September 1999 arXiv papers — page 8

P. Halevi, A. A. Krokhin, J. Arriaga

This Comment concerns the effective dielectric constant for 2D photonic crystal. We show that even in the limit of very high dielectric constant of photonic crystal's "atoms", static and quasistatic approaches give the same results, unlike it was claimed by Nicorovichi et al, PRL, 75, 1507 (1995).

Arnd Huebsch, Matthias Vojta, Klaus W. Becker

Effective Hamiltonians are usually constructed by using canonical transformations or projection techniques. In contrast to this, we present a method for systems with arbitrary Hilbert space based on the introduction of cumulants. Cumulants guarantee size consistency, a property that is not always evident in other treatments. As a nontrivial example of use th

Yasumasa Hasegawa, Kazushige Machida, Masa-aki Ozaki

Several possible odd-parity states are listed up group-theoretically and examined in light of recent experiments on Sr$_2$RuO$_4$. Those include some of the $f$-wave pairing states, ${\mib d}({\mib k})\propto{\hat{\mib z}} k_xk_y(k_x + {\rm i}k_y)$ and ${\hat{\mib z}} (k_x^2-k_y^2)(k_x + {\rm i}k_y)$ and other ${\hat{\mib z}} (k_x + {\rm i}k_y)\cos ck_z$ ($c

Nick E. Mavromatos, Sarben Sarkar

In the context of extended t-J models, with intersite Coulomb interactions, nodal liquids are discussed. We use the spin-charge separation ansatz as applied to the nodes of a d-wave superconducting gap. Such a situation may be of relevance to the physics of high-temperature superconductivity. We point out the possibility that at certain points of the paramet

M. B. Hastings

We consider an ensemble of self-dual matrices with arbitrary complex entries. This ensemble is closely related to a previously defined ensemble of anti-symmetric matrices with arbitrary complex entries. We study the two-level correlation functions numerically. Although no evidence of non-monotonicity is found in the real space correlation function, a definit

Bruno Jouault, Juergen Schmiegel, Martin Greiner

The multiplier statistics of discrete and continuous nonconservative multiplicative cascade models, employed to describe the energy cascade in fully developed turbulence, is investigated. It is found to be indistinguishable due to small-scale resummation and restoration of spatial homogeneity. Only the subclass of positively skewed weight distributions, asso

S. Courteau, J. A. Willick, M. A. Strauss, D. Schlegel

We present preliminary results from the Shellflow program, an all-sky Tully-Fisher (TF) survey of 297 Sb-Sc with redshifts between 4000 and 7500 km/s. The program was designed to ensure uniformity of the data between observing runs and between telescopes, thereby eliminating the possibility of a spurious bulk flow caused by data inhomogeneity. A simple bulk

Allen V. Sweigart

Recent Hubble Space Telescope (HST) observations by Rich et al. (1997) have shown that the metal-rich globular clusters (GCs) NGC 6388 and NGC 6441 exhibit a pronounced 2nd parameter effect. Ordinarily metal-rich GCs have only a red horizontal-branch (HB) clump. However, NGC 6388 and NGC 6441 also possess an unexpected population of blue HB stars, indicating

Richard B. Larson

How did star formation begin in the universe? Some of the questions addressed at this first meeting on "The First Stars" are summarized here from a theoretical perspective, and some brief comments are made on what we may have learned so far.

S. P. Swordy, D. B. Kieda

The small change in the spectral slope of the overall intensity of cosmic rays near 1 PeV may be associated with the endpoint energy of supernova shock acceleration. A crucial test of this connection and other ideas of the origin of the spectral `knee' is the reliable determination of the variation of elemental composition in this region. Recent measurem

Stacy Palen, John D. Fix

Arecibo spectra of the mainline OH maser emission from U Her over more than a decade show variations of the OH emission over these time scales. These observations are combined with high spatial resolution VLBA maps to investigate the causes of the variations in the velocities of the maser components. Global properties of the dust shell, such as accelerations

L. G. Balazs, A. Meszaros, I. Horvath, R. Vavrek

The anisotropy of the sky distribution of 2025 gamma-ray bursts (GRBs) collected in Current BATSE catalog is confirmed. It is shown that the quadrupole term being proportional to $\sim \sin 2b \sin l$ is non-zero with a probability 99.9%. The occurrence of this anisotropy term is then supported by the binomial test even with the probability 99.97%. It is als

Gaspard Duchene, Jean-Louis Monin, Jerome Bouvier, Francois Menard

We present low-resolution optical spectra of each component of 10 T Tauri (TT) binary systems with separations ranging from 0.9" to 3.5" and located in the Taurus star-forming region. We derive the spectral type and Halpha equivalent width of each component. Complementing these results with those of Monin et al. (1999) yields a sample of 14 binaries

A. D. Biggs, I. W. A. Browne, P. N. Wilkinson, T. W. B. Muxlow

This poster presents a new 5 GHz combined MERLIN/VLA map of B0218+357 which shows for the first time believable substructure in the Einstein ring. This will now be exploited for further constraints on the model which presently dominates the error on the estimate of H_0 derived from the time delay (10.5+/-0.4 days) measured for this system.

R. N. Mohapatra, S. Nussinov, V. L. Teplitz

Mirror matter models have been suggested recently as an explanation of neutrino puzzles and microlensing anomalies. We show that mirror supernovae can be a copious source of energetic gamma rays if one assumes that the quantum gravity scale is in the TeV range. We show that under certain assumptions plausible in the mirror models, the gamma energies could be

Phillip Helbig, Juan Francisco Macias-Perez, Ralf Quast, Althea Wilkinson

We discuss the consistency of constraints in the lambda_0-Omega_0 plane from gravitational lensing statistics, the m-z relation for type Ia supernovae and CMB anisotropies, based on our own (published or unpublished) work and results from the literature.

Lukas Grenacher, Philippe Jetzer, Marcus Strässle, Francesco De Paolis

We calculate the optical depth and the number of events due to gravitational microlensing towards the Galactic bulge, the spiral arm directions $γ$ Scutum, $β$ Scutum, $γ$ Normae, $\vartheta$ Muscae and some dwarf galaxies in the halo of the Galaxy. Using the events found by the MACHO collaboration during their first year of observation towards Baade's W

F. P. Israel, F. Baas

Maps of the J=2-1 12CO emission from the SbII galaxy NGC 7331 show a low-contrast ring at a radius of about 3.5 kpc. There is no evidence for a pronounced central hole in the CO distribution as claimed by others. The molecular ring is just outside the radius of peak emission from warm dust, but coincides with the peak of colder dust emission. Various 12CO an

Peter Berczik, Sergei G. Kravchuk

The formation and evolution of a low mass galaxy in the gravitational field of a massive disk galaxy (like the Milky Way) has been studied. Numerical simulations of complex gas-dynamic flows are based on our own variant of the Chemo-Dynamical Smoothed Particle Hydrodynamical ({\bf CD-SPH}) approach, which incorporates star formation. The dynamics of the dark

Noella L. D'Cruz, Robert W. O'Connell, Robert T. Rood, Jonathan H. Whitney

The globular cluster omega Centauri contains the largest known population of very hot horizontal branch (HB) stars. We have used the Hubble Space Telescope to obtain a far-UV/optical color-magnitude diagram of three fields in omega Cen. We find that over 30% of the HB objects are ``extreme'' HB or hot post-HB stars. The hot HB stars are not concentra

C. J. Cesarsky, M. Sauvage

From the disk of normal galaxies to the nucleus of prototype active sources, we review the wealth of results and new understanding provided by recent infrared probes and, in particular, the four instruments on-board of ISO.

E. De Filippis, G. Longo, S. Andreon, R. Scaramella

The projected multiplicity function of galaxies gives (per square degree) the density of galaxy aggregates formed by N members. We use the CRoNaRio matched catalogues to derive the low N (N<15) multiplicity function from D-POSS data. The van Albada (1982) algorithm was implemented and used to identify candidate groups in the CRoNaRio catalogues. In absence o

E. Puddu, S. Andreon, G. Longo, M. Paolillo

We present preliminary results of a simple peak finding algorithm applied to catalogues of galaxies, extracted from the Second Palomar Sky Survey in the framework of the CRoNaRio project. All previously known Abell and Zwicky clusters in a test region of 5x5 sq. deg. are recovered and new candidate clusters are also detected. This algorithm represents an alt

M. Paolillo, S. Andreon, G. Longo, E. Puddu

We present the composite luminosity function of galaxies for 24 Abell clusters studied in our survey of the Northern Hemisphere, using DPOSS data in the framework of the CRoNaRio collaboration. Our determination of the luminosity function has been computed with very high accuracy thanks to 1) the use of homogeneous data both in the cluster and in the control

R. C. Walker, V. Dhawan, J. D. Romney, K. I. Kellermann

Nearly simultaneous VLBA observations of 3C 84, the radio source associated with NGC 1275, have been made at multiple frequencies to study the free-free absorption of the northern, or &#34;counterjet&#34;, feature found by Walker, Romney, and Benson (1994, Ap.J. 430, L45) and by Vermeulen, Readhead, and Backer (1994, Ap.J. 430, L41). Our observations confirm

Janusz Kaluzny

Four large/medium size photometric surveys are being conducted by Warsaw astronomers: Warsaw-LCO survey of globular clusters, OGLE, DIRECT and ASAS. In this contribution we provide short description of these projects and discuses briefly some results obtained for pulsating variables.

J. S. Shiner

The disorder and a simple convex measure of complexity are studied for rank ordered power law distributions, indicative of criticality, in the case where the total number of ranks is large. It is found that a power law distribution may produce a high level of complexity only for a restricted range of system size (as measured by the total number of ranks), wi

Vittorio Del Duca, Alberto Frizzo, Fabio Maltoni

In the high-energy limit, we compute the gauge-invariant three-parton forward clusters, which in the BFKL theory constitute the tree parts of the NNLO impact factors. In the triple collinear limit, we obtain the polarized double-splitting functions. For the unpolarized and the spin-correlated double-splitting functions, our results agree with the ones obtain

Henryk Fuks, Anna T. Lawniczak

We investigate simplified models of computer data networks and examine how the introduction of additional random links influences the performance of these net works. In general, the impact of additional random links on the performance of the network strongly depends on the routing algorithm used in the network. Significant performance gains can be achieved i

Shao-Hsuan Chiu, T. K. Kuo

Possible outcomes of neutrino events at both Super-Kamiokande and SNO for a type-II supernova are analyzed considering the uncertainties in SN neutrino spectra (temperature) at emission, which may complicate the interpretation of the observed events. With the input of parameters deduced from the current solar and atmospheric experiments, consequences of dire

S. C. Dultz, H. W. Jiang

We present a study of the compressibility, K, of a two-dimensional hole system which exhibits a metal-insulator phase transition at zero magnetic field. It has been observed that dK/dp changes sign at the critical density for the metal-insulator transition. Measurements also indicate that the insulating phase is incompressible for all values of B. Finally, w

A. N. Timokhin, G. S. Bisnovatyi-Kogan, H. C. Spruit

We generalize a formula for the Goldreich-Julian charge density (ρ), originally derived for rotating neutron star, for arbitrary oscillations of a neutron star with arbitrary magnetic field configuration under assumption of low current density in the inner parts of the magnetosphere. As an application we consider toroidal oscillation of a neutron star with d

Sean A. Hayward

Gravitational waves in cylindrically symmetric Einstein gravity are described by an effective energy tensor with the same form as that of a massless Klein- Gordon field, in terms of a gravitational potential generalizing the Newtonian potential. Energy-momentum vectors for the gravitational waves and matter are defined with respect to a canonical flow of tim

Shun&#39;ya Mizoguchi, Germar Schroeder

We give a complete set of generators for the discrete exceptional U-duality groups of toroidal compactified type II theory and M-theory in d>2. For this, we use the DSZ quantization in d=4 as originally proposed by Hull and Townsend, and determine the discrete group inducing integer shifts on the charge lattice. It is generated by fundamental unipotents, whi

John P. Grondalski, Paul M. Alsing, Ivan H. Deutsch

We explore the use of first and second order same-time atomic spatial correlation functions as a diagnostic for probing the small scale spatial structure of atomic samples trapped in optical lattices. Assuming an ensemble of equivalent atoms, properties of the local wave function at a given lattice site can be measured using same-position first-order correla

Gastón Giribet, Carmen Núñez

We consider string theory on AdS_3 in terms of the Wakimoto free field representation. The scattering amplitudes for N unitary tachyons are analysed in the factorization limit and the poles corresponding to the mass-shell conditions for physical states are extracted. The vertex operators for excited levels are obtained from the residues and their properties

Mohab Abou-Zeid, Miguel S. Costa

The radiation emitted by accelerated fundamental strings and D-branes is studied within the linear approximation to the supergravity limit of string theory. We show that scalar, gauge field and gravitational radiation is generically emitted by such branes. In the case where an external scalar field accelerates the branes, we derive a Larmor-type formula for

K. Held, D. Vollhardt

The influence of local electronic correlations on the properties of colossal magnetoresistance manganites is investigated. To this end, a ferromagnetic two-band Kondo lattice model is supplemented with the local Coulomb repulsion missing in this model, and is analyzed within dynamical mean-field theory. Results for the spectral function, optical conductivity

P. B. Wiegmann, A. Zabrodin

We show that conformal maps of simply connected domains with an analytic boundary to a unit disk have an intimate relation to the dispersionless 2D Toda integrable hierarchy. The maps are determined by a particular solution to the hierarchy singled out by the conditions known as &#34;string equations&#34;. The same hierarchy locally solves the 2D inverse pot

Jorge Kurchan

A scenario for systems with slow dynamics is characterised by stating that there are several temperatures coexisting in the sample, with a single temperature shared by all observables at each (widely separate) time-scale. In preparation for the study of granular rheology, we show within this framework that glassy systems with driving and friction that are ge

Yuji Sugawara

We study the topologically twisted string theory on the general back-ground $AdS_3\times {\cal N}$ which is compatible with the world-sheet N=2 superconformal symmetry and is extensively discussed in the recent works (hep-th/9904024, hep-th/9904040). After summarizing the algebraic structure of the world-sheet topological theory, we show that the space-time

S. A. Abel, B. C. Allanach

We show that the current LEP2 lower bound upon the minimal supersymmetric standard model (MSSM) lightest Higgs mass rules out quasi-fixed scenarios for string scales between 10^6 and 10^{11} GeV unless the heaviest stop mass is more than 2 TeV. We consider the implications of the low string scale for charge and colour breaking (CCB) bounds in the MSSM, and d

Wolfgang Lucha, F. F. Schoberl

Besides perturbation theory, which requires, of course, the knowledge of the exact unperturbed solution, variational techniques represent the main tool for any investigation of the eigenvalue problem of some semibounded operator H in quantum theory. For a reasonable choice of the employed trial subspace of the domain of H, the lowest eigenvalues of H usually

J. E. Avron, A. Elgart

Adiabatic evolutions with a gap condition have, under a range of circumstances, exponentially small tails that describe the leaking out of the spectral subspace. Adiabatic evolutions without a gap condition do not seem to have this feature in general. This is a known fact for eigenvalue crossing. We show that this is also the case for eigenvalues at the thre

Adrian Lange, Bert Reimann, Reinhard Richter

An analytical method within the frame of linear stability theory is presented for the normal field instability in magnetic fluids. It allows to calculate the maximal growth rate and the corresponding wave number for any combination of thickness and viscosity of the fluid. Applying this method to magnetic fluids of finite depth, these results are quantitative

Hiromi Saida, Jiro Soda

For the BTZ black hole in the Einstein gravity, a statistical entropy has been calculated to be equal to the Bekenstein-Hawking entropy. In this paper, the statistical entropy of the BTZ black hole in the higher curvature gravity is calculated and shown to be equal to the one derived by using the Noether charge method. This suggests that the equivalence of t

Makoto Sakaguchi

We provide a classification of the IIB D$p$- and NS$p$-branes in which the brane action exists due to a non-trivial class of the Chevalley-Eilenberg cohomology of free differential algebras. We then present a new geometric formulation of the IIB D$p$- and NS$p$-branes ($p\leq 5$) in which the manifestly superinvariant Wess-Zumino terms are constructed in ter

I. Loutsenko, V. Spiridonov

Similarity symmetries of the factorization chains for one-dimensional differential and finite-difference Schrödinger equations are discussed. Properties of the potentials defined by self-similar reductions of these chains are reviewed. In particular, their algebraic structure, relations to $q$-special functions, infinite soliton systems, supersymmetry, coher

M. Boiti, V. G. Marikhin, F. Pempinelli, A. B. Shabat

We study self-similar solutions of NLS-type dynamical systems. Lagrangian approach is used to show that they can be reduced to three canonical forms, which are related by Miura transformations. The fourth Painleve equation (PIV) is central in our consideration - it connects Heisenberg model, Volterra model and Toda model to each other. The connection between

Marcel Reginatto

The Schrodinger equation can be derived using the minimum Fisher information principle. I discuss why such an approach should work, and also show that the Kahler and Hilbert space structures of quantum mechanics result from combining the symplectic structure of the hydrodynamical model with the Fisher information metric.

B. Roy, P. Roy

We construct even and odd nonlinear coherent states of a parametric oscillator and examine their nonclassical properties.It has been shown that these superpositions exhibit squeezing and photon antibunching which change with time.

J. L. Cohen, B. Dubetsky, P. R. Berman, J. Schmiedmayer

We propose a scheme to create high-contrast, periodic atom density distributions having period $λ/2n$ using the Talbot effect, where $% λ$ is the wave length of the optical fields that scatter the atoms and $n$ is a positive integer. This {\em filtered Talbot lens} is comprised of two standing-wave optical fields. An atomic beam propagates perpendicular to t

Bernhard Haisch, Alfonso Rueda

While still an admittedly remote possibility, the concept of an interstellar mission has become a legitimate topic for scientific discussion as evidenced by several recent NASA activities and programs. One approach is to extrapolate present-day technologies by orders of magnitude; the other is to find new regimes in physics and to search for possible new law

C. G. Bao, T. Y. Shi

An analysis of the channel wave functions is made to clarify the types of resonance emerging from Ps-Ps and Ps-Ps* collisions. The ordering of the energy levels of the states of the dipositronium is evaluated based on the inherent nodal structures of wave functions and on existing theoretical results. A few very probable low-lying narrower resonances, namely

Boris Mordvinov

Relying on a fundamental empirical identity of heavy and inertial mass it is proposed to bring a status of general theory of relativity (GTR) of Einstein up to a level of Unified Field Theory. To do this, a thoroughgoing revision of physical interpretation of energy-momentum tensor components within GTR is required. A complete system of equations for numeric

Martin T. Hill

An all optical set-reset flip flop is presented that is based on two coupled identical laser diodes. The lasers are coupled so that when one of the lasers lases it quenches lasing in the other laser. The state of the flip flop is determined by which laser is currently lasing. Rate equations are used to model the flip flop and obtain steady state characterist

B. G. Sidharth

It is shown that the mysterious quantum prescription of microphysics has analogues at the scale of stars, galaxies and superclusters, the common feature in all these cases being Brownian type fractality. These considerations are shown to lead to pleasingly meaningful results in agreement with observed data.

S. Ishikawa, J. Golak, H. Witala, H. Kamada

Effects of final state interaction on asymmetries in inclusive scattering of polarized electrons on polarized 3He are investigated using consistent 3He bound state wave function and 3N continuum scattering states. Significant effects are found, which influence the extraction of the magnetic neutron form factor from A_T&#39;. The enhancement found experimenta

Osman Yilmaz, Ahmet Gokalp, Serbulent Yildirim, Sakir Ayik

Collisional damping widths of giant dipole excitations are calculated in Thomas-Fermi approximation by employing the microscopic in-medium cross-sections of Li and Machleidt and the phenomenological Gogny force. The results obtained in both calculations compare well, but account for about 25-35% of the observed widths in $^{120}Sn$ and $^{208}Pb$ at finite t

E. Uegaki, Y. Abe

Recent particle-particle-$γ$ coincident measurements on a $^{28}\rm Si+{}^{28}Si$ resonance have suggested &#39;&#39;vanishing spin alignments&#39;&#39;. New analyses for spin alignments by using a molecular model are reported. Different aspects between di-nuclear systems with prolate deformed nuclei and those with oblate deformed nuclei are clarified.

M. Hassaïne, P. A. Horváthy

The symmetries and conserved quantities of Manton&#39;s modified superconductivity model with non-relativistic Maxwell-Chern-Simons dynamics (also related to the Quantized Hall Effect) are obtained in the ``Kaluza-Klein type&#39;&#39; framework of Duval et al.

D. Gieseker

The main object of this paper is to produce a deformation of the KdV hierarchy of partial differential equations. We construct this deformation by taking a certain limit of the Toda hierarchy. This construction also provides a deformation of the Virasoro algebra.

Oleg Gleizer, Alexander Postnikov

The purpose of this paper is to present an interpretation for the decomposition of the tensor product of two or more irreducible representations of GL(N) in terms of a system of quantum particles. Our approach is based on a certain scattering matrix that satisfies a Yang-Baxter type equation. The corresponding piecewise-linear transformations of parameters g

R. E. Borcherds

The aim of this paper is to provide evidence for the following new principle: interesting reflection groups of Lorentzian lattices are controlled by certain modular forms with poles at cusps. We use this principle to explain many of the known examples of such reflection groups, and to find several new examples of reflection groups of Lorentzian lattices, inc

Kai Cieliebak, Ana Rita Gaio, Dietmar A. Salamon

We outline the construction of invariants of Hamiltonian group actions on symplectic manifolds. These invariants can be viewed as an equivariant version of Gromov-Witten invariants. They are derived from solutions of a PDE involving the Cauchy-Riemann operator, the curvature of a connection, and the moment map.

Martin Bendersky, Donald M. Davis

For X a simply-connected finite H-space, there is a Bousfield-Kan spectral sequence which converges to the homotopy of its K-completion. When X=Spin(2n+1), we expect that these homotopy groups equal the v1-periodic homotopy groups in dimension greater than n^2. In this paper, we accomplish two things. (1) We prove that, for any X, the 1-line of this spectral

Marc A. A. van Leeuwen

We define a number of new combinatorial operations on skew semistandard domino tableaux, which together with constructions introduced earlier by C. Carre and B. Leclerc, define an elegant structure on the set of these tableaux, that closely parallels the structure defined in [math.CO/9908099] for ordinary skew semistandard tableaux, that is related to the Li

Vyjayanthi Chari, Naihuan Jing

Using vertex operators, we construct explicitly Lusztig&#39;s $\mathbb Z[q, q^{-1}]$-lattice for the level one irreducible representations of quantum affine algebras of ADE type. We then realize the level one irreducible modules at roots of unity and show that the q-dimension is still given by the Weyl-Kac character formula. As a consequence we also answer t

O. M. Khudaverdian

The action of Batalin-Vilkovisky Delta-operator on semidensities in an odd symplectic superspace is defined. This is used for the construction of integral invariants on surfaces embedded in an odd symplectic superspace and for more clear interpretation of the Batalin-Vilkovisky formalism geometry.

David M. J. Calderbank, Paul Gauduchon, Marc Herzlich

We establish refinements of the classical Kato inequality for sections of a vector bundle which lie in the kernel of a natural injectively elliptic first-order linear differential operator. Our main result is a general expression which gives the value of the constants appearing in the refined inequalities. These constants are shown to be optimal and are comp

J. F. Feinstein, D. W. B. Somerset

Let $A$ be a unital Banach function algebra with character space $Φ_A$. For $x\in Φ_A$, let $M_x$ and $J_x$ be the ideals of functions vanishing at $x$, and in a neighbourhood of $x$, respectively. It is shown that the hull of $J_x$ is connected, and that if $x$ does not belong to the Shilov boundary of $A$ then the set $\{y\inΦ_A: M_x\supseteq J_y\}$ has an

Gilad Lifschytz, Vipul Periwal

We exhibit a nonperturbative background independent dynamical truncation of the string spectrum and a quantization of the string coupling constant directly from the Hamiltonian governing the dynamics of strings constructed from Yang-Mills theories.

Manoelito M. de Souza

A discrete field formalism exposes the physical meaning and origins of gauge fields, their symmetries and singularities. They represent a lack of a stricter field-source coherence.

E. Corrigan, G. W. Delius

We present an investigation of the boundary breather states of the sinh-Gordon model restricted to a half-line. The classical boundary breathers are presented for a two parameter family of integrable boundary conditions. Restricting to the case of boundary conditions which preserve the ϕ--> -ϕsymmetry of the bulk theory, the energy spectrum of the boundary s

Max Zucker

We present some multiplets of N=2 off-shell supergravity in five dimensions. One is the Super Yang-Mills multiplet, another one is the linear multiplet. The latter one is used to establish a general action formula from which we derive an action for the Super Yang-Mills multiplet. The Super Yang-Mills multiplet is used to construct the nonlinear multiplet wit

J. -Q. Liang, H. J. W. Müller-Kirsten, Y. -B. Zhang, A. V. Shurgaia

The periodic bounce configurations responsible for quantum tunneling are obtained explicitly and are extended to the finite energy case for minisuperspace models of the Universe. As a common feature of the tunneling models at finite energy considered here we observe that the period of the bounce increases with energy monotonically. The periodic bounces do no

Marco Aurelio Diaz

In a supersymmetric model where R-Parity and lepton number are violated bilinearly in the superpotential, which can explain the solar and atmospheric neutrino problems, we study the unification of gauge and Yukawa couplings at the GUT scale. We show that bottom-tau Yukawa coupling unification can be achieved at any value of $\tanβ$, and that the strong coupl

A. Makhlin

The possible topology of quantum fluctuations which take place at the earliest stage of high-energy processes is studied. A new exact solution of Yang-Mills equations with fractional topological charge and carrying a single color is found.

A. de la Macorra, G. Piccinelli

We study the cosmological evolution of scalar fields with arbitrary potentials in the presence of a barotropic fluid (matter or radiation) without making any assumption on which term dominates. We determine what kind of potentials V(phi) permits a quintessence interpretation of the scalar field phi and to obtain interesting cosmological results. We show that

E. V. Shuryak

The lattice data on the instanton size distribution suggest an additional O($ρ^2)$ action. The small-$ρ$ effect O($ρ^4)$ predicted by the Operator Product Expansion (OPE) is not observed. Similar deviations are also found for non-perturbative response to a small static color dipoles: it is O(r) not O(r$^2$). We suggest that small instanton radii in the QCD v

K. J. Eskola, K. Kajantie, P. V. Ruuskanen, K. Tuominen

We compute how the initial energy density and produced gluon, quark and antiquark numbers scale with atomic number and beam energy in ultrarelativistic heavy ion collisions. The computation is based on the argument that the effect of all momentum scales can be estimated by performing the computation at one transverse momentum scale, the saturation momentum.

Srubabati Goswami, Debasish Majumdar, Amitava Raychaudhuri

We re-examine vacuum oscillation solutions of the solar neutrino problem taking (a) the results on total rates, electron energy spectrum, and the seasonal variations from the 708 day SuperKamiokande data and (b) those on total rates from the Chlorine and Gallium experiments. Best fit values for the mixing angle and mass splitting are found for oscillations t

R. N. Lee, A. I. Milstein

We manifest the origin of the wrong conclusion made by several groups of authors on the absence of Coulomb corrections to the cross section of the e^+e^- pair production in ultrarelativistic heavy-ion collisions. The source of the mistake is connected with an incorrect passage to the limit in the expression for the cross section. When this error is eliminate

A. Khodjamirian

Light-cone sum rules have proved to be very useful in calculating hadronic matrix elements for exclusive processes. I present recent applications of this method to the pion electromagnetic form factor and to the form factors of $γ^* ρ\to π$ and $γ^*γ\to π^0$ transitions.

J. Blümlein

The status of the resummation of small x contributions to the unpolarized and polarized deep inelastic structure functions is reviewed.

Paul H. Frampton

In this article I describe the recently-conjectured field-string duality which suggests a class of nonsupersymmetric gauge theories which are conformal (CGT) to leading order of 1/N and some of which may be conformal for finite N. If the standard model becomes conformal at TeV scales, model-building on this basis is an interesting direction. Some remarks are

Wojciech Broniowski

Gauging of effective chiral quark models with non-local regulators is discussed in the context of solitons. In particular, we show that with the P-exponent method the current algebra is satisfied and the charges are properly quantized.

E. Ruiz Morales, M. E. Peskin

We study the process $W^+ W^- \to t \bar t$ in several models of strong interaction electroweak symmetry breaking. We calculate the signals that can be expected by observing the reaction $e^+ e^- \to ν\barνt \bar t$ at an $e^+ e^-$ linear collider with 1.5 TeV center of mass energy. We also discuss how the lowest-lying resonances predicted by these models co

J. I. Skullerud, A. G. Williams

The quark propagator is calculated in the Landau gauge at beta=6.0. A method for removing the dominant, tree-level lattice artefacts is presented, enabling a calculation of the momentum-dependent dynamical quark mass.

D. Pekurovsky

This thesis presents the setup and results of numerical calculation of hadronic matrix elements of Delta S=1 weak operators, with the aim of studying the Delta I=1/2 rule and direct CP violation. Such study provides a useful comparison of the Standard Model predictions with experiment. We work within the framework of (partially quenched) Lattice QCD with the

George R. Fleming

In the domain wall fermion formulation, chiral symmetry breaking in full QCD is expected to fall exponentially with the length of the extra dimension. We measure the chiral symmetry breaking due to a finite extra dimension in two ways, which can be affected differently by finite volume and explicit fermion mass. For quenched QCD the two methods generally agr

Saumen Datta, R. V. Gavai

Adding separate chemical potentials lambda and gamma for Z2 monopoles and vortices respectively in the Villain form of the mixed fundamental-adjoint action for the SU(2) lattice gauge theory, we investigate their role in the interplay between the deconfinement and bulk phase transitions using Monte Carlo techniques. Setting lambda to be nonzero, we find that

V. Gimenez, L. Giusti, F. Rapuano, G. Martinelli

By combining the first unquenched lattice computation of the B-meson binding energy with the recently calculated two-loop contribution to the lattice HQET mass, we determine the $\bar{MS}$ b-quark mass, $\bar{m}_{b}(\bar{m}_{b})$ at the NNLO. We find $\bar{m}_{b}(\bar{m}_{b}) = (4.26\pm 0.03 \pm 0.04 \pm 0.05) {\rm GeV}$. The inclusion of the two-loop effect

YBJ Collaboration

A 50 m**2 RPC carpet was operated at the YangBaJing Cosmic Ray Laboratory (Tibet) located 4300 m a.s.l. The performance of RPCs in detecting Extensive Air Showers was studied. Efficiency and time resolution measurements at the pressure and temperature conditions typical of high mountain laboratories, are reported.

L. K. Patel, R. Tikekar, Naresh Dadhich

A generalization of the McVittie solution, representing spacetime of a mass particle placed in (n+2) dimensional Robertson-Walker universe is reported.

L. K. Patel, Naresh Dadhich

A large family of inhomogeneous non-static spherically symmetric solutions of the Einstein equation for null fluid in higher dimensions has been obtained. It encompasses higher dimensional versions of many previously known solutions such as Vaidya, charged Vaidya and Husain solutions and also some new solutions representing global monopole or string dust. It

Naresh Dadhich

By resolving the Riemann curvature relative to a unit timelike vector into electric and magnetic parts, we consider duality relations analogous to the electromagnetic theory. It turns out that the duality symmetry of the Einstein action implies the Einstein vacuum equation without the cosmological term. The vacuum equation is invariant under interchange of a

Naresh Dadhich, L. K. Patel

By decomposing the Riemann curvature into electric and magnetic parts, we define the gravoelectric duality transformation by interchange of active and passive electric parts which amounts to interchange of the Ricci and Einstein tensors. It turns out that the vacuum equation is duality-invariant. We obtain solutions dual to the Kerr solution by writing an ef

Miroslav Sukenik, Jozef Sima

In the expansive nondecelerative universe model, creation of matter occurs due to which the Vaidya metrics is applied. This fact allows for localizing gravitational energy and calculating the energy of gravitational waves using an approach alternative to the well established procedure based on quadrupole formula. Rationalization of the gradual increase in en

Naresh Dadhich, L. K. Patel, R. Tikekar

By application of the duality transformation, which implies interchange of active and passive electric parts of the Riemann curvature (equivalent to interchange of Ricci and Einstein tensors) it is shown that the global monopole solution in the Kaluza-Klein spacetime is dual to the corresponding vacuum solution. Further we also obtain solution dual to flat s