November 1993 arXiv papers — page 2

Jiro Kodaira, Yoshiaki Yasui, Ken Sasaki

We examine the radiative corrections to the mass of the lightest Higgs boson in the minimal supersymmetric extension of the standard model. We use the renormalization-group improved effective potential which includes the next-to-leading-order contributions. We find that, contrary to the result of Espinosa and Quirós, the higher-order corrections to the light

C. F. Baillie, A. Irback, W. Janke, D. A. Johnston

It has been suggested that the modified Steiner action functional has desirable properties for a random surface action. In this paper we investigate the scaling of the string tension and massgap in a variant of this action on dynamically triangulated random surfaces and compare the results with the gaussian plus extrinsic curvature actions that have been use

J. Smit, A. J. van der Sijs

A single magnetic monopole in pure SU(2) gauge theory is simulated on the lattice and its mass is computed in the full quantum theory. The results are relevant for our proposed realization of the dual superconductor hypothesis of confinement.

J. Smit, A. J. van der Sijs

A single magnetic monopole in pure SU(2) gauge theory is simulated on the lattice and its mass is computed in the full quantum theory. The results are relevant for our proposed realization of the dual superconductor hypothesis of confinement.

V. Azcoiti, G. Di Carlo, A. F. Grillo, V. Laliena

The reasons for the feasibility of the Microcanonical Fermionic Average ($MFA$) approach to lattice gauge theory with dynamical fermions are discussed. We then present a new exact algorithm, which is free from systematic errors and convergent even in the chiral limit.

Hartmut Wittig, UKQCD Collaboration

We present decay constants from a quenched simulation using both propagating quarks and the static theory at $β=6.2$ on $24^3\times48$. The results using propagating quarks are used to test scaling laws predicted by the heavy quark symmetry.

Arjan Hulsebos

The behavior of vortex loops is studied in the 3-d XY model. It is found that the phase transtiton of the 3-d XY model is caused by percolating vortex loops.

Y. Iwasaki, K. Kanaya, S. Sakai, T. Yoshié

The phase structure of QCD with various number of flavors is studied for Wilson quarks. For the case of $N_F=3$ we find that the finite temperature deconfining transition is of first order in the chiral limit on an $N_t=4$ lattice. Together with our previous results that the deconfining transition in the chiral limit is continuous for $N_F=2$ and is first or

Henri Waelbroeck

We propose a reduced constrained Hamiltonian formalism for the exactly soluble $B \wedge F$ theory of flat connections and closed two-forms over manifolds with topology $Σ^3 \times (0,1)$. The reduced phase space variables are the holonomies of a flat connection for loops which form a basis of the first homotopy group $π_1(Σ^3)$, and elements of the second c

A. Anokhin, L. Berezansky, E. Braverman

For ordinary differential equations and functional differential equations the following result is well known. Suppose any solution is bounded on the half-line for each bounded on the half-line right-hand side. Then under certain conditions the equations is exponentially stable. We prove the same result for a delay differential equation $$ \dot{x}(t) + \sum_{

O. Venäläinen, T. Ala-Nissila, K. Kaski

Dynamics of spreading of viscous non - volatile fluid droplets on surfaces is modelled using a solid - on - solid model, which is studied with Monte Carlo simulations. Tendency for dynamical layering and surface attraction are in part embedded into the effective dynamics of the model. This allows a description of the spreading process with a single parameter

A. Chaiken, L. J. Terminello, J. Wong, G. L. Doll

B and N K-edge x-ray absorption spectroscopy measurements have been performed on three BN thin films grown on Si substrates using ion-assisted pulsed laser deposition. Comparison of the films' spectra to those of several single-phase BN powder standards shows that the films consist primarily of $sp^2$ bonds. Other features in the films' spectra sugge

V. A. Hughes, G. C. MacLeod

To try and confirm the types of object in the list of 2298 potential HII regions identified by Hughes \& MacLeod from the IRAS Point Source Catalog, we selected a sample of 82 for observing at the VLA. We selected half with values of Y = log(F$_{25}$/F$_{12}$) $\geq$ 0.8, and for control purposes, half with values of 0.3 $\leq$ log(F$_{25}$/F$_{12}$) $\leq$

John W. Barrett, Bruce W. Westbury

In this paper we develop a theory for constructing an invariant of closed oriented 3-manifolds, given a certain type of Hopf algebra. Examples are given by a quantised enveloping algebra of a semisimple Lie algebra, or by a semisimple involutory Hopf algebra. The invariant is defined by a state sum model on a triangulation. In some cases, the invariant is th

Michael Mensky

The method of restricted path integrals allows one to effectively consider continuous (prolonged in time) measurements of quantum systems. Monitoring of the system coordinates is such a continuous measurement that allows one to describe a quantum system in terms of trajectories. This approach is applied to chaotic systems. The behavior of such systems is qua

Norihito Sasaki

Citations are updated; referred papers are increased. An error right after the eq.~(27) is corrected, and several chages (not serious) are made.

D. R. Phillips, I. R. Afnan

The derivation of scattering equations connecting the amplitudes obtained from diagrammatic expansions is of interest in many branches of physics. One method for deriving such equations is the classification-of-diagrams technique of Taylor. However, as we shall explain in this paper, there are certain points of Taylor's method which require clarification

M. M. Sharma, G. A. Lalazissis, W. Hillebrandt, P. Ring

Shell effects in nuclei close to the neutron-drip lines have been investigated. It has been demonstrated in the relativistic mean-field theory that nuclei very far from stability manifest the shell effects strongly. This behaviour is in accord with the predictions of nuclear masses in the finite-range droplet model including shell corrections. As a consequen

K. Tsushima, D. O. Riska

The axial exchange current operator that arises from the coupling of the axial field to the pion and effective scalar field in nuclei is constructed. The spatial dependence of this exchange current operator may be determined directly from the nucleon-nucleon interaction. This "$πσ$"-axial exchange current contributes about 5\% to the quenching of the

Andreas Peter, Wolfgang Cassing, Joern M. Haeuser, Alfred Pfitzner

Within a nonperturbative dynamical two-body approach - based on coupled equations of motion for the one-body density matrix and the two-body correlation function - we study the distribution of occupation numbers in a correlated system close to the groundstate, the relaxation of single-particle excitations and the damping of collective modes. For this purpose

G. D. Bosveld, A. E. L. Dieperink, A. G. Tenner

The cross section for semi-inclusive deep inelastic charged current neutrino scattering on hydrogen and deuterium in which a slow proton is observed in coincidence with the muon is computed as a function of Bjorken x and light-cone momentum of the detected proton. In the Impulse Approximation contributions from hadronization and (in case of the deuteron) the

Petr Horava

I present a new class of topological string theories, and discuss them in two dimensions as candidates for the string description of large-$N$ QCD. The starting point is a new class of topological sigma models, whose path integral is localized to the moduli space of harmonic maps from the worldsheet to the target. The Lagrangian is of fourth order in worldsh

Anjan Kundu, Walter Strampp

Exploiting the residual gauge freedom in the formulation of constrained KP hierarchy a number of new integrable systems are derived including hierarchies of Kundu-Eckhaus equation and higher order nonlinear extensions of Yajima-Oikawa and Melnikov hierarchy. In the multicomponent case such gauge freedom generates novel multicomponent as well as vector genera

Anjan Kundu, Walter Strampp

It is shown that the matrix KP hierarchy can yield new integrable equations in $(2+1)$-dimensions along with the corresponding Lax pair. For particular gauge choice this may result derivative and also a higher order nonlinear extension of the Devay-Stewartson equation (DSE),the higher order DSE being a higher dimensional generalisation of the Kundu- Eckhaus

Tom H. Koornwinder, Vadim B. Kuznetsov

We consider representations of quadratic $R$-matrix algebras by means of certain first order ordinary differential operators. These operators turn out to act as parameter shifting operators on the Gauss hypergeometric function and its limit cases and on classical orthogonal polynomials. The relationship with W. Miller's treatment of Lie algebras of first

P. Aschieri

We construct the space of vector fields on quantum groups . Its elements are products of the known left invariant vector fields with the elements of the quantum group itself. We also study the duality between vector fields and 1-forms. The construction is easily generalized to tensor fields. A Lie derivative along any (also non left invariant) vector field i

V. Karimipour

We present a detailed study of the representations of the algebra of functions on the quantum group $ GL_q(n) $. A q-analouge of the root system is constructed for this algebra which is then used to determine explicit matrix representations of the generators of this algebra. At the end a q-boson realization of the generators of $ GL_q(n) $ is given.

J. Ellis, N. Mavromatos, D. Nanopoulos

In the non-critical string framework that we have proposed recently, the time $t$ is identified with a dynamical local renormalization group scale, the Liouville mode, and behaves as a statistical evolution parameter, flowing irreversibly from an infrared fixed point - which we conjecture to be a topological string phase - to an ultraviolet one - which corre

Mauro Anselmino, Stefano Forte

We compute the decay rate for the process $η_c\to p\bar p$ using an effective helicity-flipping proton-antiproton-gluon vertex which incorporates nonperturbative chiral symmetry breaking effects induced by instantons. We fix the strength of the vertex by requiring it to account for the screening of the proton's axial charge observed in deep-inelastic sca

F. Guerin

A review of the properties of this alternate basis is presented. To appear in the proceedings of the 3rd Workshop on Thermal Field Theory, Banff, August 1993.

S. Dittmaier

Using computer-algebraic methods we derive compact analytical expressions for the virtual electroweak radiative corrections to polarized Compton scattering. Moreover the helicity amplitudes for double Compton scattering, which prove to be extremely simple in terms of Weyl-van der Waerden spinor products, are presented for massless electrons. The inclusion of

Istvan Montvay

Topological properties of the gauge field in a two-dimensional Higgs model are investigated. Results of exploratory numerical simulations are presented.

Ya. I. Alber, A. I. Notik

Previously unknown estimates of uniform continuity of projection operators in Banach space have been obtained. They can be used in the investigations of approximation methods, in particular, the method of quasisolutions, methods of regularization and penalty functions, for solving nonlinear problems on exact and peturbed sets.

Ya. I. Alber

This paper is an account (without proofs) of the results of our work "Metric and Generalized Projection Operators in Banach Spaces: Properties and Applications", funct-an/9311001. The Section 9 establishing a connection between variational inequalities and Wienner-Hopf equations in Banach spaces by means of metric and generalized projection operators

Sutapa Mukherji

The overlap of a $d+1$ dimensional directed polymer of length $t$ in a random medium is studied using a Renormalization Group approach. In $d>2$ it vanishes at $T_c$ for $t\rightarrow \infty$ as $t^Σ$ where $Σ=[\frac{d-1}{3-2d}]\frac{d}{z}$ and $z$ is the transverse spatial rescaling exponent. The same formula holds in $d=1$ for any finite temperature and it

S. Giovanazzi, L. Pitaevskii, S. Stringari

We present a microscopic description of edge excitations in the quantum Hall effect which is analogous to Feynman's theory of superfluids. Analytic expressions for the excitation energies are derived in finite dots. Our predictions are in excellent agreement with the results of a recent numerical diagonalization. In the large $N$ limit the dispersion law

Kunihiko KANEKO, Tetsuro KONISHI

Coexistence of various ordered chaotic states in a Hamiltonian system is studied with the use of a symplectic coupled map lattice. Besides the clustered states for the attractive interaction, a novel chaotic ordered state is found for a system with repulsive interaction, characterized by a dispersed state of particles. The dispersed and clustered states form

Kunihiko Kaneko

Network of nonlinear dynamical elements often show clustering of synchronization by chaotic instability. Relevance of the clustering to ecological, immune, neural, and cellular networks is discussed, with the emphasis of partially ordered states with chaotic itinerancy. First, clustering with bit structures in a hypercubic lattice is studied. Spontaneous for

F. Bernardeau

In this paper I consider the nonlinear evolution of a rare density fluctuation in a random density field with Gaussian fluctuations, and I rigorously show that it follows the spherical collapse dynamics applied to its mean initial profile. This result is valid for any cosmological model and is independent of the shape of the power spectrum. In the early stag

Simon L. Morris, Sidney van den Bergh

It is suggested that a significant fraction of the low column-density absorption features seen in the spectra of quasars are produced in pressure-confined tidal debris, that was built up in small groups and clusters of galaxies over a Hubble time. We show that the space-density and cross-section of tidal tails in groups of galaxies are large enough that they

Stacy McGaugh

The oxygen abundances in the \HII regions of a sample of low surface brightness (LSB) disk galaxies are presented. In general, LSB galaxies are found to be metal poor ($Z < {1 \over 3} Z\solar$). Indeed, some LSB galaxies rival the lowest abundance extragalactic objects known. These low metallicities indicate that LSB galaxies evolve slowly, forming relative

Jacob D. Bekenstein, Robert H. Sanders

We study gravitational lensing by clusters of galaxies in the context of the generic class of unconventional gravity theories of the scalar--tensor type. For positive energy scalar fields with any dynamics, the bending of light by a weakly gravitating system (galaxy or cluster) is always smaller than the bending predicted by general relativity for the mass o

Kunihiko Kaneko

The relevance of chaos to evolution is discussed in the context of the origin and maintenance of diversity and complexity. Evolution to the edge of chaos is demonstrated in an imitation game. As an origin of diversity, dynamic clustering of identical chaotic elements, globally coupled each to other, is briefly reviewed. The clustering is extended to nonlinea

Kunihiko Kaneko, Junji Suzuki

Mutual imitation games among artificial birds are studied. By employing a variety of mappings and game rules, the evolution to the edge between chaos and windows is universally confirmed. Some other general features are observed, including punctuated equilibria, and successive alternations of dominant species with temporal complexity. Diversity of species ai

Kunihiko Kaneko, Tetsuya Yomo

A novel mechanism for cell differentiation is proposed, based on the dynamic clustering in a globally coupled chaotic system. A simple model with metabolic reaction, active transport of chemicals from media, and cell division is found to show three successive stages with the growth of the number of cells; coherent growth, dynamic clustering, and fixed cell d

L. Marleau

We introduce two new classes of summable Skyrmions. The Lagrangians they originate from are explicitely constructed. We also analyse how some models could be solve. Exact solutions are found for Skyrme-like toy models.

F. Antonuccio

A theoretical framework based on a simple quasi-number algebra is investigated in a treatment of space-time and gravity.

J. Hietarinta, A. Ramani, B. Grammaticos

We discuss the freedom in the background field (vacuum) on top of which the solitons are built. If the Hirota bilinear form of a soliton equation is given by $A(D_{\vec x})\bd GF=0,\, B(D_{\vec x})(\bd FF - \bd GG)=0$ where both $A$ and $B$ are even polynomials in their variables, then there can be a continuum of vacua, parametrized by a vacuum angle $ϕ$. Th

Tanguy Altherr, David Seibert

We calculate thermal production of u, d, s, c and b quarks in ultra-relativistic heavy ion collisions. The following processes are taken into account: thermal gluon decay (g to ibar i), gluon fusion (g g to ibar i), and quark-antiquark annihilation (jbar j to ibar i), where i and j represent quark species. We use the thermal quark masses, $m_i^2(T)\simeq m_i

D. C. Zheng, B. R. Barrett, J. P. Vary, R. J. McCarthy

We apply the Lee-Suzuki iteration method to calculate the linked-folded diagram series for a new Nijmegen local NN potential. We obtain an exact starting-energy-independent effective two-body interaction for a multi-shell, no-core, harmonic-oscillator model space. It is found that the resulting effective-interaction matrix elements can be well approximated b

Bozena Nerlo-Pomorska, Beata Mach

Isotope shifts of the mean square radii (MSR) and electric quadrupole moments of even-even nuclei with 20< Z < 98$ are calculated using a dynamical microscopic model. A single particle Nilsson potential with the Seo set of correction term parameters, the pairing forces in the BCS formalism and a long range interaction in the local approximation are used. A c

Yang Lu, R. Rosenfelder

We calculate the second-order corrections to the atomic energy level shifts in ordinary and muonic deuterium due to virtual excitations of the deuteron which are important for ongoing and planned precise experiments in these systems. For light atoms a method can be used in which the shift is expressed as integrals over the longitudinal and transverse inelast

M. Baldo, G. F. Burgio, A. Rapisarda

In the framework of the time-dependent mean field theory, we solve the Vlasov-Nordheim equation and study the sensitive dependence of this highly non-linear equation on the initial conditions. We find that, when nuclear matter is inside the spinodal region, initially small differences between similar trajectories grow exponentially and produce strongly diver

D. Van Neck, A. E. L. Dieperink, O. Scholten

Dilepton production following radiative capture of a proton on a nuclear target is studied in the Impulse Approximation. The cross section is decomposed in terms of four time-like nuclear structure functions through a longitudinal-transverse separation of the nuclear current. Using a simple PWIA model, cross sections and conversion factors are calculated for

A. Kempf

We study the commutation relations, uncertainty relations and spectra of position and momentum operators within the framework of quantum group % symmetric Heisenberg algebras and their (Bargmann-) Fock representations. As an effect of the underlying noncommutative geometry, a length and a momentum scale appear, leading to the existence of minimal nonzero unc

M. Blagojević, M. Vasilić, T. Vukašinac

The conformal symmetry in the Liouville theory is analysed by using the Hamiltonian light--front formalism. The boundary conditions of dynamical variables are seen to involve an arbitrary function of time, so that the standard methods for studying gauge symmetries do not work. We develop a general method for constructing the gauge generators, which enables a

Kostas Vlachos, Anna Okopinska

Two possibile applications of the optimized expansion for the free energy of the quantum-mechanical anharmonic oscillator are discussed. The first method is for the finite temperature effective potential; the second one, for the classical effective potential. The results of both methods show a quick convergence and agree well with the exact free energy in th

R. Arnowitt, Pran Nath

Theoretical and experimental motivations behind supergravity grand unified models are described. The basic ideas of supergravity, and the origin of the soft breaking terms are reviewed. Effects of GUT thresholds and predictions arising from models possessing proton decay are discussed. Speculations as to which aspects of the Standard Model might be explained

Zachary Gurlanik

Baryon and lepton number in the standard model are violated by anomalies, even though the fermions are massive. This problem is studied in the context of a two dimensional model. In a uniform background field, fermion production arise from non-adiabatic behavior that compensates for the absence of massless modes. On the other hand, for localized instanton-li

E. Papageorgiu

Starting from a complete set of possible parametrisations of the quark-mass matrices that have the maximum number of texture zeros at the grand unification scale, and the Georgi-Jarlskog mass relations, we classify the neutrino spectra with respect to the unknown structure of the heavy Majorana sector. The results can be casted into a small number of phenome

Alexei Yu. Smirnov

Recent (first or/and the best) results from the neutrino experiments are reviewed and their implications for the theory are discussed. The sense of the experiments is the searching for neutrino masses, mixing and interactions beyond the standard model. Present laboratory experiments give upper bounds on the masses and the mixing which are at the level of pre

Antonio Riotto

We calculate the correction to the neutrino electromagnetic vertex due to background of electrons in a large class of models, as the supersymmetric model with explicit breaking of R-parity, where charged scalar bosons couple to leptons and which are able to provide an astrophysically interesting value for the neutrino magnetic (electric) moment, $μ_ν\sim 10^

M. Ciuchini, E. Franco, L. Reina, L. Silvestrini

We discuss in detail the calculation of the leading order QCD corrections to the Effective Hamiltonian which governs $b \rightarrow s\, γ$ and $b \rightarrow s \, g$ transitions in three different regularization schemes (HV, NDR and DRED). We show that intermediate stages of the calculation do depend on the regularization, but the same scheme independent coe

Arnd Leike

Model independent constraints on the mass of extra neutral gauge bosons and their couplings to charged leptons are given for LEP~II and a 500\,GeV $e^+e^-$ collider. Analytical exclusion limits are derived in the Born approximation. The $Z&#39;$ limits obtained with radiative corrections are always worse than those calculated at the Born level. Polarized bea

V. Bernard, N. Kaiser, Ulf-G. Meißner, A. Schmidt

We consider the spin-averaged nucleon forward Compton scattering amplitude in heavy baryon chiral perturbation theory including all terms to order ${\cal O} (q^4)$. The chiral prediction for the spin-averaged forward Compton scattering amplitude is in good agreement with the data for photon energies $ω\le 110$ MeV. We also evaluate the nucleon electric and m

David Brahm, Clarence L. Y. Lee

To calculate the temperature at which a first-order cosmological phase transition occurs, one must calculate $F_c(T)$, the free energy of a critical bubble configuration. $F_c(T)$ is often approximated by the classical energy plus an integral over the bubble of the effective potential; one must choose a method for calculating the effective potential when $V&

Kiwoon Choi

In supersymmetric models, there are new CP violating phases which, if unsuppressed, would give a too large neutron electric dipole moment. We examine the possibility of small SUSY phases in string-inspired supergravity models in which supersymmetry is broken by the auxiliary components of the dilaton and moduli superfields. It is found that the SUSY phases c

M. V. Ramana

We calculate the production rate of gauge-boson pairs at $e^+e^-$ colliders in a model with a ``hidden&#39;&#39; electroweak symmetry breaking sector - i.e. one in which there are a large number of particles in the symmetry breaking sector other than the $W^{\pm}$ \thinspace and the $Z^0$. In such a model, the elastic $W^{\pm}$ \thinspace and $Z^0$ scatterin

S. Gavin, A. Gocksch, R. D. Pisarski

As an extension of $QCD$, consider a theory with ``$2+1$'' flavors, where the current quark masses are held in a fixed ratio as the overall scale of the quark masses is varied. At nonzero temperature and baryon density it is expected that in the chiral limit the chiral phase transition is of first order. Increasing the quark mass from zero, the chiral transi

Hugh Shanahan, UKQCD Collaboration

Preliminary results are presented on the calculation of the relevant form factor for the radiative decay $\overline{B} \rightarrow K^* γ$ We find that the form factor is weakly dependent on the spectator quark mass. We compare the results obtained for a full chiral extrapolation and where this independence is assumed. Both results are found to be statistical

Henning Hoeber

We present a first test of heavy quark spin-flavour symmetries in matrix elements for semi-leptonic decays \bar B to D l\barνand \bar B to D^* l\barν. We show that O(1/m_Q) corrections are small at masses around the charm for form factors protected by Luke&#39;s Theorem, but are of order 30-40 \% for h_V and h_V/h_{A_{1}}.

Istvan Montvay

The investigation of topological properties of the gauge field in a two-dimensional Higgs model can help in understanding anomalous fermion number violation.

Ya. I. Alber

Metric projection operators can be defined in similar wayin Hilbert and Banach spaces. At the same time, they differ signifitiantly in their properties. Metric projection operator in Hilbert space is a monotone and nonexpansive operator. It provides an absolutely best approximation for arbitrary elements from Hilbert space by the elements of convex closed se

Attila Virosztek, Kazumi Maki

We study the effect of long-range Coulomb interaction on the phason in spin-density wave (SDW) within mean field theory. In the longitudinal limit and in the absence of SDW pinning the phason is completely absorbed by the plasmon due to the Anderson-Higgs mechanism. In the presence of SDW pinning or when the wave vector {\bf q} is tilted from the chain direc

Hyunggyu Park

We study the phase diagram of the three-state Potts model on a triangular lattice with general interactions (ferro/antiferromagnetic) between nearest neighbor spins. When the interactions along two lattice-vector directions are antiferromagnetic and infinitely strong, this model becomes equivalent to a six-vertex model and exhibits a first-order (KDP) transi

Neta A. Bahcall, Lori M. Lubin

Previous comparisons of optical and X-ray observations of clusters of galaxies have lead to the so-called ``$β$ - discrepancy&#39;&#39; that has persisted for the last decade. The standard hydrostatic-isothermal model for clusters predicts that the parameter $β_{spec} = σ_{r}^{2}/(kT/μm_{p})$, which describes the ratio of energy per unit mass in galaxies to

S. Balk, A. Ilakovac, J. G. Korner, D. Pirjol

We point out that there exist two different formulations of the Heavy Quark Effective Theory (HQET). One formulation of HQET was mostly developed at Harvard and involves the use of the equation of motion to eliminate the small components of the heavy quark field. The second formulation, developed in Mainz, involves a series of Foldy-Wouthuysen-type field tra

Ian Affleck

A brief review is given of a new method for studying the critical behavior of quantum impurity problems, based on conformal field theory techniques, which I developed with Andreas Ludwig. Some results on the overscreened Kondo problem are reviewed. It is shown that the simple open and periodic fixed points, which occur in quantum spin chain impurity models,

Gerald Dunne

The $N\to\infty$ limit of the edges of finite planar electron densities is discussed for higher Landau levels. For full filling, the particle number is correlated with the magnetic flux, and hence with the boundary location, making the $N\to\infty$ limit more subtle at the edges than in the bulk. In the $n^{\rm th}$ Landau level, the density exhibits $n$ dis

A. Yu. Dubin, A. B. Kaidalov, Yu. A. Simonov

Starting from the QCD Lagrangian we derive the effective action for massive quark and antiquark at large distances, corresponding to the minimal area low of the Wilson loop. The path integral method is used to quantize the system and the spectrum is obtained with asymptotically linear Regge trajectories. Two dynamical regimes distinguished by the string ener

P. Bouwknegt, J. Mccarthy, K. Pilch

We present results for the BRST cohomology of $\cW[\bfg]$ minimal models coupled to $\cW[\bfg]$ gravity, as well as scalar fields coupled to $\cW[\bfg]$ gravity. In the latter case we explore an intricate relation to the (twisted) $\bfg$ cohomology of a product of two twisted Fock modules.

G. A. Ladinsky, C. --P. Yuan

We study the nonperturbative functions in the Collins--Soper--Sterman resummation formalism by examing Drell--Yan data in both fixed target and collider experiments and then predict the transverse momentum distributions of the $W^\pm$ and $Z^0$ bosons at the Tevatron. Our results differ from that in the literature and agree better with published CDF data. Us

Vu B Ho

A systematic approach to the coordinate transformations in the Schwarzschild singularity problem is considered. It is shown that both singularities at r=0 and r=2m can be eliminated by suitable coordinate transformations.

Stephen P. Martin, Michael T. Vaughn

We compute the two-loop renormalization group equations for all soft supersymmetry-breaking couplings in a general softly broken N=1 supersymmetric model. We also specialize these results to the Minimal Supersymmetric Standard Model.

I. Bigi, B. Blok, M. Shifman, A. Vainshtein

The apparent gap between the measured and the expected value for the semileptonic branching ratio of $B$ mesons has become more serious over the last year. This is due to the improved quality of the data and to the increasing maturity of the theoretical treatment of non-perturbative corrections. We discuss various theoretical options to reduce the semilepton

Attila Csoto

It is demonstrated that the complex scaling method can be used in practical calculations to localize three-body resonances. Our model example emphasizes the fact that in three-body systems several essentially different asymptotic behaviors can appear. We show that the possibility of these different asymptotic configurations can lead to an apparent, resonance

M. P. Locher, Y. Lu, B. S. Zou

We study antiproton-proton annihilation at rest into $πϕ$ and $γϕ$. Rescattering by $\overline{K^*}K+K^*\overline{K}$ and $ρ^{+}ρ^{-}$ for $\overline{p}p\rightarrowπϕ$ states is sizable, of order $(0.90\, {\rm to}\,2.6)\times 10^{-4}$ in the branching ratio, but smaller than experiment. For $\overline{p}p\rightarrowγϕ$ the rescattering contributions are negl

R. D. Amado, F. Cannata, J. -P. Dedonder, M. P. Locher

A unified picture of nucleon antinucleon annihilation into pions emerges from a classical description of the pion wave produced in annihilation and the subsequent quantization of that wave as a coherent state. When the constraints of energy-momentum and iso-spin conservation are imposed on the coherent state, the pion number distribution and charge ratios ar

Richard J. Szabo, Gordon W. Semenoff

By considering the most general metric which can occur on a contractable two dimensional symplectic manifold, we find the most general Hamiltonians on a two dimensional phase space to which equivariant localization formulas for the associated path integrals can be applied. We show that in the case of a maximally symmetric phase space the only applicable Hami

P. Berglund, E. Derrick, T. Hübsch, D. Jancic

Motivated by recent developments in the computation of periods for string compactifications with $c=9$, we develop a complementary method which also produces a convenient basis for related calculations. The models are realized as Calabi--Yau hypersurfaces in weighted projective spaces of dimension four or as Landau-Ginzburg vacua. The calculation reproduces

A. Morozov

Non-abelian coordinate ring of $U_q(SL(N))$ (quantum deformation of the algebra of functions) for $N=2,3$ is represented in terms of conventional creation and annihilation operators. This allows to construct explicitly representations of this algebra, which were earlier described in somewhat more abstract algebraic fashion. Generalizations to $N>3$ and Kac-M

Sergey V. Shabanov

A general procedure for deriving the path integral representation of a transition amplitude on the gauge orbit space having a non-trivial topology is proposed. The path integral formula appears to be modified by including trajectories reflected from the physical configuration space boundary into the sum over paths. A solution of the Gribov problem of gauge f

H. Ishikawa, M. Kato

A similarity transformation, which brings a particular class of the $N=1$ string to the $N=0$ one, is explicitly constructed. It enables us to give a simple proof for the argument recently proposed by Berkovits and Vafa. The $N=1$ BRST operator is turned into the direct sum of the corresponding $N=0$ BRST operator and that for an additional topological secto

H. Saleur, N. P. Warner

We review the construction of exactly solvable lattice models whose continuum limits are $N=2$ supersymmetric models. Both critical and off-critical models are discussed. The approach we take is to first find lattice models with natural topological sectors, and then identify the continuum limits of these sectors with topologically twisted $N=2$ supersymmetri

Ariel R. Zhitnitsky

Arguments in favor of a large magnitude ( at least two- three times bigger than its factorized value) of the mixed vacuum condensate $ \la \bar{q}G_{μν}^a G_{μν}^a q \ra$ are given. The analysis is based on the strict inequalities which follow from the QCD sum rules method and on very plausible phenomenological assumptions like $ m_{B_s} > m_{B_u} $ for the

Valeri V. Dvoeglazov, Sergei V. Khudyakov

On the basis of the Kadyshevsky equal-time (quasipotential) approach, a set of partial-wave equations is derived for the wave function of a gluonium, a bound state of two gluons. The field operators of constituent gluons are considered as six component quantities according to the Joos-Weinberg $2(2S+1)$- component approach. The quasiclassical quantization co

D. Bödeker, W. Buchmüller, Z. Fodor, T. Helbig

We study the decay of the metastable symmetric phase in the standard model at finite temperature. For the SU(2)-Higgs model the two wave function correction terms $Z_{\vp}(\vp^2,T)$ and $Z_χ(\vp^2,T)$ of Higgs and Goldstone boson fields are calculated to one-loop order. We find that the derivative expansion of the effective action is reliable for Higgs masse

A. J. Buras, M. Misiak, M. Muenz, S. Pokorski

We analyze uncertainties in the theoretical prediction for the inclusive branching ratio $BR[B \rightarrow X_s γ]$. We find that the dominant uncertainty in the leading order expression comes from its $μ$-dependence. We discuss a next-to-leading order calculation of $B \rightarrow X_s γ$ in general terms and check to what extent the $μ$-dependence can be red

R. Baier

Current results in high temperature gauge theories obtained in the context of the perturbative method of resumming hard thermal loops are reviewed. Beyond leading order properties of the gluon excitation, and the recent (controversial) calculations of the damping rates are discussed. QCD predictions on plasma signatures are exemplified by the thermal product

G. A. Ladinsky

Measuring the top quark mass in its semileptonic decay mode, $t ->be^+ν$ ($b -> μ^- + X$), through the mass distribution of the $e^+$--$μ^-$ pair has been shown to provide a good measurement of the top quark mass with an uncertainty of $1.6\%$ for $m_t=150,250\,$GeV at the SSC. Here it is demonstrated that an uncertainty in the polarization of the top quark