June 1995 arXiv papers — page 3

Thibault Damour, Gilles Esposito-Farese

A new, field-theory-based framework for discussing and interpreting tests of gravity, notably at the second post-Newtonian (2PN) level, is introduced. Contrary to previous frameworks which attempted at parametrizing any conceivable deviation from general relativity, we focus on the best motivated class of models, in which gravity is mediated by a tensor fiel

Giampiero Esposito, Alexander Yu. Kamenshchik

The well-known discrepancies between covariant and non-covariant formalisms in quantum field theory and quantum cosmology are analyzed by focusing on the Coulomb gauge for vacuum Maxwell theory. On studying a flat Euclidean background with boundaries, the corresponding mode-by-mode analysis of one-loop quantum amplitudes agrees with the results of the Schwin

Giampiero Esposito, Alexander Yu. Kamenshchik, Igor V. Mishakov, Giuseppe Pollifrone

Zeta-function regularization is applied to complete a recent analysis of the quantized electromagnetic field in the presence of boundaries. The quantum theory is studied by setting to zero on the boundary the magnetic field, the gauge-averaging functional and hence the Faddeev-Popov ghost field. Electric boundary conditions are also studied. On considering t

Giampiero Esposito

This paper studies the one-loop expansion of the amplitudes of electromagnetism about flat Euclidean backgrounds bounded by a 3-sphere, recently considered in perturbative quantum cosmology, by using zeta-function regularization. For a specific choice of gauge-averaging functional, the contributions to the full zeta value owed to physical degrees of freedom,

Vicente Pleitez

It is pointed out that if gravitational interactions among ordinary bodies propagate in extra space-time dimensions the velocity of gravitational waves in vacuum could be different from the speed of light $c$.

Giampiero Esposito, Giuseppe Pollifrone

Local boundary conditions involving field strengths and the normal to the boundary, originally studied in anti-de Sitter space-time, have been recently considered in one-loop quantum cosmology. This paper derives the conditions under which spin-lowering and spin-raising operators preserve these local boundary conditions on a 3-sphere for fields of spin 0,1/2

Giampiero Esposito, Giuseppe Pollifrone

Local boundary conditions involving field strengths and the normal to the boundary, originally studied in anti-de Sitter space-time, have been recently considered in one-loop quantum cosmology. This paper derives the conditions under which spin-raising operators preserve these local boundary conditions on a 3-sphere for fields of spin 0,1/2,1,3/2 and 2. More

Bart A. van Tiggelen, Roger Maynard, Theo M. Nieuwenhuizen

We present a microscopic theory for multiple light scattering occurring in inhomogeneous 3D media subject to an external magnetic field. Magneto-optical effects (the Faraday effect and the Cotton-Mouton effect) occur inside the small inhomogeneities. We thereby take into account the spatial anisotropy, time-reversal-symmetry breaking and birefringence caused

L. Frachebourg, P. L. Krapivsky, S. Redner

We introduce a simple model of heterogeneous catalysis on a disordered surface which consists of two types of randomly distributed sites with different adsorption rates. Disorder can create a reactive steady state in situations where the same model on a homogeneous surface exhibits trivial kinetics with no steady state. A rich variety of kinetic behaviors oc

R. M. L. Evans

A theoretical study of vesicles of topological genus zero is presented. The bilayer membranes forming the vesicles have various degrees of intrinsic (tangent-plane) orientational order, ranging from smectic to hexatic, frustrated by curvature and topology. The field-theoretical model for these `$n$-atic' surfaces has been studied before in the low temper

M. G. Baring, A. K. Harding

The recent association of soft gamma repeaters (SGRs) with counterparts in other wavebands has sparked much interest in these sources. One of the recent models for these objects is that they originate in the environs of neutron stars with fields much stronger than the quantum critical field \teq{B_{cr}=4.413\times 10^{13}} Gauss. Near such neutron stars, dub

M. Fukugita, E. L. Turner

In the now well established conventional view (see Rees [1] and references therein), quasi-stellar objects (QSOs) and related active galactic nuclei (AGN) phenomena are explained as the result of accretion of plasma onto giant black holes which are postulated to form via gravitational collapse of the high density regions in the centers of massive host galaxi

Andrea Comastri, Silvano Molendi, Gabriele Ghisellini

ROSAT observations of a homogeneous sample of radio--selected BL Lac objects are presented. Results of a detailed spectral analysis in the soft 0.1-2.0 keV energy range are discussed and compared with similar previously published results. The X--ray spectral shape is discussed in relation to the overall energy distribution with particular emphasys on the hig

J. Perez--Mercader, T. Goldman, D. Hochberg, R. Laflamme

The partition function of a system of galaxies in gravitational interaction can be cast in an Ising Model form, and this reformulated via a Hubbard--Stratonovich transformation into a three dimensional stochastic and classical scalar field theory, whose critical exponents are calculable and known. This allows one to {\it compute\/} the galaxy to galaxy corre

Eduardo Cattani, David Cox, Alicia Dickenstein

We study residues on a complete toric variety X, which are defined in terms of the homogeneous coordinate ring of X. We first prove a global transformation law for toric residues. When the fan of the toric variety has a simplicial cone of maximal dimension, we can produce an element with toric residue equal to 1. We also show that in certain situations, the

R. S. Chivukula, E. H. Simmons, J. Terning

Using precision electroweak data, we put limits on non-commuting extended technicolor models. We conclude that these models are viable only if the ETC interactions are strong. Interestingly, these models predict a pattern of deviations from the standard model which can fit the data significantly better than the standard model does, even after taking into acc

G. M. Gandenberger, N. J. MacKay

We conjecture an exact S-matrix for the scattering of solitons in $d_{n+1}^{(2)}$ affine Toda field theory in terms of the R-matrix of the quantum group $U_q(c_n^{(1)})$. From this we construct the scattering amplitudes for all scalar bound states (breathers) of the theory. This S-matrix conjecture is justified by detailed examination of its pole structure.

Ruth Gregory, Mark Hindmarsh

We construct two possible metrics for abelian Higgs vortices with ends on black holes. We show how the detail of the vortex fields smooths out the nodal singularities which exist in the idealized metrics. A corollary is that apparently topologically stable strings might be able to split by black hole pair production. We estimate the rate per unit length by r

H. -C. Kim, M. V. Polyakov, A. Blotz, K. Goeke

We investigate the magnetic moments of the SU(3) octet baryons in the framework of the $SU(3)$ semibosonized Nambu--Jona--Lasinio model. The rotational $1/N_c$ corrections and strange quark mass in linear order are taken into account. We derive general relations between magnetic moments of the SU(3) octet baryons, based on the symmetry of our model. These re

Michael H. Seymour, CERN

Many analyses at the collider utilize the hadronic jets that are the footprints of QCD partons. These are used both to study the QCD processes themselves and increasingly as tools to study other physics, for example top mass reconstruction. However, jets are not fundamental degrees of freedom in the theory, so we need an {\em operational jet definition} and

Phil E. Gibbs

This essay is a tour around many of the lesser known pregeometric models of physics, as well as the mainstream approaches to quantum gravity, in search of common themes which may provide a glimpse of the final theory which must lie behind them.

Mark Gross

This paper first generalises the Bogomolov-Tian-Todorov unobstructedness theorem to the case of Calabi-Yau threefolds with canonical singularities. The deformation space of such a Calabi-Yau threefold is no longer smooth, but the general principle is that the obstructions to deforming such a threefold are precisely the obstructions to deforming the singulari

Toshiki Nakashima

Crystal base of the level 0 part of the modified quantum affine algebra $\widetilde U_q(\widehat{sl_2})_0$ is given by path. Weyl group actions, extremal vectors and crystal structure of all irreducible components are described explicitly.

S. Kharchev, S. Khoroshkin, D. Lebedev

An interpretation of Hirota bilinear relations for classical $τ$ functions is given in terms of intertwining operators. Noncommutative example of $U_q(sl_2)$ is presented.

Susumu Ariki, Tatsuhiro Nakajima, Hiro-Fumi Yamada

The reduced Schur functions are studied. Their relations to the basic representation of $A^(1)_{r-1}$ and modular representations of the symmetric groups are clarified. Littlewood-Richardson coefficients appear in the linear relations among reduced Schur functions.

Teruhisa S. Komatsu, Shin-ichi Sasa

We study traffic congestion by analyzing a one dimensional traffic flow model. Developing an asymptotic method to investigate the long time behavior near a critical point, we derive the modified Korteweg-de Vries (mKdV) equation as the lowest order model. There are an infinite number of kink solitons to the mKdV equation, while it has been found by numerical

Thomas D. Cohen, Gerald A. Miller

The role of the off-shell dependence of $ρ-ω$ mixing in the charge symmetry breaking nucleon-nucleon potential is discussed. It is shown that models describing the off-shell dependence of $ρ-ω$ mixing are not sufficient to determine the charge symmetry breaking nucleon-nucleon potential.

J. E. Seger, A. B. Balantekin

The Hamiltonian describing fermion pair production from an arbitrarily time-varying electric field in two dimensions is studied using a group-theoretic approach. We show that this Hamiltonian can be encompassed by two, commuting SU(2) algebras, and that the two-dimensional problem can therefore be reduced to two one-dimensional problems. We compare the group

Seung Hwan Son

This short article presents a table of new equations which can be regarded as the generalized equations of the dispersionless limit of several nonlinear equations. From the definition expressed in an algebraic formula, one can get an equation for any positive numbers p and q. The equations were calculated by using the computers and were examined by hand-calc

Hsien-Chung Kao, Kimyeong Lee, Taejin Lee

We study one-loop correction to the Chern-Simons coefficient $κ=k/4π$ in $N=1,2,3$ supersymmetric Yang-Mills Chern-Simons systems. In the pure bosonic case, the shift of the parameter $k$ is known to be $k\rightarrow k + c_v$, where $c_v$ is the quadratic Casimir of the gauge group. In the $N=1$ case, the fermionic contribution cancels the bosonic contributi

Fermin Aldabe

We present the Higgs mechanism in (0,2) compactifications. The existence of a vector bundle data duality (VBDD) in $(0,2)$ compactifications which is present at the Landau-Ginzburg point allows us to connect in a smooth manner theories with different gauge groups with the same base manifold and same number of effective generations. As we move along the Kahle

Atsuo Kuniba, Yasuhiro Ohta, Junji Suzuki

Analytic Bethe ansatz is executed for a wide class of finite dimensional $U_q(B^{(1)}_r)$ modules. They are labeled by skew-Young diagrams which, in general, contain a fragment corresponding to the spin representation. For the transfer matrix spectra of the relevant vertex models, we establish a number of formulae, which are $U_q(B^{(1)}_r)$ analogues of the

Hyeonjoon Shin, Young-Jai Park, Yongduk Kim, Won T. Kim

We show that the anomaly of nonlocal symmetry can be canceled by the well-known Wess-Zumino acton which cancels the gauge anomaly in the two-dimensional chiral electrodynamics.

Atish Dabholkar

It is shown that the heterotic string emerges as a soliton in the type I superstring theory in ten dimensions. The collective coordinates of the soliton are described by a smooth, chiral worldsheet theory. There are eight bosonic and eight right-moving fermionic zero modes that arise from the partially broken supertranslations. In addition, there are 496 cha

Howard E. Haber

A four generation supersymmetric model is proposed, in which the Tevatron ``top-quark'' events are reinterpreted as the production of $t^\prime$ which decays dominantly to $bW^+$. In this model, $m_t\simeq m_W$, and $t\rta\widetilde t\widetildeχ^0_1$, with $\widetilde t\rta c\widetildeχ^0_1$. This decay chain, which rarely produces a hard isolated le

Yu. L. Dokshitzer, V. A. Khoze, S. I. Troyan

Perturbative QCD formula for inclusive energy spectra of heavy quarks from heavy quark initiated jets which takes into account collinear and/or soft logarithms in all orders, the exact first order result and two-loop effects is applied to distributions of heavy flavoured hadrons in the framework of the LPHD concept. Fits to experimentally measured charm and

J. D. Manjavidze

The aim of the article is to construct the S-matrix interpretation of the perturbation theory for the Wigner functions generating functional at a finite temperature. The temperature is introduced in the theory by the way typical for the microcanonical description. The perturbation theory contains the two-temperature Green functions. The two possible boundary

A. D. Martin, W. J. Stirling, R. G. Roberts

We perform next-to-leading order global analyses of deep inelastic and related data for different fixed values of $α_S (M_Z^2)$. We present sets of parton distributions for six values of $α_S$ in the range 0.105 to 0.130. We display the $(x, Q^2)$ domains with the largest parton uncertainty and we discuss how forthcoming data may be able to improve the deter

V. Barone, U. D'alesio, M. Genovese

We present a QCD analysis of the strange and charm contributions to the neutrino deep inelastic structure function $xF_3$. We show that next-to-leading order effects, which are relatively important for $F_2$, play a lesser role in the case of $xF_3$. The neutrino--antineutrino difference $xF_3^ν - xF_3^{\bar ν}$ provides a new determination of the strange de

F. Illuminati, A. Riotto

We investigate the role played by subcritical bubbles at the onset of the electroweak phase transition. Treating the configuration modelling the thermal fluctuations around the homogeneous zero configuration of the Higgs field as a stochastic variable, we describe its dynamics by a phenomenological Langevin equation. This approach allows to properly take int

N. J. Cornish, J. W. Moffat

We critically examine the claim made by Burko and Ori that black holes are expected to form in nonsymmetric gravity and find their analysis to be inconclusive. Their conclusion is a result of the approximations they make, and not a consequence of the true dynamics of the theory. The approximation they use fails to capture the crucial equivalence principle vi

Giampiero Esposito

This paper describes recent progress in the analysis of relativistic gauge conditions for Euclidean Maxwell theory in the presence of boundaries. The corresponding quantum amplitudes are studied by using Faddeev-Popov formalism and zeta-function regularization, after expanding the electromagnetic potential in harmonics on the boundary 3-geometry. This leads

Jae-Kwon Kim

For the two dimensional randomly disordered three-state Potts ferromagnet, we find numerically that the critical exponent $η$ unchanges with the degree of disorder while those of the correlation length ($ν$) and magnetic susceptibility ($γ$) increase with it continuously. We discuss some consequences of the finding.

C. L. Kane, Matthew P. A. Fisher

We develop a simple kinetic equation description of edge state dynamics in the fractional quantum Hall effect (FQHE), which allows us to examine in detail equilibration processes between multiple edge modes. As in the integer quantum Hall effect (IQHE), inter-mode equilibration is a prerequisite for quantization of the Hall conductance. Two sources for such

K. N. Ilinski, J. M. F. Gunn

The discussion of Fractional dimensional Hilbert spaces in the context of Haldane exclusion statistics is extended from the case \cite{IG} of $g=1/p$ for the statistical parameter to the case of rational $g=q/p$ with $q,p$-coprime positive integers. The corresponding statistical mechanics for a gas of such particles is constructed. This procedure is used to

Vladimir Pericliev

A discovery system for detecting correspondences in data is described, based on the familiar induction methods of J. S. Mill. Given a set of observations, the system induces the ``causally'' related facts in these observations. Its application to empirical linguistic discovery is described.

J. Siebert, M. Matsuoka, W. Brinkmann, M. Cappi

ASCA observations of 4 high redshift radio--loud quasars with 1.44$<$z$<$3.21 are presented. The spectral analysis for three of them (PKS 0332-403, PKS 0537-286, PKS 2149-306) reveals that their X-ray continuum emission is well represented by a simple power--law model plus absorption with photon indices of $Γ=1.92^{+0.30}_{-0.20}$ (PKS 0332-403), $Γ=1.63^{+0

J. G. Bartlett, D. Barbosa, A. Blanchard

We present an argument for a {\it lower limit} to the Compton-$y$ parameter describing spectral distortions of the cosmic microwave background (CMB). The absence of a detectable Gunn-Peterson signal in the spectra of high redshift quasars demands a high ionization state of the intergalactic medium (IGM). Given an ionizing flux at the lower end of the range i

John N. Bahcall, Jacqueline Bergeron, Alec Boksenberg, George F. hartig

We present evidence that clumps of \lya lines are physically associated with about half of the extensive metal-line systems (absorption systems with four or more observed metal-line species) found in this paper, demonstrate that all four \lylimit systems discussed here correspond to extensive metal-line absorption systems, and present an extraordinary pair o

G. K. T. Hau, H. C. Ferguson, O. Lahav, D. Lynden-Bell

We have visually examined twelve Palomar red Plates for galaxies at low Galactic latitude b, where the Supergalactic Plane (SGP) is crossed by the Galactic Plane (GP), at Galactic longitude l ~135 degrees. The catalogue consists of 2575 galaxy candidates, of which 462 have major axis diameters d >= 0.8 arc min (uncorrected for extinction). Galaxy candidates

Emmanuel Davoust

This is a presentation of the purpose of astronomy in the context of modern society. After exposing two misconceptions about astronomy, I detail its role in five domains, certified knowledge, incorporated abilities, innovations, collective goods, and popular science; with each domain is associated an institution, an incentive, and a method of evaluation. Fin

Sebastien Morel, Emmanuel Davoust

We present a software package for combining three monochromatic images of an astronomical object into a trichromatic color image. We first discuss the meaning of &#34;true&#34; colors in astronomical images. We then describe the different steps of our method, choosing the relevant dynamic intensity range in each filter, inventorying the different colors, opt

H. Lange

The paper studies a rank 2 vector bundle on P1 x P3. Similarly to the Horrocks - Mumford bundle on P4 this vector bundle encodes a lot of geometric information. It is defined via the Serre construction by an abelian surface in P1 x P3. The bundle is stable with respect to O(1,1), its jumping lines are determined. Morover it is shown that it is closely relate

Jan Finjord

The two-parent reproduction model of Derrida and Peliti is simulated on a rugged fitness landscape. Fixed fitness values for each possible genotype are assigned randomly, with all fit individuals having the same probability of reproduction. The previously observed transition to a self-organized state of the population with less recombinational load, implies

Irina A. Korchemskaya

We consider elastic quark-quark scattering at high energy with fixed momentum transfer $t$ and perform factorization of soft-gluon exchanges into a vacuum expectation value of Wilson lines. Taking into account nonperturbative corrections whose structure is predicted from infrared renormalon analysis, we represent the scattering amplitude as an asymptotic ser

Michiaki Takama

We present a theory of &#39;maximal&#39; super-KP(SKP) hierarchy whose flows are maximally extended to include all those of known SKP hierarchies, including, for example, the MRSKP hierarchy of Manin and Radul and the Jacobian SKP(JSKP) introduced by Mulase and Rabin. It is shown that SKP hierarchies has a natural field theoretic description in terms of the

Mitsuko Abe

We classify the moduli spaces of the four-dimensional topological half-flat gravity models by using the canonical bundle. For a K3-surface or four-dimensional torus, they describe an equivalent class of a trio of the Einstein-Kahler forms ( the hyperkahler forms ). We calculate the dimensions of these moduli spaces by using the Atiyah-Singer Index theorem. W

Jùn Líu

We study a generalization of Aharonov-Bohm effect, the potential effect. The discussion is focused on field-free effects in simply connected region, which obviously can not have any local field-flux. Among the published discussions about this kind of effects, it is generally agreed that this kind of effects does not exist due to gauge invariance. However, th

A. Hebecker

The electroweak phase transition is investigated by means of the perturbatively calculated high temperature effective potential. An analytic result to order $g^4,λ^2$ is presented for the Abelian Higgs model, the SU(2)-Higgs model and the standard model and a complete on-shell renormalization at zero temperature is performed. Higher order corrections are fou

Alexander Reznikov

We address two fundamental and well-known problems of Gromov and Lyndon: \demo{Problem A} (Gromov, see [5]). Consider a category $M_n$ of closed manifolds of dimension $n$ with nonzero-degree ways as morphisms. Study a partial order $M \ge N \Leftrightarrow Mor (M, N) \neq ϕ$. For which $N$ the degrees of maps $f: M \to N$ are bounded for all $M$? \demo{Prob

Isa Kh. Zharekeshev, Bernhard Kramer

Using the level--spacing distribution and the total probability function of the numbers of levels in a given energy interval we analyze the crossover of the level statistics between the delocalized and the localized regimes. By numerically calculating the electron spectra of systems of up to $32^3$ lattice sites described by the Anderson Hamiltonian it is sh

Xiangdong Shi, Lawrence M. Widrow, L. Jonathan Dursi

Recent observations of Cepheids in the Virgo cluster have bolstered the evidence that supports a Hubble constant in 70-90 km/s/Mpc range. This evidence, by and large, probes the expansion of the Universe within 100 Mpc. We investigate the possibility that the expansion rate within this region is systematically higher than the true expansion rate due to the p

I. Grojnowski

This is the first in a series of papers which describe the action of an affine Lie algebra with central charge $n$ on the moduli space of $U(n)$-instantons on a four manifold $X$. This generalises work of Nakajima, who considered the case when $X$ is an ALE space. In particular, this describes the combinatorial complexity of the moduli space as being precise

Joannis Papavassiliou, Apostolos Pilaftsis

A gauge-independent approach to resonant transition amplitudes with nonconserved external currents is presented, which is implemented by the pinch technique. The analytic expressions derived with this method are $U(1)_{em}$ invariant, independent of the choice of the gauge-fixing parameter, and satisfy a number of required theoretical properties, including u

Alexei Yu. Smirnov, Francesco Vissani

We consider a possibility that $R$-parity violating interactions of particles which do not involve the first generation have large (up to 1) coupling constants, $Λ$. Such couplings, if exist, could have a number of phenomenological consequences: renormalization of $b-τ$ mass ratio, generation of $ν_τ$ mass in MeV region, {\em etc.}. In Grand Unified models,

H. D. Dahmen, S. Marculescu, T. Portmann

The four-dimensional topological Yang-Mills theory with two anticommuting charges is naturally formulated on Kähler manifolds. By using a superspace approach we clarify the structure of the Faddeev-Popov sector and determine the total action. This enables us to perform perturbation theory around any given instanton configuration by manifestly maintaining all

Jae-weon Lee, In-guy Koh

An inflation model with inverse symmetry breaking of two scalar fields is proposed. Constraints on the parameters for a successful inflation are obtained. In general the inequality $λ_1\ll g <λ_2$ should be satisfied, where $λ_{1,2}$ and $g$ are the coupling constants for self interaction and mutual interaction of two scalar fields respectively. An example w

Eric D&#39;Hoker

We propose actions for non-linear sigma models on cosets $G/H$ in 2+1 dimensions that include the most general non-linear realizations of Chern-Simons terms. When $G$ is simply connected and $H$ contains $r$ commuting U(1) factors, there are $r$ different topologically conserved charges and generically $r$ different types of topological solitons. Soliton spi

Lizeng Zhang

We propose a fermion Chern-Simons field theory describing two- dimensional electrons in the lowest Landau level. This theory is constructed with a complete set of states, and the lowest Landau level constraint is enforced through a delta-functional described by an auxiliary field lambda. Unlike the field theory constructed directly with the states in the low

Rudolf A. Römer, Alexander Punnoose

We consider a one-dimensional mesoscopic Hubbard ring with and without disorder and compute charge and spin stiffness as a measure of the permanent currents. For finite disorder we identify critical disorder strength beyond which the charge currents in a system with repulsive interactions are {\em larger} than those for a free system. The spin currents in th

Daniel Ansari

This study is centred on the generation of instructions for household appliances. We show how knowledge about a device, together with knowledge about the environment, can be used for reasoning about instructions. The information communicated by the instructions can be planned from a version of the knowledge of the artifact and environment. We present the lat

Harold Steinacker

Invariant integrals of functions and forms over $q$ - deformed Euclidean space and spheres in $N$ dimensions are defined and shown to be positive definite, compatible with the star - structure and to satisfy a cyclic property involving the $D$ - matrix of $SO_q(N)$. The definition is more general than the Gaussian integral known so far. Stokes theorem is pro

L. H. Ford, Thomas A. Roman

In this paper the averaged weak (AWEC) and averaged null (ANEC) energy conditions, together with uncertainty principle-type restrictions on negative energy (``quantum inequalities&#39;&#39;), are examined in the context of evaporating black hole backgrounds in both two and four dimensions. In particular, integrals over only half-geodesics are studied. We det

Xiangdong Ji

After making some critical comments about the traditional method of extracting the gluon condensate from lattice QCD data, I present an alternative analysis. The result is more than a factor of five larger than the phenomenological value. Two closely related subjects, the effects of the infrared renormalons on the extraction and the Lepage and Mackenzie impr

A. Efremov, D. Kharzeev

We demonstrate that the non-trivial CP-violating structure of QCD vacuum can lead to an observable effect in $e^+e^-\to q\bar q\to 2$-jet annihilation. We find that the sign of the jet handedness correlation can be opposite to that predicted by factorization of $q~\bar q$ fragmentation and CP-conjugation of the two jets. A simple model estimation of the hand

C. Dariescu, S. Hamamoto, Marina-Aura Dariescu

We present a toy model approach to the canonical non-perturbative quantization of the spatially-flat Robertson-Walker Universes with cosmological constant, based on the fact that such models are exactly solvable within the framework of a simple Lagrangian formulation. The essential quantum dynamical metric-field and the corresponding Hamiltonian, explicitly

Geir Ellingsrud, Lothar Göttsche

We study the Donaldson invariants of rational surfaces and their dependence on the chambers in the ample cone. We build on a previous joint paper in which we have expressed the change of the Donaldson invariants on an algebraic surface $S$ under crossing a so-called good wall in terms of certain intersection numbers on Hilbert schemes of points on $S$. In th

A. A. Bel&#39;kov, A. V. Lanyov, S. Scherer

We discuss the processes $γγ\toπ^0π^0$ and $η\toπ^0 γγ$ at $O(p^6)$ in the momentum expansion. The calculation involves tree--level, one--loop and two--loop diagrams of a chiral effective lagrangian which is obtained by a bosonization of the NJL model. The importance of integrating out meson resonances (reduction) is pointed out. Our final results for the to

Murray A. Moinester

Possible experimental searches of doubly charmed baryons and tetraquarks at fixed target experiments with high energy hadron beams and a high intensity spectrometer are considered here. The baryons considered are: $Ξ_{cc}^{+}$ (ccd), $Ξ_{cc}^{++}$ (ccu), and $Ω_{cc}^{+}$ (ccs); and the tetraquark is T ($cc\bar{u}\bar{d}$). Estimates are given of masses, life

C. S. Kim, Jake Lee

The transverse momentum distribution of single vector boson production at hadron colliders provides useful ways of testing the Standard Model and searching new physics beyond the Standard Model. We study large $p_{_T}$ hadroproduction of $Z$-boson as a probe of gluon distributions inside proton. We investigate how to get initial gluon-involving contributions

Lothar Göttsche

We study the Donaldson invariants of simply connected $4$-manifolds with $b_+=1$, and in particular the change of the invariants under wall-crossing. We assume the conjecture of Kotschick and Morgan about the shape of the wall-crossing terms (which Oszvath and Morgan are now able to prove), and are determine a generating function for the wall-crossing terms

Valeri Gritsenko, Klaus Hulek

In this paper we study the maximal extension $Γ_t^*$ of the subgroup $Γ_t$ of $\operatorname{Sp}_4 (\bq)$ which is conjugate to the paramodular group. The index of this extension is $2^{ν(t)}$ where $ν(t)$ is the number of prime divisors of $t$. The group $Γ_t^*$ defines the minimal modular threefold ${\Cal A}_t^*$ which is a finite quotient of the moduli sp

Thomas Ackermann

In this note we explain the relationship of the Wodzicki residue of (certain powers of) an elliptic differential operator $P$\ acting on sections of a complex vector bundle $E$\ over a closed compact manifold $M$\ and the asymptotic expansion of the trace of the corresponding heat operator $e^{-tP}$. In the special case of a generalized laplacian $\triangle$

Mark D. Gould, Jon R. Links, Yao-Zhong Zhang

We present the eigenvalues of the Casimir invariants for the type I quantum superalgebras on any irreducible highest weight module.

Eric Bergshoeff, Bert Janssen, Tomas Ortin

We study exhaustively the solution-generating transformations (dualities) that occur in the context of the low-energy effective action of superstring theory. We first consider target-space duality (``T duality&#39;&#39;) transformations in absence of vector fields. We find that for one isometry the full duality group is (SO^{\uparrow}(1,1))^{3} x D_{4}, the

R. Bousso, S. W. Hawking

We consider two quantum cosmological models with a massive scalar field: an ordinary Friedmann universe and a universe containing primordial black holes. For both models we discuss the complex solutions to the Euclidean Einstein equations. Using the probability measure obtained from the Hartle-Hawking no-boundary proposal, we find that the only unsuppressed

P. Nattermann

For the family of nonlinear Schrödinger equations derived by H.-D.~Doebner and G.A.~Goldin (J.Phys.A 27, 1771) we calculate the complete set of Lie symmetries. For various subfamilies we find different finite and infinite dimensional Lie symmetry algebras. Two of the latter lead to a local transformation linearizing the particular subfamily. One type of thes

M. G. Mustafa, A. Ansari

Considering massless $u$ and $d$ quarks, and massive (150 MeV) $s$ quarks in a bag with the bag pressure constant $B^{1/4} = 145$ MeV, a colour-singlet grand canonical partition function is constructed for temperatures $T = 1-30$ MeV. Then the stability of finite size strangelets is studied minimizing the free energy as a function of the radius of the bag. T

Yung Jo, Chang-Yong Lee

It has recently been proven from measurements of the spin-transfer coefficients $D_{xx}$ and $D_{zz}$ that there is a small but non-vanishing $ΔS=0$ component $σ_{0}$, in the inclusive $p(p,n)Nπ\,$ reaction cross section $σ\,$. It is shown that the dominant part of the measured $σ_{0}$ can be explained in terms of the projectile $Δ$ excitation mechanism. An

M. S. Fayache, S. Shelly Sharma, L. Zamick

An interaction $-χQ\cdot Q(1+B\vecτ(1)\cdot \vecτ(2))$ is used in a shell model calculation for $^{10}Be$. Whereas for $B=0$ the $2_1^+$ state is two-fold degenerate, introducing a negative $B$ causes an `isovector&#39; $2^+$ state to come down to zero energy at $B=-0.67$ and an $S=1~L=1$ triplet ($J=0^+,~1^+,~2^+$) to come down to zero energy at $B=-0.73$.

Doron Zeilberger

Fred Galvin&#39;s amazing proof of the Dinitiz conjecture is used to illustrate the method of undetermined generalization and specialization.

Tomasz Dubejko

A Bl-packing is a (branched) circle packing that ``properly covers&#39;&#39; the unit disc. We establish some fundamental properties of such packings. We give necessary and sufficient conditions for their existence, prove their uniqueness, and show that their underlying surfaces, known as carriers, are quasiconformally equivalent to surfaces of classical Bla

Lin-Yuan Chen, Nigel Goldenfeld, Y. Oono

Perturbative renormalization group theory is developed as a unified tool for global asymptotic analysis. With numerous examples, we illustrate its application to ordinary differential equation problems involving multiple scales, boundary layers with technically difficult asymptotic matching, and WKB analysis. In contrast to conventional methods, the renormal

Kris Thielemans

String theory is currently the most promising theory to explain the spectrum of the elementary particles and their interactions. One of its most important features is its large symmetry group, which contains the conformal transformations in two dimensions as a subgroup. At quantum level, the symmetry group of a theory gives rise to differential equations bet

P. Mitra

In this talk, we briefly review the basic concepts of anomalous gauge theories. It has been known for some time how theories with local anomalies can be handled. Recently it has been pointed out that global anomalies, which obstruct the quantization of certain gauge theories in the temporal gauge, get bypassed in canonical quantization.

Takeo Inami, Satoru Odake, Yao-Zhong Zhang

Integrability and supersymmetry of the supersymmetric extension of the sine-Gordon theory on a half-line are examined and the boundary potential which preserves both the integrability and supersymmetry on the bulk is derived. It appears that unlike the boundary bosonic sine-Gordon theory, integrability and supersymmetry strongly restrict the form and paramet

D. J. Summers

We calculate decays of a Standard Model Higgs boson to a virtual massive particle and discuss how this depends on the massive particle total width. If the partial width of Higgs to a virtual massive particle can be measured this gives a measurement of that massive particle&#39;s width. We discuss how one would go about measuring these partial widths of a Hig

Tadashi Yoshikawa

We study the effect of the diagonal extended technicolor(ETC) gauge boson on the oblique correction parameters. It is shown that in the $T$ parameter is unacceptably large when the $Zbb$ vertex correction and $S$ parameter are consistent with the experiments in the ETC model.

S. V. Bashinsky, B. Kerbikov

We develop a general framework to study KKbar threshold phenomena with resonances f0, a0 and K+K- atom included. Based on this formalism we predict that the production of the K+K- atom in p+d=3He+X and similar reactions exhi- bits a drastic energy dependence due to the interplay with resonances f0 (980) and a0 (980). We point out that a set of few parameters

Andrew Bordner

We calculate limits on the trilinear soft-breaking parameter, $A_{t}$, in the Minimal Supersymmetric Standard model by requiring the absence of nonzero top squark vacuum expectation values. Assuming a low $\tanβ$, which implies a large top Yukawa coupling, we also calculate one-loop corrections to the effective potential. The resulting numerical calculations