term in the action and discuss the tachyonic ground state problem.
DIRAC ELECTRON IN A COULOMB FIELD IN (2+1) DIMENSIONS
Authors: KHALILOV V. R. , HO CHOON-LIN
Published: September 2003

Exact solutions of Dirac equation in two spatial dimensions in the Coulomb field are obtained. Equation which determines the so-called critical charge of the Coulomb field is derived and solved for a simple model.
RESUMMATION ANALYSIS OF THE τ-DECAY WIDTH USING THE FOUR-LOOP β-FUNCTION
Authors: GROOTE S. , KÖRNER J. G. , PIVOVAROV A. A.
Published: September 2003

We extract the strong coupling constant [Formula: see text] from the semileptonic τ-decay width taking into account resummation effects from the running of the strong coupling constant. In the [Formula: see text] scheme. The result reads αs=0.375±0.007 to third-order and αs=0.378±0.007 to fourth-order in the β-function, respectively, where we use the recently computed four-loop coefficient β3. These values for the coupling constant have to be compared with the value αs=0.354±0.005 derived from a third-order analysis of τ-decays. We determine the exact value of the convergence radius of the perturbation series by analyzing the singularity structure of the complex coupling constant plane.
THE SPACE–TIME ATTRIBUTE OF MATTER
Authors: NODLAND BORGE
Published: September 2003

We propose that space–time is fundamentally a property of matter, inseparable from it. This leads us to suggest that all properties of matter must be elevated to the same status as that of space–time in quantum field theories of matter. We suggest a specific method for extending field theories to accommodate this, and point out how this leads to the evolution of fields through channels other than the space–time channel.
NONPERTURBATIVE FIELD CORRELATOR AND STRING REPRESENTATION FOR THE 't HOOFT LOOP AVERAGE IN THE ABELIAN HIGGS MODEL
Authors: ANTONOV D. V.
Published: September 2003

Making use of the duality transformation, we derive in the Londons' limit of the Abelian Higgs model string representation for the 't Hooft loop average defined on the string worldsheet, which yields the values of two coefficient functions parametrizing the bilocal correlator of the dual field strength tensors. The asymptotic behaviors of these functions agree with the ones obtained within the method of vacuum correlators in QCD in the lowest order of perturbation theory. We demonstrate that the bilocal approximation to the method of vacuum correlators is an exact result in the Londons' limit, i.e. all the higher cumulants in this limit vanish. We also show that at large distances, apart from the integration over metrics, the obtained string effective theory (which in this case reduces to the nonlinear massive axionic sigma model) coincides with the low energy limit of the dual version of 4D compact QED, the so-called universal confining string theory. We derive string tension of the Nambu–Goto term and the coupling constant of the rigidity term for the obtained string effective theory and demonstrate that the latter is always negative, which means the stability of strings, while the positiveness of the former is confirmed by the present lattice data. These data enable us to find the Higgs boson charge and the vacuum expectation value of the Higgs field, which well-described QCD. We also study dynamics of the weight factor of the obtained string representation for the 't Hooft average in the loop space. In conclusion, we obtain string representation for the partition function of the correlators of an arbitrary number of Higgs currents, by virtue of which we rederive the structure of the bilocal correlator of the dual field strength tensors, which yields the surface term in the string effective action.
A COMPOSITE SPACE–TIME CURVATURE MODEL
Authors: BUERS AWUOR J. , MALO J. O. , RAM SANT
Published: September 2003

We develop a curvature specification scheme in which the constraint effects of a localized gravitational potential source on the Hubble expansion comprises the characteristics of the large scale dynamics of the entire universe. Our result is a composite curvature model which has a dynamical Euclidean horizon (of zero curvature) that provides an alternative to the event horizon in the determination of the local scale evolution of space–time.
UNSTABLE PROPAGATION OF BLACK STRINGS
Authors: LEE H. W. , MYUNG Y. S. , KIM JIN YOUNG , PARK D. K.
Published: September 2003

We investigate the five- and six-dimensional black strings within Einstein–Maxwell theory. The extremal black string solutions are endowed with the null Killing symmetry. Using this symmetry, we show that one graviton is a propagating mode, while both the Maxwell (ℱ) and three-form (ℋ) fields are non-propagating modes. Further we discuss the stability and classical hair of the extremal black strings. It turns out that for any mode with l≥0, this propagation is unstable and there is no time-dependent classical hair.
COUNTING HAMILTONIAN CYCLES ON PLANAR RANDOM LATTICES
Authors: HIGUCHI SABURO
Published: September 2003

A Hamiltonian cycle of a graph is a closed path if it passs through each of the vertices once and only once. In this letter, Hamiltonian cycles on planar random lattices are considered. The generating function for the number of Hamiltonian cycles is obtained and its singularity is studied. Its relation with two-dimensional quantum gravity is discussed.
AN UPPER BOUND ON THE HIGGS BOSON MASS FROM A POSITIVITY CONDITION ON THE MASS MATRIX
Authors: AL-NAGHMOUSH ALI , ÖZER MURAT , TAHA M. O.
Published: September 2003

We impose the condition that the eigenvalues of the mass matrix in the shifted Lagrangian density be positive at ϕ=ϕ0, the vacuum expectation value of the scalar field. Using the one-loop effective potential of the standard model, this condition leads to an upper bound on the Higgs boson mass m H :m H <230 GeV, for a top quark mass of 175 GeV.
QUARK AND GLUON CONDENSATES IN THE QUARK–MESON COUPLING MODEL
Authors: SAITO K. , TSUSHIMA K. , THOMAS A. W.
Published: September 2003

Using the quark–meson coupling (QMC) model, we study the density dependence of the quark and gluon condensates in nuclear matter. We show that the change of the quark condensate is mainly driven by the scalar field in the medium and that the reduction of the quark condensate is suppressed at high density, even in the mean-field approximation. The gluon condensate decreases by 4–6% at nuclear saturation density. We also give a simple relationship between the change of the quark condensate and that of a hadron mass in the medium.
TOWARDS A GENERAL CONSTRUCTION OF NONSTANDARD Rh-MATRICES AS CONTRACTION LIMITS OF Rq-MATRICES: THE ${\mathcal U}_h ({\rm sl}(N))$ ALGEBRA CASE
Authors: ABDESSELAM B. , CHAKRABARTI A. , CHAKRABARTI R.
Published: September 2003

A class of transformations of Rq-matrices is introduced such that the q→1 limit gives explicit nonstandard Rh-matrices. The transformation matrix is singular as q→1. For the transformed matrix, the singularities, however, cancel yielding a well-defined construction. Our method can be implemented systematically on Rq-matrices of all dimensions and not only for q-deformed sl(2) algebra but also for algebras of higher dimensions. Explicit constructions are presented starting with [Formula: see text] and [Formula: see text], while choosing Rq for (fund. rep.) ⊗ (arbitrary irresp.). The treatment for the general case of [Formula: see text] algebras is indicated. Our method yields nonstandard deformations along with a nonlinear map of the h-Borel subalgebra on the corresponding classical Borel subalgebra. For [Formula: see text] this map is extended to the whole algebra and compared with the other proposed by us previously. The usual classical coproduct on [Formula: see text] and the non-cocommutative coproduct structure on [Formula: see text] are related via Drinfeld twist operators, determined up to O(h2) for both of these nonlinear maps.
A POLARISED QCD CONDENSATE: νp ELASTIC SCATTERING AS A PROBE OF UA(1) DYNAMICS
Authors: BASS S. D.
Published: September 2003

UA(1) dynamics have the potential to induce a polarised condensate inside a nucleon. The formation of this condensate is related to the realisation of UA(1) symmetry breaking by tunneling processes such as instantons. If it is present, the polarised condensate induces a term in g1 which has support only at x=0. Tunneling processes then induce a net transfer of "spin" from finite x to x=0. The polarised condensate may be measured by comparing the flavour-singlet axial charges which are extracted from polarised deep inelastic and νp elastic scattering experiments.
PHYSICAL INTERPRETATION OF CONSTANTS IN THE SOLUTIONS TO THE BRANS–DICKE EQUATIONS
Authors: BEESHAM AROONKUMAR
Published: September 2003

Using an energy–momentum complex, we give a physical interpretation to the constants in the well-known static spherically symmetric asymptotically flat vacuum solution to the Brans–Dicke equations. The positivity of the tensor mass puts a bound on parameters in the solution.
BALMER-LIKE SERIES FOR BARYON RESONANCES
Authors: LOSANOW-KIRCHBACH M.
Published: September 2003

The pole positions of various baryon resonances have been found to reveal a well-pronounced clustering, the so-called Höhler cluster. In a previous work, the Höhler clusters have been shown to be identical to Lorentz multiplets of the type [Formula: see text] with l′ integer. Here we show that the cluster positions are well-described by means of a Balmer series like recursive mass formula.
GENERALIZED PARTITION FUNCTIONS AND INTERPOLATING STATISTICS
Authors: BORGES P. F. , BOSCHI-FILHO H. , FARINA C.
Published: September 2003

We show that the assumption of quasiperiodic boundary conditions (those that interpolate continuously periodic and antiperiodic conditions) in order to compute partition functions of relativistic particles in 2+1 space–time can be related with anyonic physics. In particular, in the low temperature limit, our result leads to the well-known second virial coefficient for anyons. Besides, we also obtain the high temperature limit as well as the full temperature dependence of this coefficient.
STRESS–TENSOR FOR PARAFERMIONS FROM WINDING SUBALGEBRAS OF AFFINE ALGEBRAS
Authors: MAROTTA VINCENZO
Published: September 2003

We discuss a realization of stress–tensor for parafermion theories following a construction for higher level affine algebras, based on the projection of the standard level-one bosonic realization on the winding subalgebra. All the fields are obtained from rank free bosons compactified on torus, d. This gives an alternative realization of Virasoro algebra in terms of a nonlocal correction of a free field construction which does not fit the usual background charge of the Feigin–Fuchs approach.
UNSTABLE MODES AND CONFINEMENT IN THE LATTICE SCHRÖDINGER FUNCTIONAL APPROACH
Authors: CEA PAOLO , COSMAI LEONARDO
Published: September 2003

We analyze the problem of the Nielsen–Olesen unstable modes in the SU(2) lattice gauge theory by means of a recently introduced gauge-invariant effective action. We perform numerical simulations in the case of a constant Abelian chromomagnetic field. We find that for lattice sizes above a certain critical length, the density of effective action shows a behavior compatible with the presence of the unstable modes. We put out a possible relation between the dynamics of the unstable modes and the confinement.
ELECTROMAGNETIC DETECTION OF AXIONS IN A WAVE GUIDE
Authors: SOA DANG VAN
Published: September 2003

The conversion of photons into axions in a periodic external electromagnetic field, i.e. the TEm0 mode, is considered in details by using Feynman methods. The differential cross-sections are given. It is shown that the lowest mode gives the main contribution to the considered process.
STATISTICS FOR q-COMMUTATOR IN THE CASE OF qs+1=1
Authors: YANG YAPING , XIE SHUANGYUAN , FENG WEIGUO , WU XIANG
Published: September 2003

In this letter, we introduce a new statistics to describe particles whose creation and annihilation operators satisfy the relation aa†-qa†a=1 in the case of qs+1=1.
SQUEEZED STATES AND TWO-PARAMETER QUANTUM GROUPS
Authors: SAHAI VIVEK , JOHAL RAMANDEEP S. , GUPTA RAJ K.
Published: September 2003

We investigate two-parameter deformed Weyl–Heisenberg algebra in the Fock–Bargmann representation. The commutator [aqp,āqp] acts like squeezing operator on the space of the entire analytic functions. We find that the second parameter gets absorbed into the first parameter, yielding the same result for squeezing as in the case of single parameter study.
INFLUENCE OF SU(2) ⊗ U(1) SINGLET SCALARS ON HIGGS BOSON SIGNAL AT LHC
Authors: KRASNIKOV N. V.
Published: September 2003

We investigate a model of SU(2) ⊗ U(1) singlet scalars coupled to Standard Model. We point out that for the case of the maximal mixing between singlet scalars and the standard Higgs boson, the Higgs boson production cross-section is smaller than the standard Higgs boson production by a factor of 1/(N+1), where N is the number of singlet scalars. For the case of large mixing, Higgs boson could be unobservable at LHC. However, there is also the possibility for the observation of scalar singlets at LHC. As a semi-realistic example, we discuss supersymmetric SU(2) ⊗ U(1) electroweak model with an additional singlet chiral superfield.
BOSONIC AND FERMIONIC PARTITION FUNCTIONS ON S3
Authors: DE SIQUEIRA A. C. V. V. , BEZERRA DE MELLO E. R. , BEZERRA V. B.
Published: September 2003

Using the ζ-function regularization method, we compute expressions for the bosonic and fermionic partition functions for a field theory defined on a sphere S3. We also analyze their behavior with the radius r0 of this manifold, showing that for specific values of the field's masses closed expressions can be obtained, which give a completely different behavior as r0→∞, indicating isolated discontinuities of these partition functions with the masses of the matter fields.
EXACT DUALITY BETWEEN INTEGRABLE DEFORMATIONS OF BCn AND $C_n^{(1)}$ AFFINE TODA THEORIES
Authors: BASEILHAC P. , GRANGÉ P. , FATEEV V. A.
Published: September 2003

Integrable deformations of two affine Toda field theories based on BCn and [Formula: see text] non-simply laced algebras are studied. The proof of quantum integrability of the two theories is given and it is shown that the two theories are dual, corresponding respectively to the weak and strong coupling regimes of an intermediate theory. Perturbative calculations and the bootstrap principle permit the construction of the intermediate quantum field theory which flows from the first to the second with the coupling constant.
BRANS–DICKE AND RELATED EUCLIDEAN WORMHOLES
Authors: COULE D. H.
Published: September 2003

In a recent paper1 Euclidean wormhole solution has been obtained with a vacuum Brans–Dicke theory with parameter ω=0. These wormholes suffer from unphysical values of the gravitational constant. One can relate the various known wormholes by means of conformal transformations; although one should not transform them directly to the Einstein frame as the gravitational constant there is "forced" physical: so removing the wormholes.

However, by arguing for the existence of a fundamental minimum length scale such wormholes can now be considered as representative of quantum gravitational phenomena. One can also obtain wormholes as solutions of the quantum mechanical Wheeler–De Witt equation; now in Brans–Dicke for any ω>-3/2.
TOP QUARK LONGITUDINAL POLARIZATION NEAR THE THRESHOLD IN ℓ+ℓ- ANNIHILATION
Authors: CHIBISOV B. M. , VOLOSHIN M. B.
Published: September 2003

We show that the longitudinal polarization of the top quarks produced in the annihilation of e+e- or μ+μ- into [Formula: see text] at energies near the threshold is not affected by the large Coulomb-type corrections, which modify the total cross-section significantly. Thus the longitudinal polarization, though small, may give an independent information on the mass and the width of the top quark, largely independent of the uncertainty in αs.
DYNAMICAL GAUGE SYMMETRY BREAKING AND SUPERCONDUCTIVITY IN THREE-DIMENSIONAL SYSTEMS
Authors: FARAKOS K. , MAVROMATOS N. E.
Published: September 2003

We discuss dynamical breaking of non-Abelian gauge groups in three-dimensional (lattice) gauge systems via the formation of fermion condensates. A physically relevant example, motivated by condensed matter physics, is that of a fermionic gauge theory with group SU (2)⊗ U S(1)⊗ U E(1). In the strong U S(1) region, the SU(2) symmetry breaks down to a U(1), due to the formation of a parity-invariant fermion condensate. We conjecture a phase diagram for the theory involving a critical line, which separates the regions of broken SU(2) symmetry from those where the symmetry is restored. In the broken phase, the effective Abelian gauge theory is closely related to an earlier model of two-dimensional parity-invariant superconductivity in doped antiferromagnets. The superconductivity in the model occurs in the Kosterlitz–Thouless mode, since strong phase fluctuations prevent the existence of a local order parameter. Some physical consequences of the SU (2)× U S(1) phase diagram for the (doping-dependent) parameter space of this condensed matter model are briefly discussed.
CHARM AND BEAUTY IN SUM RULES FROM SIMPLE MODELS
Authors: DEY JISHNU , SAMANTA B. C.
Published: September 2003

There is information (and more will be known) about baryons containing one charm and beauty quark. A simple model of the charm and beauty baryons is found to give results which support the recent findings of other models including the 1/MQ expansion of QCD, where MQ is the heavy quark mass. Sum rules are found from the simple model which can be tested in the near future.
N=2 SUPERMULTIPLET OF CURRENTS AND ANOMALOUS TRANSFORMATIONS IN SUPERSYMMETRIC GAUGE THEORY
Authors: ITOYAMA H. , KOIKE M. , TAKASHINO H.
Published: September 2003

We examine some properties of supermultiplet consisting of the U (1)J current, extended supercurrents, energy–momentum tensor and the central charge in N = 2 supersymmetric Yang–Mills theory. The superconformal improvement requires adding another supermultiplet starting from the U (1)R current. We determine the anomalous (quantum mechanical) supersymmetry transformation associated with the central charge and the energy–momentum tensor to one-loop order. We find nonvanishing fermionic contribution to the central charge.
COMPARISON OF ALGORITHMS FOR SINGLET PARTON GENERATIONS IN DEEP INELASTIC SCATTERING
Authors: TANAKA HIDEKAZU , MUNEHISA TOMO
Published: September 2003

Algorithms for parton shower models are examined for singlet partons in deep inelastic scattering. We compare two different types of models: (i) based on evolution of particle number distributions as conventionally used in Monte–Carlo event generators, (ii) based on evolution of momentum distributions which has not been studied in the practical event generators. Features of these two models are qualitatively studied in order to understand the properties of these models.
SOLAR NEUTRINO FLUX VARIATION IN KAMIOKANDE DETECTOR DURING SOLAR CYCLE 22
Authors: RAYCHAUDHURI PROBHAS
Published: September 2003

The 8 B solar neutrino flux observed in Kamiokande detector (KAMIOKANDE II and III) from January 1987 to February 1995 has been analysed statistically and it has been found that solar neutrino flux data in Kamiokande detector varies with the solar activity cycle. It is also shown that solar neutrino flux data in Kamiokande detector also has five phases during the solar cycle 22 as observed in the Homestake solar neutrino flux data during the solar cycles 21 and 22 indicating that the solar activity cycle is due to the pulsating character of the nuclear energy generation inside the core of the sun.
ON GENERALIZED SELF-DUALITY EQUATIONS TOWARDS SUPERSYMMETRIC QUANTUM FIELD THEORIES OF FORMS
Authors: BAULIEU LAURENT , LAROCHE CÉLINE
Published: September 2003

We classify possible "self-duality" equations for p-form gauge fields in space–time dimension up to D=16, generalizing the pioneering work of Corrigan et al. (1982) on Yang–Mills fields (p=1) in 4<D≤8. We impose two crucial requirements. First, there should exist a 2(p+1)-form T-invariant under a subgroup H of SO D. Second, the representation for the SO D curvature of the gauge field must decompose under H in a relevant way. When these criteria are fulfilled, the "self-duality" equations can be candidates of gauge functions for SO D-covariant and H-invariant topological quantum field theories. Intriguing possibilities occur for D≥10 for various p-form gauge fields.