June 2000 arXiv papers — page 12

Eric G. Blackman

In addition to the scalar Shakura-Sunyaev $α_{ss}$ turbulent viscosity transport term used in simple analytic accretion disc modeling, a pseudoscalar transport term also arises. The essence of this term can be captured even in simple models for which vertical averaging is interpreted as integration over a half-thickness and one separately studies each hemisp

Johan Hansson

A simple experiment using radioactive decay is proposed to test the possibility of a determinsistic, but chaotic, origin of quantum mechanical randomness.

D. M. Snyder

Research methods and results from physics and psychology are used to explore a question in quantum mechanics. In this investigation, an observer variable is manipulated in an experimental context concerning the trajectory of electrons affected by their movement through a Stern-Gerlach apparatus. The basis in psychology concerning why the observer variable is

Teiji Kunihiro

After showing the characteristic features of the chiral transition in QCD at finite temperature $T$, we note the significance of the sigma-mesonic mode in the chiral transition : Sigma meson may be regarded as the "Higgs particle" in QCD, though the existence of such a mode in the real world is still unclear. We show the properties of the sigma meson

Norbert A'Campo

The geometric monodromy of a plane curve singularity is a quasi-finite diffeomorphism. In this paper we locate the reduction curves of the geometric monodromy and the quadratic vanishing cycles of the singularity. An application to the geometric monodromy group is given.

Simonetta Liuti

We examine the scale dependence in the resonance region of inclusive ep scattering. In particular we discuss the invariants other than Q^2, which have been proposed as a scale for pQCD evolution in a kinematical regime where both infrared singularities and power corrections are expected to be largest. We show that the region where most of the present data ar

Kh. M. Beshtoev

The elements of the theory of vacuum oscillations and the model of dynamical expansion of the theory of weak interactions works at the tree level, i.e. the model of dynamical analogy of Cabibbo-Kobayashi- Maskawa matrices and its further development, are given. It is shown that the quarks and massive vector bosons must be structural and these structural part

Subrata Sanyal, Dmitry Yavich, L. Gary Leal

We present the experimental results on a series of high molecular weight, entangled polystyrene solutions subjected to a ``mixed'' shear and elongational flow-type generated in a co-rotating two-roll mill. For steady-flows as well as for start-up of flows from rest, we used two different optical methods to study the dynamics of entangled polymeric fl

Lee Lindblom, Benjamin J. Owen, Greg Ushomirsky

The presence of a viscous boundary layer under the solid crust of a neutron star dramatically increases the viscous damping rate of the fluid r-modes. We improve previous estimates of this damping rate by including the effect of the Coriolis force on the boundary-layer eigenfunction and by using more realistic neutron-star models. If the crust is assumed to

A. P. Bakulev, S. V. Mikhailov

We re-analyze the leading twist light-cone distributions for transversely polarized ρ-, ρ'- and b_1-mesons in the framework of QCD sum rules with nonlocal condensates. Using different kinds of sum rules to obtain reliable predictions, we estimate the 2-, 4-, 6- and 8-th moments for transversely polarized ρ- and ρ'-meson distributions and re-estimate

Robert D. Pisarski

Effective theories for the thermal Wilson line are constructed in an SU(N) gauge theory at nonzero temperature. I propose that the order of the deconfining phase transition for Z(N) Wilson lines is governed by the behavior of SU(N) Wilson lines. In a mean field theory, the free energy in the deconfined phase is controlled by the condensate for Z(N) Wilson li

E. V. Derishev, V. V. Kocharovsky, Vl. V. Kocharovsky

Detailed information on the physical parameters in the sources of cosmological Gamma-Ray Bursts (GRBs) is obtained from few plausible assumptions consistent with observations. Model-independent requirements posed by these assumptions on the emission mechanism in GRBs are formulated. It is found that the observed radiation in sub-MeV energy range is generated

G. Lazarides, Q. Shafi

We present a solution to the cosmological problem encountered in (supersymmetric) grand unified theories due to copious monopole production at the end of hybrid inflation. By employing thermal inflation ``driven'' by the U(1) axion symmetry, the superheavy monopole flux can be naturally suppressed to values that should be accessible to dedicated larg

Won Tae Kim, John J. Oh, Marie K. Oh, Myung Seok Yoon

We study brane-world black holes from Randall-Sundrum(RS) models in ($D+1$)-dimensional anti-de Sitter spacetimes. The solutions are directly obtained by using a slightly modified RS metric ansatz in $D+1$ dimensions. The metric of the brane world can be described by the Schwarzschild solution promoted to the black cigar solution in $D+1$ dimensions, which i

A. V. Afanasjev, P. Ring

The microscopic role of nuclear magnetism in rotating frame is investigated for the first time in the framework of the cranked relativistic mean field theory. It is shown that nuclear magnetism modifies the expectation values of single-particle spin, orbital and total angular momenta along the rotational axis effectively creating additional angular momentum.

A. V. Afanasjev, P. Ring

The rotational and deformation properties of superdeformed fission isomers in the $A\sim 240$ mass region have been investigated within the framework of the cranked relativistic Hartree-Bogoliubov theory. The dependence of the results of the calculations on the parametrization of the RMF Lagrangian has been studied. The rotational properties are best describ

Dmitri Vassiliev

We consider the Dirac equation in flat Minkowski 3-space and rewrite it as the Maxwell equation in Minkowski 4-space with torsion. The torsion tensor is defined as the dual of the electromagnetic vector potential. Our model clearly distinguishes the electron and the positron without resorting to "negative frequencies": we produce a real scalar invari

Huai-Dong Cao, Jian Zhou

We describe some recent development on the theory of formal Frobenius manifolds via a construction from differential Gerstenhaber-Batalin-Vilkovisk (DGBV) algebras and formulate a version of mirror symmetry conjecture: the extended deformation problems of the complex structure and the Poisson structure are described by two DGBV algebras; mirror symmetry is i

Giovanni Felder, Jürg Fröhlich, Jürgen Fuchs, Christoph Schweigert

We give a general construction of correlation functions in rational conformal field theory on a possibly non-orientable surface with boundary in terms of 3-dimensional topological quantum field theory. The construction applies to any modular category. It is proved that these correlation functions obey modular and factorization rules. Structure constants are

Bayram Tekin

It is known that self-duality equations for multi-instantons on a line in four dimensions are equivalent to minimal surface equations in three dimensional Minkowski space. We extend this equivalence beyond the equations of motion and show that topological number, instanton moduli space and anti-self-dual solutions have representations in terms of minimal sur

Xiang-Bin Wang, L. C. Kwek, Yong Liu, C. H. Oh

We provide explicit formulae for the noncyclic geometric phases or Pancharatnam phases of neutrino oscillations. Since Pancharatnam phase is a generalization of the Berry phase, our results generalize the previous findings for Berry phase in a recent paper [Phys. Lett. B, 466 (1999) 262]. Unlike the Berry phase, the noncyclic geometric phase offers distincti

Jungil Lee

As a stringent test of the nonrelativistic QCD factorization approach for inclusive heavy-quarkonium production in high-energy hadron collision, the polarized heavy-quarkonium production at the Tevatron is discussed. The polarization of prompt J/psi at the Tevatron is predicted within the nonrelativistic QCD factorization framework. The contribution from rad

Ahmed Helmy, Sandeep Gupta, Deborah Estrin, Alberto Cerpa

The advent of multipoint (multicast-based) applications and the growth and complexity of the Internet has complicated network protocol design and evaluation. In this paper, we present a method for automatic synthesis of worst and best case scenarios for multipoint protocol performance evaluation. Our method uses a fault-oriented test generation (FOTG) algori

S. G. Chung

The spontaneous breaking of a global discrete translational symmetry in the finite, lattice quantum sine-Gordon model is demonstrated by a density matrix renormalization group. A phase diagram in the coupling constant - inverse system size plane is obtained. Comparison of the phase diagram with a Woomany-Wyld finite-size scaling leads to an identification of

H. Fehske, C. Schindelin, A. Weiße, H. Büttner

Ground-state and thermodynamical properties of the spin-1/2 two-dimensional easy-plane XXZ model are investigated by both a Green's-function approach and by Lanczos diagonalizations on lattices with up to 36 sites. We calculate the spatial and temperature dependences of various spin correlation functions, as well as the wave-vector dependence of the spin

G. Gregori, Francesco Miniati, Dongsu Ryu, T. W. Jones

We present results from three-dimensional (3-D) numerical simulations investigating the magnetohydrodynamics of cloud-wind interactions. The initial cloud is spherical while the magnetic field is uniform and transverse to the cloud motion. A simplified analytical model that describes the magnetic energy evolution in front of the cloud is developed and compar

Steven S. Gubser, Shivaji L. Sondhi

We investigate the phase structure of non-commutative scalar field theories and find evidence for ordered phases which break translation invariance. A self-consistent one-loop analysis indicates that the transition into these ordered phases is first order. The phase structure and the existence of scaling limits provides an alternative to the structure of cou

Johann Rafelski, Jean Letessier

We formulate and study a mechanical instability criterion for sudden hadronization of dense matter fireballs formed in 158A GeV Pb--Pb collisions. Considering properties of quark-gluon matter and hadron gas we obtain the phase boundary between these two phases and demonstrate that the required deep QGP supercooling prior to sudden hadronization has occurred.

Andrew E. Dolphin

A new determination of WFPC2 photometric corrections is presented, using HSTphot reduction of the WFPC2 Omega Centauri and NGC 2419 observations from January 1994 through March 2000 and a comparison with ground-based photometry. No evidence is seen for any position-independent photometric offsets (the "long-short anomaly"); all systematic errors appe

Stephen Sharpe, Noam Shoresh

We calculate various properties of pseudoscalar mesons in partially quenched QCD using chiral perturbation theory through next-to-leading order. Our results can be used to extrapolate to QCD from partially quenched simulations, as long as the latter use three light dynamical quarks. In other words, one can use unphysical simulations to extract physical quant

G. Lopez Castro, A. Mariano

We study the elastic and radiative pi+ p scattering within a full dynamical model which incorporates the finite width effects of the Delta++. The scattering amplitudes are invariant under contact transformations of the spin 3/2 field and gauge-invariance is fulfilled for the radiative case. The pole parameters of the Delta++ obtained from the elastic cross s

C. G. Beneventano, E. M. Santangelo

We obtain, through zeta function methods, the one-loop effective action for massive Dirac fields in the presence of a uniform, but otherwise general, electromagnetic background. After discussing renormalization, we compare our zeta function result with Schwinger's proper time approach.

N. D. Lambert, I. Sachs

The non-abelian flat directions in the tachyon potential of stable non-BPS branes recently found are shown to persist to all orders in alpha' at tree level in the string coupling. We also obtain the non-abelian Born-Infeld action including the tachyon potential for a stack of stable non-BPS branes on a critical orbifold. Finally we discuss stable soliton

K. S. Wood, P. S. Ray, R. M. Bandyopadhyay, M. T. Wolff

The USA experiment on ARGOS and RXTE have exensively observed the X-ray transient XTE J1118+480 during its recent outburst in 2000 April--June. We present detailed monitoring of the evolution of a low frequency QPO which drifts from 0.07 Hz to 0.15 Hz during the outburst. We examine possible correlations of the QPO frequency with the flux and spectral charac

M. Bastero-Gil, C. Hugonie, S. F. King, D. P. Roy

We study the naturalness of electroweak symmetry breaking and baryogenesis in the next-to-minimal supersymmetric standard model (NMSSM). Our study is motivated by the recent LEP bounds on the Higgs boson mass which severely constrains the low \tanβregion of the minimal supersymmetric standard model (MSSM). We show that the low \tan βregion of the NMSSM is cl

Matthew Wingate, Shigemi Ohta

We present results from numerical lattice calculations of SU(4) Yang-Mills theory. This work has two goals: to determine the order of the finite temperature deconfinement transition on an $N_t = 6$ lattice and to study the string tensions between static charges in the irreducible representations of SU(4). Motivated by Pisarski and Tytgat's argument that

D. S. Kuzmenko, Yu. A. Simonov

Field distributions generated by static quark-antiquark and QQQ sources are calculated analytically in the framework of the Field Correlator Method (FCM) using Gaussian (bilocal) correlator. In both cases the string consists mostly of longitudinal color electric field, while transverse electric field contributes locally less then 3%, in agreement with earlie

V. V. Nesterenko, G. Lambiase, G. Scarpetta

The Casimir effect at finite temperature is investigated for a dilute dielectric ball; i.e., the relevant internal and free energies are calculated. The starting point in this study is a rigorous general expression for the internal energy of a system of noninteracting oscillators in terms of the sum over the Matsubara frequencies. Summation over the angular

Rajiv V. Gavai

Suppressing monopoles and vortices by introducing large chemical potentials for them in the Wilson action for the SU(2) lattice gauge theory, we study the nature of the deconfinement phase transition on N_σ^3 \times N_τlattices for N_τ= 4, 5, 6 and 8 and N_σ= 8--16. Using finite size scaling theory, we obtain ω= 1.93 \pm 0.03 for N_τ= 4, in excellent agreeme

E. Churazov, M. Gilfanov, M. Revnivtsev

Two component X-ray spectra (soft multicolor black body plus harder power law) are frequently observed from accreting black holes. These components are presumably associated with the different parts of the accretion flow (optically thick and optically thin respectively) in the vicinity of the compact source. Most of the aperiodic variability of the X-ray flu

Christiaan Hofman, Whee Ky Ma

Deformations of topological open string theories are described, with an emphasis on their algebraic structure. They are encoded in the mixed bulk-boundary correlators. They constitute the Hochschild complex of the open string algebra -- the complex of multilinear maps on the boundary Hilbert space. This complex is known to have the structure of a Gerstenhabe

Emilian Dudas

The physical motivations and the basic construction rules for Type I strings and M-theory compactifications are reviewed in light of the recent developments. The first part contains the basic theoretical ingredients needed for building four-dimensional supersymmetric models, models with broken supersymmetry and for computing low-energy actions and quantum co

E. Bagan, M. Baig, A. Brey, R. Munoz-Tapia

Quantum states can be used to encode the information contained in a direction, i.e., in a unit vector. We present the best encoding procedure when the quantum state is made up of $N$ spins (qubits). We find that the quality of this optimal procedure, which we quantify in terms of the fidelity, depends solely on the dimension of the encoding space. We also in

M. Pawlowski, V. N. Pervushin

The reparametrization-invariant generating functional for the unitary and causal perturbation theory in general relativity in a finite space-time is obtained. The region of validity of the Faddeev-Popov-DeWitt functional is studied. It is shown that the invariant content of general relativity as a constrained system can be covered by two "equivalent"

Mario Nicodemi, Henrik Jeldtoft Jensen

We theoretically study the creep of vortex matter in superconductors. The low temperatures experimental phenomenology, previously interpreted in terms of ``quantum tunnelling'' of vortices, is reproduced by Monte Carlo simulations of a purely ``classical'' vortex model. We demonstrate that a non-zero creep rate in the limit of vanishing tempe

Hiromi Saida, Jiro Soda

We consider a model of an inhomogeneous universe including a massless scalar field, where the inhomogeneity is assumed to consist of many black holes. This model can be constructed by following Lindquist and Wheeler, which has already been investigated without including scalar field to show that an averaged scale factor coincides with that of the Friedmann m

Shin'ichi Nojiri, Sergei D. Odintsov, Sergio Zerbini

The role of bulk matter quantum effects (via the corresponding effective potential discussed on the example of conformal scalar) and of boundary matter quantum effects (via the conformal anomaly induced effective action) is considered in brane-world cosmology. Scenario is used where brane tension is not free parameter, and the initial bulk-brane classical ac

Martin Elvis, Fabrizio Fiore, Aneta Siemiginowska, Jill Bechtold

A BeppoSAX observation of the z=2.34 quasar PKS2149-306 produced a strong signal in the high energy PDS instrument up to a maximum observed energy of nearly 50 keV, 150 keV in the quasar frame. The Beppo-SAX spectrum spans almost 3 decades (0.3-150 keV, quasar frame) and shows an extremely hard (alpha=0.4+/-0.05) X-ray spectrum above 3 keV (comparable to the

F. H. Briggs, J. F. Bell, M. J. Kesteven

The growing level of radio frequency interference (RFI) is a recognized problem for research in radio astronomy. This paper describes an intuitive but powerful RFI cancellation technique that is suitable for radio spectroscopy where time-averages are recorded. An RFI ``reference signal,'' is constructed from the cross power spectrum of the signals fr

L. Vaidman

In 1993 Elitzur and Vaidman introduced the concept of interaction-free measurements which allowed finding objects without ``touching'' them. In the proposed method, since the objects were not touched even by photons, thus, the interaction-free measurements can be called as ``seeing in the dark''. Since then several experiments have been succe

Keiji Matsumoto

In this paper, it is pointed out that the Berry's phase is a good index of degree of no-commutativity of the quantum statistical model. Intrinsic relations between the `complex structure' of the Hilbert space and Berry's phase is also discussed.

C. L. Herzenberg

The pervasive presence in space of a flux of high-speed, electrically uncharged dark matter particles is examined here for potential consequences. Dark matter interactions with ordinary matter are considered, and a model of the dark matter flux is developed. In this model, the property of matter that we designate as mass is a measure of the interaction cross

Jean-Philippe Uzan, Jean-Pierre Luminet, Roland Lehoucq, Patrick Peter

If space is compact, then a traveller twin can leave Earth, travel back home without changing direction and find her sedentary twin older than herself. We show that the asymmetry between their spacetime trajectories lies in a topological invariant of their spatial geodesics, namely the homotopy class. This illustrates how the spacetime symmetry invariance gr

Takashi Sakai

A body of theory is completely different between relativity theory and quantum mechanics. Most targeting physical phenomena are different between them as well. Despite that both theories describe our time-space world, no one has succeeded in arriving at one of these theories by using the other one, deductively. Fusion of these two theories produced quantum f

G. F. Bertsch, K. Hagino

We review some possible improvements of mean field theory for application to nuclear binding systematics. Up to now, microscopic theory has been less successful than models starting from the liquid drop in describing accurately the global binding systematics. We believe that there are good prospects to develop a better global theory, using modern forms of en

Chaejun Song

The relation between the effective chiral Lagrangian whose parameters scale according to Brown and Rho scaling("BR scaling") and Landau Fermi-liquid theory for hadronic matter is discussed in order to make a basis to describe the fluctuations under the extreme condition relevant to neutron stars. It is suggested that BR scaling gives the background a

D. Cabrera, E. Oset, M. J. Vicente Vacas

In this work, propagation properties of the rho meson in symmetric nuclear matter are studied. We make use of a coupled channel unitary approach to meson-meson scattering, calculated from the lowest order Chiral Perturbation Theory lagrangian including explicit resonance fields. Low energy chiral constraints are considered by matching our expressions to thos

M. Rysavy, O. Dragoun

Possible sources of uncertainties in the calculations of the internal conversion coefficients are studied. The uncertainties induced by them are estimated.

R. Quian Quiroga

We present a method for the analysis of electroencephalograms (EEG). In particular, small signals due to stimulation, so called evoked potentials, have to be detected in the background EEG. This is achieved by using a denoising implementation based on the wavelet decomposition. One recording of visual evoked potentials, and recordings of auditory evoked pote

T. Kojima

We study the XXZ chain with a boundary at massless regime $-1<Δ<1$. We give the free field realizations of the boundary vacuum state and it&#39;s dual. Using these realizations, we give the integrable representations of the correlation functions.

Cosma Rohilla Shalizi, James P. Crutchfield

Discovering relevant, but possibly hidden, variables is a key step in constructing useful and predictive theories about the natural world. This brief note explains the connections between three approaches to this problem: the recently introduced information-bottleneck method, the computational mechanics approach to inferring optimal models, and Salmon&#39;s

Fernando Lledo

In the present paper we review in a fibre bundle context the covariant and massless canonical representations of the Poincare&#39; group as well as certain unitary representations of the conformal group (in 4 dimensions). We give a simplified proof of the well-known fact that massless canonical representations with discrete helicity extend to unitary and irr

V. Rivasseau

In this paper we review many interesting open problems in mathematical physics which may be attacked with the help of tools from constructive field theory. They could give work for future mathematical physicists trained with the constructive methods well within the 21st century.

Florin G. Radulescu

In this paper we use the description of free group factors as the von Neumann algebras of Berezin&#39;s deformation of the upper half-plane, modulo PSL$(2,{\Bbb Z})$. The derivative, in the deformation parameter, of the product in the corresponding algebras, is a positive Hochschild 2-cocycle, defined on a dense subalgebra. By analyzing the structure of the

G. Corach, A. Maestripieri, D. Stojanoff

Let H be a Hilbert space, L(H) the algebra of all bounded linear operators on H and <, >_A : H \times H \to C the bounded sesquilinear form induced by a selfadjoint A in L(H), < ξ, η>_A = < A ξ, η>, ξ, ηin H. Given T in L(H), T is A-selfadjoint if AT = T^*A. If S \subseteq H is a closed subspace, we study the set of A-selfadjoint projections onto S, P(A, S)

Clyde H. Schoolfield,

We bound the rate of convergence to stationarity for a signed generalization of the Bernoulli-Laplace diffusion model; this signed generalization is a Markov chain on the homogeneous space (Z_2 \wr S_n) / (S_r \times S_{n-r}). Specifically, for r not too far from n/2, we determine that, to first order in n, 1/4 n \log n steps are both necessary and sufficien

Clyde H. Schoolfield,

We bound the rate of convergence to uniformity for certain random walks on the complete monomial groups G \wr S_n for any group G. These results provide rates of convergence for random walks on a number of groups of interest: the hyperoctahedral group Z_2 \wr S_n, the generalized symmetric group Z_m \wr S_n, and S_m \wr S_n. These results provide benchmarks

Alice Fialowski, Dmitry Fuchs

We consider deformations of finite or infinite dimensional Lie algebras over a field of characteristic 0. There is substantial confusion in the literature if one tries to describe all the non-equivalent deformations of a given Lie algebra. It is known that there is in general no &#34;universal&#34; deformation of the Lie algebra L with a commutative algebra

J. Scott Carter, Seiichi Kamada, Masahico Saito

Geometric representations of cycles in quandle homology theory are given in terms of colored knot diagrams. Abstract knot diagrams are generalized to diagrams with exceptional points which, when colored, correspond to degenerate cycles. Bounding chains are realized, and used to obtain equivalence moves for homologous cycles. The methods are applied to prove

Amir Dembo, Bjorn Poonen, Qi-Man Shao, Ofer Zeitouni

Consider a polynomial of large degree n whose coefficients are independent, identically distributed, nondegenerate random variables having zero mean and finite moments of all orders. We show that such a polynomial has exactly k real zeros with probability n^{-b+o(1)}$ as n --> infinity through integers of the same parity as the fixed integer k >= 0. In parti

Philippe Biane

We prove a factorization-concentration result for characters of symmetric groups. This is then applied to the asymptotic behaviour of the decomposition of the tensor representations. There are connections with the Pastur-Marcenko distribution of random matrix theory, and freely infinitely divisible distributions.

Sortelano Araujo Diniz, Carlos Pinheiro, F. C. Khanna

In a gravitational field, we analyze the Maxwell equations, the correponding electromagnetic wave and continuity equations. A particular solution for parellel electric and magnetic fields in a gravitational background is presented. These solutions also satisfy the free-wave equations and the phenomenology suggested by plasma physics.

Carlos Pinheiro, F. C. Khanna

We introduce a &#39;quasi-topological` term [1] in D=1+1 dimensions and the entropy for black holes is calculated [2]. The source of entropy in this case is justified by a non-null stress-energy tensor.

Carlos Pinheiro, J. A. Helayel-Neto, Gilmar S. Dias

At first, we discuss parallels electric and magnetic fields solutions in a gravitational background. Then, considering eletromagnetic and gravitational waves symmetries we show a particular solution for stationary gravitational waves. Finally we consider gravitation as a gauge theory (effective gravitational theory), evaluate the propagators of the model, an

Carlos Pinheiro, J. A. Helayel-Neto, Gilmar S. Dias, F. C. Khanna

The existence of an electromagnetic field with parallel electric and magnetic field components in the presence of a gravitational field is considered. A non-parallel solution is shown to exist. Next, we analyse the possibility of finding stationary gravitational waves in nature. Finally, we construct a D=4 effective quantum gravity model. Tree-level unitarit

Carlos Pinheiro, F. C. Khanna

We discuss here the possibility to write the Liouville-Vlasov equation for the Wigner-function of a spinor field coupled to a gauge field with field strength tensor $F^{μν}$ in a curved space-time versus a local Lorentz manifold (introduction of local Lorentz coordinates) with an appropriate definition of a covariant derivative carried out using a spin conne

Carlos Pinheiro, F. C. Khanna

We study the contribution to entropy of Black Holes in D=2+1 dimensions from an extension of the Chern Simons theory including higher derivative in a curved space-time.

Carlos Pinheiro, F. C. Khanna, Robert Riche

We propose a time-varying parameter $\underlineα$ for Gödel metric and an energy momentum tensor corresponding to this geometry is found. To satisfy covariance arguments time-varying gravitational and cosmological term are introduced. The ``Einstein&#39;s equation&#39;&#39; for this special evolution for the Universe are written down where expansion, rotatio

P. A. Horváthy, A. J. Macfarlane, J. -W. van Holten

The hidden supersymmetry of the monopole found by De Jonghe et al. is generalized to a spin $\2$ particle in the combined field of a Dirac monopole plus a $λ^2/r^2$ potential [considered before by D&#39;Hoker and Vinet], and related to the operator introduced by Biedenharn a long time ago in solving the Dirac-Coulomb problem. Explicit solutions are obtained

Donald Marolf

In theories with Chern-Simons terms or modified Bianchi identities, it is useful to define three notions of either electric or magnetic charge associated with a given gauge field. A language for discussing these charges is introduced and the properties of each charge are described. `Brane source charge&#39; is gauge invariant and localized but not conserved

Bernd A. Berg

I consider infinitesimal translations $x&#39;^α=x^α+δx^α$ and demand that Noether&#39;s approach gives a symmetric energy-momentum tensor as it is required for gravitational sources. This argument determines the transformations of non-abelian gauge fields under infinitesimal translations to differ from the usually assumed invariance by the gauge transformati

M. Bleicher, S. Jeon, V. Koch

The event by event fluctuations of the ratio of positively to negatively charged hadrons are predicted within the UrQMD model. Corrections for finite acceptance and finite net charge are derived. These corrections are relevant to compare experimental data and transport model results to previous predictions. The calculated fluctuations at RHIC and SPS energie

Werner Vogelsang

We consider spin asymmetries for prompt photon production in collisions of longitudinally polarized hadrons. This reaction will be a key tool at the BNL-RHIC pp collider for determining the gluon spin density in a polarized proton. We study the effects of QCD corrections, such as all-order soft-gluon `threshold&#39; resummations.

A. V. Kotikov, G. Parente

We investigate the Q^2 evolution of parton distributions at small x values, recently obtained in the case of soft initial conditions. The results are in excellent agreement with deep inelastic scattering experimental data from HERA.

Aleksander Filip Zarnecki

Data from HERA, LEP and the Tevatron, as well as from low energy experiments are used to constrain the scale of possible electron-quark contact interactions. Some models are found to describe the existing experimental data much better than the Standard Model. The possibility of scalar or vector leptoquark contribution is studied using the Buchmuller-Ruckl-Wy

Barbara Clerbaux

Recent results on diffraction at HERA, from the H1 and ZEUS Collaborations, and at Tevatron, from the CDF and D0 Collaborations, are reviewed. The measurement of the diffractive structure function at HERA is presented, and the pomeron structure function is extracted from QCD fits. Diffractive dijet production is given as an example analysis of the diffractiv

Mrinal Dasgupta

We discuss the procedure to resum large logarithms to all orders for DIS event shape variable distributions. Results are described for two variants of the thrust variable, both defined wrt the boson axis in the current hemisphere of the Breit frame, but with different normalisations.

M. Botje

The parton momentum density distributions of the proton were obtained from a NLO QCD analysis of HERA and fixed target structure function data. The resulting parton distribution set includes the full information on errors and correlations.

Herbert Weigel

Within the collective quantization scheme for chiral solitons we discuss states in higher dimensional representations of flavor SU(3) and their relation to radially excited states in the octet. We also consider states which do not have counterparts of the same quantum numbers in the octet or decuplet and cannot be built from three quarks. We focus on the Z^+

Fiorenza Donato

We propose low-energy antideuterons in cosmic rays as a new possible signature for indirect detection of supersymmetric dark matter. Since the energy spectrum of the antiproton secondary component is still spoilt by considerable theoretical uncertainties, looking for low-energy antideuterons seems a plausible alternative. We apply our calculation to the AMS

D. Ebert, R. N. Faustov, V. O. Galkin

Exclusive semileptonic B decays to orbitally and radially excited charmed mesons are investigated in the first order of the heavy quark expansion. The emerging leading and subleading Isgur-Wise functions are calculated in the framework of the relativistic quark model. It is found that both relativistic and the 1/m_Q corrections play an important role and sub

D. Ebert, R. N. Faustov, V. O. Galkin

A general approach to accounting for retardation effects in the long-range (confining) part of the quark-antiquark potential is presented. The charmonium and bottomonium mass spectra are calculated with the systematic account of relativistic and retardation effects and the one-loop radiative corrections. A good fit to available experimental data on the mass

Per Osland, Tai Tsun Wu

If three right-handed neutrinos are added to the Standard Model, then, for the three known generations, there are six quarks and six leptons. It is then natural to assume that the symmetry considerations that have been applied to the quark matrices are also valid for the lepton mass matrices. Under this assumption, the solar and atmospheric neutrino data can

M. A. Kimber, J. Kwiecinski, A. D. Martin, A. M. Stasto

The gluon distribution f(x, k_t^2,mu^2), unintegrated over the transverse momentum k_t of the gluon, satisfies the angular-ordered CCFM equation which interlocks the dependence on the scale k_t with the scale μof the probe. We show how, to leading logarithmic accuracy, the equation can be simplified to a single scale problem. In particular we demonstrate how

Piero Ullio, Marc Kamionkowski

An annual modulation in the event rate of the NaI detector of the DAMA collaboration has been used to infer the existence of particle dark matter in the Galactic halo. Bounds on the WIMP mass and WIMP-nucleon cross section have been derived. These analyses have assumed that the local dark-matter velocity distribution is either isotropic or has some bulk rota

Te CLAS Collaboration, E. Anciant

The cross section for $ϕ$ meson photoproduction on the proton has been measured for the first time up to a four-momentum transfer -t = 4 GeV^2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. At low four-momentum transfer, the differential cross section is well described by Pomeron exchange. At large four-momentum transfer, abo

N. Solomey

With new forthcoming intense neutrino beams, for the study of neutrino oscillations, it is possible to consider other physics experiments that can be done with these extreme neutrino fluxes available close to the source.

Fred C. Adams

Charged extremal black holes cannot fully evaporate through the Hawking effect and are thus long lived. Over their lifetimes, these black holes take part in a variety of astrophysical processes, including many that lead to their eventual destruction. This paper explores the various events that shape the life of extremal black holes and calculates the corresp

Alan D. Rendall

An important question in mathematical relativity theory is that of the nature of spacetime singularities. The equations of general relativity, the Einstein equations, are essentially hyperbolic in nature and the study of spacetime singularities is naturally related to blow-up phenomena for nonlinear hyperbolic systems. These connections are explained and rec

Edward Malec

We investigate the Cauchy problem for the Einstein - scalar field equations in asymptotically flat spherically symmetric spacetimes, in the standard 1+3 formulation. We prove the local existence and uniqueness of solutions for initial data given on a space-like hypersurface in the Sobolev $H_1\cap H_{1,4} $ space. Solutions exist globally if a central (integ