November 1998 arXiv papers — page 18

E. C. Caparelli, V. V. Dodonov, S. S. Mizrahi

We found a new kind of soliton solutions for the 5-parameter family of the potential-free Stenflo-Sabatier-Doebner-Goldin nonlinear modifications of the Schrödinger equation. In contradistinction to the "usual'' solitons like {\cosh[b(x-kt)]}^{-a}\exp[i(kx-ft)], the new {\em Finite-Length Solitons} (FLS) are nonanalytical functions with continuou

Y. Takeuchi, Y. Hemmi, H. Kurashige, Y. Matono

In order to study photomultiplier's short-term gain stability at high counting rate, we constructed an LED pulsed light source and its output monitor system. For the monitor system, we employed a photon counting method using a photomultiplier as a monitor photon detector. It is found that the method offers a simple way to monitor outputs from a pulsed li

ShuRun Zhang

The concept of only One-dimensional time is wrong, time is Four-dimensional. The light refraction emerges directly that time is four-dimensional to us perfectly. It translates some thing incomprehensible into easily comprehensible in natural science, and translates some problems complex into easy. It would take a great transformation in physics. My paper is

S. G. Bondarenko, V. V. Burov, M. Beyer, S. M. Dorkin

We discuss the relation between the two nucleon Bethe-Salpeter amplitude and the light front wave functions. Both approaches provide a covariant description for the deuteron bound state and the two nucleon scattering state. A comparison is done for the spin-orbit functions as well explicit integrals are given on the basis of the Nakanishi integral representa

Guangjun Mao, P. Papazoglou, S. Hofmann, S. Schramm

A new chiral SU(3) Lagrangian is proposed to describe the properties of kaons and anti-kaons in the nuclear medium. The saturation properties of nuclear matter are reproduced as well as the results of the Dirac-Brückner theory. After introducing the coupling between the omega meson and the kaon, our results for effective kaon and anti-kaon energy are quite s

Kenneth P. Bogart, Douglas B. West

A short proof is given that the graphs with proper interval representations are the same as the graphs with unit interval representations.

P. Stovicek

A simplified construction of representations is presented for the quantized enveloping algebra Uq(g), with g being a simple complex Lie algebra belonging to one of the four principal series A, B, C or D. The carrier representation space is the quantized algebra of polynomials in antiholomorphic coordinate functions on the big cell of a coadjoint orbit of K w

Ranee Brylinski

In this paper, we begin a quantization program for nilpotent orbits of a real semisimple Lie group. These orbits and their covers generalize the symplectic vector space. A complex structure polarizing the orbit and invariant under a maximal compact subgroup is provided by the Kronheimer-Vergne Kaehler structure. We outline a geometric program for quantizing

Ranee Brylinski

The first obstacle in building a Geometric Quantization theory for nilpotent orbits of a real semisimple Lie group has been the lack of an invariant polarization. In order to generalize the Fock space construction of the quantum mechanical oscillator, a polarization of the symplectic orbit invariant under the maximal compact subgroup is required. In this pap

William Jaco, Eric Sedgwick

In this paper, we use normal surface theory to study Dehn filling on a knot-manifold. First, it is shown that there is a finite computable set of slopes on the boundary of a knot-manifold that bound normal and almost normal surfaces in a one-vertex triangulation of that knot-manifold. This is combined with existence theorems for normal and almost normal surf

Sultan Catto, Jonathan Huntley, Nam Jong Moh, David Tepper

Let X=Sl(3,Z)\Sl(3,R)/SO(3,R). Let N(lambda) denote the dimension of the space of cusp forms with Laplace eigenvalue less than lambda. We prove that N(lambda)=C lambda^(5/2)+O(lambda^2) where C is the appropriate constant establishing Weyl's law with a good error term for the noncompact space X. The proof uses the Selberg trace formula in a form that is

M. V. Cougo-Pinto, C. Farina, F. C. Santos. A. C. Santos

We consider the photon field between an unusual configuration of infinite parallel plates: a perfectly conducting plate $(ε\to\infty)$ and an infinitely permeable one $μ\to\infty)$. After quantizing the vector potential in the Coulomb gauge, we obtain explicit expressions for the vacuum expectation values of field operators of the form $<{\hat E}_i{\hat E}_j

Marco Cavaglia

Two-dimensional matterless dilaton gravity with arbitrary dilatonic potential can be discussed in a unitary way, both in the Lagrangian and canonical frameworks, by introducing suitable field redefinitions. The new fields are directly related to the original spacetime geometry and in the canonical picture they generalize the well-known geometrodynamical vari

Marco Cavaglia

General two-dimensional pure dilaton-gravity can be discussed in a unitary way by introducing suitable field redefinitions. The new fields are directly related to the original spacetime geometry and in the canonical picture they generalize the well-known geometrodynamical variables used in the discussion of the vacuum dilatonic black hole. So the model can b

L. Pasquali, M. H. Reno

We present an evaluation of the atmospheric tau neutrino flux in the energy range between $10^2$ and $10^6$ GeV. The main source of tau neutrinos is from charmed particle production and decay. The $ν_τN\to τX$ event rate for a detector with a water equivalent volume of 1 km$^3$ is on the order of 60-100 events per year for $E_τ>100$ GeV, reducing to 18 event

K. Zuber

Massive neutrinos open up the possibility for a variety of new physical phenomena. Among them are oscillations and double beta decay. Furthermore they influence several fields from particle physics to cosmology. In this article the concept of massive neutrinos is given and the current status of experimental research is extensively reviewed. This includes ast

Ernest Ma, D. P. Roy

We present a minimal see-saw model based on an extension of the standard model (SM) which includes an additional U(1), with gauge charge $B - \frac{3}{2} (L_μ+ L_τ)$. Requirement of anomaly cancellation implies the existence of two right-handed singlet neutrinos, carrying this gauge charge, which have normal Dirac couplings to $ν_μ$ and $ν_τ$ but suppressed

Joaquim Prades, Antonio Pich

The perturbative quark mass corrections to the tau hadronic width are studied to O(alpha_s^3 m_q^2). Including up to dimension four corrections, we get m_s(4 GeV^2)=(143 \pm 42) MeV [m_s(1 GeV^2)=(193 \pm 59) MeV ]. Possible improvements to reduce the theoretical uncertainty are pointed out.

N. G. Stefanis

Sudakov-type form factors for quark vertex functions in QCD are discussed using a worldline approach.

C. A. Dominguez, K. Schilcher

The ALEPH data on the vector and axial-vector spectral functions, extracted from tau-lepton decays is used in order to test local and global duality, as well as a set of four QCD chiral sum rules. These are the Das-Mathur-Okubo sum rule, the first and second Weinberg sum rules, and a relation for the electromagnetic pion mass difference. We find these sum ru

M. Stratmann

The QCD treatment of the parton structure of virtual photons is briefly recalled, and possible limitations and open questions are pointed out. Various models for these densities are compared, completed by a short discussion of the treatment of heavy flavors. Finally, different ways to measure the parton distributions of virtual photons in e^+e^- and ep exper

A. Deandrea, R. Gatto, G. Nardulli, A. D. Polosa

We evaluate the form factors governing the exclusive decays B->rho l nu, B->a_1 l nu, by using an effective quark-meson lagrangian. The model is based on meson-quark interactions, and the computation of the mesonic transition amplitudes is performed by considering diagrams with heavy mesons attached to loops containing heavy and light constituent quarks. Thi

David Bowser-Chao, Darwin Chang, Wai-Yee Keung

We elaborate on a new class of models proposed recently by us and compare with another class proposed by Georgi and Glashow(GG). The models can be roughly classified as the righted-handed (or left-handed) models in our (or GG&#39;s) case. Both classes of models use softly broken CP symmetry to suppress tree level KM phase as well as the strong CP phase. The

UKQCD Collaboration, M. Foster, C. Michael

We discuss the spectrum of hadrons with a heavy colour-adjoint particle - motivated by the gluino of supersymmetry. Using the lattice approach, we explore in detail the gluonic bound states - the `glueballino&#39; or `gluelump&#39;. We also make a first determination of the spectrum of the `adjoint mesons&#39; - which have a light quark and antiquark bound t

K. Ackerstaff

Exclusive incoherent electroproduction of the rho^0(770) meson from 1H, 2H, 3He, and 14N targets has been studied by the HERMES experiment at squared four-momentum transfer Q**2>0.4 GeV**2 and positron energy loss nu from 9 to 20 GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the nuclear transparency, was found to decrease with increasi

L. C. Garcia de Andrade

The theory of distributions in non-Riemannian spaces is used to obtain exact static thin domain wall solutions of Einstein-Cartan equations of gravity. Curvature $ δ$-singularities are found while Cartan torsion is given by Heaviside functions. Weitzenböck planar walls are caracterized by torsion $δ$-singularities and zero curvature. It is shown that Weitzen

M. Yu. Kalmykov, P. I. Pronin

In this paper we discuss the connection between the geometric and tetrad approaches in the quantum affine-metric gravity. The corresponding transition formulas are obtained at the one-loop level. As an example, the one-loop counterterms are calculated in the tetrad formalism in the theory with terms quadratic in the torsion field. This model possesses the ex

Helmut Friedrich, Istvan Racz, Robert M. Wald

We consider smooth electrovac spacetimes which represent either (A) an asymptotically flat, stationary black hole or (B) a cosmological spacetime with a compact Cauchy horizon ruled by closed null geodesics. The black hole event horizon or, respectively, the compact Cauchy horizon of these spacetimes is assumed to be a smooth null hypersurface which is non-d

L. C. Garcia de Andrade

Distributional sources of cosmic walls crossed by cosmic strings from Riemann-Cartan (RC) Geometry. The matter density of the planar wall is maximum at the point where the cosmic string crosses the cosmic wall. Cartan torsion is has a support on the cosmic string given by the Dirac $ δ$-function. Off the sources are left with a torsionless vacuum.

Lunjin Lu

The problem of forward abstract interpretation of {\em normal} logic programs has not been formally addressed in the literature although negation as failure is dealt with through the built-in predicate ! in the way it is implemented in Prolog. This paper proposes a solution to this problem by deriving two generic fixed-point abstract semantics $F^b and $F^\d

H. A. Mook, F. Dogan, B. C. Chakoumakos

Neutron scattering has been used to study the spin fluctuations in the YBa$_2$Cu$_3$O$_{7-x}$ and Bi$_2$Sr$_2$CaCu$_2$O$_8$ materials. Evidence is found for both incommensurate fluctuations and a commensurate resonance excitation. Measurements on the lattice dynamics for YBa$_2$Cu$_3$O$_{6.6}$ show incommensurate structure that appears to stem from charge fl

N. L. Saini, A. Bianconi, A. Lanzara, J. Avila

Here we report an asymmetric suppresion of spectral weight at the Fermi surface around the M points using angle resolved photoemission spectroscopy. The results provide direct evidence for diagonal stripes in the Bi2212 superconductors.

Kwok-On Ng, David Vanderbilt

We present first-principles calculations of the structural and electronic properties of Si(001)-SiO2 interfaces. We first arrive at reasonable structures for the c-Si/a-SiO2 interface via a Monte-Carlo simulated annealing applied to an empirical interatomic potential, and then relax these structures using first-principles calculations within the framework of

D. P. Arovas, A. Karlhede, D. Lilliehook

We have investigated skyrmions in N-component quantum Hall systems. We find that SU(N) skyrmions are the lowest energy charged excitations for filling factors ν= 1,2,...,N-1 for small enough symmetry breaking terms. N>2 skyrmions can be realized in Si QH systems based on the (110) or (111) interfaces of Si, or perhaps in Si (100) systems, where the spin and

T. Wolenski, M. Grodzicki, J. Appel

Recent neutron scattering experiments on V2O3 show that the magnetic fluctuations on the metallic side of the antiferromagnetic metal-insulator transition are not related to the spin structure of the insulator, but rather to the bandstructure-driven spin-density wave phase of the doped system V(2-y)O3. We calculate these magnetic fluctuations starting from a

A. I. Yanson, G. Rubio Bollinger, H. E. van den Brom, N. Agrait

The continuing miniaturization of microelectronics raises the prospect of nanometre-scale devices with mechanical and electrical properties that are qualitatively different from those at larger dimensions. The investigation of these properties, and particularly the increasing influence of quantum effects on electron transport, has therefore attracted much in

Amy Herhold, Deniz Ertas, Alex J. Levine, H. E. King

We report detailed nucleation studies on the liquid-to-solid transition of hexadecane using nearly monodisperse hexadecane-in-water emulsions. A careful consideration of the kinetics of isothermal and nonisothermal freezing show deviations from predictions of classical nucleation theory, if one assumes that the emulsion droplet population is homogeneous. Sim

Yu. Kagan, V. A. Kashurnikov, A. V. Krasavin, N. V. Prokof&#39;ev

We present a detailed Monte Carlo study of correlations in an interacting two-dimensional Bose gas. The data for one-particle density matrix in coordinate representation are compared to the results for the local many-particle density correlators, which are responsible for the recombination rate in real experiments. We found that the appearance and growth of

P. Ao, X. -M. Zhu

We present a microscopic calculation of core states contribution to vortex friction in a type II superconductor at zero temperature. In weak impurity limit, a perturbative calculation leads to a vortex friction proportional to the normal state resistivity. With the aid of random matrix theory, vortex friction due to core states is determined only by the Ferm

Bikas K Chakrabarti, Muktish Acharyya

When an interacting many-body system, such as a magnet, is driven in time by an external perturbation, such as a magnetic field,the system cannot respond instantaneously due to relaxational delay. The response of such a system under a time-dependent field leads to many novel physical phenomena with intriguing physics and important technological applications.

Jesper Lykke Jacobsen, Jane&#39; Kondev

We present a unifying picture of the compact, dense and dilute phases of two-dimensional polymers. The lattice dependence of the scaling exponents for compact polymers is reconciled with their universality in the dense and dilute case. In particular, we show that violations of the fully-packing constraint in the compact phase can be interpreted as magnetic s

Jizhong Lou, Shaojin Qin, Zhaobin Su, Lu Yu

Using the density matrix renormalization-group technique, we calculate the impurity energy levels for two different effective models of off-chain doping for quasi-one-dimensional Heisenberg chain compound Y$_2$ Ba Ni O$_5$: ferromagnetic bond doping and antiferromagnetic site spin-1/2 doping. Thresholds of the impurity strength for the appearance of localize

C. S. Kochanek, E. E. Falco, C. D. Impey, J. Lehar

We show that most gravitational lenses lie on the passively evolving fundamental plane for early-type galaxies. For burst star formation models (1 Gyr of star formation, then quiescence) in low Omega_0 cosmologies, the stellar populations of the lens galaxies must have formed at z_f > 2. Typical lens galaxies contain modest amounts of patchy extinction, with

M. Aslam Chaudhry

Two representations of the extended gamma functions $Γ^{2,0}_{0,2}[(b,x)]$ are proved. These representations are exploited to find a transformation relation between two Fox&#39;s $H$-functions. These results are used to solve Fox&#39;s $H$-function in terms of Meijer&#39;s $G$-function for certain values of the parameters. A closed form representation of the

Amina Helmi, HongSheng Zhao, P. Tim de Zeeuw

We investigate what the proposed ESA astrometric satellite GAIA will reveal by observing the halo of the Milky Way. Specifically, we look for halo streams which are the signatures left by the merging/accretion events experienced by a typical galaxy like the Milky Way. We run numerical simulations of the disruption of satellite galaxies in a Galactic potentia

Amina Helmi, Simon D. M. White

We study numerical simulations of satellite galaxy disruption in a potential resembling that of the Milky Way. Our goal is to assess whether a merger origin for the stellar halo would leave observable fossil structure in the phase-space distribution of nearby stars. We show how mixing of disrupted satellites can be quantified using a coarse-grained entropy.

P. Zycki, C. Done, D. Smith

We have re-analyzed archival GINGA data of the soft X-ray transient source GS2023+308 (V404 Cyg) covering the decline phase of its May 1989 outburst. Our spectral modelling includes the relativistically smeared Compton reflected continuum and iron Kαfluorescent line near 6.5 keV produced by X-ray illumination of the accretion disc. This gives a powerful diag

G. Gavazzi, A. Boselli

Using new extensive radio continuum surveys at 1.4 GHz (FIRST and NVSS), we derive the distribution of the radio/optical and radio/NIR luminosity (RLF) of late-type (Sa-Irr) galaxies (mp<15.7) in 5 nearby clusters of galaxies: A262, Cancer, A1367, Coma and Virgo. With the aim of discussing possible environmental dependences of the radio properties, we compar

G. Gavazzi, A. Boselli

We cross-correlate the galaxies brighter than mB=18 in the Virgo cluster with the radio sources in the NVSS survey (1.4 GHz), resulting in 180 radio-optical identifications. We determine the radio luminosity function of the Virgo galaxies, separately for the early- and late-types. Late-type galaxies develop radio sources with a probability proportional to th

E. Lastennet, T. Lejeune, P. Westera, R. Buser

Stromgren synthetic photometry from an empirically calibrated grid of stellar atmosphere models has been used to derive the effective temperature of each component of double lined spectroscopic (SB2) eclipsing binaries. For this purpose, we have selected a sub-sample of 20 SB2s for which b-y, m_1, and c_1 individual indices are available. This new determinat

Klaus Jaeger, Klaus J. Fricke, Jochen Heidt

A preliminary analysis of fields around 20 mainly radio-quiet QSOs (RQQs) at intermediate redshift is summarized. We find overdensities of faint sources around 50% of our observed QSOs suggesting that they are located in groups or even clusters of galaxies.

Jing Wang, Timothy Heckman, Matthew Lehnert

Deep H$α$ images of a sample of nearby late-type spiral galaxies have been analyzed to characterize the morphology and energetic significance of the ``Diffuse Ionized Medium&#39;&#39; (DIM). We find that the DIM properties can be reasonably unified as a function of relative surface brightness, by using a new method to quantify the DIM importance in galaxies.

F. H. Briggs

Surveys in the 21cm line of neutral hydrogen are testing the completeness of the catalogs of nearby galaxies. The remarkable observational fact is that the potential wells that confine gas to sufficient density that it can remain neutral in the face of ionizing radiation also provide sites for star formation, so that there are no known cases of neutral inter

N. R. Sibgatullin, R. A. Sunyaev

We analyze the effect of the quadrupole component in the mass distribution of a rapidly rotating neutron star on energy release in the boundary layer on the surface of the accreting star and in the accretion disk in the cases where the stellar radius is smaller (or larger) than the radius of the marginally stable circular orbit. We calculate the velocities a

H. C. Spruit

A weakly magnetized ($\sim 10^7$G) neutron star, slowly spun up by accretion in an X-ray binary, crosses the instability boundary for r-mode instability at P=1--2 msec. The amplitude of the oscillation, which initially increases only at the spinup time scale, is secularly unstable due to the negative temperature dependence of the viscosity in neutron star ma

A. Yonehara, S. Mineshige, J. Fukue, M. Umemura

The optical-ultraviolet continuum from active galactic nuclei (AGN) seem to originate from optically thick and/or thin disks, and occasionally from associated circumnuclear starburst regions. These different possible origins can, in principle, be discriminated by observations of gravitational microlensing event. We performed numerical simulations of microlen

George Triantaphyllou

The introduction of mirror fermions with masses between the weak scale and 1 TeV could offer a dynamical origin to the standard-model electro-weak symmetry breaking mechanism. The purpose of this work is to study the dynamics needed in order to render models with such a fermion content phenomenologically acceptable.

Ben C. Buchler, Malcolm B. Gray, Daniel A. Shaddock, Timothy C. Ralph

We present theoretical results that demonstrate a new technique to be used to improve the sensitivity of thermal noise measurements: intra-cavity intensity stabilisation. It is demonstrated that electro-optic feedback can be used to reduce intra-cavity intensity fluctuations, and the consequent radiation pressure fluctuations, by a factor of two below the qu

Eric. A. Richards

Determination of the epoch dependent star-formation rate of field galaxies is one of the principal goals of modern observational cosmology. Recently, Hughes et al. (1998) using the SCUBA instrument on the James Clerk Maxwell Telescope, report the detection of a new population of heavily dust enshrouded, star-forming galaxies at high redshifts (z > 2), dramat

S. W. Hawking, C. J. Hunter, M. M. Taylor-Robinson

In asymptotically flat space a rotating black hole cannot be in thermodynamic equilibrium because the thermal radiation would have to be co-rotating faster than light far from the black hole. However in asymptotically anti-de Sitter space such equilibrium is possible for certain ranges of the parameters. We examine the relationship between conformal field th

Abhishek Dhar, Deepak Dhar

A crucial assumption in the conventional description of thermal conduction is the existence of local thermal equilibrium. We test this assumption in two simple models of heat conduction. Our first model is a linear chain of planar spins with nearest neighbour couplings, and the second model is that of a Lorentz gas. We look at the steady state of the system

Raphael A. Ramos, Per Arne Rikvold, M. A. Novotny

The Kolmogorov-Johnson-Mehl-Avrami (KJMA) theory for the time evolution of the order parameter in systems undergoing first-order phase transformations has been extended by Sekimoto to the level of two-point correlation functions. Here, this extended KJMA theory is applied to a kinetic Ising lattice-gas model, in which the elementary kinetic processes act on

Maria Krawczyk, Jan Zochowski, Peter Mattig

The one-loop branching ratios for the process Z->h(A)+gamma are calculated in the general Two Higgs Doublet Model (Model II) taking into account existing constraints on the model parameters. For Higgs boson masses below 50 GeV and tan beta of order 1-10 the fraction of such Z decays are at the level of 10^{-7}, but can be significantly stronger for very low

Ljubinko, Kondic

We present a model for the motion of hard spherical particles on a two dimensional surface. The model includes both the interaction between the particles via collisions, as well as the interaction of the particles with the substrate. We analyze in details the effects of sliding and rolling friction, that are usually overlooked. It is found that the propertie

M. Campanelli, C. O. Lousto

We investigate higher than the first order gravitational perturbations in the Newman-Penrose formalism. Equations for the Weyl scalar $ψ_4,$ representing outgoing gravitational radiation, can be uncoupled into a single wave equation to any perturbative order. For second order perturbations about a Kerr black hole, we prove the existence of a first and second

G. I. Lykasov, W. Cassing, A. Sibirtsev, M. V. Rzjanin

We calculate the elastic and inelastic $ωN\to ωN, \to πN, \to ρN, \to ρπN, \to ππN, \to σN$ reactions within a boson exchange approximation where the $ωρπ$ coupling constant and form factor are fixed by the reaction $πN \to ωN$ in comparison to the experimental data. We find rather large $ωN$ cross sections at low relative momenta of the $ω$-meson which lead

C. Bartocci, U. Bruzzo, G. Sanguinetti

We study the structure of a modified Fukaya category ${\frak F}(X)$ associated with a K3 surface $X$, and prove that whenever $X$ is an elliptic K3 surface with a section, the derived category of $\fF(X)$ is equivalent to a subcategory of the derived category ${\bold D}(\hat X)$ of coherent sheaves on the mirror K3 surface $\hat X$.

Julien Lesgourgues

Comparisons of cosmological models to current data show that the presence of a non-trivial feature in the primordial power spectrum of fluctuations, around the scale k=0.05 h/Mpc, is an open and exciting possibility, testable in a near future. This could set new constraints on inflationary models. In particular, current data favour a Lambda-CDM model with a

A. Belyaev, O. J. P. Eboli, R. Z. Funchal, T. L. Lungov

We perform a detailed analyses of the CERN Large Hadron Collider (LHC) capability to discover first generation vector leptoquarks through their pair production. We study the leptoquark signals and backgrounds that give rise to final states containing a pair e+e- and jets. Our results show that the LHC will be able to discover vector leptoquarks with masses u

M. Diehl, T. Feldmann, R. Jakob, P. Kroll

We relate ordinary and skewed parton distributions to soft overlap contributions to elastic form factors and large angle Compton scattering, using light-cone wave functions in a Fock state expansion of the nucleon. With a simple ansatz for the wave functions of the three lowest Fock states we achieve a good description of unpolarised and polarised parton dis

G. Chaboussant, M. -H. Julien, Y. Fagot-Revurat, M. E. Hanson

In a magnetic field, spin-ladders undergo two zero-temperature phase transitions at the critical fields Hc1 and Hc2. An experimental review of static and dynamical properties of spin-ladders close to these critical points is presented. The scaling functions, universal to all quantum critical points in one-dimension, are extracted from (a) the thermodynamic q

Friederike Schmid

Computer simulations of amphiphilic systems are reviewed. Research areas cover a wide range of length and time scales, and a whole hierarchy of models and methods has been developed to address them all. They range from atomistically realistic models, idealized chain models, lattice spin models, to phenomenological models such as Ginzburg-Landau models and ra

H. Calen, J. Dyring, G. Faldt, K. Fransson

Exclusive measurements of the production of eta mesons in the p+p->p+p+eta reaction have been carried out at excess energies of 16 and 37 MeV above threshold. The deviations from phase space are dominated by the proton-proton final state interaction and this influences particularly the energy distribution of the eta meson. However, evidence is also presented

DELPHI Collaboration, P. Abreu et al

A search for stable and long-lived heavy charged particles used the data taken by the DELPHI experiment at energies from 130 to 183 GeV. The Cherenkov light detected in the Ring Imaging Cherenkov Detector and the ionization loss measured in the Time Projection Chamber identify heavy particles from masses of 2 to nearly 89 GeV/c^2. Upper limits are given on t

DELPHI Collaboration, P. Abreu et al

Promptly decaying lightest neutralinos and long-lived staus are searched for in the context of light gravitino scenarios. It is assumed that the stau is the next to lightest supersymmetric particle (NLSP) and that the lightest neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector at centre-of-mass energies from 161 to 183 \GeV are a

DELPHI Collaboration, P. Abreu et al

A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV and about 20 pb^{-1} equally shared between the centre-of-mass

Hai-Yang Cheng, Kwei-Chou Yang

Using the recent experimental data of $B\to D^{(*)}(π,ρ)$, $B\to D^{(*)} D_s^{(*)}$, $B\to J/ψK^{(*)}$ and various model calculations on form factors, we re-analyze the effective coefficients a_1 and a_2 and their ratio. QCD and electroweak penguin corrections to a_1 from $B\to D^{(*)}D_s^{(*)}$ and a_2 from $B\to J/ψK^{(*)}$ are estimated. In addition to th

Sergei Gukov, Mukund Rangamani, Edward Witten

A generalization of the Maldacena conjecture asserts that Type IIB string theory on $§^5/\Z_3$ is equivalent to a certain supersymmetric $SU(N)^3$ gauge theory with bifundamental matter. To test this assertion, we analyze the wrapped branes on $§^5/\Z_3$ and their interpretation in terms of gauge theory. The wrapped branes are interpreted in some cases as ba

David A. Buote

We examine whether isothermal models of the hot gas can successfully describe the ASCA and ROSAT spectra of NGC 1399, NGC 4472, NGC 4636, and NGC 5044. Broad-band spectral fitting of the ASCA SIS and GIS data accumulated within a radius of ~5 arcmin for each galaxy shows that isothermal models are unable to fit the SIS data near 1 keV. In addition, these iso

Kenneth Intriligator

General conjectures about the SL(2,Z) modular transformation properties of N=4 super-Yang-Mills correlation functions are presented. It is shown how these modular transformation properties arise from the conjectured duality with IIB string theory on AdS_5 x S^5. We discuss in detail a prediction of the AdS duality: that N=4 field theory, in an appropriate li

G. F. Gribakin, A. A. Gribakina, V. V. Flambaum

We show that the spectrum and eigenstates of open-shell multicharged atomic ions near the ionization threshold are chaotic, as a result of extremely high level densities of multiply excited electron states ($10^3 eV^{-1}$ in Au^{24+}) and strong configuration mixing. This complexity enables one to use statistical methods to analyse the system. We examine the

Marek Zukowski

It is shown that a careful analysis of the `wrong&#39; events (those not present in the usual formulations of the GHZ argument), which are a necessary feature of the tests of local realism involving independent sources, permits one to show that there is no local realistic model, which is capable to describe recent GHZ experiments performed in Innsbruck

Anu Venugopalan, G. S. Agarwal

We examine the revival features in wave packet dynamics of a particle confined in a finite square well potential. The possibility of tunneling modifies the revival pattern as compared to an infinite square well potential. We study the dependence of the revival times on the depth of the square well and predict the existence of superrevivals. The nature of the

Haiqing Wei, Xin Xue

It is proposed that nuclear (or electron) spins in a trapped molecule would be well isolated from the environment and the state of each spin can be measured by means of mechanical detection of magnetic resonance. Therefore molecular traps make an entirely new approach possible for spin-resonance quantum computation which can be conveniently scaled up. In the

L. P. Endresen, K. Hall, J. S. Hoye, J. Myrheim

We give an explicit formula for the membrane potential of cells in terms of the intracellular and extracellular ionic concentrations, and derive equations for the ionic currents that flow through channels, exchangers and electrogenic pumps. We demonstrate that the work done by the pumps equals the change in potential energy of the cell, plus the energy lost

Magnus Johansson, Yuri S. Kivshar

We reveal that even weak inherent discreteness of a nonlinear model can lead to instabilities of the localized modes it supports. We present the first example of an oscillatory instability of dark solitons, and analyse how it may occur for dark solitons of the discrete nonlinear Schrodinger and generalized Ablowitz-Ladik equations.

R. Alzetta, T. Bubba, R. Le Pera, G. Liberti

We show that the coherent oscillations of the e.m. field induced by the collective quantum fluctuations of the nuclear matter field associated with the giant resonances, with frequencies $ω_{A}\simeq 78A^{-{1/3}}$ MeV, give rise to a significant $(e^+e^-)$ pair production in high energy Heavy Ion collisions. The approximate parameterless calculation of such

Rajeev K. Puri, Joerg Aichelin

We present the details of the numerical realization of the recently advanced algorithm developed to identify the fragmentation in heavy ion reactions. This new algorithm is based on the Simulated Annealing method and is dubbed as Simulated Annealing Clusterization Algorithm [SACA]. We discuss the different parameters used in the Simulated Annealing method an

S. Sewerin, G. Schepers, J. T. Balewski, A. Budzanowski

Threshold measurements of the associated strangeness production reactions pp --> p K(+) Lambda and pp --> p K(+) Sigma(0) are presented. Although slight differences in the shapes of the excitation functions are observed, the most remarkable feature of the data is that at the same excess energy the total cross section for the Sigma(0) production appears to be

Rob de Jeu

In this paper we study the group K_{2n}^{(n+1)}(F) where F is the function field of a complete, smooth, geometrically irreducible curve C over a number field, assuming the Beilinson--Soulé conjecture on weights. In particular, we compute the Beilinson regulator on a subgroup of K_{2n}^{(n+1)}(F), using the complexes constructed in previous work by the author

Daqing Wan

In this paper, we give an overview of the various general methods in computing the zeta function of an algebraic variety defined over a finite field, with an emphasis on computing the reduction modulo $p^m$ of the zeta function of a hypersurface, where $p$ is the characteristic of the finite field. In particular, this applies to the problem of counting ratio

Daqing Wan

This is an expository paper which gives a quick introduction to Dwork&#39;s conjecture about p-adic meromorphic continuation of his unit root zeta function arising from algebraic geometry. Special emphasis is given to the case of elliptic family and its relation to p-adic modular forms such as Gouvêa-Mazur conjecture and some sort of p-adic Ramanujuan-Peters

J. Daniel Christensen, Mark Hovey

In the first part, we determine conditions on spectra X and Y under which either every map from X to Y is phantom, or no nonzero maps are. We also address the question of whether such all or nothing behaviour is preserved when X is replaced with V smash X for V finite. In the second part, we introduce chromatic phantom maps. A map is n-phantom if it is null

Peter Zograf

A formula for the generating function of the Weil-Petersson volumes of moduli spaces of pointed curves that is identical to the genus expansion of the free energy in two dimensional gravity is obtained. The contribution of arbitrary genus is expressed in terms of the Bessel function $J_0$.

A. L. Pirozerski, M. A. Semenov-Tian-Shansky

We define the q-deformed Gelfand-Dickey bracket on the space of q-pseudodifference symbols which agrees with the Poisson Virasoro algebra of E.Frenkel and N.Reshetikhin and its generalizations and prove its uniqueness (in a natural class of quadratic Poisson structures). The associated hierarchies of nonlinear q-difference equations are also constructed.

Andrew D. Hwang, Michael A. Singer

An ansatz of Calabi allows construction of Kahler metrics in an Hermitian disk bundle over a Kahler manifold. We attempt to give a definitive treatment of this ansatz, with the following results: We give curvature conditions on the disk bundle that guarantee existence of families of complete Kahler metrics of constant scalar curvature, including some Einstei

L. Hlavaty, L. Snobl

Yang-Baxter system related to quantum doubles is introduced and large class of both continuous and discrete symmetries of the solution manifold are determined. Strategy for solution of the system based on the symmetries is suggested and accomplished in the dimension two.The complete list of invertible solutions of the system is presented.

Greg Kuperberg

The permanent-determinant method and its generalization, the Hafnian-Pfaffian method, are methods to enumerate perfect matchings of plane graphs that was discovered by P. W. Kasteleyn. We present several new techniques and arguments related to the permanent-determinant with consequences in enumerative combinatorics. Here are some of the results that follow f

Federica Vian

In these notes the exact renormalization group formulation of the scalar theory is briefly reviewed. This regularization scheme is then applied to supersymmetric theories. In case of a supersymmetric gauge theory it is also shown how to recover gauge invariance, broken by the introduction of the infrared cutoff.

K. A. Milton

Julian Schwinger became interested in the Casimir effect in 1975. His original impetus was to understand the quantum force between parallel plates without the concept of zero point fluctuations of field quanta, in the language of source theory. He went on to consider applications to dielectrics and to spherical geometries in 1977. Although he published nothi