July 1997 arXiv papers — page 16

Matthias R. Gaberdiel, Barton Zwiebach

A generalized Chan-Paton construction is presented which is analogous to the tensor product of vector bundles. To this end open string theories are considered where the space of states decomposes into sectors whose product is described by a semigroup. The cyclicity properties of the open string theory are used to prove that the relevant semigroups are direct

Sergio Scopetta, Vicente Vento

The feasibility of measuring chiral-odd parton distribution functions in polarized Drell-Yan and semi-inclusive experiments has renewed theoretical interest in their study. Not long ago we presented an analysis of the transversity distribution functions using models of hadron structure and Leading Order evolution. In the meantime Next to Leading Order evolut

Hans Peter Nilles, Nir Polonsky

Gravitational divergences associated with singlet fields in supersymmetric theories are reexamined, and their possible contributions to the low-energy effective theory are pointed out. We demonstrate that such divergences are not necessarily harmful and that Planck-scale physics could play an important role in models of low-energy supersymmetry breaking via

M. L. Mangano, S. R. Slabospitsky

We study the contribution of B_c mesons to the search for B->tau nu decays. We find that at LEP the contributions from B_u and B_c mesons can be comparable. This observation can have a relevant impact on the extraction of constraints on new physics (such as charged-Higgs contributions) from current LEP limits on B->tau nu final states. Inclusion of the B_c c

Ranjita Deka, D. K. Choudhury

We obtain an approximate analytical form of the gluon distribution using the GLAP equation with a factorization ansatz,and test its validity by comparing it with that of Gluck,Reya and Vogt at low $x$ regime. We also present calculations of the longitudinal structure functions.

Massimo Giovannini

The resonant and non-resonant amplification of electromagnetic inhomogeneities is investigated within a phase of coherent dilaton oscillations. We show, in some explicit toy model, how the critical energy density bound applied to the amplified fluctuations of the massless gauge fields can constrain the dilaton mass.

Abdellatif Abada, Michael C. Birse

We investigate the time evolution of a system of quarks interacting with sigma and pion fields starting from an initial configuration consisting of a tube of hot quark plasma undergoing a boost-invariant longitudinal expansion. We work within the framework of the linear sigma model using classical transport equations for the quarks coupled to the mean-field

Gerhard Buchalla, Andrzej J. Buras

We consider for the first time the leading large top mass corrections, arising at higher order in electroweak interactions, to the rare decays $K\toπν\barν$ and the related modes $B\to X_sν\barν$ and $B\to l^+l^-$. Higher order effects of similar type have previously been calculated in the large-$m_t$ limit for key observables of precision electroweak physic

Sandro Ambrosanio, Ann E. Nelson

We discuss the phenomenology of a class of supersymmetric models in which some of the quark and lepton superfields are an integral part of a dynamical supersymmetry breaking sector. The corresponding squarks and sleptons are much heavier than any other superpartners, and could naturally have masses as high as ~ 40 TeV. We discuss a general set of conditions

T. Carli, M. Kuhlen

The sensitivity of existing HERA data on the hadronic final state in deep-inelastic scattering (DIS) to processes induced by QCD instantons is systematically investigated. The maximally allowed fraction of such processes in DIS is found to be on the percent level in the kinematic domain 0.0001 < x-Bjorken < 0.01 and 5 < Q squared < 100 GeV squared. The best

S. V. Chekanov

We present a comparison of local multiplicity fluctuations in angular phase-space intervals with first-order QCD predictions. The data are based on 810k hadronic events at 91.2 GeV collected with the L3 detector at LEP during 1994.

Yuri Levin

The internal thermal noise in LIGO's test masses is analyzed by a new technique, a direct application of the Fluctuation-Dissipation Theorem to LIGO's readout observable, $x(t)=$(longitudinal position of test-mass face, weighted by laser beam's Gaussian profile). Previous analyses, which relied on a normal-mode decomposition of the test-mass motion, were val

P. K. Townsend

Lecture notes for a &#39;Part III&#39; course &#39;Black Holes&#39; given in DAMTP, Cambridge. The course covers some of the developments in Black Hole physics of the 1960s and 1970s.

Nakwoo Kim, Yoonbai Kim, Kyoungtae Kimm

Global U(1) strings with cylindrical symmetry are studied in anti-de Sitter spacetime. According as the magnitude of negative cosmological constant, they form regular global cosmic strings, extremal black cosmic strings and charged black cosmic strings, but no curvature singularity is involved. The relationship between the topological charge of a neutral glo

A. Raghav Chari, F. D. M. Haldane, Kun Yang

In this paper, we propose a gauge-invariant way to define and calculate the effective mass for quasiparticles in systems with gauge interactions, and apply it to a model closely related to the half-filled Landau level problem. Our model is equivalent to the Halperin-Lee-Read $ν= 1/2$ Hamiltonian with an ultraviolet cutoff $Λ$ for the gauge fields, and we exp

V. M. Pudalov, G. Brunthaler, A. Prinz, G. Bauer

We report on magnetotransport studies of the unusual two-dimensional metallic phase in high mobility Si-MOS structures. We have observed that the magnetic field applied in the 2D plane suppresses the metallic state, causing the resistivity to increase dramatically by more than 30 times. Over the total existence range of the metallic state, we have found thre

V. M. Pudalov

Two phenomena have been recently observed in high-mobility Si MOS structures: (1) strong enhancement of the metallic conduction at low temperatures, T < 2K, and (2) the scaling behavior of the temperature and electric field dependences of the resistivity. These results evidence for the true metal-insulator transition in 2d, in apparent disagreement with the

C Godreche, J M Luck

We investigate the low-temperature dynamics of a simple stochastic model, introduced recently in the context of the physics of glasses. The slowest characteristic time at equilibrium diverges exponentially at low temperature. On smaller time scales, the nonequilibrium dynamics of the system exhibits an aging regime. We present an analytical study of the scal

H. Monien, N. Elstner, A. J. Millis

It has been claimed that the absence of the bilayer splitting in the high-temperature superconductor YBCO is a strong experimental indication that there are no coherent quasiparticles present in the CuO planes. We study a pair of strongly correlated planes which are connected by a hopping transfer integral $t_{\perp}$ in the limit of large in-plane coordinat

David Iñiguez, Enzo Marinari, Giorgio Parisi, Juan J. Ruiz-Lorenzo

We compare the probability distributions and Binder cumulants of the overlap in the 3D Ising spin glass with those of the magnetization in the ferromagnetic 2D XY model. We analyze similarities and differences. Evidence for the existence of a phase transition in the spin glass model is obtained thanks to the crossing of the Binder cumulant. We show that the

Marcus Mueller

Reactions at a strongly segregated interface of a symmetric binary polymer blend are investigated via Monte Carlo simulations. End functionalized homopolymers of different species interact at the interface instantaneously and irreversibly to form diblock copolymers. The simulations, in the framework of the bond fluctuation model, determine the time dependenc

Joachim Jacobsen, Karsten W. Jacobsen, James P. Sethna

We study the rate of activated motion over multiple barriers, in particular the correlated double-jump of an adatom diffusing on a missing-row reconstructed Platinum (110) surface. We develop a Transition Path Theory, showing that the activation energy is given by the minimum-energy trajectory which succeeds in the double-jump. We explicitly calculate this t

J. P. Bouchaud, M. Mezard

The low temperature physics of disordered systems is governed by the statistics of extremely low energy states. It is thus rather important to discuss the possible universality classes for extreme value statistics. We compare the usual probabilistic classification to the results of the replica approach. We show in detail that one class of independent variabl

V. S. U. Fazio, L. Komitov, S. T. Lagerwall

Mono-layers of stearic and behenic acids deposited with the Langmuir-Blodgett technique, were used as aligning films in nematic liquid crystal cells. During the filling process the liquid crystal adopts a deformed quasi-planar alignment with splay-bend deformation and preferred orientation along the filling direction. This state is metastable and transforms

Jean-Philippe Bouchaud, Marc Potters, Jean-Pierre Aguilar

When the available statistical information is imperfect, it is dangerous to follow standard optimisation procedures to construct an optimal portfolio, which usually leads to a strong concentration of the weights on very few assets. We propose a new way, based on generalised entropies, to ensure a minimal degree of diversification.

T. Lopez-Arias, A. Smerzi

We study, in the framework of the Boltzmann-Nordheim equation (BNE), the kinetic properties of a boson gas above the Bose-Einstein transition temperature $T_c$. The BNE is solved numerically within a new algorithm, that has been tested with exact analytical results for the collision rate of an homogeneous system in thermal equilibrium. In the classical regim

Dhurjati Prasad Datta

We prove the existence of fractal solutions to a class of linear ordinary differential equations.This reveals the possibility of chaos in the very short time limit of the evolution even of a linear one dimensional dynamical system.

Wojciech Slomczynski, Karol Zyczkowski

We show that the mean dynamical entropy of a quantum map on the sphere is positive and tends logarithmically to infinity in the semiclassical limit. A link between chaotic dynamics of classical systems and the random matrix-like properties of spectra of the corresponding quantum analogues is demonstrated.

G. A. Rutledge, J. E. Hesser, P. B. Stetson

We compare our compilation of the W&#39; calcium index for 71 Galactic globular clusters to the widely used Zinn and West (1984 ApJS, 55, 45) [Fe/H] scale and to Carretta and Gratton&#39;s (1997 A&A Supplement 121, 95) scale from high-dispersion spectra analyzed with Kurucz (1992, private communication) model atmospheres. We find our calcium ranking to be ti

G. A. Rutledge, J. E. Hesser, P. B. Stetson, M. Mateo

We have obtained 2640 CCD spectra with resolution ~4 Angstrom in the region 7250-9000 Angstroms for 976 stars lying near the red giant branches in color-magnitude diagrams of 52 Galactic globular clusters. Radial velocities of ~16 km/second accuracy per star determined from the spectra are combined with other criteria to assess quantitative membership probab

K. W. Lee, Hee-Won Lee

A Monte Carlo method is used to calculate the profiles and the polarization of the Raman scattered O VI lines(lambda lambda 6827,7088) in symbiotic stars. A point-like isotropic UV radiation source is assumed and a simple spherical wind model is adopted for the kinematics of the scattering material from the cool giant. We first investigate the case where the

G. Matt, M. Guainazzi, F. Frontera, L. Bassani

We report on the first detection above ~10 keV of the archetypal Compton-thick Seyfert 2 galaxy NGC 1068. This detection, obtained with the PDS instrument onboard BeppoSAX in the 20-100 keV range, confirms the hardness of the X--ray spectrum above a few keV (as indicated by ASCA observations and supports models envisaging a mixture of both neutral and ionize

Alberto Franceschini, Laura Silva, Gian Luigi Granato, Alessandro Bressan

We have investigated the properties of a bright K-band selected sample of early-type galaxies in the Hubble Deep Field, as representative of the field galaxy population. This dataset is unique as for the morphological information on faint high-z sources, and for complete photometric and spectroscopic coverage. The majority of bright early-type galaxies in th

Andrew Gould, D. L. DePoy

We describe a new method to search for gravitational microlensing toward the Galactic bulge that employs a small camera rather than a conventional telescope and probes new regions of parameter space. The small aperture (~65 mm) permits detection of stellar flux variations corresponding to magnitudes 7<I<16, whereas current searches are restricted by saturati

F. Favata, R. Mewe, N. S. Brickhouse, R. Pallavicini

We present a SAX/LECS X-ray observation of the active binary Capella, the first coronal source observed in the SAX Guest Investigator program. The analysis of this observation, performed using the mekal plasma emission code, shows that the LECS spectrum is well fit by a two-component optically-thin plasma model. A differential emission measure (DEM) obtained

R. G. Gratton, E. Carretta, G. Clementini, C. Sneden

Abundances for Fe, O, and the alpha-elements (Mg, Si, Ca, and Ti) have been derived from high resolution spectra of a sample of about one hundred dwarfs with high precision parallaxes measured by HIPPARCOS. The stars have metal abundances in the range -2.5<[Fe/H]<0.2. The observational data set consists of high dispersion (20,000<R<70,000), high S/N (>200) s

F. Favata, A. Maggio, G. Peres, S. Sciortino

We have studied the performance of global chi^2 fitting of low-resolution X-ray spectra in retrieving intrinsic source parameters, with emphasis on the coronal metallicity. The study has been conducted by fitting large numbers of simulated spectra with known characteristics, and studying the distribution of best-fit parameters. We have studied the behavior o

F. Favata, G. Micela, S. Sciortino

We discuss the apparent widespread presence of Weak-Line T-Tauri stars (WTTS) among stellar coronal sources detected in the ROSAT All-Sky Survey (RASS), and their relative number with respect to young main-sequence stars in the same samples. The approach taken in most of the current literature for identifying and classifying WTT stars among RASS X-ray source

F. Favata, T. Mineo, A. N. Parmar, G. Cusumano

We present a study of the X-ray coronal emission from the active binary VY Ari, using data from both the Low Energy Concentrator Spectrometer (LECS) and the Medium Energy Concentrator Spectrometer (MECS) instruments on-board the X-ray satellite BeppoSAX. Using these instruments, the X-ray spectrum of VY Ari can be studied across two full decades of energy, f

F. Favata, J. Vink, A. N. Parmar, J. S. Kaastra

We have analyzed an observation of the supernova remnant N132D in the Large Magellanic Cloud, performed with the Low Energy Concentrator Spectrometer (LECS) and the Medium Energy Concentrator Spectrometer (MECS) instruments on board the X-ray satellite BeppoSAX. Thanks to the good sensitivity of the LECS/MECS combination over the range 0.3--8.5~keV we were a

Gustavo A. Medina Tanco

The deflection of extragalactic ultra-high energy protons (E > 4E19 eV) travelling to our galaxy is studied assuming that visible matter traces both, the sources of the particles and the intergalactic magnetic field. The reversal scale and the magnitude of the magnetic field are determined by the local density of matter. The CfA Redshift Catalog is used to d

F. Favata, J. Vink, D. Dal Fiume, A. N. Parmar

We present a broad band X-ray observation of the Cas A supernova remnant, obtained with the 4 narrow field instruments on board the BeppoSAX satellite. The X-ray spectrum thus obtained spans more than two decades in energy, from ~0.5 to ~80 keV. The complete spectrum is fit with a two-component non-equilibrium ionization (NEI) model plus a power-law componen

K. Abe et al, :, The SLD Collaboration

We have measured the B hadron energy distribution in Z0 decays using a sample of semi-leptonic B decays recorded in the SLD experiment at SLAC. The energy of each tagged B hadron was reconstructed using information from the lepton and a partially reconstructed charm-decay vertex. We compared the scaled energy distribution with several models of heavy quark f

Peter Grüter, David Ceperley, Franck Laloë

We determine the critical temperature of a 3-d homogeneous system of hard-sphere Bosons by path-integral Monte Carlo simulations and finite-size scaling. At low densities, we find that the critical temperature is increased by the repulsive interactions, in the form of a power law in density with exponent 1/3: $ΔT_C/T_0\sim (na^3)^{1/3}$. At high densities th

R. Kenna

The duality transformation is applied to the Fisher zeroes near the ferromagnetic critical point in the q>4 state two dimensional Potts model. A requirement that the locus of the duals of the zeroes be identical to the dual of the locus of zeroes in the thermodynamic limit (i) recovers the ratio of specific heat to internal energy discontinuity at criticalit

Marcin Pozniak, Karol Zyczkowski, Marek Kus

Composed ensembles of random unitary matrices are defined via products of matrices, each pertaining to a given canonical circular ensemble of Dyson. We investigate statistical properties of spectra of some composed ensembles and demonstrate their physical relevance. We discuss also the methods of generating random matrices distributed according to invariant

H. A. Kastrup

Many authors - beginning with Bekenstein - have suggested that the energy levels E_n of a quantized isolated Schwarzschild black hole have the form E_n = sigma sqrt{n} E_P, n=1,2,..., sigma =O(1), with degeneracies g^n. In the present paper properties of a system with such a spectrum, considered as a quantum canonical ensemble, are discussed: Its canonical p

Matthias Klein, Jan Louis

Singularities in the Yukawa and gauge couplings of N=1 compactifications of the SO(32) heterotic string are discussed.

C. Thron, S. J. Dong, K. F. Liu, H. P. Ying

We introduce the Padé--Z$_2$ (PZ) stochastic estimator for calculating determinants and determinant ratios. The estimator is applied to the calculation of fermion determinants from the two ends of the Hybrid Monte Carlo trajectories with pseudofermions. Our results on the $8^3 \times 12$ lattice with Wilson action show that the statistical errors from the st

Michael Schubnell

We observed the BL Lac object Markarian 421 with the X-ray satellite RXTE and the Whipple Air Cerenkov Telescope during a two week correlated X-ray/gamma-ray campaign in May 1996. Two dramatic outbursts with extremely rapid and strong flux variations were observed at TeV energies during this period. The X-ray emission in the 2-10 keV band was highly variable

Oleg A. Soloviev

I comment on a curious relation between Siegel&#39;s model of random lattice strings and type IIB matrix model. The comparison of the two theories suggests that there may exist extra terms in the latter which are overlooked in the weak string coupling limit.

T. B. Liverpool, M. Stapper

We present a field-theoretic renormalization group (RG) analysis of a single flexible, screened polyelectrolyte chain (a Debye-Hückel chain) in a polar solvent. We point out that the Debye-Hückel chain may be mapped onto a local field theory which has the same fixed point as a generalised $n \to 1$ Potts model. Systematic analysis of the field theory shows t

Amitava Datta, Aseshkrishna Datta, Anirban Kundu, Biswarup Mukhopadhyaya

We show that the process $e^+e^- \to γ+$ missing energy, arising from the pair production of neutralinos, can probe the $γ-\tildeγ- \gravitino$ as well as the $Z-\tilde Z-\gravitino$ couplings in Gauge Mediated Supersymmetry Breaking models. This enables one to study the mutual relationship of the Goldstino couplings of the different gauginos, a feature whos

Y. K. Ng, G. Bertelli

New ages are computed for the stars from the Edvardsson et al. (1993) data set. The revised values are systematically larger toward older ages (t>4 Gyr), while they are slightly lower for t<4 Gyr. A similar, but considerably smaller trend is present when the ages are computed with the distances based on Hipparcos parallaxes. The resulting age-metallicity rel

A. Echeverria-Enriquez, M. C. Munoz-Lecanda, N. Roman-Roy

The integrability of multivector fields in a differentiable manifold is studied. Then, given a jet bundle $J^1E\to E\to M$, it is shown that integrable multivector fields in $E$ are equivalent to integrable connections in the bundle $E\to M$ (that is, integrable jet fields in $J^1E$). This result is applied to the particular case of multivector fields in the

S. Hosono

We present a detailed analysis of the GKZ(Gel&#39;fand, Kapranov and Zelevinski) hypergeometric systems in the context of mirror symmetry of Calabi-Yau hypersurfaces in toric varieties. As an application we will derive a concise formula for the prepotential about large complex structure limits. (Talk given at the Taniguchi Symposium ``Topological Field Theor

Ivan G. Avramidi

The Green functions of the partial differential operators of even order acting on smooth sections of a vector bundle over a Riemannian manifold are investigated via the heat kernel methods. We study the resolvent of a special class of higher-order operators formed by the products of second-order operators of Laplace type defined with the help of a unique Rie

Dao-Neng Gao, Mu-Lin Yan

In the framework of $U(3)_L\times U(3)_R$ chiral field theory, Dashen&#39;s theorem is reexamined, and the well-known result of $m_{π^\pm}^2-m_{π^0}^2$ obtained by Das, Guralnik, Mathur, Low, and Young is reproduced. We find that Dashen&#39;s theorem, which automatically holds for pseudoscalar mesons in this theory, can be generalized to the sector of axial-

C. Brif, A. Mann

We present a general theory of quasiprobability distributions on phase spaces of quantum systems whose dynamical symmetry groups are (finite-dimensional) Lie groups. The family of distributions on a phase space is postulated to satisfy the Stratonovich-Weyl correspondence with a generalized traciality condition. The corresponding family of the Stratonovich-W

C. Brif, A. Mann

We discuss a scheme for generation of single-mode photon states associated with the two-photon realization of the SU(1,1) algebra. This scheme is based on the process of non-degenerate down-conversion with the signal prepared initially in the squeezed vacuum state and with a measurement of the photon number in one of the output modes. We focus on the generat

G. Plunien, T. Beier, G. Soff, H. Persson

We present a calculation scheme for the two-loop vacuum polarization correction of order $α^2$ to the Lamb shift of hydrogen-like high-Z atoms. The interaction with the external Coulomb field is taken into account to all orders in $(Zα)$. By means of a modified potential approach the problem is reduced to the evaluation of effective one-loop vacuum polarizat

Vesselin I. Dimitrov

Arguments are presented that the assumption, implicit to traditional statistical thermodynamics, that at zero temperature all erratic motions cease, should be dispensed with. Assuming instead a random ultrarelativistic unobservable motion, similar to zitterbewegung, it is demonstrated that in an ideal gas of classical particles the energy equipartition fails

Vesselin I. Dimitrov

Discussed is the classical theoretical description of the experimentally established thermal redshift of spectral lines. Straightforward calculation of the observable spectrum from a canonical ensamble of monochromatic radiators yileds overall blueshift rather than redshift. It is concluded that the customary explanation of the thermal redshift as a second o

Jasper V. Stokman

The five parameter family of multivariable Askey-Wilson polynomials is studied with four parameters generically complex. The multivariable Askey-Wilson polynomials form an orthogonal system with respect to an explicit (in general complex) measure. A partially discrete orthogonality measure is obtained by shifting the contour to the torus while picking up res

A. Kuniba, K. C. Misra, M. Okado, T. Takagi

We study the path realization of Demazure crystals related to solvable lattice models in statistical mechanics. Various characters are represented in a unified way as the sums over one dimensional configurations which we call unrestricted, classically restricted and restricted paths. As an application characters of Demazure modules are obtained in terms of $

H. Amm, R. Stannarius, A. G. Rossberg

We characterize the director structures in electroconvection patterns of nematic liquid crystals by means of polarising microscopy. This study was stimulated by a theory put forward by Rossberg et al. (patt-sol/9701005) who propose a mechanism for chevron texture formation. We characterize the relation between the wave vector modulation and in-plane twist mo

M. Hedayati-Poor, H. S. Sherif

A relativistic model for the quasifree photoproduction of eta meson from complex nuclei is developed. The interactions between fields are introduced through effective Lagrangians. Contributions from several nucleon resonances as well as nucleon Born terms and vector meson exchange diagrams are included. Nucleon and eta wavefunctions are solutions of Dirac an

Spencer Klein, Evan Scannapieco

Ultrarelativistic heavy ion beams carry large electromagnetic and strong absorptive fields, allowing exploration of a variety of physics. Two-photon, photon-Pomeron, and double Pomeron interactions can probe a huge variety of couplings and final states. RHIC will be the first heavy ion accelerator energetic enough to produce hadronic final states via coheren

V. D. Efros, W. Leidemann, G. Orlandini

The total photodisintegration cross sections of three-body nuclei are calculated with semirealistic NN potentials below pion threshold. Full final state interaction with Coulomb force is taken into account via the Lorentz integral transform method. The experimental total cross sections are well described and the sum rule $σ_{-1}(^3$H) agrees with elastic ele

A. I. L&#39;vov, S. Scopetta, D. Drechsel, S. Scherer

Photoproduction of $e^+e^-$ pairs at small angles is investigated as a tool to determine the functions $f_1$ and $f_2$ entering the real-photon forward Compton scattering amplitude. The method is based on an interference of the Bethe-Heitler and the virtual Compton scattering mechanisms, generating an azimuthal asymmetry in the $e^+$ versus $e^-$ yield. The

A. W. Thomas

There is currently enormous interest in the investigation of how hadron properties may be altered by immersion in matter. There is strong evidence of a reduction in the mass of the rho meson from relativistic heavy ion collisions as well as a hint from a recent experiment on photoproduction in light nuclei. We briefly review the main theoretical ideas which

N. Nose-Togawa, S. Hirenzaki, K. Kume

We have studied nuclear quadrupole deformation effects in deeply bound pionic atoms theoretically. We have evaluated the level shifts and widths of the hyperfine components using the first order perturbation theory and compared them with the effects of neutron skin. We conclude that the nuclear quadrupole deformation effects for deeply bound $1s$ and $2p$ st

David J. Grabiner, Jeffrey C. Lagarias

This paper describes the cutting sequences of geodesic flow on the modular surface H/PSL(2,Z) with respect to the standard fundamental domain F = {z=x+iy: -1/2 <= x <= 1/2 and |z|>=1} of PSL(2,Z). The cutting sequence for a vertical geodesic {θ+it: t > 0} is related to a one-dimensional continued fraction expansion for θ, called the one-dimensional Minkowski

Pierre Mathieu, Gerard Watts

In this work we pursue the singular-vector analysis of the integrable perturbations of conformal theories that was initiated in hep-th/9603088. Here we consider the detailed study of the N=1 superconformal theory and show that all integrable perturbations can be identified from a simple singular-vector argument. We identify these perturbations as theories ba

Philip Candelas, Eugene Perevalov, Govindan Rajesh

We present an algorithm for obtaining the matter content of effective six-dimensional theories resulting from compactification of F-theory on elliptic Calabi-Yau threefolds which are hypersurfaces in toric varieties. The algorithm allows us to read off the matter content of the theory from the polyhedron describing the Calabi-Yau manifold. This is based on t

Charles B. Thorn

We develop possible versions of supersymmetric single particle quantum mechanics, with application to superstring-bit models in view. We focus principally on space dimensions $d=1,2,4,8$, the transverse dimensionalities of superstring in $3,4,6,10$ space-time dimensions. These are the cases for which ``classical&#39;&#39; superstring makes sense, and also th

Jean-Bernard Zuber

Graphs which generalize the simple or affine Dynkin diagrams are introduced. Each diagram defines a bilinear form on a root system and thus a reflection group. We present some properties of these groups and of their natural &#34;Coxeter element&#34;. The folding of these graphs and groups is also discussed, using the theory of C-algebras. (Proceedings of the

Noriaki Ikeda

We obtain the exact operator solution of two-dimensional quantum Born-Infeld theory. This theory has a Lagrangian density non-polynomial in the fundamental fields. So this analysis might shed some light on the analysis of non-perturbative effects of field theories. We find the new exact soluble class of quantum field theories.

Gianguido Dall&#39;Agata, Kurt Lechner, Dmitri Sorokin

Covariant actions for the bosonic fields of D=10 IIB supergravity are constructed with the help of a single auxiliary scalar field and in a formulation with an infinite series of auxiliary (anti)-self-dual 5-form fields.

Ashoke Sen

We analyse the world-volume theory of multiple Kaluza-Klein monopoles in string and M-theory by identifying the appropriate zero modes of various fields. The results are consistent with supersymmetry, and all conjectured duality symmetries. In particular for M-theory and type IIA string theory, the low energy dynamics of N Kaluza-Klein monopoles is described

W. Kummer, H. Liebl, D. V. Vassilevich

It is well known that spherically symmetric reduction of General Relativity (SSG) leads to non-minimally coupled scalar matter. We generalize (and correct) recent results to Hawking radiation for a class of dilaton models which share with the Schwarzschild black hole non-minimal coupling of scalar fields and the basic global structure. An inherent ambiguity

V. Dzhunushaliev

The spherically symmetric solution in classical SU(3) Yang - Mills theory is found. It is supposed that such solution describes a classical quark. It is regular in origin and hence the interaction between two quarks is small on the small distance. The obtained solution has the singularity on infinity. It is possible that is the reason why the free quark cann

Y. M. Cho, Kyoungtae Kimm

We present finite energy analytic monopole and dyon solutions whose size is fixed by the electroweak scale. The new solutions are obtained by regularizing the recent Cho-Maison solutions of the Weinberg-Salam model. Our result shows that genuine electroweak monopole and dyon could exist whose mass scale is much smaller than the grand unification scale.

David Atwood

In this talk I will discuss the extraction of the CKM angle $γ$ at B-factories through the interference of the subprocesses $B^-\to K^- D^0$ and $B^- \to K^-\bar D^0$. This seemingly impossible interference may be accomplished by allowing both $D^0$ and $\bar D^0$ to decay to a common final state. If only CP eigenstate decay modes of the $D$ are considered,

J. Kwiecinski, S. C. Lang, A. D. Martin

We study the transverse momentum ($p_T$) spectrum of charged particles produced in deep inelastic scattering (DIS) at small Bjorken $x$ in the central region between the current jet and the proton remnants. We calculate the spectrum at large $p_T$ with the BFKL $\ln (1/x)$ resummation included and then repeat the calculation with it omitted. We find that dat

J. R. Forshaw

Some recent developments in the physics of photon induced reactions are discussed. My presentation is biased towards HERA physics with the other summary talk (of David Miller) being biased towards the gamma-gamma topics. Within the context of the data which were presented, I concentrate upon the the following topics: diffraction; jets; prompt photons; open c

M. Scorletti

This talks examines the effect of angular ordering on the small-x evolution of the unintegrated gluon distribution, and discusses the characteristic function for the CCFM equation.

T. N. Tomaras

A new kind of classically stable static solitons called metastable quasi-topological defects (MQTD) and a systematic method to search for them is presented, with examples from realistic particle physics models. They are characterized by a topological winding number, which is not absolutely conserved so that the MQTD may be converted to radiation by quantum m

Apostolos Pilaftsis

We analyze the scenario of baryogenesis through leptogenesis induced by the out-of-equilibrium decays of heavy Majorana neutrinos and pay special attention to CP violation. Extending a recently proposed resummation formalism for two-fermion mixing to decay amplitudes, we calculate the resonant phenomenon of CP violation due to the mixing of two nearly degene

D. L. Bennett, C. D. Froggatt, H. B. Nielsen

We consider the application of the Multiple Point Criticality Principle to the Standard Model and its extension to the anti-grand gauge group $SMG^3 \otimes U(1)_f$ at the Planck scale. In particular we discuss the predictions for the fine structure constants: $α^{-1}(0) = 137 \pm 9$, $α^{-1}_{1}(M_Z) =99 \pm 5$, $α^{-1}_{2}(M_Z) =29 \pm 6$, $α^{-1}_{3}(M_Z)

Kim Maltman

We investigate the size of potential higher pseudoscalar resonance contaminations of the estimates of isospin-conserving and isospin-violating $πNN$ couplings obtained using the 3-point function method in QCD sum rules. For the isospin-conserving case it is shown that conventional models of the isovector pseudoscalar spectral function imply resonance decay c

Kim Maltman, Carl E. Wolfe

We employ Chiral Perturbation Theory (ChPT) to evaluate the complete set of pseudoscalar matrix elements, <0|P_f|pi^0,eta>, with P_f any of the flavor-diagonal pseudoscalar currents (f=u,d,s), to order (m_d-m_u), and to next-to-leading order in the chiral expansion. These matrix elements represent the basic input to a QCD sum rule analysis of isospin breakin

David Atwood, Marc Sher

Jenkins has pointed out that the process $t\to cW^+W^-$ is GIM suppressed in the standard model. In this note, we calculate the branching ratio for a wide range of models, in which the decay occurs at tree level through exchange of a scalar, fermion or vector. In the case of scalar exchange, a scalar mass between $2m_W$ and 200 GeV leads to a resonant enhanc

Bo-Qiang Ma

The small mass difference $m_n-m_p=1.3 MeV$ between the proton and neutron leads to an excess of $n=π^- p$ over $p=π^+ n$ fluctuations which can be calculated by using a light-cone meson-baryon fluctuation model of intrinsic quark-antiquark pairs of the nucleon sea. The Gottfried sum rule violation may partially be explained by isospin symmetry breaking betw

Janet M. Conrad, Michael H. Shaevitz, Tim Bolton

Neutrino scattering measurements offer a unique tool to probe the electroweak and strong interactions as described by the Standard Model (SM). Electroweak measurements are accessible through the comparison of neutrino neutral- and charged-current scattering. These measurements are complimentary to other electroweak measurements due to differences in the radi

The OPAL Collaboration, K. Ackerstaff et al

This paper reports a study of B meson oscillations using hadronic Z^0 decays with two identified leptons, and updates a previous publication by including data collected in 1994. Decay times are reconstructed for each of the semileptonic B decays by forming vertices which include the lepton and by estimating the B meson momentum. The mass difference, Delta(m_

The OPAL Collaboration, K. Ackerstaff et al

An event sample enriched in semileptonic decays of b hadrons is selected using an inclusive lepton selection from approximately 3.0 million hadronic Z^0 decays collected with the OPAL detector. This sample is used to investigate B meson oscillations by reconstructing a proper decay time for the parent of each lepton, using a jet charge method to estimate the

S. Kaniel, Y. Itin

General relativity postulates that the gravity field is defined on a Riemannian manifold. The field equations are $R^μ_ν= 0$ i.e. Ricci&#39;s curvature tensor vanishes. The field equations have to be augmented by natural physical requirements like orientability, time orientability and existence of a spinorial structure. Moreover, it is impossible to define t

Ugo Moschella, Richard Schaeffer

We solve a continuing controversy when dealing with density fluctuations in open Friedman-Robertson-Walker universes, on the physical relevance of a class of exponential modes. We show explicitly and rigorously that these modes enter the expansion of quantum fields. In the maximally symmetric de Sitter case, encountered in inflationary models, they are excit

I. Oda

We study an $N + 1$ dimensional generalization of the Schwarzschild black hole from the quantum mechanical viewpoint. It is shown that the mass loss rate of this higher dimensional black hole due to the black hole radiation is proportional to $1 \over r^{N-1}$ where $r$ is the radial coordinate. This fact implies that except in four dimensions the quantum fo