October 1997 arXiv papers — page 12

M. Schiffer

In this article we explain sonoluminescence from ideas borrowed from superradiance. The model has no free parameters and the predicted energies of quanta agree with experiment. It also hints why noble gases play a pivotal role in the effect.

Stefano Mancini, Paolo Tombesi

We propose a tomographic scheme to reconstruct the quantum state of a Bose-Einstein condensate, exploiting the radiation field as a probe and considering the atomic internal degrees of freedom. The density matrix in the number state basis can be directly retrieved from the atom counting probabilities.

Janusz Miskiewicz

The role and the form of detectors applicable to the quantum information transfer are investigated. The detectors are described within the Event - Enhanced Quantum Theory.

Lev Vaidman

A brief review of the time-symmetrized quantum formalism originated by Aharonov, Bergmann and Lebowitz is presented. Symmetry of various measurements under the time reversal is analyzed. Time-symmetrized counterfactuals are introduced. It is argued that the time-symmetrized formalism demonstrates novel profound features of quantum theory and that recent crit

Yves Brihaye, Stefan Giller, Piotr Kosinski

Series of finite dimensional representations of the superalgebras spl(p,q) can be formulated in terms of linear differential operators acting on a suitable space of polynomials. We sketch the general ingredients necessary to construct these representations and present examples related to spl(2,1) and spl(2,2). By revisiting the products of projectivised repr

Valery Telnov

Using the laser backscattering method at future TeV linear colliders one can obtain gamma-gamma and electron-gamma colliding beams (photon colliders) with the energy and luminosity comparable to that in e+e- collisions. Now this option is included to conceptual designs of linear colliders. This paper (talk at the conference on nonlinear optics) is a short in

G. Q. Li, C. M. Ko, W. S. Chung

Kaon production cross sections in nucleon-nucleon, nucleon-delta and delta-delta interactions are studied in a boson exchange model. For the latter two interactions, the exchanged pion can be on-mass shell, only contributions due to a virtual pion are included via the Peierls method by taking into account the finite delta width. With these cross sections and

G. Dunne, J. Mannix

We discuss supersymmetry breaking in some supersymmetric quantum mechanical models with periodic potentials. The sensitivity to the parameters appearing in the superpotential is more acute than in conventional nonperiodic models. We present some simple elliptic models to illustrate these points.

J. J. M. Verbaarschot

In these lectures we review recent results on universal fluctuations of QCD Dirac spectra and applications of Random Matrix Theory (RMT) to QCD. We review general properties of Dirac spectra and discuss the relation between chiral symmetry breaking and correlations of Dirac eigenvalues. In particular, we will focus on the microscopic spectral density density

Manuel Torres

We study an Abelian Maxwell-Chern-Simons model in $2 +1 $ dimensions which includes a magnetic moment interaction. We show that this model possesses domain wall as well as vortex solutions.

Yves Brihaye, Piotr Kosinski

We reconsider the quasi exactly solvable matrix models constructed recently by R. Zhdanov. The 2$\times$2 matrix operators representing the algebra sl(2) are generalized to matrices of arbitrary dimension and a similar construction is achieved for the algebra sl(n).

A. N. Vall, S. E. Korenblit, V. M. Leviant, A. V. Sinitskaya

Various exact solutions of two-particle eigenvalue problems for nonrelativistic contact four-fermion current-current interaction are obtained. Specifics of Goldstone mode is investigated. The connection between a renormalization procedure and construction of self-adjoint extensions is revealed.

A. N. Vall, S. E. Korenblit, V. M. Leviant, D. V. Naumov

On a nonrelativistic contact four-fermion model we have shown that the simple Lambda-cut-off prescription together with definite fine-tuning of the Lambda dependency of "bare"quantities lead to self-adjoint semi-bounded Hamiltonian in one-, two- and three-particle sectors. The fixed self-adjoint extension and exact solutions in two-particle sector co

Oleg Andreev

A set of physical operators which are responsible for touching interactions in the framework of c<1 unitary conformal matter coupled to 2D quantum gravity is found. As a special case the non-critical bosonic strings are considered. Some analogies with four dimensional quantum gravity are also discussed, e.g. creation-annihilation operators for baby universes

X. M. Ding, L. Zhao

A realization of the Yangian double with center $DY_\hbar(sl_2)_k$ of level $k(\not=0,-2)$ in terms of free boson fields is constructed. The screening currents are also presented, which commute with $DY_\hbar(sl_2)$ modulo total difference. In the $\hbar\to 0$ limit, the currents of Yangian double $DY_\hbar(sl_2)_k$ becomes the Feigin-Fuchs realization of af

Csaba Csaki, Hitoshi Murayama

We extend the well-known &#39;t Hooft anomaly matching conditions for continuous global symmetries to discrete groups. We state the matching conditions for all possible anomalies which involve discrete symmetries explicitly. There are two types of discrete anomalies. For Type I anomalies, the matching conditions have to be always satisfied regardless of the

Shaouly Bar-Shalom

The possibility of observing large signatures of new CP-violating and flavor-changing Higgs-Top couplings in a future e^+e^- collider experiments such as e^+e^- -> t bar-t h, t bar-t Z and e^+e^- -> t bar-c ν_e bar-ν_e, t bar-c e^+ e^- is discussed. Such, beyond the Standard Model, couplings can occur already at the tree-level within a class of Two Higgs Dou

A. S. Deakin, V. Elias, N. H. Fuchs, Fang Shi

Instanton contributions to pseudoscalar finite-energy sum rules are extracted from the explicit single-instanton contribution to the pseudoscalar Laplace sum rule in the instanton liquid model.

Stephen Parke

In this presentation I will concentrate on top quark physics, the W-boson mass and the possibility of discovering a light Higgs boson via associated production at the Fermilab Tevatron.

Thomas G. Rizzo

In this talk I summarize the capability of future lepton colliders to discover leptoquarks and to determine their electroweak quantum numbers. This analysis is an updated discussion based on the results presented in the Snowmass 1996 New Phenomena Working Group report as well as some more recent work that has appeared in the literature as a result of the HER

M. C. Bañuls, J. Bernabéu

We show that, contrary to the flavour mixing amplitude q/p, both Re(epsilon) and Im(epsilon) are observable quantities, where epsilon is the phase- convention-independent CP mixing. We consider semileptonic B_d decays from a CP tag and build appropriate time-dependent asymmetries to separate out Re(epsilon) and Im(epsilon). &#34;Indirect&#34; CP violation wo

W. Vogelsang

We study photoproduction of jets and single-inclusive hadrons in a polarized ep collider mode of HERA at sqrt(s)=300 GeV, examining the sensitivity of the cross sections and their asymmetries to the proton&#39;s polarized gluon distribution and to the completely unknown parton distributions of polarized photons. We also present for the first time the NLO cor

P. Colangelo

I discuss the issue of quark-hadron duality in the system of heavy-light quark mesons. As an example, I consider a correlator of two currents comprising heavy quark operators, and I compare the OPE expression with the result obtained by a complete insertion of hadronic states. After a smearing procedure, OPE and hadronic spectral functions agree with each ot

P. M. Saffin, E. J. Copeland

We investigate the possibility that the Higgs sector of the Weinberg-Salam model admits the existence of electrically charged, sphaleron states. Evidence is provided through an asymptotic and numerical perturbative analysis about the uncharged sphaleron. By introducing a toy model in two dimensions we demonstrate that such electrically charged, unstable stat

H. J. Lipkin

The availability of data on $B_s$ decays to strange quasi-two-body final states, either with or without charmonium opens new possibilities for understanding different contributions of weak diagrams and in particular the relative contributions of tree and penguin diagrams. Corresponding $B_d$ and $B_s$ decays to charge conjugate final states are equal in the

Johan Bijnens

Various topics in and around Goldstone Boson Production and Decay in CHPT are discussed, in particular I describe some of the progress in $p^6$ Chiral Perturbation Theory Calculations, the progress in calculating hadronic contributions to the muon anomalous magnetic moment, here comparing the two latest results of the light-by-light in some detail. I also pr

Jan Rafelski, Jean Letessier, Ahmed Tounsi

We describe the remarkable accomplishments of the current heavy ion Pb--Pb collision experiments involving strange particle production, carried out at 158A GeV at CERN--SPS. These experimental results, together with the earlier 200A GeV S-induced reactions, imply that, at central rapidity, a novel mechanism of strangeness production arises, accompanied by ex

A. V. Berezhnoy, V. V. Kiselev, A. K. Likhoded, A. I. Onishchenko

In the leading order of perturbative QCD one calculates the total and differential cross-sections for the hadronic production of doubly charmed baryons $Ξ_{cc}$ and $Ξ_{cc}^*$ in different experiments. The experimental evaluation of cross-sections for the $J/Ψ+D + \bar D$ production would allow one to decrease the uncertainty in the determination of cross-se

Jiunn-Wei Chen, Martin J. Savage

We examine the hadronic interactions of quarkonia, focusing on the decays psi(2s)->psi pi pi and upsilon(2s)-> upsilon pi pi. The leading gluonic operators in the multipole expansion are matched onto the chiral lagrangian with the coefficients fit to available data, both at tree-level and loop-level in the chiral expansion. A comparison is made with naive ex

Davide Gabrielli

We deduce the appearance of a polymeric phase in 4-dimensional simplicial quantum gravity by varying the values of the coupling constants and discuss the geometric structure of the phase in terms of ergodic moves. A similar result is true in 3-dimensions.

The ALEPH Collaboration

The data recorded by the ALEPH detector at centre-of-mass energies of 161, 170, and 172 GeV are analysed for signals of chargino and neutralino production. No evidence of a signal is found, although candidate events consistent with the expectations from Standard Model processes are observed. Limits at 95% C.L. on the production cross sections are derived and

Hisa-aki Shinkai, Gen Yoneda

We examine the advantages of the SO(3)-ADM (Ashtekar) formulation of general relativity, from the point of following the dynamics of the Lorentzian spacetime in direction of applying this into numerical relativity. We describe our strategy how to treat new constraints and reality conditions, together with a proposal of new variables. We show an example of pa

Hisa-aki Shinkai, Wai-Mo Suen, F. Douglas Swesty, Malcolm Tobias

We present two of our efforts directed toward the numerical analysis of neutron star mergers, which are the most plausible sources for gravitational wave detectors that should begin operating in the near future. First we present Newtonian 3D simulations including radiation reaction (2.5PN) effects. We discuss the gravitational wave signals and luminosity fro

N. R. Pantoja, H. Rago

An approach to computing, withing the framework of distribution theory, the distributional valued energy-momentum tensor for the Schwarzschild spacetime is disscused. This approach avoids the problems associated with the regularization of singularities in the curvature tensors and shares common features with the by now standard treatment of discontinuities i

B. Boisseau, C. Charmousis, B. Linet

We assume that a self-gravitating string is locally described by a thin tube of matter represented by a ``smoothed conical metric&#39;&#39;. If we impose a specific constraint on the model of string then its central line obeys the Nambu-Goto dynamics in the limit where the radius of the tube tends to zero. If no constraint is added then the world sheet of th

Danny Birmingham

The analytic structure of the Regge action on a cone in $d$ dimensions over a boundary of arbitrary topology is determined in simplicial minisuperspace. The minisuperspace is defined by the assignment of a single internal edge length to all 1-simplices emanating from the cone vertex, and a single boundary edge length to all 1-simplices lying on the boundary.

Janusz Grabowski, Pawel Urbanski

Generalized Schouten, Froelicher-Nijenhuis and Froelicher-Richardson brackets are defined for an arbitrary Lie algebroid. Tangent and cotangent lifts of Lie algebroids are introduced and discussed and the behaviour of the related graded Lie brackets under these lifts is studied. In the case of the canonical Lie algebroid on the tangent bundle, a new common g

Eugene Demler, Hiroshi Kohno, Shou-Cheng Zhang

In this paper, we present analytical and numerical calculations of the pi resonance in the t-J model. We show in detail how the pi resonance in the particle-particle channel couples to and appears in the dynamical spin correlation function in a superconducting state. The contribution of the pi resonance to the spin excitation spectrum can be estimated from g

A. Losev, F. Babalievski

We studied the rigidity percolation (RP) model for aperiodic (quasi-crystal) lattices. The RP thresholds (for bond dilution) were obtained for several aperiodic lattices via computer simulation using the &#34;pebble game&#34; algorithm. It was found that the (two rhombi) Penrose lattice is always floppy in view of the RP model. The same was found for the Amm

A. N. Tahvildar-Zadeh, M. Jarrell, J. K. Freericks

We present numerically exact predictions of the periodic and single-impurity Anderson models to address photoemission experiments on heavy Fermion systems. Unlike the single impurity model the lattice model is able to account for the enhanced intensity, dispersion, and apparent weak temperature dependence of the Kondo resonant peak seen in recent controversi

A. D. Mirlin, D. G. Polyakov, P. Woelfle

We study transport in a smooth random magnetic field, with emphasis on composite fermions (CF) near half-filling of the Landau level. When either the amplitude of the magnetic field fluctuations or its mean value $\bar B$ is large enough, the transport is of percolating nature. While at $\bar{B}=0$ the percolation effects enhance the conductivity $σ_{xx}$, i

Durga P. Choudhury, H. Srikanth, S. Sridhar, ; P. C. Canfield

We report the observation of novel behaviour in the radio frequency (rf) and microwave response of DyNi_2B_2C over a wide range of temperature (T) and magnetic field (H) in the antiferromagnetic (AFM) and superconducting (SC) states. At microwave frequencies of 10 GHz, the T dependence of the surface impedance Z_s=R_s+iX_s was measured which yields the T dep

Hans C. Fogedby

The noisy Burgers equation in one spatial dimension is analyzed by means of the Martin-Siggia-Rose technique in functional form. In a canonical formulation the morphology and scaling behavior are accessed by mean of a principle of least action in the asymptotic non-perturbative weak noise limit. The ensuing coupled saddle point field equations for the local

C. Bennemann, W. Paul, K. Binder, B. Duenweg

We present Molecular Dynamics simulations of the thermal glass transition in a dense model polymer liquid. We performed a comparative study of both constant volume and constant pressure cooling of the polymer melt. Great emphasis was laid on a careful equilibration of the dense polymer melt at all studied temperatures. Our model introduces competing length s

R. W. Godby, I. D. White

A comment is made on the large-cluster limit of the self-energy correction for the quasiparticle energy gap in silicon clusters presented by Serdar Ogut, James R. Chelikowsky and Steven G. Louie in Phys. Rev. Lett. 79, 1770 (1997).

F. Brosens, J. T. Devreese, L. F. Lemmens

The thermodynamical properties are calculated for a three-dimensional model of $N$ harmonically interacting spin-polarized fermions in a parabolic potential well. The obtained dependences of the chemical potential and of the internal energy on the complete range of the temperature and of the number of particles turn out to obey a scaling law, similar to the

Kang-Hun Ahn, K. J. Chang

We find an analogy between the single skyrmion state in the quantum Hall system and the BCS superconducting state and address that the quantum mechanical origin of the skyrmion is electronic pairing. The skyrmion phase is found to be unstable for magnetic fields above the critical field $B_{c}(T)$ at temperature $T$, which is well represented by the relation

M. J. Steel, M. J. Collett

We consider the precise quantum state of two trapped, coupled Bose Einstein condensates in the two-mode approximation. We seek a representation of the state in terms of a Wigner-like distribution on the two-mode Bloch sphere. The problem is solved using a self-consistent rotation of the unknown state to the south pole of the sphere. The two-mode Hamiltonian

Michael Hammond

In this paper, I propose to implement syllabification in OT as a parser. I propose several innovations that result in a finite and small candidate set. The candidate set problem is handled with several moves: i) MAX and DEP violations are not hypothesized by the parser, ii) candidates are encoded locally, and iii) EVAL is applied constraint by constraint. Th

Philippe Blache

In this paper, we propose a disambiguating technique called controlled disjunctions. This extension of the so-called named disjunctions relies on the relations existing between feature values (covariation, control, etc.). We show that controlled disjunctions can implement different kind of ambiguities in a consistent and homogeneous way. We describe the inte

Zoltan Kovacs

We study the stability properties of orbits in dispersing billiards in a homogeneous magnetic field by using a modified formalism based on the Bunimovich-Sinai curvature (horocycle method). We identify simple periodic orbits that can be stabilized by the magnetic field in the four-disk model and the square-lattice Lorentz gas. The stable orbits can play a ke

Rue-Ron Hsu, Jyh-Long Chern, Wei-Fu Lin, Chia-Chu Chen

We analytically determine the correlation functions of the stochastic response of a generic mapping system driven by colored noise. We also address the issue of noise cascading in coupled-element systems, particularly in a uni-directionally coupled system with dc-filtered coupling. A noise-feedback method and an opposite-pairing method are introduced to cont

David C. Black

The difference in formation process between binary stars and planetary systems is reflected in their composition as well as their orbital architecture, particularly orbital eccentricity as a function of orbital period. It is suggested here that this difference can be used as an observational criterion to distinguish between brown dwarfs and planets. Applicat

Insu Yi, Eric G. Blackman

Cosmological gamma-ray bursts (GRBs) could be driven by dissipation of pure electromagnetic energy (Poynting flux) extracted from rapidly rotating compact objects with strong magnetic fields. One such possibility is a young millisecond pulsar (MSP) formed from accretion-induced collapse (AIC) of a white dwarf. The combination of an efficient magnetic dynamo,

Insu Yi, J. Craig Wheeler

The observed abrupt torque reversals in X-ray pulsars, 4U 1626-67, GX 1+4, and OAO 1657-415, can be explained by transition in accretion flow rotation from Keplerian to sub-Keplerian, which takes place at a critical accretion rate, $\sim 10^{16}-10^{17}g/s$. When a pulsar system spins up near equilibrium spin before the transition, the system goes into spin-

Insu Yi, Stephen P. Boughn

Recent studies of the cosmic X-ray background (XRB) have suggested the possible existence of a population of relatively faint sources with hard X-ray spectra; however, the emission mechanism remains unclear. If the hard X-ray emission is from the radiatively inefficient, advection dominated accretion flows (ADAFs) around massive black holes in galactic nucle

T. J. Davidge, D. A. Simons, F. Rigaut, R. Doyon

High angular resolution J, H, K, and L&#39; images are used to investigate the stellar content within 6 arcsec of SgrA*. The data, which are complete to K ~ 16, are the deepest multicolor observations of the region published to date.

F. W. Stecker, O. C. De Jager

We discuss the problem of the absorption of very high-energy gamma-rays by pair production interactions with extragalactic photons which originate from stellar emission in the near IR-UV and reradiation of starlight in the mid- and far-IR. The absorption of gamma-rays above 1 TeV is dominated by interactions with infrared photons. We make a new determination

Q. Daniel Wang

I characterize the global distribution of the 3/4 keV band background with a simple model of the hot Galactic corona, plus an isotropic extragalactic background. The corona is assumed to be approximately polytropic (index = 5/3) and hydrostatic in the gravitational potential of the Galaxy. The model accounts for X-ray absorption, and is constrained iterative

Q. Daniel Wang

A definite prediction from recent N-body/hydro simulations of the structure formation of the universe is the presence of a diffuse intergalactic medium (IGM) in a temperature range of 10^5 - 10^7 K. This hot phase of the IGM may account for most of the baryon content of the universe and may provide unique information on various physical and chemical processe

Priscilla C. Frisch

The properties of the Local Bubble, Local Fluff complex of nearby interstellar clouds, and the heliosphere are mutually constrained by data and theory. Observations and models of the diffuse radiation field, interstellar ionization, pick-up ion and anomalous cosmic-ray populations, and interstellar dust link the physics of these regions. The differences betw

F. Governato, Jeffrey P. Gardner, J. Stadel, T. Quinn

Using cosmological N-body simulations of critical (SCDM) and open (Omega_0=0.3, OCDM) cold dark matter models we have identified dark matter halos which are associated with the progenitors of present day bright early type galaxies. By following their merging history, we show how early type galaxies that formed within massive halos at redshift around 3 are no

F. Haberl, L. Angelini, C. Motch, N. E. White

We present ASCA and ROSAT observations of the Be/X-ray binary pulsars RX J0146.9+6121 and X Persei between 1990 and 1996. Measuring the neutron star spin period and X-ray luminosity of X Persei shows that the episode of low X-ray luminosity and monotonic spin-down since 1978 continued to at least August 1995. ASCA and ROSAT HRI observations of RX J0146.9+612

J. Marti, I. F. Mirabel, S. Chaty, L. F. Rodriguez

The radio, infrared and optical counterparts of the hard X-ray source GRS 1734-292 (l{II}=358.9 deg, b{II}=+1.4 deg) are reported. The optical spectrum exhibits broad (>1000 km s^-1) H alpha emission at a redshift of 0.0214 +/- 0.0005. The radio counterpart is a double-sided synchrotron jet of 5 arcsec, which at a distance of 87 Mpc corresponds to a size of

B. J. Boyle, Roberto Terlevich

We demonstrate that the evolution of the QSO luminosity density with epoch displays a striking similarity to the cosmological evolution of the field galaxy star formation rate, recently derived from a number of independent surveys. The QSO luminosity density at 2800A is approximately one-fortieth that implied by the star formation rate in galaxies throughout

Michael Lashkevich, Yaroslav Pugai

A free field representation for the type $I$ vertex operators and the corner transfer matrices of the eight-vertex model is proposed. The construction uses the vertex-face correspondence, which makes it possible to express correlation functions of the eight-vertex model in terms of correlation functions of the SOS model with a nonlocal insertion. This new no

A. H. Castro Neto, G. Castilla, B. A. Jones

We study the interplay among disorder, RKKY and Kondo interactions in {\it f}-electron alloys. We argue that the non-Fermi liquid behavior observed in these systems is due to the existence of a Griffiths phase close to a quantum critical point. The existence of this phase provides a unified picture of a large class of materials. We also propose new experimen

Romuald A. Janik, Maciej A. Nowak, Gabor Papp, Ismail Zahed

We discuss random matrix models in terms of elementary operations on Blue&#39;s functions (functional inverse of Green&#39;s functions). We show that such operations embody the essence of a number of physical phenomena whether at/or away from the critical points. We illustrate these assertions by borrowing on a number of recent results in effective QCD in va

M. Capone S. Ciuchi, C. Grimaldi

We study the crossover from quasi free electron to small polaron in the Holstein model for a single electron by means of both exact and self-consistent calculations in one dimension and on an infinite coordination lattice. We show that the crossover occurs when both strong coupling and multiphonon conditions are fulfilled leading to different relevant coupli

M. Ciuchini, G. Degrassi, P. Gambino, G. F. Giudice

We present the QCD corrections to the matching conditions of the Delta B =1 magnetic and chromo-magnetic operators in the Standard Model and in two-Higgs doublet models. We use an off-shell matching procedure which allows us to perform the computation using Taylor series in the external momenta, instead of asymptotic expansions. In the Standard Model case, w

Robert Fleischer

The decays $B_d\toπ^\mp K^\pm$ and $B^\pm\toπ^\pm K$ provide interesting constraints on the angle $γ$ of the unitarity triangle of the CKM matrix. It is shown that bounds on $γ$ can also be obtained from the time evolution of untagged $B_s\to K^+K^-$ and $B_s\to K^0\bar{K^0}$ decays, provided the $B_s$ system exhibits a sizeable width difference $ΔΓ_s$. A de

C. Bachas

I compare the calculations of special $F^4$ and $R^4$ terms in the (toroidally-compactified) heterotic and type-I effective actions. Besides checking duality, this elucidates the quantitative rules of D-brane calculus. I explain in particular (a) why D-branes do not run in loops, and (b) how their instanton contributions arise from orbifold fixed points of t

M. K. Parida, N. Nimai Singh

Using radiative correction and seesaw mechanism,we derive analytic formulas for neutrino masses in SUSY unified theories exhibiting, for the first time, a new hierarchial relation among them.The new hierarchy is found to be quite significant especially for smaller values of $\tanβ$.

J. Viehoff, N. Eicker, S. Guesken, H. Hoeber

Disconnected diagrams are expected to be sensitive to the inclusion of dynamical fermions. We present a feasibility study for the observation of such effects on the nucleonic matrix elements of the axial vector current, using SESAM full QCD vacuum configurations with Wilson fermions on $16^3\times 32$ lattices, at $β=5.6$. Starting from the standard methods

J. P. Rodriguez

The equilibrium magnetization for layered superconducting films that experience a nonzero component, $H_{\parallel}$, of magnetic field applied parallel to the layers is computed at temperatures and at perpendicular field components in the vicinity of the decoupling transition. A fermion analogy is exploited for this purpose, whereby it is found that the par

I. H. Brevik, V. V. Nesterenko, I. G. Pirozhenko

The Casimir energy of a solid ball placed in an infinite medium is calculated by a direct frequency summation using the contour integration. It is assumed that the permittivity and permeability of the ball and medium satisfy the condition $ε_1 μ_1=ε_2μ_2$. Upon deriving the general expression for the Casimir energy, a dilute compact ball is considered $(ε_1

Masakazu Murakami, Hidetoshi Fukuyama

Effects of the backward scattering with large momentum transfer are examined in two-dimensional electron system with a special emphasis on electrons around ($π$,0), (0,$π$). The phase diagram is shown in the plane of temperature $T$ and hole doping $δ$ in the mean field approximation and it is found that d-wave superconductivity, antiferromagnetism and $π$-t

T. Tashiro, H. Noda, S. Nakariki, K. Ishii

We investigate the meson, baryon and anti-baryon productions in πp and Kp collisions in terms of a constituent cascade model which includes charm flavour. The constituent diquark in an incident baryon has a tendency to get a large momentum fraction, resulting in considerable difference of subenergies for particle productions from quark-diquark and quark-anti

Dean Lee, Howard Georgi

We introduce a new sum-rule for large-$N_c$ QCD which relates the density of heavy quarkonium states, the state-averaged square of the wavefunction at the origin, and the heavy quark current-current correlator. Focusing on the region of energy just above perturbative threshold, we calculate the correlator by incorporating arbitrarily high orders in the QCD c

E. Alfinito, V. Grassi, R. A. Leo, G. Profilo

A system of equations of the reaction-diffusion type is studied in the framework of both the direct and the inverse prolongation structure. We find that this system allows an incomplete prolongation Lie algebra, which is used to find the spectral problem and a whole class of nonlinear field equations containing the original ones as a special case.

G. Morigi, J. I. Cirac, K. Ellinger, P. Zoller

We propose a scheme that allows to laser cool trapped atoms to the ground state of a one-dimensional confining potential. The scheme is based on the creation of a dark state by designing the laser profile, so that the hottest atoms are coherently pumped to another internal level, and then repumped back. The scheme works beyond the Lamb-Dicke limit. We presen

R. G. Nazmitdinov, W. D. Heiss

The main aim of the results presented here is to demonstrate and analyse the importance of shell effects in nuclei, metallic clusters and quantum dots.

G. Chanfray, P. Schuck

We discuss medium modification of the rho meson originating from its coupling to in medium quasi-pions and delta-hole states. This medium effect leads to a marked structure of the rho meson strength function in the $500 MeV$ invariant mass region. We suggest that this effect may provide an explanation of the structure observed by the DLS collaboration in the

D. Drechsel, G. Krein, O. Hanstein

A forward dispersion calculation is implemented for the spin polarizabilities $γ_1, ... ,γ_4$ of the proton and the neutron. These polarizabilities are related to the spin structure of the nucleon at low energies and are structure-constants of the Compton scattering amplitude at ${\cal O}(ω^3)$. In the absence of a direct experimental measurement of these qu

Makito Oi, Naoki Onishi, Naoki Tajima, Takatoshi Horibata

In terms of the exaxt angular momentum projection, properties of the three dimensional cranked HFB (3d-CHFB) states are analyzed quantitatively in the context of the relation between the signature of an intrinsic symmetry and the parity of angular momentum, (-1)^I. We found that the tilted states have favorable features to describe states involved with high-

Marcin Mazur

We prove that any Galois extension of commutative rings with normal basis and abelian Galois group of odd order has a self dual normal basis. Also we show that if S/R is an unramified extension of number rings with Galois group of odd order and $R$ is totally real then the normal basis does not exist for S/R.

Petr E. Pushkar

The Chekanov theorem generalizes the classic Lyusternik-Shnirel&#39;man and Morse theorems concerning critical points of a smooth function on a closed manifold. A Legendrian submanifold Λof space of 1-jets of the functions on a manifold M defines a multi-valued function whose graph is the projection of Λin J^0 M = M x R. The Chekanov theorem asserts that if

Jan Plefka, Andrew Waldron

We present a study of M(atrix) theory from a purely canonical viewpoint. In particular, we identify free particle asymptotic states of the model corresponding to the supergraviton multiplet of eleven dimensional supergravity. These states have a natural interpretation as excitations in the flat directions of the matrix model potential. Furthermore, we provid

P. M. Lavrov, P. Yu. Moshin

We consider two-dimensional gravity with dynamical torsion in the Batalin - Vilkovisky and Batalin - Lavrov - Tyutin formalisms of gauge theories quantization as well as in the background field method.

Marc Kamionkowski, Ali Kinkhabwala

Rates for detection of weakly-interacting massive-particle (WIMP) dark matter are usually carried out assuming the Milky Way halo is an isothermal sphere. However, it is possible that our halo is not precisely spherical; it may have some bulk rotation; and the radial profile may differ from that of an isothermal sphere. In this paper, we calculate detection

A. J. Buras, A. Kwiatkowski, N. Pott

The initial condition at the matching scale $μ_W = O(M_W)$ for the Wilson coefficient of the magnetic photon-penguin operator in the decay $B\to X_s γ$ is calculated in the next-to-leading-order approximation. The technical details of the necessary two-loop calculation in the full theory are described and the matching with the corresponding result in the eff

Bo Andersson, Markus Ringner

We show how a difference in the correlation length longitudinally and transversely, with respect to the jet axis in e+e- annihilation, arises naturally in a model for Bose-Einstein correlations based on the Lund string model. In genuine three-particle correlations the difference is even more apparent and they provide therefore a good probe for the longitudin

S. Catani, B. R. Webber

We show that QCD observables defined as infrared- and collinear-safe, according to the usual Sterman-Weinberg criteria, can nevertheless be infinite at accessible points inside phase space, to any finite order of perturbation theory. Infrared finiteness is restored after resummation of divergent terms to all orders. The resulting characteristic structure, wh

Arthur Lue

We examine the quantum corrections to the static energy for Higgs winding configurations. We evaluate the effective action for such configurations in Weinberg-Salam theory without U(1)-gauge fields or fermions. For a configuration whose size is much smaller than the inverse W-mass, quantum contributions to the energy are comparable to the classical energy. M

Mauro Anselmino

Spin observables may reveal much deeper properties of non perturbative hadronic physics than unpolarized quantities. We discuss here possible origins of single spin asymmetries in DIS, absent in the elementary lepton-quark interactions, and suggest strategies to isolate and understand some non perturbative spin dependence of distribution and fragmentation fu

Antonio Riotto

An inflationary stage dominated by a D-term avoids the slow-roll problem of inflation in supergravity and can naturally emerge in theories with a non-anomalous or anomalous U(1) gauge symmetry. In this talk different aspects of D-term inflation are discussed.

R. Rueckl, H. Spiesberger

Theoretical interpretations of the high-Q^2 events recently observed in deep-inelastic positron-proton scattering at HERA are reviewed. We discuss leptoquarks, squarks with R-parity violating couplings, and contact interactions. Bounds from and implications on other experiments are taken into consideration.

Ulrich Ellwanger

An effective low energy action for Yang-Mills theories is proposed, which invokes an additional auxiliary field $H_{μν}$ for the field strength $F_{μν}$. For a particular relation between the parameters of this action a gluon propagator with a $1/p^4$ behaviour for $p^2 \to 0$ in the Landau gauge is obtained. The abelian subsector of this action admits a dua

Debsankar Mukhopadhyay, WA98 Collaboration

We have analyzed the joint charged particle to photon density correlations in WA98 experiment at CERN-SPS in order to study the formation of the chirally disoriented vacuum in Pb + Pb collisions at 158 AGeV. The method of analysis is based on the event-by-event estimation of a set of robust observables which are the ratios of normalized bivariate factorial m

C. Q. Geng, C. C. Lih, Wei-Min Zhang

Within the light front framework, we calculate the form factors for $B\toγ$ transitions directly in the entire physical range of momentum transfer. Using these form factors, we study the radiative decays of $B\to lν_lγ$ and $B_{s(d)}\toν\barνγ$. We show that the decay rates of $B\to lν_lγ(l=e,μ)$ and $B\toν\barνγ$ are larger than that of the corresponding pu