March 1996 arXiv papers — page 2

Salavat Abdullin, Howard Baer, Chung Kao, Nikita Stepanov

The prospects of detecting the CP-odd Higgs pseudoscalar ($A$) in the minimal supersymmetric model via its decay into a $Z$ boson and the lighter CP-even Higgs scalar ($h$) at the CERN Large Hadron Collider are investigated. The final state of $Z \to l^+l^-$ and $h \to b\bar{b}$, may provide a promising way to simultaneously detect the $A$ and the $h$. The c

Colin Froggatt

Recent developments on approaches to the quark lepton mass problem are reviewed. In particular we discuss dynamical calculations of the top quark mass at (a) the infrared quasifixed point of the Minimal Supersymmetric Standard Model renormalisation group equations, and (b) a strongly first order critical point of the Standard Model effective potential. The p

W. Grimus, P. Stockinger

We study the conditions for neutrino oscillations in a field theoretical approach by taking into account that only the neutrino production and detection processes, which are localized in space around the coordinates $\vec{x}_P$ and $\vec{x}_D$, respectively, can be manipulated. In this sense the neutrinos whose oscillations are investigated appear as virtual

Wolfgang Lucha, Franz F. Schöberl

The spinless relativistic Coulomb problem is the bound-state problem for the spinless Salpeter equation (a standard approximation to the Bethe--Salpeter formalism as well as the most simple generalization of the nonrelativistic Schrödinger formalism towards incorporation of relativistic effects) with the Coulomb interaction potential (the static limit of the

D. Boer, R. D. Tangerman

In this letter we extend the factorization procedure of the deep-inelastic hadron tensor, proposed by Qiu, to include non-zero quark masses. The manifest gauge invariance of both soft and hard parts is preserved. Using a so-called spurion to generate the quark-mass terms, the simple parton-model interpretation is also kept. The calculation of the deep-inelas

T. Binoth, J. J. van der Bij

We investigate the influence of massless scalar singlets on Higgs signals at the NLC. An exclusion bound is presented which restricts large regions of the parameter space but on the other hand implies that for strong interactions between the Higgs boson and the singlet fields of the hidden sector, detection of such a non standard Higgs signal can become impo

Paul Singer, Da-Xin Zhang

The heavy quark effective theory and the factorization approximation are used to treat the Cabibbo-suppressed decays of charmed baryons to vector mesons, $Λ_C\rightarrow p{ρ^0}, pω$, $Ξ_C^{+,0}\rightarrowΣ^{+,0}ϕ, Σ^{+,0}{ρ^0}, Σ^{+,0}ω$ and $Ξ_C^{0}\rightarrowΛϕ, Λρ, Λω$. The input from two recent experimental results on $Λ_C$ decays allows the estimation o

Z. Haba

We express the unitary time evolution in non-relativistic regularized quantum electrodynamics at zero and positive temperature by a Feynman integral defined in terms of a complex Brownian motion. An average over the quantum electromagnetic field determines the form of the quantum mechanics in an environment of a quantum black body radiation. In this non-pert

Bas V. de Bakker

We confirm recent claims that, contrary to what was generally believed, the phase transition of the dynamical triangulation model of four-dimensional quantum gravity is of first order. We have looked at this at a volume of 64,000 four-simplices, where the evidence in the form of a double peak histogram of the action is quite clear.

F. Csikor, Z. Fodor

We calculate the ${\cal O}(g^2,λ)$ corrections to the coupling anisotropies of the SU(2)-Higgs model on lattices with asymmetric lattice spacings. These corrections are obtained by a one-loop calculation requiring the rotational invariance of the gauge- and Higgs-boson propagators in the continuum limit.

Takeshi Chiba, Jiro Soda

The collapse of a massless scalar field in the Brans-Dicke theory of gravitation is studied in the analysis of both analytical solution and numerical one. By conformally transforming the Roberts's solution into the Brans-Dicke frame, we find for $ω> -3/2$ that a continuous self-similarity continues and that the critical exponent does depend on $ω$. By co

Anshu Gupta, Sai Iyer, A. R. Prasanna

Using the optical reference geometry approach, we have derived in the following, a general expression for the ellipticity of a slowly rotating fluid configuration using Newtonian force balance equation in the conformally projected absolute 3-space, in the realm of general relativity. Further with the help of Hartle-Thorne (H-T) metric for a slowly rotating c

M. R. Norman, A. H. MacDonald

We report on a numerical study intended to examine the possibility that magnetic oscillations persist in type II superconductors beyond the point where the pairing self-energy exceeds the normal state Landau level separation. Our work is based on the self-consistent numerical solution for model superconductors of the Bogoliubov-deGennes equations for the vor

Y. Sasago, N. Koide, K. Uchinokura, Michael C. Martin

A series of high-quality single crystals of Cu$_{1-x}$Zn$_x$GeO$_3$ have been examined by neutron scattering techniques. An antiferromagnetic (AF) ordering is confirmed for samples with $x\geq 0.02$, in complete agreement with previous reports. We show that the spin-Peierls (SP) phase transition persists to 6\% Zn, whereas previous magnetic susceptibility me

W. Krech, K. Yu. Platov

We present numerical simulations of the dynamics of two-dimensional Josephson junction arrays to study the mechanism of mutual phase locking. We show that in the presence of an external magnetic field two mechanisms are playing a role in phase locking: feedback through the external load and internal coupling between rows due to microwave currents induced by

Carlo Presilla, Roberto Onofrio, Ubaldo Tambini

Measurement quantum mechanics, the theory of a quantum system which undergoes a measurement process, is introduced by a loop of mathematical equivalencies connecting previously proposed approaches. The unique phenomenological parameter of the theory is linked to the physical properties of an informational environment acting as a measurement apparatus which a

A. Allakhverdian, D. Saakian

The free energy and finite size effects are calculated for the system of 2 Derrida's models with fixed constraint between the spin configurations. Calculation were performed for the Random Energy Model approach.

F. Despa

Jellium correction on the fissionability parameter is estimated within a Liquid Drop Model of the charged metallic cluster. This correction modifies the critical condition of fission and, it becomes relevant for small multicharged clusters.

Nobuhiko Taniguchi, Vladimir N. Prigodin

The mesoscopic fluctuations of the absorption at optical transitions from a low energy regular state to high energy chaotic states in an aggregate of semiconductor quantum dots is studied. We provide a universal dependence of the distribution of the absorption coefficient on the total number of dots and the ratio of the level broadening to the level spacing.

P. L. Krapivsky, S. Redner

The survival probability, S_N(t), of a diffusing prey (``lamb'') in the proximity of N diffusing predators (a ``pride of lions'') in one dimension is investigated. When the lions are all to one side of the lamb, the survival probability decays as a non-universal power law, S_N(t) is proportional to t^{-beta_N}, with the decay exponent beta_N

Mark Srednicki, Frank Stiernelof

We study the fluctuations that are predicted in the autocorrelation function of an energy eigenstate of a chaotic, two-dimensional billiard by the conjecture (due to Berry) that the eigenfunction is a gaussian random variable. We find an explicit formula for the root-mean-square amplitude of the expected fluctuations in the autocorrelation function. These fl

G. F. Smoot, D. Scott

We review the current status of experimental data for spectral distortions and angular anisotropies of the cosmic microwave background, as well as discussing the relevant physical processes. This is one of a number of new articles in astrophysics and cosmology which will appear in the 1996 Review of Particle Properties (Phys. Rev. D. in press). Other relevan

Zacharias A. M. Protogeros, Robert J. Scherrer

We examine local Lagrangian approximations for the gravitational evolution of the density distribution function. In these approximations, the final density at a Lagrangian point q at a time t is taken to be a function only of t and of the initial density at the same Lagrangian point. A general expression is given for the evolved density distribution function

D. J. Crary, C. Kouveliotou, J. van Paradijs, F. van der Hooft

We have examined the power spectral behavior of Cygnus X-1 using approximately 1100 days of BATSE data. These data have been searched for correlations between different power spectral features, and for correlations between power spectral features and energy spectral parameters derived from BATSE occultation analysis.

P. B. Tissera, D. G. Lambas, M. G. Abadi

We present a hydrodynamical code based on the Smooth Particle Hydrodynamics technique implemented in an AP3M code aimed at solving the hydrodynamical and gravitational equations in a cosmological frame. We analyze the ability of the code to reproduce standard tests and perform numerical simulations to study the formation of galaxies in a typical region of a

Karl Forster, Jules P. Halpern

A ROSAT observation of the narrow-line Fe II QSO PHL 1092 shows rapid variability that requires an efficiency of at least 0.13, exceeding the theoretical maximum for an accretion disk around a non-rotating black hole. Plausible explanations for this high efficiency incorporate anisotropic emission and/or accretion onto a rapidly rotating black hole, the latt

T. Di Matteo, A. C. Fabian

We discuss the possibility that a significant contribution of the hard X-ray Background is the integrated emission from a population of galaxies undergoing advection-dominated accretion in their nuclei. Owing to poor coupling between ions and electrons and to efficient radiative cooling of the electrons, the accreting plasma is two-temperature, with the ions

Elena Pierpaoli, Peter Coles, Silvio Bonometto, Stefano Borgani

We investigate the properties of large--scale structure predicted in a class of mixed dark matter models in which the volatile component (made of particles with high rms velocity) derives from the decay of a heavier particle. Such models based on cold+volatile dark matter (CVDM) differ from the standard mixture of CDM and massive neutrinos, usually known as

Takeshi Kawachi

Let $(X,L)$ be an $n$-dimensional polarized variety. Fujita's conjecture says that if $L^n>1$ then the adjoint bundle $K_X+nL$ is spanned and $K_X+(n+1)L$ is very ample. There are some examples such that $K_X+nL$ is not spanned or $K_X+(n+1)L$ is not very ample. These are $(¶^n,Ø(1))$, hypersurface $M$ of degree $6$ in weighted projective space $¶(3,2,1,

Takeshi Kawachi

We extend Reider&#39;s freeness criterion to normal surfaces of characteristic 0. Let Y be a normal surface. Let D be a nef divisor on Y such that K_Y+D is a Cartier divisor. Let x be a point on Y. If x is a base point of |K_Y+D| and D^2>δ_x (δ_x is determined by x, δ_x <= 4) then there exists a non zero effective divisor E on Y passing through x such that 0

Nivaldo A. Lemos

This is in fact an Erratum to the paper published in Physics Letters A221 (1996) 359. The reduced-phase-space discussion remains essentially valid in spite of the fact that many equations are changed. However, the analysis based on the Wheeler-DeWitt equation should be very different from the one given in the paper, which must be disregarded.

K. Amir-Azimi-Nili, H. Müther, L. D. Skouras, A. Polls

The influence of correlations on the momentum distribution of nucleons in nuclei is evaluated starting from a realistic nucleon-nucleon interaction. The calculations are performed directly for the finite nucleus $\,^{16}$O making use of the Green&#39;s function approach. The emphasis is focused on the correlations induced by the excitation modes at low energ

D. Fargion, R. Conversano

The Shapiro Phase Shift on Pulsars (SPSP) influence at low , but detectable level the pulsars&#39; (PSR) periods and their derivatives. This effect may be already written in PSRs&#39; time derivative deviation and in particular it may explain the presence of a few negative pulse derivatives among 558 known PSRs. We describe in detail the phenomenon and predi

Adrian R. Lugo

We compute the exact string vacuum backgrounds corresponding to the non-compact coset theory $SU(2,1)/SU(2)$. The conformal field theory defined by the level $k= 4$ results in a five dimensional singular solution that factorizes in an asymptotic region as the linear dilaton solution and a $S^3$ model. It presents two abelian compact isometries that allow to

Ch. Schaab, F. Weber, M. K. Weigel, N. K. Glendenning

A collection of modern, field-theoretical equations of state is applied to the investigation of cooling properties of compact stars. These comprise neutron stars as well as hypothetical strange matter stars, made up of absolutely stable 3-flavor strange quark matter. Various uncertainties in the behavior of matter at supernuclear densities, e.g., hyperonic d

Mario Salerno

We show how to construct SO(4) invariant functions for strongly correlated Fermi systems on lattices of finite sizes. We illustrate the method on the case of the 1D Hubbard chain with four and with six sites.

C. S. Reynolds, A. C. Fabian, A. Celotti, M. J. Rees

Recent observations have allowed the geometry and kinematics of the M87 jet to be tightly constrained. We combine these constraints with historical Very Long Baseline Interferometry (VLBI) results and the theory of synchrotron self-absorbed radio cores in order to investigate the physical properties of the jet. Our results strongly suggest the jet to be domi

H. W. Braden, Andrew N. W. Hone

The solitons of affine Toda field theory are related to the spin-generalised Ruijsenaars-Schneider (or relativistic Calogero-Moser) models. This provides the sought after extension of the correspondence between the sine-Gordon solitons and the Ruijsenaars-Schneider model.

Mario Salerno

We use group theory to derive the exact analytical expression of the ferromagnetic ground states of the Hubbard model on a complete graph for arbitrary lattice sites f and for arbitrary fillings $N$. We find that for $t>0$ and for $N=f+1$ the ground state is maximally ferromagnetic with total spin $S=(f-1)/2$. For $N > f+1$ the ground state is still ferromag

Mario Salerno

We derive the analytical expression of the ground state of the Hubbard model with unconstrained hopping at half filling and for arbitrary lattice sites.

Kang Li, Dao-Mu Zhao, Shao-Min Wang

By using the theory of deformed quantum mechanics, we study the deformed light beam theoretically. The deformed beam quality factor $M_q^2$ is given explicitly under the case of deformed light in coherent state. When the deformation parameter $q$ being a root of unity, the beam quality factor $M_q^2 \leq 1$.

Madappa Prakash, Ignazio Bombaci, Manju Prakash, Paul J. Ellis

We investigate the structure of neutron stars shortly after they are born, when the entropy per baryon is of order 1 or 2 and neutrinos are trapped on dynamical timescales. In all cases, the thermal effects for an entropy per baryon of order 2 or less are small when considering the maximum neutron star mass. Neutrino trapping, however, significantly changes

A. S. Rinat, M. F. Taragin

Using the Abel inversion for the eikonal phase as function of the interaction we derive simple integral relations between half and on-shell eikonal phases. A frequently used short-range approximation for the half off-shell phase and profile appears supported by the above-mentioned relation. We work out some examples and also address the half off-shell eikona

P. Binétruy, F. Pillon, G. Girardi, R. Grimm

We derive the couplings of the 3-form supermultiplet to the general supergravity-matter-Yang-Mills system. Based on the methods of superspace geometry, we identify component fields, establish their supergravity transformations and construct invariant component field actions. Two specific applications are adressed: the appearance of fundamental 3-forms in the

E. C. Marino

Gauge invariant local creation operators of charged states are introduced and studied in pure gauge theories of the Maxwell type in 2+1D. These states are usually unphysical because of the subsidiary condition imposed on the physical subspace by Gauss&#39; law. A dual Maxwell theory which possesses a topological electric charge is introduced. Pure Electrodyn

A. P. Polychronakos

The propagator and corresponding path integral for a system of identical particles obeying parastatistics are derived. It is found that the statistical weights of topological sectors of the path integral for parafermions and parabosons are simply related through multiplication by the parity of the permutation of the final positions of the particles. Appropri

Koji Harada, Atsushi Okazaki, Masa-aki Taniguchi

The massive Schwinger model is quantized on the light cone with great care on the bosonic zero modes by putting the system in a finite (light-cone) spatial box. The zero mode of $A_{-}$ survives Dirac&#39;s procedure for the constrained system as a dynamical degree of freedom. After regularization and quantization, we show that the physical space condition i

S. Dawson, A. Djouadi, M. Spira

We calculate the two-loop QCD corrections to the production of the neutral supersymmetric Higgs bosons via the gluon fusion mechanism at hadron colliders, including the contributions of squark loops. To a good approximation, these additional contributions lead to the same QCD corrections as in the case where only top and bottom quark loops are taken into acc

R. L. Jaffe

Opening talk presented at the Adriatico Research Conference -- Trends in Collider Spin Physics and at the RIKEN Symposium -- Spin Structure of the Nucleon. We present an overview of the opportunities to explore QCD at a very high energy polarized hadron collider. We review connections to low energy flavor physics, transverse spin in QCD and higher twist. It

Varun Sheel, Hiranmaya Mishra, Jitendra C. Parikh

Phenomenological results of equal time, point to point spatial correlation functions of hadronic currents are used to deduce the structure of the QCD vacuum. It is found that a model with only quark condensate is not adequate to explain the observations. Inclusion of condensate fluctuations (explicit four point structure in the vacuum) leads to excellent ove

Abachi et al.

This study reports the first measurement of the azimuthal decorrelation between jets with pseudorapidity separation up to five units. The data were accumulated using the DØdetector during the 1992--1993 collider run of the Fermilab Tevatron at $\sqrt{s}=$ 1.8 TeV. These results are compared to next--to--leading order (NLO) QCD predictions and to two leading-

S. Aid

The $Q^{2}$ dependence and the total cross sections for charged and neutral current processes are measured in $e^{\pm}p$ reactions for transverse momenta of the outgoing lepton larger than 25 GeV. Comparable size of cross sections for the neutral current process and for the weak charged current process are observed above $Q^2~\approx~5000$ GeV$^2$. Using the

Gregorio Bernardi

Preliminary results on a measurement of the proton structure function F_2 are reported for momentum transfers squared Q^2 between 1.5~GeV^2 and 5000 GeV^2 and for Bjorken x between 5.10^{-5} and 0.32 using data collected by the HERA experiments H1 and ZEUS in 1994. F_2 increases significantly with decreasing x, even in the lowest reachable Q^2 region. The da

Robert Graham, Hugh Luckock

The version of supergravity formulated by Ogievetsky and Sokatchev is almost identical to the conventional $N=1$ theory, except that the cosmological constant $Λ$ appears as a dynamical variable which is constant only by virtue of the field equations. We consider the canonical quantisation of this theory, and show that the wave function evolves with respect

James E. Lidsey

The existence of point symmetries in the cosmological field equations of generalized vacuum scalar--tensor theories is considered within the context of the spatially homogeneous cosmologies. It is found that such symmetries only occur in the Brans--Dicke theory when the dilaton field self--interacts. Moreover, the interaction potential of the dilaton must ta

Matthew W. Choptuik, Tadeusz Chmaj, Piotr Bizon

We present results from a numerical study of spherically-symmetric collapse of a self-gravitating, SU(2) gauge field. Two distinct critical solutions are observed at the threshold of black hole formation. In one case the critical solution is discretely self-similar and black holes of arbitrarily small mass can form. However, in the other instance the critica

Clare C. Yu, M. Guerrero

We study an Anderson impurity in a semiconducting host using the density matrix renormalization group technique. We use the $U=0$ one--dimensional Anderson Hamiltonian at half filling as the semiconducting host since it has a hybridization gap. By varying the hybridization of the host, we can control the size of the semiconducting gap. We consider chains wit

Michael C. Martin, G. Shirane, Y. Fujii, M. Nishi

Neutron scattering measurements on a large single crystal of CuGeO$_3$ have been used to determine the temperature-dependence of the spin-Peierls energy gap. While the power law behavior of the intensity of structural superlattice peaks is well fit by $I({\rm T})\propto ({\rm T}_c - {\rm T})^{2β}$ with an exponent of $β=0.33$, the exponent for the temperatur

J. Feinberg, A. Zee

We analyze the $1+1$ dimensional Nambu-Jona-Lasinio model non-perturbatively. In addition to its simple ground state saddle points, the effective action of this model has a rich collection of non-trivial saddle points in which the composite fields $\sigx=\lag\barψψ\rag$ and $\pix=\lag\barψi\gam_5ψ\rag$ form static space dependent configurations because of no

N. Rajewsky, A. Schadschneider, M. Schreckenberg

We present a solution for the stationary state of an asymmetric exclusion model with sequential update and open boundary conditions. We solve the model exactly for random hopping in both directions by applying a matrix-product formalism which was recently used to solve the model with sublattice-parallel update[1]. It is shown that the matrix-algebra describi

Fausto Borgonovi, Dima L. Shepelyansky

We investigated the effect of noise on propagation of two interacting particles pairs in a quasi one--dimensional random potential. It is shown that pair diffusion is strongly enhanced by short range interaction comparing with the non--interacting case.

Jané Kondev, Jan de Gier, Bernard Nienhuis

We develop a Coulomb gas description of the critical fluctuations in the fully packed loop model on the honeycomb lattice. We identify the complete operator spectrum of this model in terms of electric and magnetic {\em vector}-charges, and we calculate the scaling dimensions of these operators exactly. We also study the geometrical properties of loops in thi

Yasuhiro Hatsugai, Xiao-Gang Wen, Mahito Kohmoto

Random bond Hamiltonians of the $π$ flux state on the square lattice are investigated. It has a special symmetry and all states are paired except the ones with zero energy. Because of this, there are always zero-modes. The states near $E=0$ are described by massless Dirac fermions. For the zero-mode, we can construct a random lattice fermion without a doubli

P. B. Sunil Kumar, Madan Rao

We propose a new Monte Carlo scheme to study the late-time dynamics of a 2-dim hard sphere fluid, modeled by a tethered network of hard spheres. Fluidity is simulated by breaking and reattaching the flexible tethers. We study the diffusion of a tagged particle, and show that the velocity autocorrelation function has a long-time $t^{-1}$ tail. We investigate

Leo Kadanoff, Detlef Lohse, Norbert Schorghofer

The GOY model is a model for turbulence in which two conserved quantities cascade up and down a linear array of shells. When the viscosity parameter, $ν$, is small the model has a qualitative behavior which is similar to the Kolmogorov theories of turbulence. Here a static solution to the model is examined, and a linear stability analysis is performed to obt

Andrew Gould

Extreme microlensing events, defined as events with maximum magnification $A_\max\gsim 200$ are a potentially powerful probe of the mass spectrum and spatial distribution of objects along lines of sight toward the Galactic bulge. About 75 yr${}^{-1}$ such events are expected for main-sequence sources with $I_0<19$. For many of these it is possible to measure

D. J. Crary, C. Kouveliotou, J. van Paradijs, F. van der Hooft

We have examined fifteen days of CGRO/BATSE data, obtained during the first outburst of the black-hole candidate source GRO J1655-40, to search for rapid variability of its X-ray flux. We find no evidence for significant variability of GRO J1655-40 during our observations, with a 2 sigma upper limit to the fractional r.m.s. amplitude in the frequency range 0

R. Pello, J. M. Miralles, J. -F. Le Borgne, J. -P. Picat

This paper describes new results on the identification of the complex gravita- tional lens responsible for the double quasar Q2345+007. A gravitational shear field was detected recently about 45&#39;&#39; away from the QSO, centered on an excess of faint blue galaxies. We present deep photometric data in the near-IR (J & K&#39;), which are used together with

Eli Waxman, Paolo Coppi

A scenario in which cosmic rays (CRs) above $10^{20}{\rm eV}$ are produced by cosmological gamma-ray bursts (GRBs) is consistent with observations provided that deflections by the inter-galactic magnetic field (IGMF) delay and spread the arrival time of the CRs over $\geq50{\rm yr}$. The energy lost by the CRs as they propagate and interact with the microwav

Johan H. Knapen

I discuss new observations of circumnuclear regions in barred galaxies, both of their kinematics and their near-infrared (NIR) morphology. New kinematic observations of M100 confirm that (1) the inner bar-like feature detected before in this galaxy is in fact a continuation of the large-scale stellar bar; and (2) the spiral arm-like sites of star formation i

B. J. Teegarden, T. L. Cline, N. Gehrels, D. Palmer

The TGRS (Transient Gamma-Ray Spectrometer) experiment is a high-resolution germanium detector launched on the WIND satellite on Nov. 1, 1994. Although primarily intended to study gamma-ray bursts and solar flares, TGRS also has the capability of studying slower transients (e.g. x-ray novae) and certain steady sources. We present here results on the narrow 5

Peter Coles, Andrew G. Davies, Russell C. Pearson

We propose and investigate a new algorithm for quantifying the topological properties of cosmological density fluctuations. We first motivate this algorithm by drawing a formal distinction between two definitions of relevant topological characteristics, based on concepts, on the one hand, from differential topology and, on the other, from integral geometry.

C. J. Horowitz

Neutrino-nucleus elastic scattering is reduced in dense matter because of correlations between ions. The static structure factor for a plasma of electrons and ions is calculated from Monte Carlo simulations and parameterized with a least squares fit. Our results imply a large increase in the neutrino mean free path. This strongly limits the trapping of neutr

Hyung Mok Lee, Sungsoo S. Kim, Hyesung Kang

We have examined consequences of strong tidal encounters between a neutron star and a normal star using SPH as a possible formation mechanism of isolated recycled pulsars in globular clusters. We have made a number of SPH simulations for close encounters between a main-sequence star of mass ranging from 0.2 to 0.7 Solar masses represented by an n=3/2 polytro

Alexander B. Givental

We develop general theory of equivariant quantum cohomology for ample Kahler manifolds and prove the mirror conjecture for projective complete intersections.

Christoph Greub, Tobias Hurth, Mikolaj Misiak, Daniel Wyler

The $c \to u γ$ transition does not occur at the tree level in the Standard Model and is strongly GIM-suppressed at one loop. The leading QCD logarithms are known to enhance the amplitude by two orders of magnitude. We point out that the amplitude increases further by two orders of magnitude after including the complete 2-loop QCD contributions. Nevertheless

Dan-di Wu, Yue-liang Wu

O(10) grand unification models which do not necessarily have an extra global symmetry are discussed, taking the model with one 10-plet in the Yukawa sector as an example. A strong correlation between mass ratios and CP is found. The mass relation $m_t/m_b=v_u/v_d$ is recovered when $G_W=0$; and another special relation $m_t/m_b=G_E/G_W$ appears when $v_d=0$,

Luc Blanchet

This paper derives the total power or energy loss rate generated in the form of gravitational waves by an inspiralling compact binary system to the five halves post-Newtonian (2.5PN) approximation of general relativity. Extending a recently developed gravitational-wave generation formalism valid for arbitrary (slowly-moving) systems, we compute the mass mult

M. Bowick, S. Catterall, M. Falcioni, G. Thorleifsson

We present the results of a high-statistics Monte Carlo simulation of a phantom crystalline (fixed-connectivity) membrane with free boundary. We verify the existence of a flat phase by examining lattices of size up to $128^2$. The Hamiltonian of the model is the sum of a simple spring pair potential, with no hard-core repulsion, and bending energy. The only

Philip Candelas, Anamaria Font

We discuss how transitions in the space of heterotic K3*T^2 compactifications are mapped by duality into transitions in the space of Type II compactifications on Calabi-Yau manifolds. We observe that perturbative symmetry restoration, as well as non-perturbative processes such as changes in the number of tensor multiplets, have at least in many cases a simpl

Stephen Wiesner

We suggest that quantum computers can solve quantum many-body problems that are impracticable to solve on a classical computer.

G. Martinez-Pinedo, A. Poves, E. Caurier, A. P. Zuker

We have calculated the Gamow-Teller matrix elements of 64 decays of nuclei in the mass range A=41--50. In all the cases the valence space of the full pf-shell is used. Agreement with the experimental results demands the introduction of an average quenching factor, q=0.744 +/- 0.015, slightly smaller but statistically compatible with the $sd$-shell value, thu

S. Chattopadhyay

To study the role of fluctuation in the collisional dynamics, Boltzmann- Langevin formalism is applied in a two dimensional scenario. The importance of collective flow towards the formation of hollow structure is exhibited in our simulation result. The observation of large clusters along the transverse direction indicates the non-equilibrium aspects of the f

V. P. Frolov, D. V. Fursaev, A. I. Zelnikov

The thermodynamical one-loop entropy $S^{TD}$ of a two-dimensional black hole in thermal equilibrium with the massless quantum gas is calculated. It is shown that $S^{TD}$ includes the Bekenstein-Hawking entropy, evaluated for the quantum corrected geometry, and the finite difference of statistical mechanical entropies $-Tr\hatρ\ln\hatρ$ for the gas on the b

S. L. Lyakhovich, A. Yu. Segal, A. A. Sharapov

A universal model for D=4 spinning particle is constructed with the configuration space chosen as ${\bf R}^{3,1}\times S^2$, where the sphere corresponds to the spinning degrees of freedom. The Lagrangian includes all the possible world--line first order invariants of the manifold. Each combination of the four constant parameters entering the Lagrangian give

Makoto Natsuume, Norisuke Sakai, Masamichi Sato

The $SL(2, R)/Z$ WZW orbifold describes the (2+1)-dimensional black hole which approaches anti-de~Sitter space asymptotically. We study the $1 \rightarrow 1$ tachyon scattering off the rotating black hole background and calculate the Hawking temperature using the Bogoliubov transformation.

B. Geyer, S. D. Odintsov

We investigate the gauged NJL--model in curved spacetime using the RG formulation and the equivalency with the gauge Higgs--Yukawa model in a modified 1/N_c -expansion. The strong curvature induced chiral symmetry breaking is found in the non-perturbative RG approach (presumably equivalent to the ladder Schwinger--Dyson equations). Dynamically generated ferm

K. N. Zyablyuk

The reduction from N=1, D=10 to N=4, D=4 supergravity with the Yang-Mills matter is considered. For this purpose a set of constraints is imposed in order to exclude six additional abelian matter multiplets and conserve the supersymmetry. We consider both the cases of usual and dual N=1, D=10 supergravity using the superspace approach. Also the effective pote

Michael R. Douglas, Gregory Moore

Effective field theories in type I and II superstring theories for D-branes located at points in the orbifold C^2/Z_n are supersymmetric gauge theories whose field content is conveniently summarized by a `quiver diagram,&#39; and whose Lagrangian includes non-metric couplings to the orbifold moduli: in particular, twisted sector moduli couple as Fayet-Iliopo

M. Carena, M. Quiros, C. E. M. Wagner

We perform an analysis of the behaviour of the electroweak phase transition in the Minimal Supersymmetric Standard Model, in the presence of light stops. We show that, in previously unexplored regions of parameter space, the order parameter $v(T_c)/T_c$ can become significantly larger than one, for values of the Higgs and supersymmetric particle masses consi

Georgij Takhtamyshev

The problem of mirror-reflection symmetry (MRS) and time-reversal symmetry (TRS) in our world is discussed. The opinion is expressed, that well-known experiments on parity violation and CP-violation can be treated as signals of some new, yet unknown, level of matter. An hypothesis, which can be used as a base for some future model or theory is formulated. In

Suraj N. Gupta, James M. Johnson, Glenn A. Ladinsky, Wayne W. Repko

We have extended our earlier treatment of the gauge-boson scattering with radiative corrections in the standard model at supercollider energies, and computed the rates for gauge-boson scattering modes in $pp$ collisions leading to the final states $W^+W^-$, $ZZ(4l)$, $ZZ(2l2ν)$, $W^\pm Z$, and $W^\pm W^\pm $. Our results at the LHC \hbox{energy} of $\sqrt{s}

Tatsu Takeuchi

I will discuss the current status of the determination of $\alpha(m_Z)$ and $\alpha_s(m_Z)$, emphasizing the pitfalls that one must avoid in performing statistical analyses.

Irinel Caprini, Matthias Neubert

We derive a theoretically allowed domain for the slope $\widehat\varrho^2$ and curvature $\widehat c$ of the physical form factor appearing in the decay $\bar B\to D^*\ell\barν$. Using heavy-quark symmetry, we relate this function to a particular $\bar B \to D$ form factor free of ground-state $B_c$ poles below the threshold for $B D$ production, for which a

G. Karra, R. J. Rivers

We present a model for the formation of relativistic global vortices (strings) at a quench, and calculate their density and correlations. The significance of these results to early universe and condensed-matter physics is discussed. In particular, there is always open, or infinite, string.

M. Chaichian, K. Huitu

The lepton number violating process $μ\rightarrow eγ$ is used to study the lepton number violating couplings in MSSM extended by terms violating $R$-parity explicitly. Bounds are obtained for the products of $λ$- or $λ&#39;$-type couplings. It is found that many of these limits are more stringent than the ones obtained previously.

Wim Beenakker, Geert Jan van Oldenborgh

We investigate the uncertainty induced by the Higgs-boson mass on the determination of $m_W$ from the LEP-2 run near the threshold for $W$-pair production. For a light Higgs boson the Yukawa interaction between the two slowly-moving $W$ bosons gives rise to a correction of close to 1\% to the total cross-section. This corresponds to a 15 MeV shift in the ded

A. Bartl, H. Eberl, S. Kraml, W. Majerotto

We present a comprehensive study of pair production and decay of stops, sbottoms, and staus in $e^+ e^-$ annihilation at LEP2. We give numerical predictions within the Minimal Supersymmetric Standard Model for cross sections and decay rates, and discuss the important signatures. In the case of stau production we also study the polarization of the tau in the

W. Kilian, M. Krämer, P. M. Zerwas

The angular distributions in the Higgs-strahlung process $e^+e^-\to HZ\to H\bar f f$ are uniquely determined in the Standard Model. We study how these predictions are modified if non-standard couplings are present in the $ZZH$ vertex, as well as lepton-boson contact terms. We restrict ourselves to the set of operators which are singlets under standard $SU_3\

A. V. Radyushkin, R. T. Ruskov

The transition gamma*(q_1)gamma*(q_2) -> \pi0(p) is studied within the QCD sum rule framework. As a first step, we analyze the kinematic situation when both photon virtualities are spacelike and large. We construct a QCD sum rule for F(q_1^2,q_2^2) and show that, in the asymptotic limit |q_1^2|, |q_2^2| \to \infty, it reproduces the leading-order pQCD result