April 1998 arXiv papers — page 6

L. H. Ford

The interaction between a polarizable particle and a reflecting wall is examined. A macroscopic approach is adopted in which the averaged force is computed from the Maxwell stress tensor. The particular case of a perfectly reflecting wall and a sphere with a dielectric function given by the Drude model is examined in detail. It is found that the force can be

Richard J. Szabo

The most general gauge-invariant marginal deformation of four-dimensional abelian BF-type topological field theory is studied. It is shown that the deformed quantum field theory is topological and that its observables compute, in addition to the usual linking numbers, smooth intersection indices of immersed surfaces which are related to the Euler and Chern c

Sumit R. Das, Sandip P. Trivedi

Recently, a relation between N=4 Super Yang Mills in 3+1 dimensions and supergravity in an $AdS_5$ background has been proposed. In this paper we explore the idea that the correspondence between operators in the Yang Mills theory and modes of the supergravity theory can be obtained by using the D3 brane action. Specifically, we consider two form gauge fields

Sharmanthie Fernando, Freydoon Mansouri

We study anti-de Sitter black holes in 2+1 dimensions in terms of Chern Simons gauge theory of anti-de Sitter group coupled to a source. Taking the source to be an anti-de Sitter state specified by its Casimir invariants, we show how all the relevant features of the black hole are accounted for. The requirement that the source be a unitary representation lea

G. Tavares-Velasco, M. A. Perez, M. Maya, B. Vega

We study the radiative decay Z-->neutrino antineutrino gamma whitin an effective Lagrangian approach. Using the search for energetic single-photon events in the data collected by the L3 collaboration, we get direct bounds on the dimension-six and the dimension-eight operators associated with the tau-neutrino magnetic moment and the anomalous electromagnetic

Tony Gherghetta, Antonio Riotto, Leszek Roszkowski

The supersymmetric flavour and CP problems can be avoided if the first two generations of sfermions are heavier than a few TeV and approximately degenerate in mass. However using flavour and CP-violating constraints on the third sfermion generation, together with the decoupling of the first two generations, can dramatically affect cosmological predictions su

George Lavrelashvili

Positive definiteness of the quadratic part of the action of the Hawking-Turok instanton is investigated. The Euclidean quadratic action for scalar perturbations is expressed in terms of a single gauge invariant quantity $q$. The mode functions satisfy a Schrödinger type equation with a potential $U$. It is shown that the potential $U$ tends to a positive co

S. N. Gninenko, N. V. Krasnikov

An anomaly in time distribution of neutrinos from the ISIS pulsed beam stop source observed by the KARMEN collaboration is discussed. We show that the anomaly can be interpreted as a superposition of two exponentials, both having time constants consistent with the $μ^{+}$ lifetime of 2.2 $μs$. % and, therefore, It is assumed that they both originate from muo

Hans-Thomas Elze

Master equations describe the quantum dynamics of open systems interacting with an environment. They play an increasingly important role in understanding the emergence of semiclassical behavior and the generation of entropy, both being related to quantum decoherence. Presently we derive the exact master equation for a homogeneous scalar Higgs or inflaton lik

C. Adloff

The multiplicity structure of the hadronic system X produced in deep-inelastic processes at HERA of the type ep -> eXY, where Y is a hadronic system with mass M_Y< 1.6 GeV and where the squared momentum transfer at the pY vertex, t, is limited to |t|<1 GeV^2, is studied as a function of the invariant mass M_X of the system X. Results are presented on multipl

Charles H. Bennett, David P. DiVincenzo, Christopher A. Fuchs, Tal Mor

We exhibit an orthogonal set of product states of two three-state particles that nevertheless cannot be reliably distinguished by a pair of separated observers ignorant of which of the states has been presented to them, even if the observers are allowed any sequence of local operations and classical communication between the separate observers. It is proved

Sergei B. Leble, Marek Czachor

A new form of a binary Darboux transformation is used to generate analytical solutions of a nonlinear Liouville-von Neumann equation. General theory is illustrated by explicit examples.

Peter Schwab, Roberto Raimondi, Claudio Castellani

We consider the thermodynamic behavior of a disordered interacting electron system in two dimensions. We show that the corrections to the thermodynamic potential in the weakly localized regime give rise to a non monotonic behavior of the specific heat both in temperature and magnetic field. From this effect we predict the appearance of adiabatic hysteresis i

Oliver Schoenborn, Rashmi C. Desai

We show how the interface curvature autocorrelation function (ICAF) and associated structure factor (ICSF), of relevance in non-equilibrium pattern-formation problems where sharp interfaces are present, provide new and interesting information on domain structure, as yet not visible via the order-parameter structure factor (OPSF). This is done by discussing n

Oliver Schoenborn, Rashmi C. Desai

An interface description and numerical simulations of model A kinetics are used for the first time to investigate the intra-surface kinetics of phase ordering on corrugated surfaces. Geometrical dynamical equations are derived for the domain interfaces. The dynamics is shown to depend strongly on the local Gaussian curvature of the surface, and can be fundam

Hiroshi Fujisaki, Akira Shimizu

From the microscopic quantum Langevin equations (QLEs) we derive the effective semiconductor QLEs and the associated noise correlations which are valid at a low-injection level and in real devices. Applying the semiconductor QLEs to semiconductor light-emitting devices (LEDs), we obtain a new formula for the Fano factor of photons which gives the photon-numb

Konrad Banaszek

An iterative algorithm for reconstructing the photon distribution from the random phase homodyne statistics is discussed. This method, derived from the maximum-likelihood approach, yields a positive definite estimate for the photon distribution with bounded statistical errors even if numerical compensation for the detector imperfection is applied.

Lu Lin

It is shown that, in Dirac theory, there is a spatial velocity of a free electron which commutes with the Hamiltonian, so it is a conserved quantity of the motion. Furthermore, there is a spatial orbital angular momentum which also commutes with the Hamiltonian and is a constant of the motion.

J. Usukura, K. Varga, Y. Suzuki

The positronium molecule (Ps$_2$) has not been experimentally observed yet because its tiny (4.5 eV) binding energy cannot be detected when the molecule annihilates by emitting two photons with energy of 0.51 MeV each. It is shown in this paper that the electric dipole transition between the recently found L=1 excited-state and the L=0 ground-state with its

Avijit K. Ganguly

We discuss, in this review, the existing models for the production of QGP in Relativistic Heavy Ion Collisions. We shall try to give a brief description of the models available for the pre-equilibrium production of QGP, ranging from soft process dominated QCD regime to the pQCD dominated regime. We also present the estimates for the initial energy density, t

H. Haberzettl, C. Bennhold, T. Mart, T. Feuster

We show how the gauge-invariance formulation given by Haberzettl is implemented in practice for photoproduction amplitudes at the tree level with form factors describing composite nucleons. We demonstrate that, in contrast to Ohta&#39;s gauge-invariance prescription, this formalism allows electric current contributions to be multiplied by a form factor, i.e.

V. I. Komarov, A. V. Lado, Yu. N. Uzikov

The one- and two-step mechanisms of the $pd\to ^3H_ΛK^+$ reaction in the range of incident proton kinetic energy 1.13-3.0 GeV have been investigated. A remarkable peculiarity of the two-step mechanism which incorporates subprocesses $pp\to dπ^+$ and $π^+n\to K^+Λ$ is the so called velocity matching providing the presence of all intermediate particles nearly

I. P. Matamba, M. Braun, S. A. Sofianos

Photoexcitation of the nucleon is studied in the framework of the constituent quark model with nonrelativistic quark-quark interactions. Utilizing the dominance of the pairwise structure of the relevant three-quark potential, the bound and excited state wave functions have been constructed using the Faddeev-type Integrodifferential Equation Approach. The met

Yu. N. Uzikov

The contribution of nucleon isobar $N^*$ exchanges to backward elastic pd-scattering is calculated on the basis of deuteron 6q-model and found to be negligible in comparison with the neutron exchange. It is shown that the pole amplitude of neutron pickup from the deuteron $nN^*$-component is favoured in the reaction $pd\to dN^*$ for backward going $N^*(1440)

L. D. Blokhintsev, A. V. Lado, Yu. N. Uzikov

The two-body transfer amplitude for the rearrangement process i+(jkl) - j+(ikl) is constructed on the basis of technique of 4-dimensional covariant nonrelativistic graphs. The developed formalism is applied to describing backward elastic $p^3He$ scattering in the energy range 0.5 - 1.7 GeV. Numerical calculations performed using the 5- channel wave function

P. Garbaczewski, R. Olkiewicz

By departing from the previous attempt (Phys. Rev. {\bf E 51}, 4114, (1995)) we give a detailed construction of conditional and perturbed Markov processes, under the assumption that the Cauchy law of probability replaces the Gaussian law (appropriate for the Wiener process) as the model of primordial noise. All considered processes are regarded as probabilis

Jeffrey Bergen, Mark C. Wilson

Many important quantum algebras such as quantum symplectic space, quantum Euclidean space, quantum matrices, $q$-analogs of the Heisenberg algebra and the quantum Weyl algebra are semi-commutative. In addition, enveloping algebras $U(L_+)$ of even Lie color algebras are also semi-commutative. In this paper, we generalize work of Montgomery and examine the $X

Bernd Siebert

For a complex projective manifold Gromov-Witten invariants can be constructed either algebraically or symplectically. Using the versions of Gromov-Witten theory by Behrend and Fantechi on the algebraic side and by the author on the symplectic side, we prove that both points of view give the same results. A similar statement has been obtained independently by

Noson S. Yanofsky

We study what happens when coherence fails. Categories with a tensor product and a natural associativity isomorphism that does not necessarily satisfy the pentagon coherence requirements (called associative categories) are considered. Categorical versions of associahedra where naturality squares commute and pentagons do not, are constructed (called Catalan g

Saad Baaj, Etienne Blanchard, Georges Skandalis

A pre-subgroup of a multiplicative unitary $V$ on a finite dimensionnal Hilbert space $H$ is a vector line $L$ in $H$ such that $V(L\otimes L)=L\otimes L$. We show that there are finitely many pre-subgroups, give a Lagrange theorem and generalize the construction of a `bi-crossed product&#39;. Moreover, we establish bijections between pre-subgroups and coide

Eduard Looijenga

Paper withdrawn. (Lemma 2.1 is false.)

L. V. Belvedere, R. L. P. G. Amaral, C. G. Carvalhaes, N. A. Lemos

We consider the canonical quantization of a generalized two-dimensional massive fermion theory containing higher odd-order derivatives. The requirements of Lorentz invariance, hermiticity of the Hamiltonian and absence of tachyon excitations suffice to fix the mass term, which contains a derivative coupling. We show that the basic quantum excitations of a hi

C. Fosco, F. A. Schaposnik

One loop effects due to virtual gauge field propagation in 2+1 dimensional Born-Infeld theory are investigated. Although this field theory model is not power counting renormalizable, it can be consistently interpreted as an effective field theory. We derive the one-loop effective action in this framework. Halpern&#39;s field strength&#39;s formulation is the

A. Ali, G. Kramer, C. D. Lu

Using a theoretical framework based on the next-to-leading order QCD-improved effective Hamiltonian and a factorization Ansatz for the hadronic matrix elements of the four-quark operators, we reassess branching fractions in two-body non-leptonic decays $B \to PP, PV, VV$, involving the lowest lying light pseudoscalar $(P)$ and vector $(V)$ mesons in the stan

Loyal Durand, Gregory Jaczko

We apply Pade summation to the β(λ) function for the quartic Higgs coupling λin the standard electroweak model. We use the βfunction calculated to five loops in the minimal subtraction scheme to demonstrate the improvement resulting from the summation, and then apply the method to the more physical on-mass-shell renormalization scheme where βis known to thre

I. V. Akushevich, A. N. Ilyichev, N. M. Shumeiko

The one-loop electroweak radiative correction of the lowest order to lepton current for deep inelastic scattering of longitudinally polarized leptons by polarized nucleons is obtained in model independent way. The detailed numerical analysis within kinematical requirements of future polarization collider experiments is performed. The possibility to reduce ra

M. Shmatikov

Modifications of the mass spectrum the quarkonium induced by its virtual dissociation into a pair of heavy mesons is considered. Coupling between quark and mesonic channels results in noticeable corrections to spin-dependent mass splitting. In particular, the observable hierarchy of mass splittings in the $χ_c, χ_b$ and $χ&#39;_b$ multiplets is reproduced.

Xiang-Qian Luo, Shuo-Hong Guo, H. Kröger, Dieter Schütte

Lepage&#39;s improvement scheme is a recent major progress in lattice $QCD$, allowing to obtain continuum physics on very coarse lattices. Here we discuss improvement in the Hamiltonian formulation, and we derive an improved Hamiltonian from a lattice Lagrangian free of $O(a^2)$ errors. We do this by the transfer matrix method, but we also show that the alte

The D0 Collaboration

The physics that can be done with 30 fb$^{-1}$ of data at the Tevatron (TeV33) will significantly advance our understanding of particle physics. In this document we consider the potential of the DO detector for running with the TeV33 Collider. In that era, the instantaneous luminosity is expected to rise by a factor of two to five. We show that the DO detect

Patrick R. Brady, Jolien D. E. Creighton, Kip S. Thorne

Gravitational radiation arising from the inspiral and merger of binary black holes (BBH's) is a promising candidate for detection by kilometer-scale interferometric gravitational wave observatories. This paper discusses a serious obstacle to searches for such radiation and to the interpretation of any observed waves: the inability of current computational te

Domenico Giulini

We review in a pedagogical fashion the 3+1-split which serves to put Einstein&#39;s equations into the form of a dynamical system with constraints. We then discuss the constraint equations under the simplifying assumption of time-symmetry. Multi-Black-Hole data are presented and more explicitly described in the case of two holes. The effect of different topo

Eric Gourgoulhon

Various formalisms proposed recently for irrotational binary systems in general relativity are compared and explicit relations between them are exhibited. It is notably shown that the formalisms of (i) Teukolsky, (ii) Shibata and (iii) Bonazzola et al. (as corrected by Asada) are equivalent, i.e. yield exactly the same solution, although the former two are s

S. Capozziello, R. de Ritis, A. A. Marino

In the framework of extended gravity theories, we discuss the meaning of a time dependent &#34;cosmological constant&#34; and give a set of conditions to recover asymptotic de Sitter behaviour for a class of cosmological models independently of initial data. To this purpose we introduce a time-dependent (effective) quantity which asymptotically becomes the t

Alexander Vilenkin

Linde&#39;s proposal of a Euclidean path integral with the ``wrong&#39;&#39; sign of Euclidean action is often identified with the tunneling proposal for the wave function of the universe. However, the two proposals are in fact quite different. I illustrate the difference and point out that recent criticism by Hawking and Turok does not apply to the tunnelin

Michael R. Geller

A novel chiral interferometer is proposed that allows for a direct measurement of the phase of the transmission coefficient for transport through a variety of mesoscopic structures in a strong magnetic field. The effects of electron-electron interaction on this phase is investigated with the use of finite-size bosonization techniques combined with perturbati

H. Aliaga, R. Allub, B. Alascio

We present a simple model to study the electron doped manganese perovskites. The model considers the competition between double exchange mechanism for itinerant electrons and antiferromagnetic superexchange interaction for localized electrons. It represents each Mn^{4+} ion by a spin 1/2, on which an electron can be added to produce Mn^{3+}; we include a hop

Neng-ping Wang, J. M. Pitarke

The electronic energy-loss straggling of protons and antiprotons moving at arbitrary nonrelativistic velocities in a homogeneous electron gas are evaluated within a quadratic response theory and the random-phase approximation (RPA). These results show that at low and intermediate velocities quadratic corrections reduce significantly the energy-loss stragglin

Mark Wensell, Henry Krakauer

A key to optimizing the growth of the new single-crystal relaxor ferroelectrics is resolving basic questions concerning their structural properties and energetics. We report on initial first-principles total energy and force calculations, examining the energetics of local order in PZN type relaxors.

Alessandro Cuccoli, Valerio Tognetti, Paola Verrucchi, Ruggero Vaia

Theoretical predictions of a semiclassical method - the pure-quantum self-consistent harmonic approximation - for the correlation length and staggered susceptibility of the Heisenberg antiferromagnet on the square lattice (2DQHAF) agree very well with recent quantum Monte Carlo data for S=1, as well as with experimental data for the S=5/2 compounds Rb2MnF4 a

L. W. Bernardi, N. Lemke, P. O. Mari, I. A. Campbell

Numerical simulations on Ising Spin Glasses show that spin glass transitions do not obey the usual universality rules which hold at canonical second order transitions. On the other hand the dynamics at the approach to the transition appear to take up a universal form for all spin glasses. The implications for the fundamental physics of transitions in complex

D. K. Klimov, D. Thirumalai

We consider equilibrium folding transitions in lattice protein models with and without side chains. A dimensionless measure, $Omega_{c}$, is introduced to quantitatively assess the degree of cooperativity in lattice models and in real proteins. We show that larger values of $Ω_{c}$ resembling those seen in proteins are obtained in lattice models with side ch

G. S. Uhrig, F. Schoenfeld, J. P. Boucher

A magnetic model is proposed for describing the incommensurate I phase of spin-Peierls systems. Based on the harmonicity of the lattice distortion, its main ingredient is that the distortion of the lattice adjusts to the average magnetization such that the system is always gapful. The presence of dynamical incommensurabilities in the fluctuation spectra is a

M. Houbiers, H. T. C. Stoof

We apply the closed time-path formalism to evaluate the dynamics of the BCS transition to the superfluid state in trapped atomic $^6$Li. We find that the Fokker-Planck equation for the probability distribution of the order parameter is, sufficiently close to the critical temperature, identical to the equation that describes the switching on of a single-mode

P. Nagel, V. Pasler, S. Lebedkin, C. Meingast

The thermal stability of C60 dimers and 2D pressure-polymerized C60 is studied using high-resolution capacitance dilatometry. The transformation of both the dimer and the polymer phases back to &#39;normal&#39; C60 is excellently described by a simple thermally activated process, with activation energies of 1.75 1 0.1 eV (dimer) and 1.9 1 0.2 eV (polymer). T

M. T. Batchelor, B. I. Henry, S. D. Watt

The surface width scaling of Eden A clusters grown from a single aggregate site on the square lattice is investigated as a function of the noise reduction parameter. A two-exponent scaling ansatz is introduced and used to fit the results from simulations covering the range from fully stochastic to the zero-noise limit.

L. Biferale, G. Boffetta, A. Celani, F. Toschi

A multifractal-like representation for multi-time multi-scale velocity correlation in turbulence and dynamical turbulent models is proposed. The importance of subleading contributions to time correlations is highlighted. The fulfillment of the dynamical constraints due to the equations of motion is thoroughly discussed. The prediction stemming from this repr

J. Lopez-Suarez, R. Canal

We investigate the possibility of accounting for the currently inferred primordial abundances of D, 3He, 4He, and 7Li by big bang nucleosynthesis in the presence of baryon density inhomogeneities plus the effects of late-decaying massive particles (X), and we explore the allowed range of baryonic fraction of the closure density Omega_b in such context. We fi

Lin Yan, Patrick McCarthy, Lisa Storrie-Lombardi, Ray Weymann

We present deep galaxy counts and half-light radii from F160W ($λ_c=1.6μ$) images obtained with NICMOS on HST. Nearly 9 arcmin$^2$ have been imaged with camera 3, with $3σ$ depths ranging from H = 24.3 to 25.5 in a 0.6$&#39;&#39;$ diameter aperture. The slope of the counts fainter than H~$= 20$ is 0.31, and the integrated surface density to H$\leq 24.75$ is

Ewa Szuszkiewicz, John C. Miller

Nonlinear time-dependent calculations are being carried out in order to study the evolution of vertically-integrated models of non-selfgravitating, transonic accretion discs around black holes. In this paper we present results from a new calculation for a high-alpha model similar to one studied previously by Honma, Matsumoto and Kato who found evidence for l

Brian D. Fields, Katherine Freese, David S. Graff

[Abridged] We estimate the contribution of Massive Compact Halo Objects (Machos) and their stellar progenitors to the mass density of the Universe. If the Machos that have been detected reside in the Halo of our Galaxy, then a simple extrapolation of the Galactic population (out to 50 kpc) of Machos to cosmic scales gives a cosmic density $ρ_{Macho} = (1-5)

Eric J. Bakker, David L. Lambert

We have made the first detection of circumstellar absorption lines of the 12C13C (Phillips) system 1-0 band and the 12C16O first-overtone 2-0 band in the spectrum of the post-AGB star HD56126 (IRAS07134+1005). The rotational temperatures are lower for molecules with a higher permanent dipole moment. Derived relative column densities ratios are 12C12C/12C13C=

F. Bernardeau

Sujets qui sont plus particulierement abordes dans ce cours: 1. Elements de cosmologie, l&#39;Univers homogene Les principes cosmologiques et leurs verifications observationnelles Histoire thermique de l&#39;Univers Inflation, motivations et principe de base 2. Elements de cosmologie, l&#39;Univers inhomogene La croissance des fluctuations Pourquoi un modele

J. B. Hutchings, D. Crampton, A. P. Cowley, P. C. Schmidtke

We present and discuss 25 spectra obtained in November 1996, covering all phases of the CAL 87 binary system. These spectra are superior both in signal-to-noise and wavelength coverage to previously published data so that additional spectral features can be measured. Photometry obtained on the same nights is used to confirm the ephemeris and to compare with

W. Zhang, A. P. Smale T. E. Strohmayer, J. H. Swank

We report results from a long-term monitoring data set obtained with the Rossi X-ray Timing Explorer (RXTE) from the bright globular cluster binary source 4U 1820-30. During this monitoring, the source intensity varied from a flux of 2.9E-9 ergs/cm**2/s to 8.5E-9 ergs/cm**2/s in the 2-10 keV band, which correspond to, respectively, a count rate of 1,600 cps

A. P. Cowley, P. C. Schmidtke, D. Crampton, J. B. Hutchings

A comparison is made between the properties of CAL 83, CAL 87, RX J0513.9-6951, 1E 0035.4-7230 (SMC 13), RX J0019.8+2156, and RX J0925.7-4758, all supersoft X-ray binaries. Spectra with the same resolution and wavelength coverage of these systems are compared and contrasted. Some new photometry is also presented. The equivalent widths of the principal emissi

S. V. W. Beckwith, D. Thompson, F. Mannucci, S. G. Djorgovski

An object discovered during an infrared survey of the field near the quasar B2 0149+33 has an emission line at 2.25$μ$m that we interpret as H$α$ at a redshift of 2.43. The K-band image shows two compact components 10 kpc apart surrounded by more extended emission over ~20 kpc. The H$α$ emission appears to be extended over ~15 kpc (2&#34;) in a coarsely samp

W. Zhang, T. E. Strohmayer, J. H. Swank

We report the discovery of two simultaneous quasi-periodic oscillations in the persistent flux of GX 349+2 at frequencies 712 +/- 9 and 978 +/- 9 Hz, with rms amplitudes 1.25% +/- 0.34% and 1.34 +/- 0.32%, respectively. During our 152 ks observation with the Rossi X-ray Timing Explorer, GX 342+2 was in either the normal branch or the flaring branch with coun

P. M. Chadwick, M. R. Dickinson, N. A. Dipper, J. Holder

Observations made with the University of Durham Mark 6 atmospheric Cerenkov telescope confirm that PSR B1706-44 is a very high energy gamma-ray emitter. There is no indication from our dataset that the very high energy gamma-rays are pulsed, in contrast to the findings at < 20 GeV, which indicate that more than 80% of the flux is pulsed. The flux at E > 300

S. Samurovic, V. Milosevic-Zdjelar, M. M. Cirkovic, V. Celebonovic

We review recent research on the Milky Way galaxy and try to investigate whether its shape is similar to other barred galaxies. The emphasis is given on microlensing research because this method can be useful in determining the shape of the Galaxy with the minimal set of assumptions. By analyzing plots of the microlensing optical depth, $τ$ as a function of

A. F. Heavens

The bispectrum of the microwave background sky is a possible discriminator between inflationary and defect models of structure formation in the Universe. The bispectrum, which is the analogue of the temperature 3-point correlation function in harmonic space, is zero for most inflationary models, but non-zero for non-gaussian models. The expected departures f

Yasuhiro Shioya, Kenji Bekki

We investigate a one-zone chemophotometric evolution model of disk-disk galaxy mergers in order to clarify whether or not galaxy mergers with the widely spread merging epoch can reproduce reasonably well the observed small scatter of the color-magnitude (C-M) relation in cluster ellipticals at low and intermediate redshift (z<1). We consider that merger prog

Kenji Bekki

We numerically investigate stellar and gas dynamics in star-forming and dissipative galaxy mergers between two disk galaxies with specific orbital configurations. We find that violent relaxation combined with gaseous dissipation in galaxy merging transforms two disk galaxies into one S0 galaxy with polar-rings: Both the central S0-like host and the polar-rin

Paul H. Frampton

It is proposed that the highest energy $\sim 10^{20}$eV cosmic ray primaries are protons, decay products of a long-lived progenitor whose high kinetic energy arises from decay of a distant (cosmological) superheavy particle, G. Such a scenario can occur in e.g. SU(15) grand unification and in some preon models, but is more generic; if true, these unusual cos

Evanthia Hatziminaoglou, Ludovic Van Waerbeke, Guy Mathez

The evolution of optically selected quasars is usually supposed to be well described by a single constant parameter, either k_L or k_D, depending whether we refer to luminosity or density evolution. In this paper we present a study of the variations of the evolution parameters with redshift, for different cosmological models, in order to probe the differenti

Brent H. Allen, Robert J. Perry

We develop a systematic method for computing a renormalized light-front field theory Hamiltonian that can lead to bound states that rapidly converge in an expansion in free-particle Fock-space sectors. To accomplish this without dropping any Fock sectors from the theory, and to regulate the Hamiltonian, we suppress the matrix elements of the Hamiltonian betw

A. P. Balachandran, G. Bimonte, T. R. Govindarajan, K. S. Gupta

In this paper, we discuss the behavior of conformal field theories interacting at a single point. The edge states of the quantum Hall effect (QHE) system give rise to a particular representation of a chiral Kac-Moody current algebra. We show that in the case of QHE systems interacting at one point we obtain a ``twisted&#39;&#39; representation of the current

Pedro D. Fonseca

We confirm the non-integrability of the multi-deformed Ising Model, an already expected result. After deforming with the energy operator $ϕ_{1,3}$ we use the Majorana free fermionic representation for the massive theory to show that, besides the trivial one, no local integrals of motion can be built in the theory arising from perturbing with both energy and

V. P. Gusynin, I. A. Shovkovy

The derivative expansion of the one-loop effective action in QED$_3$ and QED$_4$ is considered. The first term in such an expansion is the effective action for a constant electromagnetic field. An explicit expression for the next term containing two derivatives of the field strength $F_{μν}$, but exact in the magnitude of the field strength, is obtained. The

K. S. Babu, Christopher Kolda, John March-Russell, Frank Wilczek

Supersymmetric extensions of the standard model generically contain additional sources of CP violation. We discuss how at one loop a potentially large CP violating coupling of the lightest Higgs, h^0, to leptons is induced in the minimal supersymmetric standard model (MSSM). The CP violating couplings of h^0 in extensions of the MSSM, such as the next-to-min

Xin-Nian Wang

Since large $p_T$ particles in high-energy hadronic or nuclear collisions come from jet fragmentation, jet quenching due to parton energy loss in dense matter will cause the suppression of large $p_T$ hadron spectra in high-energy heavy-ion collisions. Assuming an effective energy loss $dE/dx$ for the high $E_T$ partons, effective jet fragmentation functions

M. K. Volkov, M. Nagy, V. L. Yudichev

We calculate the mass spectra of the pseudoscalar and scalar meson nonets in the Nambu--Jona-Lasinio model with the &#39;t Hooft interaction. We obtain satisfactory result for the pseudoscalar mesons. For the scalar mesons, the &#39;t Hooft interaction somewhat increases the values of the masses. However, it is not sufficient to explain the whole scalar mass

Howard A. Masur, Yair N. Minsky

The Complex of Curves on a Surface is a simplicial complex whose vertices are homotopy classes of simple closed curves, and whose simplices are sets of homotopy classes which can be realized disjointly. It is not hard to see that the complex is finite-dimensional, but locally infinite. It was introduced by Harvey as an analogy, in the context of Teichmuller

Massimo Pietroni

The plasmon damping rate in scalar field theory is computed close to the critical temperature. It is shown that the divergent result obtained in perturbation theory is a consequence of neglecting the thermal renormalization of the coupling. Taking this effect into account, a vanishing damping rate is obtained, leading to the critical slowing down of the equi

Harald Grosse, Gert Reiter

We introduce the fuzzy supersphere as sequence of finite-dimensional, noncommutative $Z_{2}$-graded algebras tending in a suitable limit to a dense subalgebra of the $Z_{2}$-graded algebra of ${\cal H}^{\infty}$-functions on the $(2| 2)$-dimensional supersphere. Noncommutative analogues of the body map (to the (fuzzy) sphere) and the super-deRham complex are

Patrick Irwin

A zero mode quantization of the minimal energy SU(2) Skyrmions for nucleon numbers four to nine and seventeen is described. This involves quantizing the rotational and isorotational modes of the configurations. For nucleon numbers four, six and eight the ground states obtained are in agreement with the observed nuclear states of Helium, Lithium and Beryllium

Gerhard Baur, Kai Hencken, Dirk Trautmann

In central collisions at relativistic heavy ion colliders like the Relativistic Heavy Ion Collider RHIC/Brookhaven and the Large Hadron Collider LHC (in its heavy ion mode) at CERN/Geneva, one aims at detecting a new form of hadronic matter - the Quark Gluon Plasma. It is the purpose of this review to discuss a complementary aspect of these collisions, the v

M. Governale, M. Macucci, G. Iannaccone, C. Ungarelli

We have investigated the behavior of bistable cells made up of four quantum dots and occupied by two electrons, in the presence of realistic confinement potentials produced by depletion gates on top of a GaAs/AlGaAs heterostructure. Such a cell represents the basic building block for logic architectures based on the concept of Quantum Cellular Automata (QCA)

Teruhiko Kawano, Kazumi Okuyama

We construct the classical configurations of BPS states with 1/4 unbroken supersymmetries in four-dimensional N=4 SU(n+1) supersymmetric Yang-Mills theory, and discuss that these configurations correspond to string networks connecting (n+1) D3-branes in Type IIB string theory.

J. Nemeth, G. Papp, H. Feldmeier

An extensive comparison of the recent experimental data published by the FOPI collaboration at GSI with the results of a relativistically covariant formulation of a QMD code is presented. For most of the quantities we find agreement with the experimental results showing that the derived force has a reasonable momentum dependence.

Yuri Martinez-Raton, Jose A. Cuesta

We provide an exact mapping between the density functional of a binary mixture and that of the effective one-component fluid in the limit of infinite asymmetry. The fluid of parallel hard cubes is thus mapped onto that of parallel adhesive hard cubes. Its phase behaviour reveals that demixing of a very asymmetric mixture can only occur between a solvent-rich

Ai-Ko Liu

The family Blow Up formula is recalled. Certain combinatoric graphs are introduced for the discussion of the counting of nodal curves on an Kahler surface.

Abhijit Bhattacharyya

The temperature and density dependence of the $ρ-ω$ mixing amplitude has been studied from a purely hadronic model. The in-medium baryon masses and chemical potentials have been obtained at the Mean Field (MF) Level and these results have been used to calculate the mixing amplitude. It has been observed that the mixing amplitude changes substantially at high

A. I. Sokolov, K. B. Varnashev

The critical behavior of a model describing phase transitions in 3D antiferromagnets with 2N-component real order parameters is studied within the renormalization-group (RG) approach. The RG functions are calculated in the three-loop order and resummed by the generalized Pade-Borel procedure preserving the specific symmetry properties of the model. An anisot

N. Bralic, C. A. A. de Carvalho, R. M. Cavalcanti, P. Donatis

We study a relativistic two-dimensional electron gas in the presence of a uniform external magnetic field and a random static scalar potential. We compute, in first order perturbation theory, the averages of the charge density and of the transverse conductivity for a white-noise potential, and show that, within this treatment, their quantized values are modi

Alexander I. Titov, Yongseok Oh, Shin Nan Yang, Tosiyuki Morii

The polarization observables in phi meson photoproduction is studied to probe the strangeness content of the nucleon. In addition to the dominant diffractive production and the one-pion-exchange process, we take into account the direct knockout mechanism that arises from the possible hidden strangeness content of the nucleon. We find that some double polariz

Jun-Jie Cao, Jian-Xiong Wang, Jin Min Yang, Bing-Lin Young

We study in the effective Lagrangian approach the possibility of probing anomalous top quark charged current couplings in the single top production at a high energy eγcollider. We analyzed all possible dimension-six CP-conserving operators which can give rise to an anomalous Wtb coupling which represent new physics effect generated at a higher energy scale.

A. Garcia, R. Huerta, G. Sanchez-Colon

A priori mixings of eigenstates in physical states are quantum mechanical effects well known in several realms of physics. The possibility that such effects are also present in particle physics, in the form of flavor and parity mixings, is studied. Applications to weak radiative and non-leptonic decays of hyperons are discussed.

A. Garcia, R. Huerta, G. Sanchez-Colon

Non-leptonic Decays of Hyperons can provide a detailed determination of the a priori mixing angles that appear in physical hadrons in the approach in which non-perturbative flavor and parity violations are present in tiny pieces of the hadron mass operator. The determination of such angles in these decays will provide a bench mark to test their necessary uni

S. Bar-Shalom, G. Eilam, A. Soni

The sneutrino resonance reactions p \bar p -> sneutrino -> l^+ l^- +X, for l=e,μ,τ, in the MSSM without R-parity are considered. We perform a cross-section analysis and show that present limits on some products of R-parity violating couplings in the sneutrino sector can be significantly improved in future upgraded Fermilab Tevatron runs. Furthermore, we intr

John R. Klauder, Sergei V. Shabanov

Canonical quantization entails using Cartesian coordinates, and Cartesian coordinates exist only in flat spaces. This situation can either be questioned or accepted. In this paper we offer a brief and introductory overview of how a flat phase space metric can be incorporated into a covariant, coordinate-free quantization procedure involving a continuous-time