April 1995 arXiv papers — page 4

Hanqing Zheng

We study the final state strong interactions of the $B\rightarrow DK$ decay processes, using the Regge model. We conclude that the final state interaction phases are very small, typically a few degrees. Neglecting final state interactions in obtaining the weak decay amplitudes is a good approximation.

Emmanuel A. Paschos, Utpal Sarkar, Hiroto So

In $E_6$ models there are new particles whose baryon number is not uniquely assigned. We point out that the baryon and lepton number assignment to these particles can change the baryogenesis scenario significantly. We consider left-right symmetric extension of the standard model in which $(B-L)$ quantum number is gauged. The identification of $(B-L)$ with a

A. V. Kotikov

The paper presents the $QCD$ description of the hard and semihard processes in the framework of the Wilson operator product expansion. The smooth transition between the cases of the soft and hard Pomerons is obtained.

M. A. Braun

The forward elastic amplitude for scattering of real and weakly virtual photons is studied in the framework of the theory of reggeized gluons, with large $N_{c}$ and a running coupling constant introduced in the manner which preserves the bootstrap condition. Transition from a single to multiple pomeron exchanges is observed as $x$ gets smaller. For very low

H. Shiomi, T. Hatsuda

The pion-nucleon coupling constant $g_{πN}$ is studied on the basis of the QCD sum rules. Both the Borel sum rules and the finite energy sum rules for $g_{πN}$ are used to examine the effects of higher dimensional operators (up to dim. 7) and $α_s$ corrections in the operator product expansion. Agreement with the experimental number is reached only when $S_π

Zhen Cao, Rudolph C. Hwa

For systems that involve particle production through branching processes the concept of chaos is explored. The measures that can describe their behaviors are investigated. Monte Carlo simulation is used to generate events according to perturbative QCD and an Abelian model. It is shown how the measures proposed distinguish the two cases in ways that character

D. J. Broadhurst, D. Kreimer

We evaluate all the primitive divergences contributing to the 7--loop $β$\/--function of $ϕ^4$ theory, i.e.\ all 59 diagrams that are free of subdivergences and hence give scheme--independent contributions. Guided by the association of diagrams with knots, we obtain analytical results for 56 diagrams. The remaining three diagrams, associated with the knots $

Grigorios I. Poulis, Howard D. Trottier

We calculate the potential between ``quarks'' which are in the adjoint representation of SU(2) color in the three-dimensional lattice theory. We work in the scaling region of the theory and at large quark separations $R$. We also calculate the masses $M_{Qg}$ of color-singlet bound states formed by coupling an adjoint quark to adjoint glue (``gluelum

Stefano Capitani, Giancarlo Rossi

Using the formal languages Schoonschip and Form, we have developed general codes that are able to carry out all the algebraic manipulations needed to perform analytic lattice calculations, starting from the elementary building blocks (propagators and vertices) of each Feynman diagram. The main difficulty resides in the fact that, although there are many buil

H1 Collaboration

A contact interaction analysis is presented to search for new phenomena beyond the Standard Model in deep inelastic $e^\pm p \rightarrow e^\pm \, hadrons$ scattering. The data are collected with the H1 detector at HERA and correspond to integrated luminosities of $0.909 \ {\rm pb}^{-1}$ and $2.947 \ {\rm pb}^{-1}$ for electron and positron beams, respectivel

Domenico Giulini, Jorma Louko

We address the role of large diffeomorphisms in Witten's 2+1 gravity on the manifold ${\bf R} \times T^2$. In a ``spacelike sector" quantum theory that treats the large diffeomorphisms as a symmetry, rather than as gauge, the Hilbert space is shown to contain no nontrivial finite dimensional subspaces that are invariant under the large diffeomorphism

A. E. Pavlov

The question of the integrability of the mixmaster model of the Universe, presented as a dynamical system with finite degrees of freedom, is investigated in present paper. As far as the model belongs to the class of pseudo-Euclidean generalized Toda chains, the method of getting Kovalevskaya exponents developed for chains of Euclidean type, is used. The gene

A. Barrat, M. Mézard

We study the dynamical evolution of a system with a phase space consisting of configurations with random energies. The dynamics we use is of Glauber type. It allows for some dynamical evolution ang aging even at very low temperatures, through the search of configurations with lower energies.

A. Kudrolli, V. Kidambi, S. Sridhar

Wavefunctions in chaotic and disordered quantum billiards are studied experimentally using thin microwave cavities. The chaotic wavefunctions display universal density distributions and density auto-correlations in agreement with expressions derived fro m a 0-D nonlinear $σ$-model of supersymmetry, which coincides with Random Matrix Theory. In contrast, diso

J. N. Bahcall, Kirhakos, Sofia, D. P. Schneider

HST images (WFC2) of \pks show that this luminous nearby quasar is interacting with diffuse (presumably galactic) material. Two thin wisps that have a total extent of about 20 kpc (for $H_0 = 100$ \kms ${\rm Mpc}^{-1}$ and $Ω_0 = 1.0$) are observed to approximately surround the quasar. One of the wisps appears to pass through a companion galaxy that is locat

E. E. Fenimore, J. J. M. in 't Zand, J. P. Norris, J. T. Bonnell

Gamma-ray burst time histories often consist of many peaks. These peaks tend to be narrower at higher energy. If gamma-ray bursts are cosmological, the energy dependence of gamma-ray burst time scales must be understood in order to correct the time scale dependence due to the expansion of the universe. By using the average autocorrelation function and the av

Marek A. Abramowicz, Xingming Chen, Ronald E. Taam

The global nonlinear time dependent evolution of accretion disk-corona systems in X-ray binary sources has been investigated to provide an understanding of the low frequency ($\sim 0.04$~Hz) quasi-periodic oscillations (QPOs) observed recently in the Rapid Burster MXB 1730-335 and in some black hole candidates sources (Cyg X--1 and GRO~J0422+32). We consider

T. Yano, M. Nagashima, N. Gouda

The Press-Schechter(PS) formalism for the mass function of the collapsed objects are reanalyzed. The factor of two in the Press-Schechter formalism is argued to be correct in the sharp $k$-space filter even when we use the another approach proposed by Jedamzik(1994) in the cloud-in-cloud problem, which is different from the previous approach by Peacock & Hea

Hisao Hayakawa, Su Yue, Daniel C. Hong

We present a hydrodynamic model that captures the essence of granular dynamics in a vibrating bed. We carry out the linear stability analysis and uncover the instability mechanism that leads to the appearance of the convective rolls via a supercritical bifurcation of a bouncing solution. We also explicitly determine the onset of convection as a function of c

Arthur Kosowsky, Michael S. Turner

Accurate ($\lesssim 1\% $) predictions for the anisotropy of the Cosmic Background Radiation (CBR) are essential for using future high-resolution ($\lesssim 1^\circ$) CBR maps to test cosmological models. In many inflationary models the variation (``running'') of the spectral index of the spectrum of density perturbations is a significant effect and leads to

A. Bialas, A. Krzywicki

We show that the effects of quantum interference can be implemented in Monte-Carlo generators by modelling the generalized Wigner functions. A specific prescription for an appropriate modification of the weights of events produced by standard generators is proposed.

Felix Ritort

We propose a microscopic model without energy barriers in order to explain some generic features observed in structural glasses. The statics can be exactly solved while the dynamics has been clarified using Monte Carlo calculations. Although the model has no thermodynamic transition it captures some of the essential features of real glasses, i.e., extremely

C. Athanassopoulos, L. B. Auerbach, R. Bolton, B. Boyd

A search for $\nuebar$'s in excess of the number expected from conventional sources has been made using the Liquid Scintillator Neutrino Detector, located 30 m from a proton beam dump at LAMPF. A $\nuebar$ signal was detected via the reaction $\nuebar\,p \rightarrow e^{+}\,n$ with $e^+$ energy between 36 and $60\mev$, followed by a $\gamma$ from $np\rightarr

David Polarski, Alexei A. Starobinsky

Transition to the semiclassical behaviour and the decoherence process for inhomogeneous perturbations generated from the vacuum state during an inflationary stage in the early Universe are considered both in the Heisenberg and the Schrödinger representations to show explicitly that both approaches lead to the same prediction: the equivalence of these quantum

E. T. Akhmedov, M. N. Chernodub, M. I. Polikarpov

First we discuss various topological objects (monopoles, ``minopoles'' and ``hybrids'') which may be important for the confinement mechanism in various abelian projections. The second topic is the string between quark and antiquark. The standard quantum string with the Nambu-Goto action exists only in D=26. If we start from the field theory,

J. A. N. Filipe, A. J. Bray, S. Puri

The late-time phase-ordering kinetics of the O(n) model for a non-conserved order parameter are considered for the case where the O(n) symmetry is broken by the initial conditions or by an external field. An approximate theoretical approach, based on a `gaussian closure' scheme, is developed, and results are obtained for the time-dependence of the mean o

Dana Stanley Fine

Previous path integral treatments of Yang-Mills on a Riemann surface automatically sum over principal fiber bundles of all possible topological types in computing quantum expectations. This paper extends the path integral formulation to treat separately each topological sector. The formulation is sufficiently explicit to calculate Wilson line expectations ex

S. B. Popov, V. M. Lipunov, L. M. Ozernoy, K. A. Postnov

X-ray binary population at the Galactic center is proposed here to form as a result of a starburst, which is synthesized by using the ``Scenario Machine'' code of binary star evolution. For the currently assumed starburst age of 4-7 millions years, our results are consistent with the recent {\it GRANAT} X-ray observations of the Galactic center and p

L. P. Colatto, J. L. Matheus-Valle

Based on the idea of quantum groups and paragrassmann variables, we presenta generalization of supersymmetric classical mechanics with a deformation parameter $q= \exp{\frac{2 πi}{k}}$ dealing with the $k =3$ case. The coordinates of the $q$-superspace are a commuting parameter $t$ and a paragrassmann variable $θ$, where $% θ^3 = 0$. The generator and covari

R. J. Cova, W. J. Zakrzewski

In the spirit of previous papers, but using more general field configurations, the non-linear O(3) model in (2+1)-D, modified by the addition of both a potential-like term and a Skyrme-like term, is considered. The instanton solutions are numerically evolved in time and some of their stability properties studied. They are found to be stable, and a repulsive

Shuxue Ding

We investigate the dynamics of a Yang-Mills cosmology (YMC, the FRW type spacetime) bubble in the Bartnik-McKinnon (BK) spacetimes. Because a BK spacetime can be identified to a YMC spacetime with a finite scale factor in the neighborhood of the origin, we can give a natural initial condition for the YMC bubble. The YMC bubble can smoothly emerge from the or

A. Kazarnovski-Krol

In this paper cycles for asymptotic solutions for Heckman-Opdam hypergeometric system of type $A_n$ are described. Cycles are enumerated by elements of symmetric group. Leading asymptotic and leading coefficient are calculated. Value of certain multiple integral over special cycles is calculated with the help of result of Opdam.

Klaus Schertler, Markus H. Thoma

The addition of angular momenta can be reduced to elementary coupling processes of spin-$\frac{1}{2}$-particles. In this way, a method is developed which allows for a non-recursive, simultaneous computation of all Clebsch-Gordan coefficients concerning the addition of two angular momenta. The relevant equations can be interpreted easily, analogously to simpl

Vitaly Tarasov, Alexander Varchenko

We prove that Bethe vectors generically form a base in a tensor product of irreducible heighest weight $gl_2$-modules or $U_q(gl_2)$-modules. We apply this result to difference equations with regular singular points. We show that if such an equation has local solutionss at each of its singular point, then generically it has a polynomial solution.

Timm Plefka

A multiple-time scaling analysis of the dissipative, transversely driven Landau-Lifshitz equation in presence of exchange, shape demagnetisation and week anisotropy fields is performed for a dynamic domain state. Stationary solutions of the resulting equations explain the spatiotemporal structure of the walls and are in agreement with previous simulations.

Dirk H. Rischke, Yaris Puersuen, Joachim A. Maruhn

We investigate the compression of nuclear matter in relativistic hydrodynamics. Nuclear matter is described by a $σ-ω$--type model for the hadron matter phase and by the MIT bag model for the quark--gluon plasma, with a first order phase transition between both phases. In the presence of phase transitions, hydrodynamical solutions change qualitatively, for i

S. A. Rakityansky, S. A. Sofianos, V. B. Belyaev, W. Sandhas

The scattering lengths of eta-meson collisions with light nuclei d,t,3He, and 4He are calculated on the basis of few-body equations in coherent approximation. It is found that the eta-nucleus scattering length depends strongly on the number of nucleons and the potential-range parameter. By taking into account the off-shell behavior of the eta-N amplitude, th

Ling-Lie Chau, Itaru Yamanaka

We find a conserved monodromy matrix differential operator T in the quantum Self-Dual Yang-Mills (SDYM) system and show that it satisfies the exchange algebra RTT=TTR. From its two infinitesimal forms, we obtain the infinite conserved quantum nonlocal-charge algebras and the infinite conserved Yangian algebras. It is remarkable that such conserved algebras e

G. Grignani, G. Semenoff, P. Sodano

We argue that, at finite temperature, parity invariant non-compact electrodynamics with massive electrons in 2+1 dimensions can exist in both confined and deconfined phases. We show that an order parameter for the confinement-deconfinement phase transition is the Polyakov loop operator whose average measures the free energy of a test charge that is not an in

Ali Yegulalp

We consider the field theory of $N$ massless bosons which are free except for an interaction localized on the boundary of their 1+1 dimensional world. The boundary action is the sum of two pieces: a periodic potential and a coupling to a uniform abelian gauge field. Such models arise in open string theory and dissipative quantum mechanics, and possibly in ed

Ulf H. Danielsson, Bo Sundborg

We write down the weak-coupling limit of N=2 supersymmetric Yang-Mills theory with arbitrary gauge group \( G \). We find the weak-coupling monodromies represented in terms of \( Sp(2r,\bzeta ) \) matrices depending on paths closed up to Weyl transformations in the Cartan space of complex dimension r, the rank of the group. There is a one to one relation bet

Nobuyoshi Ohta, Takashi Shimizu

It was previously shown that most of the superstrings can be obtained from those with higher world-sheet supersymmetry as spontaneously broken phases. In this paper, we show that the small $N=4$ superstring, which was left out of this hierarchy of the universal string, can be obtained from the large $N=4$ strings. We also show that the $N=2$ string is a spec

G. Lopez Castro, J. L. Lucio M., J. Pestieau

We address the problem of properly defining the $W^{\pm}, Z^0$ propagator in the resonance region. Particular attention is paid to the longitudinal piece of this propagator. We also discuss the related renormalization procedures and the unitarity property.

G. López Castro, J. Pestieau

We assume the vanishing of the quadratic divergences in the $SU(2)_L \otimes U(1)$ electroweak theory. Using $\,$ the $\,$ top $\,$ mass $\,$ value reported recently by the CDF Collaboration $m_t = 176 \pm 8 \pm 10 GeV$, we predict the mass of the Higgs boson to be $m_H = 321 \pm 29 GeV$. If we assume the vanishing of both quadratic and logarithmic divergenc

VALERY A. KHOZE

The identification of the intermediate-mass Higgs process $γγ\rightarrow H \rightarrow b\overline{b}$ will be one of the most important goals of a future photon linear collider. Backgrounds from the continuum $γγ\rightarrow c\overline{c}, b\overline{b}$ leading-order processes can be suppressed by using polarized photon beams in the $J_z = 0$ initial-state.

S. Peris

We discuss the QCD corrections to the large-$m_t$ electroweak contributions to $Δr$ and to the process $Z\to b \bar b$ as two of the most representative examples. This needs the construction of an effetive field theory below the top quark. We discuss the issue of what $μ$ scale is the appropriate one at every stage and argue that, while matching corrections

Jiro KODAIRA, Hiroshi TOCHIMURA, Yoshiaki YASUI, Isamu WATANABE

We apply the pinch technique , which is a method to construct the gauge independent off-shell Green's functions, to the process $e^-γ\rightarrow W^-ν$ to study the effects of radiative corrections to $WWγ$ three gauge boson vertex. The one-loop contributions to the anomalous gauge boson couplings are estimated in the standard model.

M. L. Stong

Possibilites for measuring the $J^{PC}$ quantum numbers of the Higgs particle through its interactions with gauge bosons and with fermions are discussed. Observables which indicate CP violation in these couplings are also identified.

J. P. Ma, B. H. J. McKellar

Using Nonrelativistic QCD on the lattice we studied the mass spectrum of quarkonium systems nonperturbatively for a range of the bar quark mass. We determined two products of the matrix elements involved in quarkonium decays and studied the mass dependence of the results. We predict from our calculations the leptonic decay width of $Υ$, and use the mass depe

Mark P. Haugan, Thierry F. Kauffmann

Recent research has established that nonsymmetric gravitation theories like Moffat's NGT predict that a gravitational field singles out an orthogonal pair of polarization states of light that propagate with different phase velocities. We show that a much wider class of nonmetric theories encompassed by the $χg$ formalism predict such violations of the Ei

Gregory A. Burnett

We study the problem of how long a journey within a black hole can last. Based on our observations, we make two conjectures. First, for observers that have entered a black hole from an asymptotic region, we conjecture that the length of their journey within is bounded by a multiple of the future asymptotic ``size'' of the black hole, provided the spa

G. Gonzalez de la Cruz, Yu. G. Gurevich

In this paper thermal conductivity and thermal diffusivity of a two layer system is examined from the theoretical point of view. We use the one dimensional heat diffusion equation with the appropriate solution in each layer and boundary conditions at the interfaces to calculate the heat transport in this bounded system. We also consider the heat flux at the

Leon Balents, Matthew P. A. Fisher

We consider the non--equilibrium steady states of a driven charge density wave in the presence of impurities and noise. In three dimensions at strong drive, a true dynamical phase transition into a temporally periodic state with quasi--long--range translational order is predicted. In two dimensions, impurity induced phase slips are argued to destroy the peri

D. F. Wang, C. Gruber

In this work, the stability of the insulating phase of the 1D chiral Kondo lattice model is studied at half-filling, within the framework of self-consistent variational theory. It is found that arbitrarily small interaction would drive the system from a conducting phase to an insulating phase, in spite of the chirality of the conducting band.

Peter Fulde, Burkhard Schmidt, Peter Thalmeier

We present a model which can explain semiquantitatively a number of the unusual properties of \mbox{Yb$_4$As$_3$}. The structural phase transition at $T_{\text{c}}\simeq300\,\mbox{K}$ is described by a band Jahn-Teller effect of correlated electrons and is interpreted as a charge ordering of the Yb ions. The low carrier concentration in the low-temperature p

P. Lecheminant, B. Bernu, C. Lhuillier, L. Pierre

On the triangular lattice, for $J_2/J_1$ between $1/8$ and $1$, the classical Heisenberg model with first and second neighbor interactions presents four-sublattice ordered ground-states. Spin-wave calculations of Chubukov and Jolicoeur\cite{cj92} and Korshunov\cite{k93} suggest that quantum fluctuations select amongst these states a colinear two-sublattice o

Laura Cayon, George Smoot

Density perturbations at the decoupling epoch produce angular fluctuations in the temperature of the Cosmic Microwave Background (CMB) radiation that may appear as hot and cold spots. Observational data of the CMB includes instrumental noise in addition to the cosmological signal. One would like to determine which of the observed spots are produced by the no

R. O. Marzke, M. J. Geller, L. N. da Costa, J. P. Huchra

(compressed version) We combine the CfA Redshift Survey (CfA2) and the Southern Sky Redshift Survey (SSRS2) to estimate the pairwise velocity dispersion of galaxies $\sig12$ on a scale of $\sim 1 \hmpc$. Both surveys are complete to an apparent magnitude limit $B(0)=15.5$. Our sample includes 12,812 galaxies distributed in a volume $1.8 \times 10^6 \hmpc3$.

B. J. Boyle, T. Shanks, S. M. Croom

We present the first results of a campaign to secure deep UBVRI CCD photometric calibration in all UK Schmidt equatorial fields with galactic latitudes |b| > 50deg. In this paper we provide information on deep BVRI sequences (B<22) in 14 UK Schmidt survey fields centred at declination=0deg. Deep U sequences have been obtained for 11 of these fields.

B. J. Boyle, R. G. McMahon, B. J. Wiles, M. Elvis

We present the results of an intermediate-resolution (1.5Å) spectroscopic study of 17 X-ray luminous narrow emission-line galaxies previously identified in the Cambridge-Cambridge {\it ROSAT} Serendipity Survey and the {\it Einstein} Extended Medium Sensitivity Survey. Emission-line ratios reveal that the sample is composed of ten Seyfert and seven starburst

B. J. Boyle, R. J. Smith, S. J. Maddox

Based on a cross-correlation analysis of X-ray selected QSOs with faint (B<20.5) galaxies, we find a 5sigma galaxy excess around low-redshift (z<0.3) QSOs with an amplitude identical to that of the galaxy angular correlation function. The similarity between QSO-galaxy clustering and galaxy-galaxy clustering suggests that QSOs are unbiased with respect to gal

V. M. Lipunov, S. B. Popov

The distribution of neutron stars (NS's) is determined by stationary solution of the Fokker-Planck equation. In this work using the observed period changes for four systems: Vela X-1, GX 301-2, Her X-1 and Cen X-3 we determined D, the 'diffusion coefficient',-parameter from the Fokker-Planck equation. Using strong dependence of D on the velocity for Vela X-1

M. Böttcher, C. D. Dermer

We calculate the time- and energy-dependent opacity of high-energy gamma-rays attenuated by pair production interaction with accretion-flare photons that are scattered by gas and dust surrounding thenuclei of active galaxies. We show that the temporal behavior of the high-energy opacity cutoff can be used in conjunction with the time history of the accretion

Ed E. Fenimore, Joshua S. Bloom

The isotropic distribution of gamma-ray bursts as observed with the Burst and Transient Experiment (BATSE) strongly suggests that the bursts are at cosmological distances. At such distances, the expansion of the universe should redshift the spectra and stretch the temporal structure. We relate the observed peak intensities, spectral shapes, and time dilation

Hongguang BI, Jian GE, Li-Zhi FANG

Our goal in this paper is to test some popular dark matter models by Ly-alpha forest in QSO spectra. Recent observations of the size and velocity of Ly-alpha forest clouds have indicated that the Ly-alpha absorption is probably not given by collapsed objects, but pre-collapsed regions in the baryonic density field. Therefore, a linear approximation descripti

Benoit Lussier, Brett Ellman, Louis Taillefer

The thermal conductivity, $κ$, of the heavy fermion superconductor UPt$_3$ was measured down to T$_c$/10. The absence of a linear term in the temperature dependence as T$\rightarrow$0 strongly suggests there are no zero energy quasiparticle excitations, in contradiction with the gapless behaviour often inferred from specific heat. A non-vanishing anisotropy

Gary T. Horowitz, Donald Marolf

It is shown that there are static spacetimes with timelike curvature singularities which appear completely nonsingular when probed with quantum test particles. Examples include extreme dilatonic black holes and the fundamental string solution. In these spacetimes, the dynamics of quantum particles is well defined and uniquely determined.

I. I. Mazin, A. A. Golubov, A. D. Zaikin

We point out that all current Josephson-junction experiments probing directly the symmetry of the superconducting state in YBa2Cu3O7, can be interpreted in terms of the bilayer antiferromagnetic spin fluctuation model, which renders the superconducting state with the order parameters of extended $s$ symmetry, but with the opposite signs in the bonding and an

H. J. de Vega, N. Sánchez

Progress on string theory in curved spacetimes since 1992 are reviewed. After a short introduction on strings in Minkowski and curved spacetimes, we focus on strings in cosmological spacetimes. The classical behaviour of strings in FRW and inflationary spacetimes is now understood in a large extent from various types of explicit string solutions. Three diffe

Stephen R. Lau

This paper presents a complete set of quasilocal densities which describe the stress-energy-momentum content of the gravitational field and which are built with Ashtekar variables. The densities are defined on a two-surface $B$ which bounds a generic spacelike hypersurface $Σ$ of spacetime. The method used to derive the set of quasilocal densities is a Hamil

Ernest Ma, Probir Roy

Motivated by existing and recent data on possible neutrino oscillations, we propose a model of four light neutrinos ($\nu_e, \nu_\mu, \nu_\tau$, and a singlet $\nu_S$) with a pattern of masses and mixing derivable from a $Z_5$ discrete symmetry and the seesaw mechanism. Atmospheric neutrino oscillations occur between $\nu_\mu$ and $\nu_\tau$ as pseudo-Dirac

A. B. Lahanas, V. C. Spanos

We study the $C$ and $P$ even $WWγ$ and $WWZ$ trilinear gauge boson vertices (TGV&#39;s), in the context of the MSSM as functions of the soft SUSY breaking parameters $A_0, m_0, M_{1/2}$ and the momentum $q$ carried by $γ, Z$, assuming the external $W$&#39;s are on their mass shell. We follow a complete renormalization group analysis taking into account all

A. H. Chamseddine, Herbi Dreiner

We discuss local \R-symmetry as a potentially powerful new model building tool. We first review and clarify that a $U(1)$ \R-symmetry can only be gauged in local and not in global supersymmetry. We determine the anomaly-cancellation conditions for the gauged \R-symmetry. For the standard superpotential these equations have {\it no} solution, independently of

J. R. Forshaw R. G. Roberts R. S. Thorne

We present a method for the analytic solution of small $x$ structure functions. The essential small $x$ logarithms are summed to all orders in the anomalous dimensions and coefficient functions. Although we work at leading logarithmic accuracy, the method is general enough to allow the systematic inclusion of sub-leading logarithms. Results and predictions a

L. Feretti, D. Dallacasa, G. Giovannini, A. Tagliani

The polarization data of the radio galaxy NGC4869, belonging to the Coma cluster and located in its central region, allow us to obtain information on the structure of magnetic field associated with the cluster itself. A magnetic field of $\sim$ 8.5 $μ$G, tangled on scales of the order of less than 1 kpc, is required to explain the observed fluctuations of th

A. Hamid Bougourzi, Luc Vinet

We define a natural quantum analogue for the ${\cal Z}$ algebra, and which we refer to as the ${\cal Z}_q$ algebra, by modding out the Heisenberg algebra from the quantum affine algebra $U_q(\hat{sl(2)})$ with level $k$. We discuss the representation theory of this ${\cal Z}_q$ algebra. In particular, we exhibit its reduction to a group algebra, and to a ten

K. Langanke, D. J. Dean, P. B. Radha, Y. Alhassid

We study the gross properties of even-even and $N=Z$ nuclei with $A=48-64$ using shell-model Monte Carlo methods. Our calculations account for all $0 \hbar ω$ configurations in the $fp$-shell and employ the modified Kuo-Brown interaction KB3. We find good agreement with data for masses and total $B(E2)$ strengths, the latter employing effective charges $e_p=

Dirk H. Rischke, Stefan Bernard, Joachim A. Maruhn

We present algorithms to solve relativistic hydrodynamics in 3+1--dimensional situations without apparent symmetry to simplify the solution. In simulations of heavy--ion collisions, these numerical schemes have to deal with the physical vacuum and with equations of state with a first order phase transition between hadron matter and a quark--gluon plasma. We

W. E. Ormand, B. A. Brown

Isospin-mixing corrections for superallowed Fermi transitions in {\it fp}-shell nuclei are computed within the framework of the shell model. The study includes three nuclei that are part of the set of nine accurately measured transitions as well as five cases that are expected to be measured in the future at radioactive-beam facilities. We also include some

Giovanni Panti

This is the final version of a survey on many-valued logic to appear as Chapter 2 of Volume 1 ``Quantified Representation of Uncertainty and Imprecision&#39;&#39; of a ``Handbook of Defensible Reasoning and Uncertainty Management Systems&#39;&#39; to be published by Kluwer. The editors of the Handbook are D. Gabbay and P. Smets, and the editors of Volume 1 a

Jan de Boer, Bas Peeters, Kostas Skenderis, Peter van Nieuwenhuizen

By carefully analyzing the relations between operator methods and the discretized and continuum path integral formulations of quantum-mechanical systems, we have found the correct Feynman rules for one-dimensional path integrals in curved spacetime. Although the prescription how to deal with the products of distributions that appear in the computation of Fey

Antal Jevicki, Miao Li, Tamiaki Yoneya

We discuss the origin of the leg factors appearing in 2D string theory. Computing in the world sheet framework we use the semiclassical method to study string amplitudes at high energy. We show that in the case of a simplest 2-point amplitude these factors correspond entirely to the time delay for reflection off the Liouville wall. Our semiclassical calculat

David Saltzberg

I describe an attempt to understand the significance of the atmospheric neutrino deficit observed by the Kamiokande neutrino detector. In particular, I am concerned with the statistical significance quoted for the zenith-angle dependence of the deficit, which has been cited as evidence for neutrino flavor oscillations free of systematic uncertainties.

A. Shuvaev

The evolution equation for high twist operators is solved in the Double Logarithmic Approximation for cylinder-type diagrams which dominate in the limit of large number of colors. The asymptotic behaviour of the parton correlation function is shown to be determined by the spectrum of the Ising model for a one-dimensional chain of spin-1/2 magnets.

Michael Spira

The two--loop ${\cal O}(α_s G_F m_t^2)$ corrections to the $b\bar b$ decay rate of the Standard Model Higgs boson as well as its production via $e^+e^- \to ZH$ will be presented. These QCD corrections are obtained by using a low-energy theorem for light Higgs bosons compared to the top quark mass. The results yield strong screening effects of the ${\cal O}(G

D. Kharzeev, L. McLerran, H. Satz

We calculate the dissociation rates of quarkonium ground states by tunnelling and direct thermal activation to the continuum. For hadronic matter at temperatures $T \leq 0.2$ GeV, neither of these mechanisms leads to a sufficiently large dissociation to explain the experimentally observed suppression of charmonium. Dissociation by sequential excitation to ex

Volker DRIESEN, Wolfgang HOLLIK

Within the MSSM we calculate the electroweak 1-loop box contributions to the processes $ e^+ e^- \rightarrow Z^0 h^0 $ and $ e^+ e^- \rightarrow A^0 h^0 $. We present detailed results for c. m. energies $\sqrt{s}=200$ GeV and $\sqrt{s}=500$ GeV as well as for $\tanβ=2$ and $\tanβ=50$. The box contributions to the process $ e^+ e^- \rightarrow Z^0 h^0 $ are,

S. Narison

We re-examine the estimate of $\als$ and of the QCD condensates from $e^+e^-\rar I=1$ hadrons data. We conclude that $e^+e^-$ at low energies gives a value of $Λ$ compatible with the one from LEP and from tau inclusive decay. Using a $τ$-like inclusive process and QCD spectral sum rules, we estimate the size of the $D$=4 to 9 condensates by a fitting procedu

S. Narison

We determine the strange quark running mass of the $\overline{MS}$-scheme by $simulating$ $τ$-$like$ inclusive processes for the $old$ Das-Mathur-Okubo sum rule relating the $e^+e^-$ into $I=0$ and $I=1$ hadrons total cross-sections data. We obtain to three-loop accuracy: $\overline{m}_s$(1 GeV)=($196.7\pm 29.1$) MeV. By combining this result with the pseudo

Kaoru Hagiwara, Noriaki Kitazawa

We show that the flavor-diagonal gauge boson of the extended technicolor theory contributes with opposite sign to the standard model correction for the $Zbb$ vertex. This mechanism can naturally explain the deviation of the LEP result from the standard model prediction for the partial width $Γ(Z \rightarrow b{\bar b})$. A smaller value of the QCD coupling, $

Jean Delorme, Magda Ericson, Torleif Ericson

The production of positive pions and neutrons by cosmic muons at underground sites of various depths is investigated. We first test the equivalent photon method in the particular case of $Δ$ excitation by the muon. We find that this method, when it neglects the momentum dependence of the transverse response, reproduces remarkably well the theoretical muon cr

V. Barger, M. Berger, J. Gunion, T. Han

High luminosity muon-muon colliders would provide a powerful new probe of Higgs boson physics through $s$-channel resonance production. We discuss the prospects for detection of Higgs bosons and precision measurements of their masses and widths at such a machine.

Heinz J. Rothe

We reconsider the derivation of the Michael lattice sum rules, which relate the energy and action stored in a flux tube of a quark-antiquark pair to the static interquark potential, and show that they require essential corrections. We then find, using the coupling constant sum rule of Karsch, that the total Minkowski field energy does not match the interquar

Thorsten Ohl

This manual describes version 1.6 of the programming language hepawk, designed for convenient scanning of data structures arising in the simulation of high energy physics events. The interpreter for this language has been implemented in FORTRAN77, therefore hepawk runs on any machine with a FORTRAN77 compiler.

Harald Anlauf, Hans Dieter Dahmen, Angelika Himmler, Panagiotis Manakos

We describe the Monte Carlo event generator WOPPER for four fermion production through W-pairs including resummed leading logarithmic QED radiative corrections.

Bjørn Jensen, Ulf Lindström

We consider the axially symmetric coupled system of gravitation, electromagnetism and a dilaton field. Reducing from four to three dimensions, the system is described by gravity coupled to a non-linear $σ$-model. We find the target space isometries and use them to generate new solutions. It seems that it is only possible to generate rotating solutions from n

Fernando Lund, Victor Steinberg

A new method of detection and measurement of quantum vorticity by scattering second sound off quantized vortices in superfluid Helium is suggested. Theoretical calculations of the relative amplitude of the scattered second sound waves from a single quantum vortex, a vortex ring, and bulk vorticity are presented. The relevant estimates show that an experiment

Kiyohide Nomura

A number of two-dimensional(2D) critical phenomena can be described in terms of the 2D sine-Gordon model. With the bosonization, several 1D quantum systems are also transformed to the same model. However, the transition of the 2D sine-Gordon model, Berezinskii-Kosterlitz-Thouless(BKT) transition, is essentially different from the second-order transition. The

Thomas Powers, Philip Nelson

Thermal fluctuations are important for amphiphilic bilayer membranes since typical bending stiffnesses can be a few $k_B T$. The rod-like constituent molecules are generically tilted with respect to the local normal for packing reasons. We study the effects of fluctuations on membranes with nematic order, a simplified idealization with the same novel feature

Tai Kai Ng

In this paper we study the properties of vortices in two dimensional quantum antiferromagnets with spin magnitude S on a square lattice within the framework of Schwinger-boson mean field theory. Based on a continuum description, we show that vortices are stable topological excitations in the disordered state of quantum antiferromagnets. Furthermore, we argue