June 2001 arXiv papers — page 5

S. N. Gninenko, M. M. Kirsanov, N. V. Krasnikov, V. A. Matveev

We study lepton flavour-violating interactions which could result in the $τ$-lepton production in the $ν_μN$ scattering or in $μ\to τ$ conversion on nucleons at high energies. Phenomenological bounds on the strength of $\barτν_μ\bar{q}q^{'}$ interactions are extracted from the combined result of the NOMAD and CHORUS experiments on searching for $ν_μ - ν_

E. Gedalin, A. Moalem, L. Razdolskaya

We show that for any effective field theory of colorless meson fields, the mixing schemes of particle states and decay constants are not only related but also determined exclusively by the kinetic and mass Lagrangian densities. In the general case, these are bilinear in terms of the intrinsic fields and involve non-diagonal kinetic and mass matrices. By appl

G. Ridolfi

We present a short review of experimental and theoretical constraints on the mass of the Standard Model Higgs boson. We briefly illustrate the unsatisfactory aspects of the standard theory, and we present some general considerations about possible non-standard scenarios.

Virendra Gupta, Xiao-Gang He

In this paper we study three active neutrino oscillations, favored by recent data from SuperK and SNO, using a new parametrization of the lepton mixing matrix $V$ constructed from a linear combination of the unit matrix $I$, and a hermitian unitary matrix $U$, that is, $V = \cosθI + i\sin θU$. There are only three real parameters in $V$ including the paramet

M. Hirai, S. Kumano, M. Miyama

Optimum nuclear parton distributions are determined by an analysis of muon and electron deep inelastic scattering data. Assuming simple A dependence and polynomial functions of x and 1-x for nuclear modification of parton distributions, we determine the initial distributions by a chi^2 analysis. Although valence-quark distributions are relatively well determ

T. Barakat

The rare $B\to K^{*}ν\barν$ decay when $K^{*}$ meson is longitudinally or transversely polarized is analysed in the context of the fourth generation model. A significant enhancement to the missing energy spectrum over the SM is recorded.

Savas Dimopoulos, Greg Landsberg

If the scale of quantum gravity is near a TeV, the LHC will be producing one black hole (BH) about every second. The BH decays into prompt, hard photons and charged leptons is a clean signature with low background. The absence of significant missing energy allows the reconstruction of the mass of the decaying BH. The correlation between the BH mass and its t

F. Maltoni, K. Paul, T. Stelzer, S. Willenbrock

We study the production of the Higgs boson in association with a single top quark at hadron colliders. The cross sections for the three production processes (t-channel, s-channel, and W-associated) at both the Tevatron and the LHC are presented. We investigate the possibility of detecting a signal for the largest of these processes, the t-channel process at

A. D. Dolgov, S. H. Hansen

This paper has been withdrawn by the authors. This paper started with a wrong term describing elastic scattering. The correct form of the kinetic equations for the density matrix are derived e.g. in A. Dolgov, Yad. Fiz. 33 (1981) 1309; K. Enqvist, K. Kainulainen and J. Maalampi, Nucl. Phys. B 349 (1991) 754; G. Sigl and G. Raffelt, Nucl. Phys. B 406 (1993) 4

Jiri Chyla

An attempt is made to sort out ambiguities existing in the current usage of several basic concepts describing hard collisions of photons. It is argued that appropriate terminology is often a prerequisite for correct physics.

S. M. Gerasyuta, V. I. Kochkin

The relativistic four-quark equations are found in the framework of the dispersion relation technique. The calculations of non-qq meson amplitudes estimate the contributions of three subamplitudes: four-quark amplitude, glueball amplitude and hadronic molecule amplitudes.

K. Abe

We search for direct CP violation in flavor specific B -> K pi decays by measuring the rate asymmetry between charge conjugate modes. The search is performed on a data sample of 11.1 million B B bar events recorded on the Upsilon(4S) resonance by the Belle experiment at KEKB. We measure 90% confidence intervals in the partial rate asymmetry A_CP of -0.25 < A

M. Kado

An excess of signal-like events above the expected background, corresponding to approximately three standard deviations, was observed in the search for the Standard Model Higgs boson at LEP in 2000. This excess is consistent with the existence of a Higgs boson with mass 115GeV/c2. Relevant consistency and robustness checks, which further support the signal i

Mayeul Arminjon

Cosmology is investigated within a new, scalar theory of gravitation, which is a preferred-frame bimetric theory with flat background metric. Before coming to cosmology, the motivation for an &#34; ether theory &#34; is exposed at length; the investigated concept of ether is presented: it is a compressible fluid, and gravity is seen as Archimedes&#39; thrust

J. C. Phillips

The nature of the phase diagrams of HTSC is clarified by discussing two kinds of phase diagrams, that of the host crystalline lattice, and that of the dopant glass. The latter is associated with changes in the electronic properties, while the former is much more accessible to direct experimental identification, by diffraction, of nanoscale phase separation.

Kenji Hirose, Ned S. Wingreen

For unpolarized electrons in a clean quantum wire, density functional theory reveals a thermally activated suppression of conductance. The activation temperature T_A grows slowly (roughly quadratically) with gate voltage due to pinning of the band edge at the chemical potential. Similar results were obtained experimentally by Kristensen et al. [Phys. Rev. B6

P. Kim, L. Shi, A. Majumdar, P. L. McEuen

The thermal conductivity and thermoelectric power of a single carbon nanotube were measured using a microfabricated suspended device. The observed thermal conductivity is more than 3000 W/K m at room temperature, which is two orders of magnitude higher than the estimation from previous experiments that used macroscopic mat samples. The temperature dependence

S. L. Bud&#39;ko, V. G. Kogan, P. C. Canfield

The recently discovered intermetallic superconductor MgB2 appears to have a highly anisotopic upper critical field with Hc2(max)/Hc2(min} = γ> 5. In order to determine the temperature dependence of both Hc2(max) and Hc2(min) we propose a method of extracting the superconducting anisotropy from the magnetization M(H,T) of randomly oriented powder samples. The

V. V. Struzhkin, A. F. Goncharov, R. J. Hemley, H. K. Mao

We report measurements of the superconducting critical temperature Tc of polycrystalline MgB2 samples containing isotopically pure (10)B and (11)B under quasi-hydrostatic pressure conditions in He pressure media up to 44 GPa. Measurements to volume compressions V/V_0 ~ 0.82 allow us to observe a kink in the volume dependence of Tc for Mg(10)B2 (at 20 GPa) an

Eugene H. Kim

We consider the Kondo effect in quantum dots coupled to Luttinger liquid leads, focussing on the case of repulsive interactions and spin SU(2) symmetry in the leads. We find that the system can flow to the 1-channel or 2-channel Kondo fixed points, depending on the interactions in the system. We compute the conductance and find that the qualitative behavior

Azadeh Samadani, A. Kudrolli

We study the effect of fluids on the angle of repose and the segregation of granular matter poured into a silo. The experiments are conducted in two regimes where: (i) the volume fraction of the fluid is small and it forms liquid bridges between particles, and (ii) the particles are completely immersed in the fluid. The data is obtained by imaging the pile f

Nicolas Sourlas

I will show that there is a deep relation between error-correction codes and certain mathematical models of spin glasses. In particular minimum error probability decoding is equivalent to finding the ground state of the corresponding spin system. The most probable value of a symbol is related to the magnetization at a different temperature. Convolutional cod

J. A. Hernando

Density functional theory stems from the Hohenberg-Kohn-Sham-Mermin (HKSM) theorem in the grand canonical ensemble (GCE). However, as recent work shows, although its extension to the canonical ensemble (CE) is not straightforward, work in nanopore systems could certainly benefit from a mesoscopic DFT in the CE. The stumbling block is the fixed $N$ constraint

C. Godreche, J. M. Luck

We investigate the distribution of the time spent by a random walker to the right of a boundary moving with constant velocity v. For the continuous-time problem (Brownian motion), we provide a simple alternative proof of Newman&#39;s recent result [J.Phys.A 34, L89 (2001)] using a method due to Kac. We then discuss the same problem for the case of a random w

T. Sharpee, M. I. Dykman, P. M. Platzman

We provide a semiclassical theory of tunneling decay in a magnetic field and a three-dimensional potential of a general form. Because of broken time-reversal symmetry, the standard WKB technique has to be modified. The decay rate is found from the analysis of the set of the particle Hamiltonian trajectories in complex phase space and time. In a magnetic fiel

Maria A. Davidovich, E. V. Anda, C. A. Busser, G. Chiappe

A numerically exact calculation of the T=0 transport properties of a quantum wire interacting with a lateral two-level quantum dot is presented. The wire conductance is calculated for all different states of charge and spin of the quantum dot. For a dot with two electrons we obtain an enhancement of the Kondo temperature at the singlet-triplet transition and

G. Burnell, D. -J. Kang, H. N. Lee, S. H. Moon

Since the discovery of superconductivity in MgB2 considerable progress has been made in determining the physical properties of the material, which are promising for bulk conductors. Tunneling studies show that the material is reasonably isotropic and has a well-developed s-wave energy gap (&#8710;), implying that electronic devices based on MgB2 could operat

P. V. Komissinski, E. Il&#39;ichev, G. A. Ovsyannikov, M. Grajcar

The superconducting current-phase relation (CPR) of Nb/Au/(001)YBa2Cu3Ox heterojunctions prepared on epitaxial c-axis oriented YBa2Cu3Ox thin films has been measured in a single-junction interferometer. For the first time, the second harmonic of the CPR of such junctions has been observed. The appearance of the second harmonic and the relative sign of the fi

G. George Batrouni, Alex Hansen, Jean Schmittbuhl

We investigate numerically the failure process when two elastic media, one hard and one soft that have been glued together thus forming a common interface, are pulled apart. We present three main results: (1) The area distribution of simultaneously failing glue (bursts) follows a power law consistent with the theoretically expected exponent 2.5, (2) the maxi

Audun Bakk, Johan S. Hoye, Alex Hansen

We study theoretically the thermodynamics, over a broad temperature range (5 C to 125 C), related to hydrated water upon protein unfolding. The hydration effect is modeled as interacting dipoles in an external field, mimicking the influence from the unfolded surfaces on the surrounding water compared to bulk water. The heat capacity change upon hydration is

Yuval Gefen, Richard Berkovits, Igor V. Lerner, Boris L. Altshuler

We study the Anderson orthogonality catastrophe (AOC) in finite conductors with diffusive disorder. The disorder averaged logarithm of $χ$, the overlap between the ground states before and after adding a static impurity, is found to depend nonmonotonically on the disorder. In two dimensions $<\lnχ^{-1}> \propto \ln^2 N$ in the weak disorder limit, thus showi

R. P. S. M. Lobo, E. Ya. Sherman, D. Racah, Y. Dagan

The ab-plane reflectivity of (Y{1-x}Prx)Ba2Cu3O7 thin films was measured in the 30-30000 cm-1 range for samples with x = 0 (Tc = 90 K), x = 0.4 (Tc = 35 K) and x = 0.5 (Tc = 19 K) as a function of temperature in the normal state. The effective charge density obtained from the integrated spectral weight decreases with increasing x. The variation is consistent

Hikaru Kawamura, Mai Suan Li

Spin and chirality orderings of a three-dimensional XY spin glass are studied by extensive Monte Carlo simulations. By calculating an appropriately defined spin-overlap distribution function, we show that the finite-temperature chiral-glass transition does not accompany the standard spin-glass order, giving support to the spin-chirality decoupling picture. C

A. S. Wilson, Y. Yang, G. Cecil

This paper presents high resolution X-ray observations with Chandra of NGC 4258 and infers the nature of the so called ``anomalous arms&#39;&#39; in this galaxy. The anomalous arms dominate the X-ray image; diffuse X-ray emission from the ``plateaux&#39;&#39; regions, seen in radio and H$α$ imaging, is also found. X-ray spectra have been obtained at various

Norman K. Glendenning, F. Weber

A neutron star in binary orbit with a low-mass non-degenerate companion becomes a source of x-rays with millisecond variability when mass accretion spins it up. Centrifugally driven changes in density profile may initiate a phase transition in a growing region of the core parallel to what may take place in an isolated millisecond pulsar, but in reverse. Such

David W. Hogg, Douglas P. Finkbeiner, David J. Schlegel, James E. Gunn

An unsupervised software ``robot'' that automatically and robustly reduces and analyzes CCD observations of photometric standard stars is described. The robot measures extinction coefficients and other photometric parameters in real time and, more carefully, on the next day. It also reduces and analyzes data from an all-sky $10 \mu m$ camera to detect clouds

M. Vestergaard, B. J. Wilkes

Iron emission is often a severe contaminant in optical-ultraviolet spectra of active galaxies. Its presence complicates emission line studies. A viable solution, already successfully applied at optical wavelengths, is to use an empirical iron emission template. We have generated FeII and FeIII templates for ultraviolet active galaxy spectra based on HST arch

Mordecai-Mark Mac Low, Dinshaw Balsara, Miguel A. Avillez, Jongsoo Kim

Observations have suggested substantial departures from pressure equilibrium in the interstellar medium (ISM) in the plane of the Galaxy, even on scales under 50 pc. Nevertheless, multi-phase models of the ISM assume at least locally isobaric gas. The pressure then determines the density reached by gas cooling to stable thermal equilibrium. We use two differ

H. Bradt, R. Rothschild, J. Swank

Observations with the Rossi X-ray Timing Explorer (RXTE) have led to fundamental progress in the study of compact objects, in particular neutron stars and black holes. In this paper we present briefly some highlights from ~5 years of RXTE operations.

L. Cambresy, F. Boulanger, G. Lagache, B. Stepnik

We present an extinction map of the Polaris molecular cirrus cloud derived from star counts and compare it with the Schlegel et al. (1998) extinction map derived from the far--infrared dust opacity. We find that, within the Polaris cloud, the Schlegel et al. Av values are a factor 2 to 3 higher than the star count values. We propose that this discrepancy res

A. W. Strong, I. V. Moskalenko

In studies of cosmic-ray (CR) propagation and diffuse continuum gamma-ray emission from the Galaxy it has usually been assumed that the source function can be taken as smooth and time-independent. However, especially for electrons at high energies where energy losses are rapid, the effect of the stochastic nature of the sources becomes apparent and indeed ha

A. W. Strong, I. V. Moskalenko

The GALPROP cosmic-ray (CR) propagation model has been extended to three dimensions including the effects of stochastic SNR sources, a comprehensive cross-section database, and nuclear reaction networks. A brief description of the new code is given and some illustrative results for the distribution of CR protons presented. Results for electrons and gamma ray

I. V. Moskalenko, A. W. Strong, J. F. Ormes, M. S. Potgieter

High energy collisions of cosmic ray (CR) nuclei with interstellar gas are believed to be the mechanism producing the majority of CR antiprotons. The distinguishing spectral shape with a maximum at 2 GeV and a sharp decrease towards lower energies makes antiprotons a unique probe of the models of particle propagation in the Galaxy and modulation in the helio

Barbara Ryden, Jeremy Tinker

Elliptical galaxies formed in a major merger tend to become more nearly spherical with time, thanks to the gravitational effect of their central black hole (or black holes). Observational results indicate that elliptical galaxies with older stellar populations (t > 7.5 Gyr) have rounder central isophotes than ellipticals with younger stellar populations. In

G. Rudiger, V. V. Pipin

The rotational influence on the eddy-diffusivity tensor D_ij for anisotropic turbulence fields is considered in order to explain the lithium decay law during the spin-down process of solar-type stars. Rotation proves to be highly effective in the transfer of chemicals through the solar tachocline (beneath the convection zone) which is assumed to contain only

Nikos Prantzos, Yuhri Ishimaru

On the basis of arguments from galactic chemical evolution we suggest that the recent observations of D/H vs. metallicity in several high redshift absorbers are best understood if the primordial D value is in the range 2-3 10$^{-5}$. This range points to a rather high baryonic density ($Ω_Bh^2$=0.019-0.026) compatible to the one obtained by recent estimates

R. D. Blum, D. Schaerer, A. Pasquali, M. Heydari-Malayeri

Canada-France-Hawaii-Telescope adaptive optics bonnette images through narrow-band filters in the $K-$band are presented for the Arches cluster. Continuum fluxes, line fluxes, and equivalent widths are derived from high angular resolution images, some near diffraction limited, for the well known massive stars in the Arches cluster. Images were obtained in th

C. S. Kochanek

We use comparisons between the shapes of gravitational lens galaxies and models for their mass distributions to derive statistical constraints on the alignment of the mass distribution relative to the observed lens galaxy and on the strength of tidal shear perturbations. The mass distributions are aligned with the luminous galaxies, with a 10 degree upper li

KASCADE Collaboration, T. Antoni, M. Risse

An analysis of muon and hadron rates observed in the central detector of the KASCADE experiment has been carried out. The data are compared to CORSIKA simulations employing the high-energy hadronic interaction models QGSJET, DPMJET, HDPM, SIBYLL, and VENUS. In addition, first results with the new hadronic interaction model neXus 2 are discussed. Differences

J. Bouvier, G. Duchene, J. -C. Mermilliod, T. Simon

With the aim of investigating the binary population of the 700 Myr old Praesepe cluster, we have observed 149 G and K-type cluster members using adaptive optics. We detected 26 binary systems with an angular separation ranging from less than 0.08 to 3.3 arcsec (15-600 AU). After correcting for detection biases, we derive a binary frequency (BF) in the logP (

A. S. Miroshnichenko, J. Fabregat, K. S. Bjorkman, D. C. Knauth

The bright star delta Sco has been considered a typical B0-type object for many years. Spectra of the star published prior to 1990 showed no evidence of emission, but only of short-term line profile variations attributed to nonradial pulsations. Speckle interferometric observations show that delta Sco is a binary system with a highly-eccentric orbit and a pe

H. R. de Ruiter, P. Parma, R. Fanti, A. Capetti

We discuss HST images in V and I of radio galaxies selected from the B2 sample of low luminosity radio galaxies. Absorption maps were constructed which highlight the presence of circumnuclear dust on scales of typically few kpc or less.

Michael Hilker

In this contribution, first results of deep VLT photometry (V,I) in the central region of the Hydra I galaxy cluster are presented. Many star clusters have been identified not only around several early-type galaxies, but also in the intra-cluster field, as far as 250 kpc from the cluster center. Outside the bulges of the central galaxies NGC 3311 and NGC 330

Jun Ma, Xu Zhou, Xu Kong, Hong Wu

In this paper we present CCD spectrophotometry of the star clusters that were detected by Chandar, Bianchi, & Ford in the nearby spiral galaxy M33, using the images obtained with the Beijing Astronomical Observatory 60/90 cm Schmidt Telescope in 13 intermediate-band filters from 3800 to 10000Å. The observations cover the whole area of M33 with a total integr

S. Malhotra, M. J. Kaufman, D. Hollenbach, G. Helou

The most important cooling lines of the neutral interstellar medium (ISM) lie in the far-infrared (FIR). We present measurements by the Infrared Space Observatory Long Wavelength Spectrometer of seven lines from neutral and ionized ISM of 60 normal, star-forming galaxies. The galaxy sample spans a range in properties such as morphology, FIR colors (indicatin

Mauricio Bellini

I study a stochastic approach to the recently introduced fresh inflation model for super Hubble scales. I find that the state loses its coherence at the end of the fresh inflationary period as a consequence of the damping of the interference function in the reduced density matrix. This fact should be a consequence of a) the relative evolutions of both the sc

B. Eden, E. Sokatchev

The content of the OPE of two 1/2 BPS operators in N=4 SCFT$_4$ is given by their superspace three-point functions with a third, a priori long operator. For certain 1/2 BPS short superfields these three-point functions are uniquely determined by superconformal invariance. We focus on the cases where the leading ($θ=0$) components lie in the tensor products $

A. Harindranath, L. Martinovic, J. P. Vary

We study the S-matrix of two-dimensional λϕ^4 theory in Discretized Light Cone Quantization and show how the correct continuum limit is reached for various processes in lowest order perturbation theory.

Alejandro Corichi, Ulises Nucamendi, Daniel Sudarsky

The Isolated Horizon formalism, together with a simple phenomenological model for colored black holes was recently used to predict a formula for the ADM mass of the solitons of the EYM system in terms of horizon properties of black holes {\it for all} values of the horizon area. In this note, this formula is tested numerically --up to a large value of the ar

J. Fernandez-Rossier, L. J. Sham

A density functional theory of ferromagnetism in heterostructures of compound semiconductors doped with magnetic impurities is presented. The variable functions in the density functional theory are the charge and spin densities of the itinerant carriers and the charge and localized spins of the impurities. The theory is applied to study the Curie temperature

Natalia G. Berloff, Paul H. Roberts

The Gross-Pitaevskii (GP) equation admits a two-dimensional solitary wave solution representing two mutually self-propelled, anti-parallel straight line vortices. The complete sequence of such solitary wave solutions has been computed by Jones and Roberts (J. Phys. A, 15, 2599, 1982). These solutions are unstable with respect to three-dimensional perturbatio

LHPC Collaboration, QCDSF Collaboration, UKQCD Collaboration, M. Gockeler

We present a calculation of the mass of the lowest-lying negative-parity J=1/2- state in quenched QCD. Results are obtained using a non-perturbatively O(a)-improved clover fermion action, and a splitting is found between the mass of the nucleon and its parity partner. The calculation is performed on two lattice volumes and at three lattice spacings, enabling

D. L. Block, I. Puerari, M. Takamiya, R. Abraham

Images from the Hubble Deep Field (HDF) North and South show a large percentage of dusty, high redshift galaxies whose appearance falls outside traditional classification systems. The nature of these objects is not yet fully understood. Since the HDF preferentially samples restframe UV light, HDF morphologies are not dust or `mask&#39; penetrated. The appear

R. Hank Donnelly, W. Forman, C. Jones, H. Quintana

We study three prominent bi-modal X-ray clusters: A3528, A1750 and A3395. Using observations taken with ROSAT and ASCA, we analyze the temperature and surface brightness distributions. We also analyze the velocity distributions of the three clusters using new measurements supplemented with previously published data. We examine both the overall cluster proper

Katherine Freese, Paolo Gondolo, Leo Stodolsky

We consider the direct detection of WIMPs reaching the Earth from outside the Milky Way. If these WIMPs form a distinct population they will, although of much lower flux than typical galactic halo WIMPs, have a number of features which might aid in their ultimate detectability: a high and essentially unique velocity ($\sim 600$ km/s in the galactic rest fram

Snezana Bogdanovich, Dragana Popovic

The time-dependent fluctuations of conductivity σhave been studied in a two-dimensional electron system in low-mobility, small-size Si inversion layers. The noise power spectrum is ~1/f^α with αexhibiting a sharp jump at a certain electron density n_s=n_g. An enormous increase in the relative variance of σis observed as n_s is reduced below n_g, reflecting a

Dietmar Klemm

We discuss several aspects of the proposed correspondence between quantum gravity on de Sitter spaces and Euclidean conformal field theories. The central charge appearing in the asymptotic symmetry algebra of three-dimensional de Sitter space is derived both from the conformal anomaly and the transformation law of the CFT stress tensor when going from dS_3 i

John A. Tomsick, William A. Heindl, Deepto Chakrabarty, Jules P. Halpern

We measured the radial velocity curve of the companion of the neutron star X-ray transient XTE J2123-058. Its semi-amplitude (K_2) of 298.5 +/- 6.9 km/s is the highest value that has been measured for any neutron star LMXB. The high value for K_2 is, in part, due to the high binary inclination of the system but may also indicate a high neutron star mass. The

P. Khorsand, T. R. Taylor

We consider a sigma model formulation of open string theory with boundary fermions carrying Chan-Paton charges at the string ends. This formalism is particularly suitable for studying world-volume potentials on D-branes. We perform explicit two-loop sigma model computations of the potential T-dual to the non-abelian Born-Infeld action. We also discuss the wo

SDSS Collaboration, Idit Zehavi, Michael R. Blanton, Joshua A. Frieman

We present the first measurements of clustering in the Sloan Digital Sky Survey (SDSS) galaxy redshift survey. Our sample consists of 29,300 galaxies with redshifts 5,700 km/s < cz < 39,000 km/s, distributed in several long but narrow (2.5-5 degree) segments, covering 690 square degrees. For the full, flux-limited sample, the redshift-space correlation lengt

Donam Youm

We study the localization properties of bulk form potentials on dilatonic domain walls. We find that bulk form potentials of any ranks can be localized as form potentials of the same ranks or one lower ranks, for any values of the dilaton coupling parameter. For large enough values of the dilaton coupling parameter, bulk form potentials of any ranks can be l

Paul M. N. Feehan, Thomas G. Leness

This article is based on a lecture by the first author at the International Georgia Topology Conference 2001 (Athens, Georgia) and the Mathematische Arbeitstagung 2001 (Bonn, Germany). We sketch a proof of Witten&#39;s formula relating the Donaldson and Seiberg-Witten series modulo powers of degree c+2, with c = -{1/4}(7 chi + 11 sigma), for four-manifolds o

F. Maltoni, J. M. Niczyporuk, S. Willenbrock

Unitarity of longitudinal weak vector boson scattering implies an upper bound on the scale of electroweak symmetry breaking, $Λ_{EWSB}\equiv \sqrt{8π}v\approx$ 1 TeV. Appelquist and Chanowitz have derived an analogous upper bound on the scale of fermion mass generation, proportional to $v^2/m_f$, by considering the scattering of same-helicity fermions into p

A. Bonanno, M. Reuter

Cosmologies with a time dependent Newton constant and cosmological constant are investigated. The scale dependence of $G$ and $Λ$ is governed by a set of renormalization group equations which is coupled to Einstein&#39;s equation in a consistent way. The existence of an infrared attractive renormalization group fixed point is postulated, and the cosmological

Aurel Bulgac, Yongle Yu

We introduce a natural and simple to implement renormalization scheme of the Hartree-Fock-Bogoliubov (HFB) equations for the case of zero range pairing interaction. This renormalization scheme proves to be equivalent to a simple energy cut-off with a position dependent running coupling constant.

Lisa Freyhult

We compute the effective potential of SU(2) Yang-Mills theory using the background field method and the Faddeev-Niemi decomposition of the gauge fields. In particular, we find that the potential will depend on the values of two scalar fields in the decomposition and that its structure will give rise to a symmetry breaking.

W. A. Hofer, A. J. Fisher, R. A. Wolkow, P. Gruetter

We have performed the most realistic simulation to date of the operation of a scanning tunneling microscope. Probe-sample distances from beyond tunneling to actual surface contact are covered. We simultaneously calculate forces, atomic displacements, and tunneling currents, allowing quantitative comparison with experimental values. A distance regime below wh

T. M. Aliev, A. Ozpineci, M. Savci

The contribution of the fourth generation quarks to the rare (B_s -> l^+ l^-) and (B_s -> l^+ l^- gamma) decays are studied. Constraints on the extended Cabibbo-Kobayashi-Maskawa matrix elements |V_{tb} V_{ts}*| and |V_{t&#39;b} V_{t&#39;s}*| are obtained from the existing experimental result for the branching ratio of the (B -> X_s gamma) decay. The branchi

David Delepine, Francesco Vissani

Motivated by the interest in lepton number violating processes, we study the connection between the rate of Z -> mu e decay and those of the low-energy processes mu ->3 e, and mu -> e conversion in nuclear field. We show that if the vector or axial Z form factors are dominant, Br(Z->mu e) is not observable, while if the Z dipole form factors are dominant, th

Z. Y. Zeng, F. Claro, Alejandro Pérez

We study the Aharonov-Bohm effect in a coupled 2$\times$2 quantum dot array with two-terminals. A striking conductance dip arising from the Fano interference is found as the energy levels of the intermediate dots are mismatched, which is lifted in the presence of a magnetic flux. A novel five peak structure is observed in the conductance for large mismatch.

F. G. Chmela, G. M. Obermair

The square tight-binding model in a magnetic field leads to the almost-Mathieu operator which, for rational fields, reduces to a $q\times q$ matrix depending on the components $μ$, $ν$ of the wave vector in the magnetic Brillouinzone. We calculate the corresponding Green&#39;s function without explicit knowledge of eigenvalues and eigenfunctions and obtain a

D. Falcone

Several phenomenological features of fermion masses and mixings can be accounted for by a simple model for fermion mass matrices, which suggests an underlying U(2) horizontal symmetry. In this context, it is also proposed how an approximate quark-lepton symmetry can be achieved without unified gauge theories.

Danny Birmingham, Massimiliano Rinaldi

We consider a static brane in the background of a topological black hole, in arbitrary dimensions. For hyperbolic horizons, we find a solution only when the black hole mass assumes its minimum negative value. In this case, the tension of the brane vanishes, and the brane position coincides with the location of the horizon. For an elliptic horizon, we show th

Tomaz Prosen

General relation is derived which expresses the fidelity of quantum dynamics, measuring the stability of time evolution to small static variation in the hamiltonian, in terms of ergodicity of an observable generating the perturbation as defined by its time correlation function. Fidelity for ergodic dynamics is predicted to decay exponentially on time-scale p

J. Gluza, M. Zralek

We consider analytically the domain of the three mixing angles $Θ_{ij}$ and the CP phase $δ$ for three flavour neutrino oscillations both in vacuum and matter. Similarly to the quark sector, it is necessary and sufficient to let all the mixing angles $Θ_{12},Θ_{13},Θ_{23}$ and $δ$ be in the range $<0,\fracπ{2}>$ and $0 \leq δ< 2 π$, respectively. To exploit

Scott T. Kay, Frazer R. Pearce, Carlos S. Frenk, Adrian Jenkins

We investigate phenomenological models of star formation and supernova feedback in N-body/SPH simulations of galaxy formation. First, we compare different prescriptions in the literature for turning cold gas into stars neglecting feedback effects. We find that most prescriptions give broadly similar results: the ratio of cold gas to stars in the final galaxi

Sibasish Ghosh, Guruprasad Kar, Anirban Roy, Aditi Sen De

More than two multipartite orthogonal states cannot always be discriminated (with certainty) if only local operations and classical communication (LOCC) are allowed. Using an existing inequality among the measures of entanglement, we show that any three Bell states cannot be discriminated by LOCC. Exploiting the inequality, we calculate the distillable entan

Bo Qin, Xiang-Ping Wu

Other nongravitational heating processes are needed to resolve the disagreement between the absence of cool gas components in the centers of galaxy clusters revealed recently by Chandra and XMM observations and the expectations of conventional radiative cooling models. Here we propose that the interaction between dark matter particles and ordinary baryonic m

John L. Haller

The thermal diffusion of a free particle is a random process and generates entropy at a rate equal to twice the particle temperature in natural units of information per second. The rate is calculated using a Gaussian process with a variance as a combination of quantum and classical diffusion. The solution to the diffusion of a free particle is derived from t

John L. Haller

A unifying theory is put forward that entropy is equal to action. The crowning derivation is based on information theoretic methods and uses our hypothesis that &#34;particles move via the discrete Bernoulli Process.&#34; While this hypothesis matches special relativity for the mean value of a particle&#39;s location, the variance appears to open the possibi

D. Salgado, J. L. Sanchez-Gomez

We consider the simple hypothesis of letting quantum systems have an inherent random nature. Using well-known stochastic methods we thus derive a stochastic evolution operator which let us define a stochastic density operator whose expectation value under certain conditions satisfies a Lindblad equation. As natural consequences of the former assumption decoh

Tomaz Prosen, Marko Znidaric

We consider stability of a general quantum algorithm with respect to a fixed but unknown residual interaction between qubits, and show a surprising fact, namely that the average fidelity of quantum computation increases by decreasing average time correlation function of the perturbing operator in sequences of consecutive quantum gates. Our thinking is applie

V. Ramakrishna

The purpose of the paper is to point out some typos and to observe that the main result of V. Ramakrishna, K. Flores, H. Rabitz and R. J. Ober, Phys. Rev. A Volume 62, 054309, 2000 remains valid (and this validity can be verified in a constructive fashion) with only the requirement that the su(2) matrices A and B in the paper in the title be linearly indepen

Paul Benioff

Quantum robots are described as mobile quantum computers and ancillary systems that move in and interact with arbitrary environments. Their dynamics is given as tasks which consist of sequences of alternating computation and action phases. A task example is considered in which a quantum robot searches a space region to find the location of a system. The poss

Adrian Constantin

We construct a family of explicit rotational solutions to the nonlinear governing equations for water waves, describing edge waves propagating over a plane-sloping beach. A detailed analysis of the edge wave dynamics and of the run-up pattern is made possible by the use of the Lagrangian approach to the water motion. A graphical representation of the edge wa

Anna Painelli, Luca Del Freo, Francesca Terenziani

Two-photon absorption (TPA) spectra of push-pull chromophores are described in terms of a two-state model accounting for electron-vibration coupling. Vibrations have two main effects in TPA spectra. The most obvious one is the appearance of a vibrational structure in the spectrum; in this respect we find large Herzberg-Teller contributions. The second effect

Luca Del Freo, Francesca Terenziani, Anna Painelli

The reliability of the approximations commonly adopted in the calculation of static optical (hyper)polarizabilities is tested against exact results obtained for an interesting toy-model. The model accounts for the principal features of typical nonlinear organic materials with mobile electrons strongly coupled to molecular vibrations. The approximations intro

Masao Kuriki, Hitoshi Hayano, Katsushi Hasegawa

KEK-ATF is doing R&D establishing high-current and low-emittance electron beam for the future linear colliders. In ATF, 15 ps length electron beam is generated by combination of a thermionic gun, a couple of 357 MHz SHBs, and a S-band TW buncher. In the linac, beam instability caused by the fluctuated amplitude and phase of SHBs has been observed. The reason

M. Dorado, M. Morales Furio, J. L. Perez, J. L. Sanchez Gomez

In this work, we put forward a theoretical explanation of a peculiar effect found very recently (A. Gonzalez Urena et al., Chem. Phys. Lett. 341 (2001) 495). They have observed the deflection of a beam of molecules posessing a permanent electric dipole moment by a homogeneous electric field when a resonant oscillating field is superposed transverse to the st

P. Ring, Zhong-yu Ma, Nguyen Van Giai, D. Vretenar

The Relativistic Random Phase Approximation (RRPA) is derived from the Time-dependent Relativistic Mean Field (TD RMF) theory in the limit of small amplitude oscillations. In the no-sea approximation of the RMF theory, the RRPA configuration space includes not only the usual particle-hole states, but also a-h configurations, i.e. pairs formed from occupied s