August 1993 arXiv papers — page 2

Christof Schmidhuber, Caltech Ph. D. thesis

The theory of embedded random surfaces, equivalent to two--dimensional quantum gravity coupled to matter, is reviewed, further developed and partly generalized to four dimensions. It is shown that the action of the Liouville field theory that describes random surfaces contains terms that have not been noticed previously. These terms are used to explain the p

Christof Schmidhuber

The renormalization group flow in two--dimensional field theories that are coupled to gravity is discussed at the example of the sine-Gordon model. In order to derive the phase diagram in agreement with the matrix model results, it is necessary to generalize the theory of David, Distler and Kawai.

K. Hagiwara, R. Szalapski, D. Zeppenfeld

A non-standard symmetry breaking sector may lead to derivative couplings of the Higgs boson and thereby to anomalous interactions with the electroweak gauge bosons. In the framework of gauge-invariant effective Lagrangians the resulting changes in Higgs boson production and decay mechanisms are related to anomalous triple vector boson couplings. Using low en

Ralf Bönisch, Arnd Leike

We obtain mass limits on the extra neutral gauge boson which is predicted in a model with hidden gauge symmetry and dynamical breaking of the electroweak symmetry by a top quark condensate. For typical model assumptions, present LEP data exclude masses below 3\,TeV. With LEP200 or an electron-positron collider of a c.m. energy of 500 GeV masses below 15\,TeV

R. H. Dalitz, Gary R. Goldstein

Possibilities are discussed for determining the top quark mass $m_t$ from observations on the decay processes for top-antitop pairs produced in antiproton-proton collisions, assuming that the $t \to bW^+$ decay channel is dominant and much faster than hadronization. The final states $t \bar{t} \to \bar{b} b μ^\pm e^\mp$ provide the most striking signal, with

Fermilab E653 Collaboration

We report the first observation of the Cabibbo disfavored semileptonic decay mode D+ -> rho0(770) mu+ nu, and measure its decay rate relative to the Cabibbo favored mode D+ -> K*0(892) mu+ nu to be Gamma(D+ -> rho0(770) mu+ nu) / Gamma(D+ -> K*0(892) mu+ nu) = 0.044 +0.031 -0.025 (stat.) +/- 0.014 (sys). The results are compared to theoretical predictions an

Fawzi Boudjema

I first review a few basic guiding principles that lead to the notion of a hierarchy of couplings in searches of New Physics involving weak bosons processes. The hierarchies within a linear and a non-linear realization of symmetry breaking are compared to the usual {\em phenomenological} parameterization of the $WWV$ vertex. Limits that one expects to obtain

M. Baillargeon, F. Boudjema

Exploiting the fact that $W$ pair production in high-energy $γγ$ collisions is very large, we use this process to trigger Higgs, $Z$ or photon radiation. We find that there are sizeable rising cross-sections for triple bosons production. At energies about $1TeV$ the new mechanism for Higgs production becomes very competitive with the dominant Higgs productio

Frank Wilczek

After briefly reviewing work I've done recently with Krishna Rajagopal on the nature of the equilibrium phase transition in QCD at finite temperature and zero baryon number and on the possibility of forming misaligned vacuum by a quench, I discuss -- also briefly -- two new items. These are extension of the arguments concerning the order of the transitio

K. Nakamura, S. Konno, Y. Shiro, A. Tomimatsu

By using the minisuperspace model for the interior metric ofstatic black holes, we solve the Wheeler-DeWitt equation to study quantum mechanics of the horizon geometry. Our basic idea is to introduce the gravitational mass and the expansions of null rays as quantum operators. Then, the exact wave function is found as a mass eigenstate, and the radius of the

O. Brodbeck, N. Straumann

We present a classification of the possible regular, spherically symmetric solutions of the Einstein-Yang-Mills system which is based on a bundle theoretical analysis for arbitrary gauge groups. It is shown that such solitons must be of magnetic type, at least if the magnetic Yang-Mills charge vanishes. Explicit expressions for the Chern-Simons numbers of th

C. A. Stafford, S. Das Sarma

We investigate the electron addition spectrum in a class of Hubbard-like models which describe arrays of coupled quantum dots. Interdot tunneling leads to a sequence of two phase transitions separating a region of collective Coulomb blockade from a region where the Coulomb blockade of individual dots is maintained and a region where the Coulomb blockade is d

Baolian Cheng, David N. Schramm, James W. Truran

In this paper, we have derived the the effects of strong magnetic fields ${\bf \vec B}$ on nucleon and particle reaction rates of astrophysical significance. We have explored the sensitivity to the presence of arbitrary degeneracy and polarization. The possible astrophysical applications of our results are discussed.

Paul Mansfield

Many field theories of physical interest have configuration spaces consisting of disconnected components. Quantum mechanical amplitudes are then expressed as sums over these components. We use the Faddeev-Popov approach to write the terms in this topological expansion as moduli space integrals. A cut-off is needed when these integrals diverge. This introduce

Paul Mansfield

We solve Schrödinger's equation for the ground-state of {\it four}-dimensional Yang-Mills theory as an expansion in inverse powers of the coupling. Expectation values computed with the leading order approximation are reduced to a calculation in {\it two}-dimensional Yang-Mills theory which is known to confine. Consequently the Wilson loop in the four-dim

A. A. Slavnov

A manifestly gauge invariant lattice action for nonanomalous chiral models is proposed which leads in the continuum limit to the theory free of doublers.

P. P. Domitrovich, H. Müther

The self-energy of quarks is investigated for various models which are inspired by the Nambu--Jona-Lasinio (NJL) model. Including, beyond the Hartree-Fock approximation, terms up to second-order in the quark interaction, the real and imaginary parts of scalar and vector components of the self-energy are discussed. The second-order contributions depend on the

I. Ya. Aref'eva, R. Parthasarathy, K. S. Viswanathan, I. V. Volovich

Coherent states on the quantum group $SU_q(2)$ are defined by using harmonic analysis and representation theory of the algebra of functions on the quantum group. Semiclassical limit $q\rightarrow 1$ is discussed and the crucial role of special states on the quantum algebra in an investigation of the semiclassical limit is emphasized. An approach to $q$-defor

Nadeem A. Ansari, L. Di Fiore, M. A. Man'ko, V. I. Man'ko

We discuss a model for interferometric GW antennas without dissipative or active elements. It is predicted that the even and odd coherent states may play an alternative role to squeezed vacuum states in reducing the optimal power of the input laser.

Edwin Langmann, Manfred Salmhofer, Alex Kovner

We analyze the Gribov problem for $\SU(N)$ and $\U(N)$ Yang-Mills fields on $d$-dimensional tori, $d=2,3,\ldots$. We give an improved version of the axial gauge condition and find an infinite, discrete group $\cG'=\Z^{dr}\rtimes({\Z_2}^{N-1}\rtimes\Z_2)$, where $r=N-1$ for $\GG=\SU(N)$ and $r=N$ for $\GG=\U(N)$, containing all gauge transformations compa

G. Azuelos, A. Djouadi

We discuss the production, at high--energy e$^+$e$^-$ linear colliders, of new heavy fermions predicted by extensions of the Standard Model. We analyze in great details the various signals and the corresponding backgrounds for both pair production and single production in association with ordinary fermions. Concentrating on new leptons, we use a model detect

A. Djouadi

We analyze the production in $e^+e^-$ collisions of new heavy fermions stemming from extensions of the Standard Model. We write down the most general expression for the production of two heavy fermions and their subsequent decays, allowing for the polarization of the e$^+$e$^-$ initial state and taking into account the final polarization of the fermions. We

A. Djouadi, P. Gambino

We derive the QCD corrections to the electroweak gauge bosons vacuum polarization functions at high and zero--momentum transfer in the case of arbitrary internal quark masses. We then discuss in this general case (i) the connection between the $O(αα_S)$ calculations of the vector bosons self--energies using dimensional regularization and the one performed vi

Estia J. Eichten, Christopher T. Hill, Chris Quigg

Orbitally excited heavy-light mesons are potentially important as tools for tagging the flavors and momenta of ground-state pseudoscalars detected through weak decays. We use heavy-quark symmetry supplemented by insights gleaned from potential models to estimate masses and widths of $p$-wave $B$, $B_s$, and $D_s$ mesons. We generalize these results to higher

J. Lopez, D. Nanopoulos, X. Wang

We compute the supersymmetric contribution to the anomalous magnetic moment of the muon within the context of $SU(5)\times U(1)$ supergravity models. The largest possible contributions to $a^{susy}_μ$ occur for the largest allowed values of $\tanβ$ and can easily exceed the present experimentally allowed range, even after the LEP lower bounds on the sparticl

D. J. Castano, E. J. Piard, P. Ramond

In this paper we summarize the minimal supersymmetric standard model as well as the renormalization group equations of its parameters. We proceed to examine the feasability of the model when the breaking of supersymmetry is parametrized by the soft terms suggested by supergravity theories. In such models, the electroweak symmetry is exact at tree level and i

I. B. Khriplovich, A. I. Vainshtein

The logarithmic ultraviolet divergence in the theta-term induced by electroweak interactions in the Kobayashi-Maskawa model of CP-violation, found by Ellis and Gaillard, is discussed. We relate it to the Jarlskog CP-odd invariant of quark mass matrix. The divergence arises in 14th order in Higgs coupling as well as in 12th order plus 2nd order in U(1) gauge

G. Anderson, S. Raby, S. Dimopoulos, L. J. Hall

A new approach for deducing the theory of fermion masses at the scale of grand unification is proposed. Combining SO(10) grand unification, family symmetries and supersymmetry with a systematic operator analysis, the minimal set of fermion mass operators consistent with low energy data is determined. Exploiting the full power of SO(10) to relate up, down and

S. J. Dong, K. F. Liu

We introduce a $Z_2$ noise for the stochastic estimation of matrix inversion and discuss its superiority over other noises including the Gaussian noise. This algorithm is applied to the calculation of quark loops in lattice quantum chromodynamics that involves diagonal and off-diagonal traces of the inverse matrix. We will point out its usefulness in its app

L. Smrcka, T. Jungwirth

The electronic structure of a 2D gas subjected to a tilted magnetic field, with a strong component parallel to the GaAs/AlGaAs interface and a weak component oriented perpendicularly, is studied theoretically. It is shown that the parallel field component modifies the originally circular shape of a Fermi contour while the perpendicular component drive an ele

Geoffrey V. Bicknell

This paper focuses on two aspects of the Physics of Radio Galaxies in which it has been proposed that relativistic beaming of radiation is necessary to account for the observations. Physical arguments are presented which show that it is quite plausible that the jets in FRI radio galaxies are relativistic on the parsec scale and decelerate to subrelativistic

Geoffrey V. Bicknell

The idea that Fanaroff-Riley Class~I Radio Galaxies contain core jets with Lorentz factors of the order of a few and are the parent population for BL~Lac Objects is examined, with particular reference to the data on two FRI Radio Galaxies, NGC~315 and NGC~6251. Conservation laws for an entraining relativistic jet are derived and are used to determine a relat

M. Gasperini R. Ricci G. Veneziano

We investigate duality transformations in a class of backgrounds with non-Abelian isometries, i.e. Bianchi-type (homogeneous) cosmologies in arbitrary dimensions. Simple duality transformations for the metric and the antisymmetric tensor field, generalizing those known from the Abelian isometry (Bianchi I) case, are obtained using either a Lagrangian or a Ha

Alon E. Faraggi, Benjamin Grinstein

Supersymmetric Grand Unified Theories have a rich spectrum of particles barely heavier than the intermediate vector bosons. As their non-supersymmetric counterparts, they lead to many relations among low energy observables. But the precise form of the predictions is modified by the extended spectrum. If the masses of these new particles are comparable to $M_

Marius Junge, Gilles Pisier

Let $E,F$ be exact operators (For example subspaces of the $C^*$-algebra $K(H)$ of all the compact operators on an infinite dimensional Hilbert space $H$). We study a class of bounded linear maps $u\colon E\to F^*$ which we call tracially bounded. In particular, we prove that every completely bounded (in short $c.b.$) map $u\colon E\to F^*$ factors boundedly

Gilles Pisier

We introduce the notion of a regular mapping on a non-commutative $L_p$-space associated to a hyperfinite von Neumann algebra for $1\le p\le \infty$. This is a non-commutative generalization of the notion of regular or order bounded map on a Banach lattice. This extension is based on our recent paper [P3], where we introduce and study a non-commutative versi

Christopher Leary

Normal ideals on regular uncountable cardinals are familiar objects. We investigate ideals that are pleasant--while a normal ideal is closed under arbitrary diagonal unions, a pleasant ideal is closed only under diagonal unions indexed by sets that are elements of the ideal. We show any selective ideal extending the nonstationary ideal must be normal.

H. Lu, C. N. Pope, K. Thielemans, X. J. Wang

We study the spectrum of physical states for higher-spin generalisations of string theory, based on two-dimensional theories with local spin-2 and spin-$s$ symmetries. We explore the relation of the resulting effective Virasoro string theories to certain $W$ minimal models. In particular, we show how the highest-weight states of the $W$ minimal models decomp

Rene Lafrance, Robert C. Myers

Several new results on the multicritical behavior of rectangular matrix models are presented. We calculate the free energy in the saddle point approximation, and show that at the triple-scaling point, the result is the same as that derived from the recursion formulae. In the triple-scaling limit, we obtain the string equation and a flow equation for arbitrar

John M Charap

Talk given at the Workshop on "Constraint Theory and Quantization Methods"; Montepulciano, Italy, June 1993 --- Instead of attempting to give a summary or to identify highlights of the workshop, the history of the development of analytical mechanics is outlined, with an emphasis on the themes of \lq natural motion' and the variational principle.

D. R. Grigore

A geometric generalization of first-order Lagrangian formalism is used to analyse a conformal field theory for an arbitrary primary field. We require that global conformal transformations are Noetherian symmetries and we prove that the action functional can be taken strictly invariant with respect to these transformations. In other words, there does not exis

Soo-Jong REY

An effective field theory describing the QCD diffraction scattering is constructed. The constituent quarks interacting with multiperi- pheral gluons and Goldstone bosons are described by impact- parameter two-dimensional sigma models for the color and the flavor degrees of freedom. The elastic scattering amplitude is then shown to factorize into the hard and

M. B. Einhorn

Based on an Invited Plenary Talk given at ``Workshop on Physics and Experiments with Linear $e^+e^-$ Colliders,'' Waikoloa, Hawaii, April 26--30, 1993. This paper reviews theoretical issues concerning the structure of vector bosons, with emphasis on deviations of triple-vector-boson interactions from the predictions of the Standard Model. Particular

Duane A. Dicus, Chung Kao

The $ZZ$ pair production rate in high energy $γγ$ collisions is evaluated with photons from laser backscattering. We find that searching for the Standard Model Higgs boson with a mass up to, or slightly larger than, 400 GeV via the $ZZ$ final state is possible via photon fusion with backscattered laser photons at a linear $e^+e^-$ collider with energies in t

Riazuddin, N. Paver, F. Simeoni

Using a current algebra framework, we discuss the contribution of vector meson exchanges to the CP violating asymmetry in the decay $K^{\pm}\rightarrowπ^{\pm}π^0$, resulting from the interference of the $K\rightarrowππ$ amplitude with the radiative correction $K\rightarrowππγ$.

R. Alkofer, H. Weigel

We comment on recently discovered $1/N_C$ corrections to the ` nucleon axial current in the framework of the Nambu--Jona-Lasinio soliton. This kind of corrections arises only for a special treatment of ordering ambiguities of collective coordinates and operators in the semiclassical quantization. In addition to the missing derivation of this special quantiza

D. A. Morris

We discuss the prospects for observing multiple weak gauge boson production at the SSC and LHC. We summarize conventional perturbative cross sections for processes involving 1-6 final state weak gauge bosons and compare them with more speculative scenarios including 1) a toy model of a strongly interacting Higgs sector patterned after hadronic multipion prod

B. de Carlos, J. A. Casas, F. Quevedo, E. Roulet

We show that if there is a realistic 4-d string, the dilaton and moduli supermultiplets will generically acquire a small mass O(m_{3/2}), providing the only vacuum-independent evidence of low-energy physics in string theory beyond the supersymmetric standard model. The only assumptions behind this result are (i) softly broken supersymmetry at low energies wi

K. Schilling, G. S. Bali

We describe the Wuppertal university pilot project in applied parallel computing. We report on a comprehensive high statistics determination of the static quark-antiquark potential and related quantities from quenched quantum chromodynamics. New data for the string tension and the plaquette action for the region 5.5 < beta < 6.8 is presented.

P. T. Landsberg, R. B. Mann

For normal thermodynamic systems superadditivity $§$, homogeneity $\H$ and concavity $\C$ of the entropy hold, whereas for $(3+1)$-dimensional black holes the latter two properties are violated. We show that $(1+1)$-dimensional black holes exhibit qualitatively new types of thermodynamic behaviour, discussed here for the first time, in which $\C$ always hold

R. Graham, H. Luckock

We construct Nicolai maps for $N=2$ supersymmetric extensions of minisuperspace models. It is shown that Nicolai maps exist for only a very restricted set of states. In the models considered these are the two states corresponding to the empty and the filled fermion sectors. The form of the Nicolai maps in these sectors is given explicitly, and it is shown th

Gary A. Mamon

The different dynamical processes (relaxation, dynamical friction, tides and mergers) operating in groups and clusters are reviewed. The small-scale substructure observed in clusters is argued to be the remnants of the cores of rich clusters that merged together, rather than large groups falling into the cluster. The {\sl ROSAT\/} X-ray observations of two g

Heino Falcke, Karl Mannheim, Peter L. Biermann

Recent observations of the radio and NIR source Sgr A* reinforce the interpretation of the Galactic Center as a scaled down version of an AGN. The discovery of an elongated structure at 43 GHz and increasing evidence for the presence of an accretion disk surrounding a Black Hole lead us to assume that both, an accretion disk and a jet, are present in the Gal

Heino Falcke, Peter L. Biermann

The Galactic Center shows evidence for the presence of three important AGN ingredients: a Black Hole ($M_\bullet\sim10^6M_\odot$), an accretion disk ($10^{-8.5} - 10^{-7} M_\odot/{\rm yr}$) and a powerful jet (jet power $\ge$ 10\% disk luminosity). However, the degree of activity is very low and can barely account for the energetics of the whole central regi

Hitoshi Nakada, Takashi Sebe, Takaharu Otsuka

Energy levels and electromagnetic properties of with $N=28\sim 30$ nuclides are studied in terms of a large-scale shell model calculation, which contains no newly adjusted parameters. The Kuo-Brown $G$-matrix interaction is shown to reproduce energy levels of 205 low-lying states of these nuclei. We evaluate effective charges by incorporating the core-polari

William J. Anderson, Hans J. Haubold, Arak Mathai Mathai

Stars are gravitationally stabilized fusion reactors changing their chemical composition while transforming light atomic nuclei into heavy ones. The atomic nuclei are supposed to be in thermal equilibrium with the ambient plasma. The majority of reactions among nuclei leading to a nuclear transformation are inhibited by the necessity for the charged particip

E. G. Kalnins, V. B. Kuznetsov, Willard Miller,

We consider integrable systems that are connected with orthogonal separation of variables in complex Riemannian spaces of constant curvature. An isomorphism with the hyperbolic Gaudin magnet, previously pointed out by one of us, extends to coordinates of this type. The complete classification of these separable coordinate systems is provided by means of the

A. Petermann, A. Zichichi

We investigate $2d$ sigma-models with a $2+N$ dimensional Minkowski signature target space metric and Killing symmetry, specifically supersymmetrized, and see under which conditions they might lead to corresponding exact string vacua. It appears that the issue relies heavily on the properties of the vector $M_μ$, a reparametrization term, which needs to poss

A. Casher, O. Pelc

We analyze the quantum hair model proposed recently by Coleman, Preskill and Wilczek. We give arguments suggesting that the potential hair is expected to be destroyed by the instability of the black-hole. We also discuss the general implications of such arguments on the prospects for formulating a quantum extension of the classical ``no hair&#39;&#39; theore

Guido Cognola, Klaus Kirsten, Luciano Vanzo

Free and self-interacting scalar fields in the presence of conical singularities are analized in some detail. The role of such a kind of singularities on free and vacuum energy and also on the one-loop effective action is pointed out using $ζ$-function regularization and heat-kernel techniques.

Toby Falk, Richard Madden, Keith A. Olive, Mark Srednicki

We consider corrections to bino annihilation due to sfermion mixing.

J. Lopez

An introduction to the most important concepts in the subject of supersymmetric unified theories is presented. The emphasis is on the practical aspects leading to state-of-the-art calculations in this renascent subject. The topics covered include: generalities of supersymmetric unified theories, gauge and Yukawa coupling unification including the most up-to-

Richard Ball, Stefano Forte

We discuss nonperturbative QCD evolution of nonsinglet nucleon structure functions, with particular application to the Gottfried sum. We show that the coupling of the quark partons to bound state mesons leads to nonperturbative contributions to the Altarelli--Parisi equations which, due to the axial anomaly, result in a strong scale dependence of nonsinglet

J. L. Hewett

Signatures of extended gauge models at high energy \epem\ linear colliders are summarized. Talk presented at the Workshop on Physics and Experiments with Linear \epem\ Colliders, Waikoloa, Hawaii, April 1993.

Ronald Kleiss

We present an approximation to the matrix element for the process e+e- --> e+e-gamma, appropriate to the situation where one or both of the fermions are scattered over very small angles. The leading terms in the situation where all scattering angles are small contains not only terms quadratic in the electron mass, but also quartic and even sextic terms must

Sourendu Gupta

Aspects of the dilepton spectrum in heavy-ion collisions are discussed, with special emphasis on using lattice computations to guide the phenomenology of finite temperature hadronic matter. The background rates for continuum dileptons expected in forthcoming experiments are summarised. Properly augmented by data from ongoing measurements at HERA, these rates

A. Ilakovac, B. A. Kniehl, A. Pilaftsis

We analyze the possibility of $CP$ violation induced by heavy Majorana neutrinos in the decays of the Higgs particle into top-quark, $W$- and $Z$-boson pairs. In the framework of various ``see-saw&#34; models with interfamily mixings, we find that Majorana neutrinos may give rise to sizable $CP$-odd observables at the one-loop electroweak order. Numerical es

C. Kiefer

This paper gives an elementary introduction to some of the conceptual problems of quantum cosmology. Contents: 1. Why quantum cosmology? 2. Time in quantum gravity 3.Decoherence and the recovery of the Schrodinger equation 4. The direction of time

Claus Kiefer, Rainer Mueller, Tejinder P. Singh

We discuss the relevance of quantum gravitational corrections to the functional Schrödinger equation for the information loss paradox in black hole evaporation. These corrections are found from the Wheeler-DeWitt equation through a semiclassical expansion scheme. The dominant contribution in the final evaporation stage, when the black hole approaches the Pla

V. I. Belinicher, L. V. Popovich

The low-energy properties of the two-dimensional Heisenberg model with spin-$\frac{1}{2}$ on a square lattice are investigated on the basis of the local dimer order. The lattice is divided into square blocks consisting of the quartet of spins. The spin variables and the Heisenberg Hamiltonian are expressed in terms of the low-energy quartet variables. On the

Avishai Dekel, Martin Rees

We propose a method for deriving a dynamical lower bound on $Ω$ from diverging flows in low-density regions, based on the fact that large outflows are not expected in a low-$Ω$ universe. The velocities are assumed to be induced by gravity from small initial fluctuations, but no assumptions are made regarding their exact Gaussian nature, galaxy biasing, or $Λ

Robert Friedman

This paper, the last in a series of three, studies vector bundles on an elliptic surface whose determinant has odd intersection number with a general fiber and uses this study to calculate certain coefficients of Donaldson polynomials.

José M. Figueroa-O'Farrill

We study the problem of constructing N=2 superconformal algebras out of an N=1 affine Lie algebra. Following a recent independent observation of Getzler and the author, we derive a simplified set of N=2 master equations, which we then proceed to solve for the case of sl(2). There is a unique construction for all noncritical values of the level, which can be

Stephen Parrott

Original abstract: Consider the worldline of a charged particle in a static spacetime. Contraction of the time-translation Killing field with the retarded electromagnetic energy-momentum tensor gives a conserved electromagnetic energy vector which can be used to define the radiated electromagnetic energy. This note points out that for a conformally flat spac

M. N. Butler, M. J. Savage, R. P. Springer

We compute the leading contributions to the magnetic dipole and electric quadrupole moments of the baryon decuplet in chiral perturbation theory. The measured value for the magnetic moment of the $Ω^-$ is used to determine the local counterterm for the magnetic moments. We compare the chiral perturbation theory predictions for the magnetic moments of the dec

Giovannni Gallavotti

Rotation axis variation due to spin orbit resonance: conference report; keywords: planetary precession, rigid body, chaos, KAM, Arnold diffusion, averaging, celestial mechanics, classical mechanics, large deviations

Kazuo Ghoroku

A calculational scheme of quantum-gravitational effects on the physical quantities is proposed. The calculations are performed in 4-$ε$ dimension with $1/N$-expansion scheme, where the Einstein gravity is renormalizable and it has an ultraviolet fixed-point within the 1/N-expansion. In order to perform a consistent perturbation in $4-ε$ dimension, spin-3/2 f

Francis J. Alexander, Salman Habib, Alex Kovner

We investigate the thermal equilibrium properties of kinks in a classical $\F^4$ field theory in $1+1$ dimensions. From large scale Langevin simulations we identify the temperature below which a dilute gas description of kinks is valid. The standard dilute gas/WKB description is shown to be remarkably accurate below this temperature. At higher, ``intermediat

S. Riemersma, R. Meng

Results for b-quark production at hadron colliders, both current and proposed, are presented. Distributions in $p_t$ are presented for the TeVatron and SSC. Confirmation of agreement between the ${\cal O}(α_S^3)$ calculations and UA1 data is presented, and the discrepancy between the ${\cal O}(α_S^3)$ calculations and the CDF results is updated with the most

J. R. Espinosa, J. M. Moreno, M. Quirós

We revise a recently proposed mechanism for spontaneous CP breaking at finite temperature in the Higgs sector of the Minimal Supersymmetric Standard Model, based on the contribution of squarks, charginos and neutralinos to the one-loop effective potential. We have included plasma effects for all bosons and added the contribution of neutral scalar and charged

Jishnu Dey, Mira Dey

We find remarkable agreement with the observed excitations of hadrons with a simple three parameter mass relation of the SU(3) subgroup of the underlying U(15/30) graded Lie group. The baryons are the appropriate supersymmetric partners of the mesons. An interesting feature, which is a focus of current interest, is that the baryons and isobars show parity do

Wei-Shu Hou, Gwo-Guang Wong

If new sequential leptons $E^\pm$ and $N^0$ exist, the LEP bound implies $m_E$, $m_N > M_Z/2$. The heaviness of the neutral lepton breaks away from the pattern of the first three generations. The minimal model is to have 4 left-handed lepton doublets and 4 right-handed charged lepton singlets, but only one right-handed neutral lepton singlet. Since in genera

George Wei-Shu Hou

Talk presented at 2nd International Workshop on Physics and Experiments with Linear $e^+e^-$ Colliders (Hawaii, April 1993).

Salman Habib

Physical situations involving multiplicative noise arise generically in cosmology and field theory. In this paper, the focus is first on exact nonlinear Langevin equations, appropriate in a cosmologica setting, for a system with one degree of freedom. The Langevin equations are derived using an appropriate time-dependent generalization of a model due to Zwan

A. Krasnitz, R. Potting

We measure the diffusion rate of Chern-Simons number in the (1+1)-dimensional Abelian Higgs model interacting with a realistic heat bath for temperatures between 1/13 and 1/3 times the sphaleron energy. It is found that the measured rate is close to that predicted by one-loop calculation at the lower end of the temperature range considered but falls at least

Jose A. Riera

A generalization of the $t-J$ model in a system of two coupled chains or planes is studied by numerical diagonalization of small clusters. In particular, the effect of density fluctuations between these one- or two-dimensional coupled layerson intralayer phase separation and pairing is analyzed. The most robust signals of superconductivity are found at quart

Hiroko Ichie, Arata Hatashigaki, Akira Suzuki, Masahiro Kimura

The effective masses and sizes of N(939), $Δ(1232)$ and N(1440) in nuclear medium are calculated for a model in which quarks are subjected to a confinement force quenched by the scalar part of nuclear interactions. At the nuclear matter density, the nucleon swells by 50\% relative to the free nucleon. The masses of $Δ(1232)$ and N(1440) decrease in nuclear m

G. Q. Li, R. Machleidt

We derive in-medium PROTON-PROTON cross sections in a microscopic model based upon the Bonn nucleon-nucleon potential and the Dirac-Brueckner approach for nuclear matter. We demonstrate the difference between proton-proton and neutron-proton cross sections and point out the need to distinguish carefully between the two cases. We also find substantial differe

Saharon Shelah, Juris Steprāns

Upon presenting the proof of Theorem 3.3 in &#34;Maximal chains in $$ and ultrapowers of the integers&#34; I discovered that it is not entirely correct and certainly some details should be added. I have therefore written an addendum to the paper and made it available by ftp. Unfortunately the published version will be somewhat wanting.

Yang-Mills Instantons Carlos Castro

We conjecture that $W$ gravity can be interpreted as the gauge theory of $ϕ$ diffeomorphisms in the space of dimensionally-reduced $D=2+2$ $SU^*(\infty)$ Yang-Mills instantons. These $ϕ$ diffeomorphisms preserve a volume-three form and are those which furnish the correspondence between the dimensionally-reduced Plebanski equation and the KP equation in $(1+2

Carlos Castro

Starting from a self-dual $SU(\infty)$ Yang-Mills theory in $(2+2)$ dimensions, the Plebanski second heavenly equation is obtained after a suitable dimensional reduction. The self-dual gravitational background is the cotangent space of the internal two-dimensional Riemannian surface required in the formulation of $SU(\infty)$ Yang-Mills theory. A subsequent

L. Susskind, L. Thorlacius

Analysis of several gedanken experiments indicates that black hole complementarity cannot be ruled out on the basis of known physical principles. Experiments designed by outside observers to disprove the existence of a quantum-mechanical stretched horizon require knowledge of Planck-scale effects for their analysis. Observers who fall through the event horiz

Herbert W. Hamber, Ruth M. Williams

A model for quantized gravity coupled to matter in the form of a single scalar field is investigated in four dimensions. For the metric degrees of freedom we employ Regge&#39;s simplicial discretization, with the scalar fields defined at the vertices of the four-simplices. We examine how the continuous phase transition found earlier, separating the smooth fr

Z. Hasiewicz, P. Siemion

Second-order equations of motion on a group manifold that appear in a large class of so-called chiral theories are presented. These equations are presented and explicitely solved for cases of semi-simple, finite-dimensional Lie groups. With three figures avaliable from the authors upon request.

I. V. Volovich

We use the recently discovered universality of Einstein equations in the first order formalism to suggest a positive definite Euclidean action. Possible implications for quantum gravity are considered. We discuss the Hawking and Coleman approach to the vanishing of the cosmological constant by using the new action and find that the cosmological constant is p

Takanori Fujiwara, Yuji Igarashi, Jisuke Kubo

In two-dimensional dilaton gravity theories, there may exist a global Weyl invariance which makes black hole spurious. If the global invariance and the local Weyl invariance of the matter coupling are intact at the quantum level, there is no Hawking radiation. We explicitly verify the absence of anomalies in these symmetries for the model proposed by Callan,

B. Holdom, M. Sutherland

A simple relativistic model of heavy-light mesons is applied to the rare decay B -> K* gamma in the standard model. We find Gamma(B -> K* gamma)/Gamma(b -> s gamma)=(17 \pm 4)% and BR(B -> K* gamma)=(4.8 \pm 1.9) \times 10^{-5}(V_cb/.04)^2. These numbers are reduced by only 20% in the heavy-quark limit.

J. Baacke, S. Junker

We present an analysis of the quantum fluctuations around the electroweak sphaleron and calculate the associated determinant which gives the 1--loop correction to the sphaleron transition rate. The calculation differs in various technical aspects from a previous analysis by Carson et al. so that it can be considered as independent. The numerical results diff

T. Elliott, S. F. King, P. L. White

We perform a systematic study of radiative corrections to the masses of the Higgs bosons in the minimal supersymmetric standard model (MSSM) augmented by a single gauge singlet, the so-called next-to-minimal supersymmetric standard model (NMSSM). Our method is based on the one-loop effective potential and includes effects of top quark, squark, Higgs and Higg

Michael Gronau, Jonathan L. Rosner

We introduce a method for the study of CP-violating asymmetries in tagged states of neutral $B$ mesons with arbitrary coherence properties. A set of time-dependent measurements is identified which completely specifies the density matrix of the initial state in a two-component space with basis vectors $B^0$ and $\overline B^0$, and permits a determination of