July 1994 arXiv papers — page 9

Joseph Polchinski, Andrew Strominger

The problem of information loss is considered under the assumption that the process of black hole evaporation terminates in the decay of the black hole interior into a baby universe. We show that such theories can be decomposed into superselection sectors labeled by eigenvalues of the third-quantized baby universe field operator, and that scattering is unita

Shalosh B. Ekhad, Doron Zeilberger

L. Weinstein's brilliant short proof of de Branges's Theorem is made even shorter by using computer algebra.

Doron Zeilberger

The number of $n \times n$ matrices whose entries are either -1, 0, or 1, whose row- and column- sums are all 1, and such that in every row and every column the non-zero entries alternate in sign, is proved to be $[1!4! >... (3n-2)!]/[n!(n+1)! ... (2n-1)!]$, as conjectured by Mills, Robbins, and Rumsey.

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

The ununified standard model is an extension of the standard model that contains separate electroweak gauge groups for quarks and leptons. When it was originally proposed, data allowed the new gauge bosons to be quite light. We use recent data from precision electroweak measurements to put stringent bounds on the ununified standard model. In particular, at t

M. Carena, C. E. M. Wagner

The minimal supersymmetric SO(10) model, in which not only the gauge but also the third generation fermion Yukawa couplings are unified, provides a simple and highly predictive theoretical scenario for the understanding of the origin of the low energy gauge interactions and fermion masses. In the framework of the MSSM, with universal soft supersymmetry break

M. Carena, C. E. M. Wagner

We analyse the general features of the Higgs and supersymmetric particle spectrum associated with the infrared fixed point solution of the top quark mass in the Minimal Supersymmetric Standard Model. We consider the constraints on the mass parameters, which are derived from the condition of a proper radiative electroweak symmetry breaking in the low and mode

K. Funakubo, A. Kakuto, S. Otsuki, K. Takenaga

By treating CP-violating interaction as a perturbative term, we solved in a previous paper the Dirac equation in the background of electroweak bubble wall, and obtained the transmission and reflection coefficients for a chiral fermion incident from the symmetric-phase region. We give the transmission and reflection coefficients under the other boundary condi

Rohini M. Godbole

In this talk I first briefly explain the puzzle presented by the high muon content observed in air-showers which point to the ultra high-energy $γ$ sources like the HER-X-1. Since it had been suggested that a possible explanation of the puzzle might come from the effects of the hadronic structure of the photon, I briefly explain the concept of photon structu

J. Kiskis

This paper discusses the global $Z(N)$ symmetry of finite-temperature, $SU(N)$, pure Yang-Mills lattice gauge theory and the physics of the phase of the Wilson line expectation value. In the high $T$ phase, $\langle L \rangle$ takes one of $N$ distinct values proportional to the $Nth$ roots of unity in $Z(N)$, and the $Z(N)$ symmetry is broken. Only one of t

W. Barford, W. H. Beere, M. Steer

A simple one dimensional model to simulate the establishment of the Bean critical state is introduced. It is shown that the dynamics of the flux lines as they enter the superconductor are dominated by `avalanches'. The distribution of distances moved by vortices in the avalanches obeys a power law with an exponent of -1. This suggests that the Bean state

W. Barford, S. Jadhav

The Schwinger Boson mean field theories of the `t-J' model are extended by the consideration of anisotropic order parameters. This has two effects. First, a collinear phase, in which the spins are anti-ferromagnetically aligned in one direction and ferromagnetically aligned in the other, is found to be stable over a significant range of the phase diagram

Craig J Copi, David N. Schramm, Michael S. Turner

Big-bang nucleosynthesis is one of the cornerstones of the standard cosmology. For almost thirty years its predictions have been used to test the big-bang model to within a fraction of a second of the bang. The concordance that exists between the predicted and observed abundances of D, $^3$He, $^4$He and $^7$Li provides important confirmation of the standard

E. Kiritsis, C. Kounnas

Exact string solutions are presented, where moduli fields are varying with time. They provide examples where a dynamical change of the topology of space is occurring. Some other solutions give cosmological examples where some dimensions are compactified dynamically or simulate pre-big bang type scenarios. Some lessons are drawn concerning the region of valid

Hung Jung Lu, Joseph Milana

We study the exclusive, double--diffractive production of the Standard Model Higgs particle in hadronic collisions at LHC and FNAL (upgraded) energies. Such a mechanism would provide an exceptionally clean signal for experimental detection in which the usual penalty for triggering on the rare decays of the Higgs could be avoided. In addition, because of the

J. M. Landsberg

The exposition has been significantly altered, hopefully improved.

S. Liberati

A complete RST quantization of a CGHS model plus Strominger term is carried out. In so doing a conformal invariant theory with $κ=\frac{N}{12}$ is found, that is, without ghosts contribution. The physical consequences of the model are analysed and positive definite Hawking radiation is found.

J. Diaz Alonso, E. Gallego, A. Perez

We calculate the low-momentum N-N effective potential obtained in the OBE approximation, inside a nuclear plasma at finite temperature, as described by the relativistic $ \sigma $-$ \omega $ model. We analyze the screening effects on the attractive part of the potential in the intermediate range as density or temperature increase. In the long range the poten

Asher Yahalom

The conservation of helicity in ideal barotropic fluids is discussed from a group theoretical point of view. A new symmetry group is introduced i.e. the alpha group of translations. It is proven via the Noether theorem that this group generates helicity conservation.

Ken-ichiro Arita

Semiclassical analysis of the shell structure for a reflection-asymmetric deformed oscillator potential with irrational frequency ratio $ω_\perp/ω_z=\sqrt{3}$ is presented. Strong shell effects associated with bifurcations of short periodic orbits are found, which occur for a combination of quadrupole and octupole deformations.

H. Meyer

Treating the quark and diquark as elementary particles, the Bethe-Salpeter equation for the nucleon is solved numerically. The dependence of the mass on the diquark mass and on the coupling constants is investigated. The resulting relativistic quark-diquark-nucleon vertex is presented and discussed.

C. J. Horowitz, J. Piekarewicz

We calculate all spin-transfer observables for the quasielastic $(\vec{p},\vec{n})$ reaction in a relativistic plane-wave impulse approximation. The nuclear-structure information is contained in a large set of nuclear-response functions that are computed in nuclear matter using a relativistic random-phase approximation to the Walecka model. A reduced value o

Georgia Triantafillou

We show that the group ${\Cal D}(M)$ of pseudoisotopy classes of diffeomorphisms of a manifold of dimension $\geq 5$ and of finite fundamental group is commensurable to an arithmetic group. As a result $π_0(\text{\it Diff\,M})$ is a group of finite type.

Karl Rubin, Alice Silverberg

In lectures at the Newton Institute in June of 1993, Andrew Wiles announced a proof of a large part of the Taniyama-Shimura Conjecture and, as a consequence, Fermat's Last Theorem. This report for nonexperts discusses the mathematics involved in Wiles' lectures, including the necessary background and the mathematical history.

M. Ram Murty

The author reviews results and conjectures of Selberg on a class of Dirichlet series functions which share properties with the Riemann zeta function, and he relates this work to the theory of Artin L-functions.

Ittai Kan

We announce the discovery of a diffeomorphism of a three-dimensional manifold with boundary which has two disjoint attractors. Each attractor attracts a set of positive $3$-dimensional Lebesgue measure whose points of Lebesgue density are dense in the whole manifold. This situation is stable under small perturbations.

Seiichi Kamada

Alexander's and Markov's theorems state that any link type in $R^3$ is represented by a closed braid and that such representations are related by some elementary operations called Markov moves. We generalize the notion of a braid to that in 4-dimensional space and establish an analogue of these theorems.

Reese Harvey, H. Blaine Jr. Lawson

This note announces a general construction of characteristic currents for singular connections on a vector bundle. It develops, in particular, a Chern-Weil-Simons theory for smooth bundle maps $\alpha : E \rightarrow F$ which, for smooth connections on $E$ and $F$, establishes formulas of the type $$ \phi \ = \ \text{\rm Res}_{\phi}\Sigma_{\alpha} + dT. $$ H

Jean Esterle, Elizabeth Strouse, Fouad Zouakia

Let $Γ$ be the unit circle, $A(Γ)$ the Wiener algebra of continuous functions whose series of Fourier coefficients are absolutely convergent, and $A^+$ the subalgebra of $A(Γ)$ of functions whose negative coefficients are zero. If $I$ is a closed ideal of $A^+$, we denote by $S_I$ the greatest common divisor of the inner factors of the nonzero elements of $I

M. Shifman, A. Smilga

We consider two-dimensional QED with several fermion flavors on a finite spatial circle. A modified version of the model with {\em flavor-dependent} boundary conditions $ψ_p(L) = e^{2πip/ N} ψ_p(0)$, $p = 1, \ldots , N$ is discussed ($N $ is the number of flavors). In this case a non-contactable contour in the space of the gauge fields is {\em not} determine

R. Mohayaee

We consider the anomalies of $W_\infty$ gravity in the context of path-integralquantization. We derive the ghost-loop anomalies to all orders in $\hbar$ directly from the path-integral measure by the Fujikawa method. We also show that in the matter sector the higher-loop anomalies can be obtained by implementation of the Wess-Zumino consistency condition usi

E. Kiritsis, C. Kounnas

The four-dimensional superstring solutions define at low energy effective supergravity theories. A class of them extends successfully the validity of the standard model up to the string scale (${\cal O}(10^{17})~TeV$). We stress the importance of string corrections which are relevant for low energy (${\cal O}(1)~TeV$) predictions of gauge and Yukawa coupling

Jonathan Beck

This note has two purposes. First we establish that the map defined in [L, $§40.2.5$ (a)] is an isomorphism for certain admissible sequences. Second we show the map gives rise to a convex basis of Poincaré--Birkhoff--Witt (PBW) type for $\bup$, an affine untwisted quantized enveloping algebra of Drinfel$'$d and Jimbo. The computations in this paper are m

S. N. Solodukhin

For general finite temperature different from the Hawking one there appears a well known conical singularity in the Euclidean classical solution of gravitational equations. The method of regularizing the cone by regular surface is used to determine the curvature tensors for such a metrics. This allows one to calculate the one-loop matter effective action and

Hai-sheng Li

We first formulate a definition of tensor product for two modules for a vertex operator algebra in terms of a certain universal property and then we give a construction of tensor products. We prove the unital property of the adjoint module and the commutativity of tensor products, up to module isomorphism. We relate this tensor product construction with Fren

F. E. Close, R. G. Roberts

We show that if the Lorentz transformation properties of diffraction are other than scalar, the $x \rightarrow 0$ behaviour of $g_1(x,Q^2)$ can grow. We compare with new data on $g_1^p$ from SMC, assess implications for sum rules and for future studies of sea polarisation.

P. Bamert, C. P. Burgess

Motivated by the difference between SLD's recent measurement of ALR and the corresponding LEP results, we explore which kinds of new particles can (1) contribute dominantly to new physics through oblique corrections, (2) produce negative values for S and T, and (3) not be in conflict with any other experiments, on or off the Z resonance. We are typically

Damien Pierce

I discuss the weak scale threshold corrections in supersymmetric models. I describe the ``match and run" approximation to the threshold corrections and compare with the exact one-loop results. With explicit examples I show that in cases without large hierarchies in the mass spectra the ``match and run" approximation can lead to order $\cal{O}$(1) err

G. Domokos, S. Kovesi-Domokos

A class of physical phenomena outside the framework of the perturbatively treated Standard Model of electroweak and strong interactions gives rise to characteristic signatures in neutrino telescopes. In essence, the signature is a large energy deposition in the neighborhood of the telescope, giving rise to large and concentrated Cherenkov light emission, and

Daesung Hwang, C. S. Kim, Wuk Namgung

The Fermi motion parameter $p_{_F}$ is the most important parameter of ACCMM model, and the value $p_{_F} \sim 0.3$ GeV has been used without clear theoretical or experimental evidence. So, we attempted to extract the possible value for $p_{_F}$ theoretically in the relativistic quark model using quantum mechanical variational method. We obtained $p_{_F} \si

J. R. Cudell

The Donnachie-Landshoff model of diffractive scattering, which accounts for all confirmed diffractive data, is briefly reviewed. The picture emerging from this model is shown to directly contradict that coming from perturbative leading-log s calculations. The inclusion of non-perturbative effects brings the two pictures in closer agreement.

Howard A. Masur, Michael Wolf

We prove that the Teichmuller Space of Riemann Surfaces of genus g>1, equipped with the Teichmuller metric, is not a Gromov Hyperbolic space.

D. Manske, C. T. Rieck, D. Fay

The critical temperature of high-$T_c$ superconductors is determined, at least in part, by the electron-phonon coupling. We include the effect of an exchange interaction between the electrons and calculate the renormalization of the bare phonon frequencies and the electron-phonon verticies in a random phase approximation and obtain a strongly enhanced attrac

K. Sekar, G. Kuri, P. V. Satyam, B. Sundaravel

Growth of epitaxial gold silicide islands on bromine-passivated Si(111) substrates has been studied by optical and electron microscopy, electron probe micro analysis and helium ion backscattering. The islands grow in the shape of equilateral triangles up to a critical size beyond which the symmetry of the structure is broken, resulting in a shape transition

Angel Sanchez, Francisco Dominguez-Adame, Enrique Macia

Incoherent transport of excitations in one-dimensional disordered lattices with pairs of traps placed at random is studied by numerically solving the corresponding master equation. Results are compared to the case of lattices with the same concentration of unpaired traps, and it is found that pairing of traps causes a slowdown of the decay rate of both the m

C. Vermeulen, W. Barford, E. R. Gagliano

The effects of the nearest neighbour Coulomb repulsion, V, are considered in the one dimensional copper-oxide chain using the modified Lanczos method. Above a critical value of V we find that charge transfer excitons are the lowest lying energy exitations in the insulating phase. Close to the metal-insulator transition and $V=0$ there is good `particle-hole&

Yacov Kantor, Mehran Kardar

We use complete enumeration and Monte Carlo techniques to study self--avoiding walks with random nearest--neighbor interactions described by $v_0q_iq_j$, where $q_i=\pm1$ is a quenched sequence of ``charges'' on the chain. For equal numbers of positive and negative charges ($N_+=N_-$), the polymer with $v_0>0$ undergoes a transition from self--avoidi

M Harrison, W Barford

Anisotropic London Theory is used to predict the Abriskosv flux lattice in planar crystals of YBaCuO. By taking into account the orientation of the flux lattice as a function of applied field it is shown that the vortex chain state is observed in Bitter pattern experiments.

S. M. Quinlan, D. J. Scalapino

We calculate the spin susceptibility at and below T_c for a d_{x^2-y^2}-wave superconductor with resonant impurity scattering and Coulomb correlations. Both the impurity scattering and the Coulomb correlations act to maintain peaks in the spin susceptibility, as a function of momentum, at the Brillouin zone edge. These peaks would otherwise be suppressed by

David Band

Norris et al. (1994) report that the temporal structure of faint gamma ray bursts is longer than that of bright bursts, as expected for time dilation in the cosmological models of burst origin. I show that the observed trends can easily be produced by a burst luminosity function and thus may not result from cosmological effects. A cosmological signature may

Gerald D. Quinlan, Lars Hernquist, Steinn Sigurdsson

We add black holes to nonrotating, spherical galaxy models, with the assumption that the black-hole growth is slow compared with the dynamical time but fast compared with the relaxation time. The outcome differs depending on whether the core of the initial galaxy does or does not resemble that of an isothermal sphere. For the isothermal case the previously-k

Nick Kaiser, Gordon Squires, Greg Fahlman, David Woods

Massive clusters of galaxies gravitationally shear the images of faint background galaxies. At large impact parameters the shear is weak, but can still be measured, to a reasonable degree of significance, as a statistical anisotropy of the faint galaxy images. We describe techniques for measuring the shear and discuss the interpretation of the shear field. W

D. Trevese, R. G. Kron, S. R. Majewski, M. A. Bershady

A refined sample of 64 variable objects with stellar image structure has been identified in SA 57 to $B \sim 22.5$, over a time baseline of 15 years, sampled at 11 distinct epochs. The photometric data typically have a root-mean-square error at $B = 22$ of only 0.05 mag. Thirty-five quasars in this field have already been spectroscopically confirmed, 34 of w

R. Nesci, G. C. Perola, A. Wolter

A ROSAT HRI observation of the cluster MS0839.9+2938 at z=0.194 is presented. It confirms the earlier suggestion, based on the detection of extended H$α$ emission, that the inner regions of this cluster are dominated by a cooling flow. The surface brightness distribution within the cooling radius shows structures which can be interpreted as evidence of a hig

Biman B. Nath, Peter L. Biermann

We consider $γ$-ray emission from heavy nuclei that are accelerated in the shocks of stellar winds and are excited in interactions with the ambient matter in the Orion complex. We show that the recent detection of $γ$-ray lines in the Orion complex by COMPTEL telescope can be explained by such a scenario, assuming cosmic abundances. The scenario is consisten

Matthias Holschneider

In this paper we want to show, that the finite impulse response quadratic mirror filters (QMF) associated to a tower of grids $Γ\subset H=\bf Z^n$ can be identified with a right coset of the subgroup Fix$(T_{Γ^{\perp}}$,Map$ ({\bf T}^n\to U(N)$: poly) of the group of polynomial loops Map$({\bf T}^n\to U(N)$: poly) with $N=|H/Γ|$. The QMF with some vanishing