January 1994 arXiv papers — page 4

Dean M. Petrich, Raymond E. Goldstein

Pattern formation exhibited by a two-dimensional reaction-diffusion system in the fast inhibitor limit is considered from the point of view of interface motion. A dissipative nonlocal equation of motion for the boundary between high and low concentrations of the slow species is derived heuristically. Under these dynamics, a compact domain of high concentrati

Gennadi Uimin

In connection with numerous X-ray and neutron investigations of some high temperature superconductors (YBa$_2$Cu$_3$O$_{6+x}$ and related compounds) a non-trivial part of the structure factor, coming from partly disordered Cu-O-$\dots$-O-Cu chain fragments, situated within basal planes, CuO$_x$, can be a subject of theoretical interest. Closely connected to

Nigel. B. Wilding, Christian Muenkel, Dieter W. Heermann

This paper describes the application of finite-size scaling concepts to domain growth in systems with a non-conserved order parameter. A finite-size scaling ansatz for the time-dependent order parameter distribution function is proposed, and tested with extensive Monte-Carlo simulations of domain growth in the 2-D spin-flip kinetic Ising model. The scaling p

S. Sakhi

The effective action of nonrelativistic fermions in 2+1 dimensions is analyzed at finite temperature and chemical potential in the presence of a uniform magnetic field perpendicular to the plane. The method used is a generalization of the derivative expansion technique. The induced Chern-Simons term is computed and shown to exhibit the Hall quantization. Eff

Detlef Lohse

The Taylor-Reynolds and Reynolds number ($Re_λ$ and $Re$) dependence of the dimensionless energy dissipation rate $\ceps =\eps L / \u1rms^3$ is derived for statistically stationary isotropic turbulence, employing the results of a variable range mean field theory. Here, $\eps$ is the energy dissipation rate, $L$ is the (fixed) outer length scale, and $\u1rms$

J. Chiang, R. W. Romani

We describe a refined calculation of high energy emission from rotation-powered pulsars based on the Outer Gap model of Cheng, Ho \&~Ruderman (1986a,b). We have improved upon previous efforts to model the spectra from these pulsars (e. g. Cheng, et al. 1986b; Ho 1989) by following the variation in particle production and radiation properties with position in

Ruth Durrer

In this letter a new formula for light deflection is derived using only physically observable concepts. The general result is specialized to cosmological perturbation theory and expressed in terms of gauge--invariant perturbation variables. The resulting scalar, vector and tensor equations are supplemented by simple examples for illustration. The gravity wav

K. Hulek, G. K. Sankaran

Let A be the moduli space of (1,p)-polarised abelian surfaces with a level structure, for p an odd prime. Let X be a desingularisation of any algebraic compactification of A. Then X is simply-connected.

Yong Baek Kim, Xiao-Gang Wen

We calculate the instanton-anti-instanton action $S_{M {\bar M}} (τ)$ in the gauge theory of the half-filled Landau level. It is found that $S_{M {\bar M}} (τ) = (3 - η) \left [ Ω_0 (η) \ τ\right ]^{1 / (3 - η)}$ for a class of interactions $v ({\bf q}) = V_0 / q^η \ ( 0 \leq η< 2 )$ between electrons. This means that the instanton-anti-instanton pairs are c

Hans-Jürgen Pohle

A central object in the interpretation of quantum mechanics of closed systems with decoherent histories is the decoherence matrix. But only for a very small number of models one is able to give explicit expressions for its elements. So numerical methods are required. Unfortunately the dimensions of this matrices are usually very high, which makes also a dire

P. Aurenche, J. -Ph. Guillet, M. Fontannaz, Y. Shimizu

We study jet production in photon-photon reactions at the next-to-leading logarithm accuracy. Special emphasis is placed on the discussion of the theoretical uncertainties and on the role of the hadronic component of the photon structure function. We also discuss subtleties in the quasi-real photon spectrum when the photon is involved in a large transverse m

V. A. Bednyakov, H. V. Klapdor-Kleingrothaus, S. G. Kovalenko

We consider the SUSY-model neutralino as a dominant Dark Matter particle in the galactic halo and investigate some general issues of direct DM searches via elastic neutralino-nucleus scattering. On the basis of conventional assumptions about the nuclear and nucleon structure, without referring to a specific SUSY-model, we prove that it is impossible in princ

L. V. Bogdanov

We derive the expressions for $ψ$-functions and generic solutions of lattice principal chiral equations, lattice KP hierarchy and hierarchy including lattice N-wave type equations. $τ$-function of $n$ free fermions plays fundamental role in this context. Miwa&#39;s coordinates in our case appear as the lattice parameters.

D. V. Shirkov, S. V. Mikhailov

There is an intriguing discrepancy between α_s(M_Z) values measured directly at the CERN $Z_0$-factory and low-energy (at few GeV) measurements transformed to $Q=M_{Z_0}$ by a massless QCD α_s(Q) evolution relation. There exists an attempt to reconcile this discrepancy by introducing a light gluino $\gl$ in the MSSM. We study in detail the influence of heavy

Shun-Jin Wang, Wei Zuo, Wolfgang Cassing

We generalize the methods used in the theory of correlation dynamics and establish a set of equations of motion for many-body correlation green&#39;s functions in the non-relativistic case. These non-linear and coupled equations of motion describe the dynamical evolution of correlation green&#39;s functions of different order and transparently show how many-

Vincenzo Branchina, Janos Polonyi

It is shown that the inhomogeneous saddle points of scale invariant theories make the semiclassical expansion sensitive on the choice of non-renormalizable operators. In particular, the instanton fugacity and the beta function of the two dimensional non-linear sigma model depends on apparently non-renormalizable operators. This represents a non-perturbative

M. R. Niedermaier

The exact eigenvalues of the infinite set of conserved charges on the multi-particle states in affine Toda theories are determined. This is done by constructing a free field realization of the Zamolodchikov-Faddeev algebra in which the conserved charges are realized as derivative operators. The resulting eigenvalues are renormalization group (RG) invariant,

Tatsuhiro Nakajima, Hirofumi Yamada

Basic representations of A_{2l}^(2) and D_{l+1}^(2) are studied. The weight vectors are represented in terms of Schur&#39;s $Q$-functions. The method to get the polynomial solutions to the reduced BKP hierarchies is shown to be equivalent to a certain rule in Maya game.

I. G. Korepanov

The tetrahedron equation arises as a generalization of the famous Yang--Baxter equation to the 2+1-dimensional quantum field theory and the 3-dimensional statistical mechanics. Very little is still known about its solutions. Here a systematic method is described that does produce non-trivial solutions to the tetrahedron equation with spin-like variables on t

Enrico Nardi

Superstring derived $\E$ models can accommodate small neutrino masses if a discrete symmetry is imposed which forbids tree level Dirac neutrino masses but allows for radiative mass generation. The only possible symmetries of this kind are known to be generation dependent. We explore the possibility that, as a consequence of such a symmetry, the three sets of

A. Kusenko, R. Shrock

We give a detailed discussion of our general determination of (i) the number of unremovable, physically meaningful phases in quark mass matrices and (ii) which elements of these matrices can be rendered real by rephasings of fermion fields. The results are applied to several currently viable models. New results are presented for an arbitrary number of fermio

Martin J. Savage

The six independent formfactors describing the weak decay \semi\ are determined in terms of one universal function when both the $b$ and $c$ quarks are treated as heavy. The relations between these formfactors are modified by terms suppressed by inverse powers of the charm quark mass. We compute the formally leading long-distance corrections to these relatio

F. Pisano, V. Pleitez

Assuming the existence of right-handed neutrinos, we consider an electroweak model based on the gauge symmetry $SU(4)_L\otimes U(1)_N$. We study the neutral currents coupled to all neutral vector bosons present in the theory. There are no flavor changing neutral currents at tree level, coupled with the lightest neutral vector boson.

Wolfgang Lucha, Franz F. Schöberl, Michael Moser

We construct effective Hamiltonians which despite their apparently nonrelativistic form incorporate relativistic effects by involving parameters which depend on the relevant momentum. For some potentials the corresponding energy eigenvalues may be determined analytically. Applied to two-particle bound states, it turns out that in this way a nonrelativistic t

A. G. Grozin, O. I. Yakovlev

We estimate the couplings in the Heavy Hadron Chiral Theory (HHCT) lagrangian from the QCD sum rules in an external axial field. Stability of the sum rules at moderate values of the Borel parameter is poor that probably signals a slow convergence of the OPE series. At large values of the Borel parameter they stabilize, and yield the couplings much lower than

W. J. Stirling

The production of jet pairs with small transverse momentum and large relative rapidity in high energy hadron-hadron collisions is studied. The rise of the parton-level cross section with increasing rapidity gap is a fundamental prediction of the BFKL `perturbative pomeron&#39; equation of Quantum Chromodynamics. However, at fixed collider energy it is diffic

Michael Dine, Scott Thomas

Electroweak baryogenesis can occur in the ``adiabatic limit,&#39;&#39; in which expanding bubbles of true vacuum are assumed to have rather thick walls and be slowly moving. Here the problem of calculating the baryon asymmetry in this limit is reconsidered. A simple prescription for obtaining the relevant kinetic equations is given. An additional suppression

Cenalo Vaz, Louis Witten

In 2+1 dimensional Chern-Simons gravity, Wilson loops in the three dimensional Anti de Sitter group, $SO(2,2)$, reproduce the spinning black hole of Bañados, Teitelboim and Zanelli (BTZ) by naturally duplicating the necessary identification of points of a four dimensional globally $SO(2,2)$ invariant space in which the hole appears as an embedding.

P. T. Chrusciel, J. Isenberg

We discuss various features of the dynamical system determined by the flow of null geodesic generators of Cauchy horizons. Several examples with non--trivial (``chaotic&#39;&#39;, ``strange attractors&#39;&#39;, etc.) global behaviour are constructed. Those examples are relevant to the ``chronology protection conjecture&#39;&#39;, and they show that the occu

Edward Malec, Niall Ó Murchadha

We demonstrate that the Penrose inequality is valid for spherically symmetric geometries even when the horizon is immersed in matter. The matter field need not be at rest. The only restriction is that the source satisfies the weak energy condition outside the horizon. No restrictions are placed on the matter inside the horizon. The proof of the Penrose inequ

Lei-Han Tang, Yu Tang

Liquid in grooved capillaries, made by e.g. inserting a plate in a cylindrical tube, exhibits unusual spreading and flow properties. One example is capillary rise, where a long, upward tongue on top of the usual meniscus has been observed along the groove. We attribute the underlying mechanism to a thermodynamic instability against spreading for a (partial o

M. B. Davies, W. Benz, T. Piran, F. K. Thielemann

We present 3D Newtonian simulations of the coalescence of two neutron stars, using a Smoothed Particle Hydrodynamics (SPH) code. We begin the simulations with the two stars in a hard, circular binary, and have them spiral together as angular momentum is lost through gravitational radiation at the rate predicted by modeling the system as two point masses. We

Tsvi Piran

The sudden release of copious $\g$-ray photons into a compact region creates an opaque photon--lepton fireball due to the prolific production of electron--positron pairs. The photons that we observe in the bursts emerge only at the end of the fireball phase after it expanded sufficiently to become optically thin or after it converted its energy to the kineti

T. Piran

Binary neutron stars merger (NS$^2$M) at cosmological distances is probably the only $γ$-ray bursts model based on an independently observed phenomenon which is known to be taking place at a comparable rate. We describe this model, its predictions and some open questions.

P. Mazzei, G. De Zotti

If indeed early type galaxies used up most of their gas to form stars in a time short compared to their collapse time and if a roughly constant fraction of metals is locked up in dust grains, these galaxies may easily become opaque to starlight and emit most of their luminosity in the far-IR. The corresponding spectral energy distribution matches remarkably

Matthew Colless, David Schade, T J Broadhurst, R S Ellis

We have used HRCam on the CFHT to obtain subarcsecond images of 26 galaxies with z=0.1--0.7. The primary sample of 17 galaxies have enhanced star formation indicated by [OII] equivalent widths greater than 20Å, while the comparison sample of 9 galaxies have equivalent widths less than 10Å. By fitting disks or bulges to BVI images we derive scalelengths for t

Joerg Winkelmann

Let G be complex linear-algebraic group, H a subgroup, which is dense in G in the Zariski-topology. Assume that G/[G,G] is reductive and furthermore that (1) G is solvable, or (2) the semisimple elements in G&#39;=[G,G] are dense. Then every H-invariant holomorphic function on G is constant. If G=G&#39;, furthermore every H-invariant meromorphic or plurisubh

Y. Meurice, G. Ordaz, V. G. J. Rodgers

We study numerically the magnetic susceptibility of the hierarchical model with Ising spins ($σ=\pm 1$) above the critical temperature and for two values of the epsilon parameter. The integrations are performed exactly, using recursive methods which exploit the symmetries of the model. Lattices with up to $2^18$ sites have been used. Surprisingly, the numeri

L. Berezansky, E. Braverman

Suppose any solution of a linear impulsive delay differential equation $$ \dot{x} (t) + \sum_{i=1}^m A_i (t) x[h_i (t)] = 0,~t \geq 0, x(s) = 0, s < 0, $$ $$ x(τ_j +0) = B_j x(τ_j -0) + α_j, ~j=1,2, ... ,$$ is bounded for any bounded sequence $\{ α_i \}$. The conditions ensuring exponential stability of this equation are presented. The behavior of solutions

F. A. Rasio, S. L. Shapiro

We have performed a series of three-dimensional hydrodynamic calculations of binary coalescence using the smoothed particle hydrodynamics (SPH) method. The initial conditions are exact polytropic equilibrium configurations with $\gam > 5/3$, on the verge of dynamical instability. We calculate the emission of gravitational radiation in the quadrupole approxim

A. Loeb, F. A. Rasio

The formation of quasar black holes during the hydrodynamic collapse of protogalactic gas clouds is discussed. The dissipational collapse and long- term dynamical evolution of these systems is analysed using three-dimensional numerical simulations. The calculations focus on the final collapse stages of the inner baryonic component and therefore ignore the pr

J. C. B. Papaloizou, E. Szuszkiewicz

We construct models of the inner part of a transonic adiabatic accretion disc assuming constant specific angular momentum taking the vertical structure fully into account.\\ For comparison purposes, we construct the corresponding one dimensional viscous disc models derived under vertical averaging assumptions. The conditions under which a unique location for

L. Susskind, J. Uglum

In this paper the entropy of an eternal Schwarzschild black hole is studied in the limit of infinite black hole mass. The problem is addressed from the point of view of both canonical quantum gravity and superstring theory. The entropy per unit area of a free scalar field propagating in a fixed black hole background is shown to be quadratically divergent nea

M. Anselmino, P. Gambino, J. Kalinowski

A comprehensive analysis of deep inelastic scattering of polarized charged leptons on polarized nucleons is presented; weak interaction contributions, both in neutral and charged current processes, are taken into account and the parity violating polarized nucleon structure functions are studied. Possible ways of their measurements and their interpretations i

V. A. Bednyakov, H. V. Klapdor-Kleingrothaus, S. G. Kovalenko

We investigate the role of nuclear spin in elastic scattering of Dark Matter (DM) neutralinos from nuclei in the framework of the Minimal SUSY standard model (MSSM). The relative contribution of spin-dependent axial-vector and spin-independent scalar interactions to the event rate in a DM detector has been analyzed for various nuclei. Within general assumpti

Saharon Shelah, Juris Steprāns

Let dec be the least cardinal kappa such that every function of first Baire class can be decomposed into kappa continuous functions. Cichon, Morayne, Pawlikowski and Solecki proved that cov(Meager) <= dec <= d and asked whether these inequalities could, consistently, be strict. By cov(Meager) is meant the least number of closed nowhere dense sets required to

Renling Jin, Saharon Shelah

By an omega_1 --tree we mean a tree of size omega_1 and height omega_1. An omega_1 --tree is called a Kurepa tree if all its levels are countable and it has more than omega_1 branches. An omega_1 --tree is called a Jech--Kunen tree if it has kappa branches for some kappa strictly between omega_1 and 2^{omega_1}. A Kurepa tree is called an essential Kurepa tr

Renling Jin, Saharon Shelah

In section 1 of this paper, we characterize the isomorphism property of nonstandard universes in terms of the realization of some second--order types in model theory. In section 2, several applications are given. One of the applications answers a question of D. Ross about infinite Loeb measure spaces

Haim Judah, Saharon Shelah

We will kill the old Luzin and Sierpinski sets in order to build a model where U(Meager) = U(Null)= aleph_1 and there are neither Luzin nor Sierpinski sets. Thus we answer a question of J. Steprans, communicated by S. Todorcevic on route from Evans to MSRI.

Saharon Shelah, Joel Spencer

The main result is the following Theorem: Let p=p(n) be such that p(n) in [0,1] for all n and either p(n)<< n^{-1} or for some positive integer k, n^{-1/k}<< p(n)<< n^{-1/(k+1)} or for all epsilon >0, n^{- epsilon}<< p(n) and n^{- epsilon}<< 1-p(n) or for some positive integer k, n^{-1/k}<< 1-p(n)<< n^{-1/(k+1)} or 1-p(n)<< n^{-1}. Then p(n) satisfies the Ze

Steven Givant, Saharon Shelah

We investigate a notion called uniqueness in power kappa that is akin to categoricity in power kappa, but is based on the cardinality of the generating sets of models instead of on the cardinality of their universes. The notion is quite useful for formulating categoricity-like questions regarding powers below the cardinality of a theory. We prove, for (uncou

Akihiro Kanamori, Saharon Shelah

For I a proper, countably complete ideal on P(X) for some set X, can the quotient Boolean algebra P(X)/I be complete? This question was raised by Sikorski in 1949. By a simple projection argument as for measurable cardinals, it can be assumed that X is an uncountable cardinal kappa, and that I is a kappa-complete ideal on P(kappa) containing all singletons.

Saharon Shelah, Joel Spencer

Paul Erdős and Alfred Renyi considered the evolution of the random graph G(n,p) as p ``evolved&#39;&#39; from 0 to 1. At p=1/n a sudden and dramatic change takes place in G. When p=c/n with c<1 the random G consists of small components, the largest of size Theta(log n). But by p=c/n with c>1 many of the components have ``congealed&#39;&#39; into a ``giant co

Saharon Shelah, Lajos Soukup

Let K be the family of graphs on omega_1 without cliques or independent subsets of size omega_1 . We prove that: 1) it is consistent with CH that every G in K has 2^{omega_1} many pairwise non-isomorphic subgraphs, 2) the following proposition holds in L: (*) there is a G in K such that for each partition (A,B) of omega_1 either G cong G[A] or G cong G[B], 3

Mark Evans, Ioannis Giannakis, D. V. Nanopoulos

Symmetry transformations of the space-time fields of string theory are generated by certain similarity transformations of the stress-tensor of the associated conformal field theories. This observation is complicated by the fact that, as we explain, many of the operators we habitually use in string theory (such as vertices and currents) have ill-defined commu

H. Genz, S. Tatur

In a model of isospin symmetry breaking we obtain the ($e^{-} e^{+} \rightarrow π^{-} π^{+}$) amplitude $Q$ and the isospin $I=0$ and $I=1$ relative phase $ψ$ at the $ϕ(1020)$ resonance in aproximate agreement with experiment. The model predicts $Γ(ϕ\rightarrow ωπ^{0}) \approx 4 \cdot 10^{-4} \;\mbox{MeV}$. We have also obtained $Γ(ϕ\rightarrow η&#39; γ)=5.2

C. Martin, D. Vautherin

We describe a nonperturbative calculation of the spectrum of SU(2) Yang-Mills theory based on a Hamiltonian formulation. Our approach exploits gauge invariant variables similar to those used in nuclear physics to describe collective motion in nuclei.

Enrico Nardi, Thomas G. Rizzo

Recently it was shown that, in the framework of superstring inspired $\E$ models, the presence of generation dependent discrete symmetries allows us to construct a phenomenologically viable class of models in which the three generations of fermions do not have the same embedding within the fundamental {\bf 27} dimensional representation of E$_6$. In this sce

Sergio Caracciolo, Andrea Pelissetto

We compute the beta-function and the anomalous dimension of all the non-derivative operators of the theory up to three-loops for the most general nearest-neighbour O(N)-invariant action together with some contributions to the four-loop beta-function. These results are used to compute the first analytic corrections to various long-distance quantities as the c

M. Campanelli, C. O. Lousto, J. Audretsch

We develop a method for solving the field equations of a quadratic gravitational theory coupled to matter. The quadratic terms are written as a function of the matter stress tensor and its derivatives in such a way to have, order by order, a set of Einstein field equations with an effective $T_{μν}$. We study the cosmological scenario recovering the de Sitte

K. Penc, A. Zawadowski

Orbital Kondo effect is treated in a model, where additional to the conduction band there are localized orbitals close to the Fermi energy. If the hopping between the conduction band and the localized heavy orbitals depends on the occupation of the atomic orbitals in the conduction band then orbital Kondo correlation occurs. The noncommutative nature of the

Curtin Callan, Frank Wilczek

We show that a geometrical notion of entropy, definable in flat space, governs the first quantum correction to the Bekenstein-Hawking black hole entropy. We describe two methods for calculating this entropy -- a straightforward Hamiltonian approach, and a less direct but more powerful Euclidean (heat kernel) method. The entropy diverges in quantum field theo

Mikhail S. Volkov

It is shown that in the Einstein-Yang-Mills (EYM) theory, as well as in the pure flat space Yang-Mills (YM) theory, there always exists an opportunity to pass over the potential barrier separating homotopically distinct vacuum sectors, because the barrier height may be arbitrarily small. However, at low energies all the overbarrier histories are suppressed b

Bjoern Lillekjendlie, Dimitris Kugiumtzis, Nils Christophersen

This paper is the second in a series of two, and describes the current state of the art in modelling and prediction of chaotic time series. Sampled data from deterministic non-linear systems may look stochastic when analysed with linear methods. However, the deterministic structure may be uncovered and non-linear models constructed that allow improved predic

Dimitris Kugiumtzis, Bjoern Lillekjendlie, Nils Christophersen

Certain deterministic non-linear systems may show chaotic behaviour. Time series derived from such systems seem stochastic when analyzed with linear techniques. However, uncovering the deterministic structure is important because it allows for construction of more realistic and better models and thus improved predictive capabilities. This paper describes key

Stefano Capitani, Giancarlo Rossi

We present the complete 1-loop perturbative computation of the renormalization constants and mixing coefficients of the operators that measure the first moment of deep inelastic scattering structure functions, employing the nearest neighbor improved lattice QCD action. The interest of using this action in Monte Carlo simulations lies in the fact that all ter

D. Juriev

This article is devoted to some interesting geometric and informatic interpretations of peculiarities of 2D quantum field theory, which become re- vealed after its visualization. Contents. I. Geometry of Mobilevision: 1.1. Interpretational geometry and anomalous virtual realities; 1.2. Quantum projective field theory and Mobilevision; 1.3. Quantum conformal

A Kundu, Orlando Ragnisco

A lattice version of quantum nonlinear Schrodinger (NLS) equation is considered, which has significantly simple form and fullfils most of the criteria desirable for such lattice variants of field models. Unlike most of the known lattice NLS, the present model belongs to a class which does not exhibit the usual symmetry properties. However this lack of symmet

H. Kawabe, T. Kobayashi, N. Ohtsubo

We examine whether a minimal string model possessing the same massless spectra as the MSSM can be obtained from $Z_4$, $Z_6$ and $Z_8$ orbifold constructions. Using an anomaly cancellation condition of the target space duality symmetry, we derive allowable values of a level $k_1$ of U(1)$_Y$ for the minimal string model on the orbifolds through computer anal

Jerome Leon

We propose a general algebraic analytic scheme for the spectral transform of solutions of nonlinear evolution equations. This allows us to give the general integrable evolution corresponding to an arbitrary time and space dependence of the spectral transform (in general nonlinear and with non-analytic dispersion relations). The main theorem is that the compa

A. Mariano, F. Krmpotić, A. F. R. de Toledo Piza

The response functions for the extended second and third random phase approximation are compared. A second order perturbation calculation shows that the first-order amplitude for the direct $3p3h$ excitation from the ground state cancels with those that are engendered by the $1p1h$-$3p3h$ coupling. As a consequence nonvanishing $3p3h$ effects to the $1p1h$ r

Chungsik Song, Che Ming Ko, Charles Gale

Dilepton production from hot hadronic matter is studied in an effective chiral Lagrangian with pions, $\rho$-mesons, and $a_1$ mesons, We find that the production rates from reactions that involve axial-vector mesons dominate over contributions from all other reactions when the dilepton invariant mass is above 1.5 GeV.

E. Caurier, A. Poves, A. P. Zuker

Gamow-Teller strength functions in full $(pf)^{8}$ spaces are calculated with sufficient accuracy to ensure that all the states in the resonance region have been populated. Many of the resulting peaks are weak enough to become unobservable. The quenching factor necessary to bring into agreement the low lying observed states with shell model predictions is sh

T. C. Ferrée, D. S. Koltun

A Coulomb sum rule is derived for the response of nuclei to $(e,e^\prime)$ scattering with large three-momentum transfers. Unlike the nonrelativistic formulation, the relativistic Coulomb sum is restricted to spacelike four-momenta for the most direct connection with experiments; an immediate consequence is that excitations involving antinucleons, e.g., $N{\

Lee Brekke, Michael J. Dugan, Tom D. Imbo

We develop general techniques for computing the fundamental group of the configuration space of $n$ identical particles, possessing a generic internal structure, moving on a manifold $M$. This group generalizes the $n$-string braid group of $M$ which is the relevant object for structureless particles. In particular, we compute these generalized braid groups

Michael R. Douglas

We try to draw lessons for higher dimensions from the string representations recently derived for large $N$ Yang-Mills theory by Gross and Taylor, Kostov, and others, and call attention to three characteristics that should be expected of a string theory precisely equivalent to a higher dimensional gauge theory: continuous world-sheets; strong coupling at sho

T. Damour, A. M. Polyakov

It is pointed out that string-loop modifications of the low-energy matter couplings of the dilaton may provide a mechanism for fixing the vacuum expectation value of a massless dilaton in a way which is naturally compatible with existing experimental data. Under a certain assumption of universality of the dilaton coupling functions , the cosmological evoluti

J. S. Apps, J. S. Dowker

We calculate the Riemann curvature tensor and sectional curvature for the Lie group of volume-preserving diffeomorphisms of the Klein bottle and projective plane. In particular, we investigate the sign of the sectional curvature, and find a possible disagreement with a theorem of Lukatskii. We suggest an amendment to this theorem.

C. Duval, P. A. Horvathy, L. Palla

The non-relativistic conformal symmetry found by Jackiw and Pi for the coupled Chern-Simons and gauged nonlinear Schrödinger equations in the plane is derived in a non-relativistic Kaluza-Klein framework.

T. Kashiwa, S. Sakoda, S. V. Zenkin

We derive general form of finite-dimensional approximations of path integrals for both bosonic and fermionic canonical systems in terms of symbols of operators determined by operator ordering. We argue that for a system with a given quantum Hamiltonian such approximations are independent of the type of symbols up to terms of $O(ε)$, where $ε$ is infinitesima

Michael R. Douglas, Keke Li, Matthias Staudacher

We study two-dimensional gauge theories with fundamental fermions and a general first order gauge-field Lagrangian. For the case of U(1) we show how standard bosonization of the Schwinger model generalizes to give mesons interacting through a general Landau-Ginzburg potential. We then show how for a subclass of SU(N) theories, &#39;t Hooft&#39;s solution of

Lev Rozansky

We use the Chern-Simons quantum field theory in order to prove a recently conjectured limitation on the 1/K expansion of the Jones polynomial of a knot and its relation to the Alexander polynomial. This limitation allows us to derive a surgery formula for the loop corrections to the contribution of the trivial connection to Witten&#39;s invariant. The 2-loop

Lev Rozansky

We review two different methods of calculating Witten&#39;s invariant: a stationary phase approximation and a surgery calculus. We give a detailed description of the 1-loop approximation formula for Witten&#39;s invariant and of the technics involved in deriving its exact value through a surgery construction of a manifold. Finally we compare the formulas pro

Marco A. Diaz, Thomas J. Weiler

We explore the phenomenology of a fermiophobic Higgs: a Higgs whose couplings to fermions are suppressed. We calculate the branching ratios of a Higgs decaying to $γγ$, $W^*W^*$, $Z^*Z^*$, $Zb\bar b$, $Zγ$, $γb\bar b$, and final states involving vector mesons like $Υ$, $J/Ψ$ and $ρ$. In order to calculate these branching ratios we perform a complete one-loop

T. Stelzer, W. F. Long

The program MadGraph is presented which automatically generates postscript Feynman diagrams and Fortran code to calculate arbitrary tree level helicity amplitudes by calling HELAS[1] subroutines. The program is written in Fortran and is available in Unix and VMS versions. MadGraph currently includes standard model interactions of QCD and QFD, but is easily m

C. E. Carlson, J. Milana

Systematic analysis of the high recoil decay channels of the B-meson, two body mesonic decay channels in particular. For decays involving D-mesons, all experimentally observed rates are in reasonable accord with our calculations. Noticeable corrections to heavy quark symmetry are found, appearing most prominently when comparing D and D* decay modes. Calculat

C. H. Jin, W. F. Palmer, E. A. Paschos

The parton model for semileptonic B meson decays is studied with special attention to the decay distributions. We find that the spectra show dramatic variations when we introduce cuts on the hadronic energy or invariant mass of hadrons. Results for both $b\rightarrow u$ and $b\rightarrow c$ decays are presented. The detailed spectra may help to separate the

G. Cella, G. Curci, G. Ricciardi, A. Vicere&#39;

In this work we compute the leading logarithmic corrections to the b -> s gamma decay in a dimensional scheme which does not require any definition of the gamma5 matrix. The scheme does not exhibit unconsistencies and it is therefore a viable alternative to the t&#39;Hooft Veltman scheme, particularly in view of the next-to-leading computation. We confirm th

P. Q. Hung

A phenomenological theory of fermion masses and mixings is constructed within the framework of a four- family symmetry. It is found that the most favored set of relevant CKM elements are $|V_{us}|\approx 0.222$, $|V_{cb}|\approx 0.044$, $|V_{ub}/V_{cb}|\approx 0.082$, $|V_{ud}|\approx 0.974$, $|V_{cs}|\approx 0.9736$, $|V_{cd}|\approx 0.224$ with $\hat{B}_K

L. Brücher, J. Franzkowski, D. Kreimer

We present a new program package for calculating one-loop Feynman integrals, based on a new method avoiding Feynman parametrization and the contraction due to Passarino and Veltman. The package is calculating one-, two- and three-point functions both algebraically and numerically to all tensor cases. This program is written as a package for Maple. An additio

Gwo-Guang Wong, Wei-Shu Hou

We construct a $Z_8$ model for leptons where all Yukawa couplings are of order unity, but known lepton masses are generated radiatively, {\it order by order}. The seed is provided by fourth generation leptons $E$ and $N$, which receive (Dirac) mass in usual way. Two additional Higgs doublets with nontrivial $Z_8$ charge are introduced to give nearest neighbo

J. P. Ma

Fragmentation functions for hadrons composed of heavy quarks are calculated directly from the definitions given by Collins and Soper and are compared with those calculated in another way. A new fragmentaion function for a P-wave meson is also obtained and the singularity arising at the leading order is discussed.

John N. Bahcall

A precise test of the theory of stellar evolution can be performed by measuring the average difference in energy between the neutrino line produced by ${\rm ^7Be}$ electron capture in the solar interior and the corresponding neutrino line produced in a terrestrial laboratory. This energy shift is calculated to be 1.29~keV (to an accuracy of a few percent) fo

A. Berera, L. Z. Fang

It is shown that the evolution of the density perturbations during certain eras of substantial entropy generation in the universe can be described in the scheme of the KPZ equation. Therefore, the influence on cosmological structure formation by stochastic forces arising from various dissipations can be studied through the universal characteristics of surfac

H. Aratyn, E. Nissimov, S. Pacheva

We present a new form of the multi-boson reduction of KP hierarchy with Lax operator written in terms of boson fields abelianizing the second Hamiltonian structure. This extends the classical Miura transformation and the Kupershmidt-Wilson theorem from the (m)KdV to the KP case. A remarkable relationship is uncovered between the higher Hamiltonian structures

Avishai Dekel

CONTENTS: 1. INTRODUCTION 2. GRAVITATIONAL INSTABILITY 3. MEASURING PECULIAR VELOCITIES 4. ANALYSIS OF OBSERVED PECULIAR VELOCITIES 5. PREDICTED MOTIONS FROM THE GALAXY DISTRIBUTION 6. TESTING BASIC HYPOTHESES 7. THE INITIAL FLUCTUATIONS 8. THE VALUE OF OMEGA 9. DISCUSSION: ARE THE HYPOTHESES JUSTIFIED? REFERENCES

Chang-Hwan Lee, Hong Jung, Dong-Pil Min, Mannque Rho

The s-wave $K^{\pm}N$ scattering amplitude is computed up to one-loop order corresponding to next-to-next-to-leading order (or N$^2$LO in short) with a heavy-baryon effective chiral Lagrangian. Constraining the low-energy constants by on-shell scattering lengths, we obtain contributions of each chiral order up to N$^2$LO and find that the chiral corrections

Peter A. Clarkson, Elizabeth L. Mansfield

In this paper we study a shallow water equation derivable using the Boussinesq approximation, which includes as two special cases, one equation discussed by Ablowitz et. al. [Stud. Appl. Math., 53 (1974) 249--315] and one by Hirota and Satsuma [J. Phys. Soc. Japan}, 40 (1976) 611--612]. A catalogue of classical and nonclassical symmetry reductions, and a Pai

Stefan Teis, Wolfgang Cassing, Tomoyuki Maruyama, Ulrich Mosel

We calculate the subthreshold production of antiprotons in the Lorentz-covariant RBUU approach employing a weighted testparticle method to treat the antiproton propagation and absorption nonperturbatively. We find that the pbar differential cross sections are highly sensitive to the baryon and antiproton selfenergies in the dense baryonic environment. Adopti

Jacobus Verbaarschot

We argue that the spectrum of the QCD Dirac operator near zero virtuality can be described by random matrix theory. As in the case of classical random matrix ensembles of Dyson we have three distinct classes: the chiral orthogonal ensemble (chGOE), the chiral unitary ensemble (chGUE) and the chiral symplectic ensemble (chGSE). They correspond to gauge groups