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Sep 22, 2013
09/13

by
Simone Alioli; Paolo Nason; Carlo Oleari; Emanuele Re

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We present a next-to-leading-order calculation of W/Z production interfaced to shower Monte Carlo, implemented according to the POWHEG method. Finite width effects, Z/gamma interference and angular correlations of decay products are included. A detailed comparison with MC@NLO and PYTHIA is carried out.

Source: http://arxiv.org/abs/0805.4802v1

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Sep 22, 2013
09/13

by
H. Saarikoski; A. Harju; J. Christensson; S. Bargi; M. Manninen; S. M. Reimann

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The rotation of a quantum liquid induces vortices to carry angular momentum. When the system is composed of multiple components that are distinguishable from each other, vortex cores in one component may be filled by particles of the other component, and coreless vortices form. Based on evidence from computational methods, here we show that the formation of coreless vortices occurs very similarly for repulsively interacting bosons and fermions, largely independent of the form of the particle...

Source: http://arxiv.org/abs/0812.3366v1

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Sep 21, 2013
09/13

by
B. Czerny; M. Moscibrodzka

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Sgr A* is the closest massive black hole and can be observed with the highest angular resolution. Nevertheless, our current understanding of the accretion process in this source is very poor. The inflow is almost certainly of low radiative efficiency and it is accompanied by a strong outflow and the flow is strongly variable but the details of the dynamics are unknown. Even the amount of angular momentum in the flow is an open question. Here we argue that low angular momentum scenario is better...

Source: http://arxiv.org/abs/0808.2883v1

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Sep 21, 2013
09/13

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Alexandr Andoni; Andrew McGregor; Krzysztof Onak; Rina Panigrahy

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Estimating frequency moments of data streams is a very well studied problem and tight bounds are known on the amount of space that is necessary and sufficient when the stream is adversarially ordered. Recently, motivated by various practical considerations and applications in learning and statistics, there has been growing interest into studying streams that are randomly ordered. In the paper we improve the previous lower bounds on the space required to estimate the frequency moments of a...

Source: http://arxiv.org/abs/0808.2222v1

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Sep 17, 2013
09/13

by
Alessio D'Alessandro; Massimo D'Elia

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We investigate the properties of thermal abelian magnetic monopoles in the high temperature phase of Yang--Mills theories, following a recent proposal for their identification on lattice configurations. The study is done for SU(2) pure gauge theory, for temperatures going up to about 10 times the deconfining temperature and using the Maximal Abelian gauge to perform the abelian projection. We find that the monopole density has a well defined continuum limit. Its temperature dependence disagrees...

Source: http://arxiv.org/abs/0711.1266v3

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Sep 18, 2013
09/13

by
Astha Sethi; Srihari Keshavamurthy

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The aim of this work is to understand the influence of chaotic states in control problems involving strong fields. Towards this end, we numerically construct and study the strong field control landscape of a bichromatically driven double well. A novel measure based on correlating the overlap intensities between Floquet states and an initial phase space coherent state with the parametric motion of the quasienergies is used to construct and interpret the landscape features. "Walls" of...

Source: http://arxiv.org/abs/0803.3115v1

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Sep 18, 2013
09/13

by
Radovan Dermisek

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We study the Higgs sector of supersymmetric models containing two Higgs doublets with a light MSSM-like CP odd Higgs, $m_A \lesssim 10$ GeV, and $\tan \beta \lesssim 2.5$. In this scenario all of the Higgses resulting from two Higgs doublets: light and heavy CP even Higgses, $h$ and $H$, the CP odd Higgs, $A$, and the charged Higgs, $H^\pm$, could have been produced at LEP or the Tevatron, but would have escaped detection because they decay in modes that have not been searched for or the...

Source: http://arxiv.org/abs/0806.0847v2

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Sep 22, 2013
09/13

by
Karl Rökaeus

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We use the theory of motivic integration in order to give a geometric explanation of the behavior of some p-adic integrals.

Source: http://arxiv.org/abs/0812.2043v1

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Sep 22, 2013
09/13

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Jeffrey M. Kubo; Sahar S. Allam; James Annis; Elizabeth J. Buckley-Geer; H. Thomas Diehl; Donna Kubik; Huan Lin; Douglas Tucker

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We present new results of our program to systematically search for strongly lensed galaxies in the Sloan Digital Sky Survey (SDSS) imaging data. In this study six strong lens systems are presented which we have confirmed with follow-up spectroscopy and imaging using the 3.5m telescope at the Apache Point Observatory. Preliminary mass models indicate that the lenses are group-scale systems with velocity dispersions ranging from 466-878 km s^{-1} at z=0.17-0.45 which are strongly lensing source...

Source: http://arxiv.org/abs/0812.3934v1

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Sep 22, 2013
09/13

by
R. A. Treumann

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We investigate the role of the form of the spatial diffusion coefficient in shock acceleration of fast particles. Referring to non-classical diffusion and using the results of numerical (hybrid) simulations tailored for the downstream shock population in quasi-perpendicualr high-Mach number collisionless shocks to which we apply the theory, we demonstrate that the inferred diffusion coefficients are in excellent agreement with the requirements of the theory and its predictions. Diffusion in the...

Source: http://arxiv.org/abs/0811.3938v1

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Sep 18, 2013
09/13

by
C. Godreche; J. M. Luck

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We introduce a novel stochastic growth process, the record-driven growth process, which originates from the analysis of a class of growing networks in a universal limiting regime. Nodes are added one by one to a network, each node possessing a quality. The new incoming node connects to the preexisting node with best quality, that is, with record value for the quality. The emergent structure is that of a growing network, where groups are formed around record nodes (nodes endowed with the best...

Source: http://arxiv.org/abs/0809.3377v2

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Sep 18, 2013
09/13

by
Yasuhisa Inada; Munekazu Horikoshi; Shuta Nakajima; Makoto Kuwata-Gonokami; Masahito Ueda; Takashi Mukaiyama

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We detected the formation of p-wave Feshbach molecules for all three combinations of the two lowest atomic spin states of 6Li. By creating a pure molecular sample in an optical trap, we measured the inelastic collision rates of p-wave molecules. The elastic collision rate was measured from the thermalization rate of a breathing mode excited spontaneously upon molecular formation.

Source: http://arxiv.org/abs/0803.1405v3

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Sep 18, 2013
09/13

by
S. Johnston; F. Vernay; T. P. Devereaux

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Recent scanning tunneling microscopy studies have shown that local nanoscale pairing inhomogenities are correlated with interstitial oxygen dopants in Bi-2212. Combining electrostatic and cluster calculations, in this paper the impact of a dopant on the local Madelung and charge transfer energies, magnetic exchange J, Zhang-Rice mobility, and interactions with the lattice is investigated. It is found that electrostatic modifications locally increases the charge transfer energy and slightly...

Source: http://arxiv.org/abs/0809.2841v1

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Sep 21, 2013
09/13

by
C. A. Ullrich; V. Turkowski

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Time-dependent density-functional theory (TDDFT) is widely used to describe electronic excitations in complex finite systems with large numbers of atoms, such as biomolecules and nanocrystals. The first part of this paper will give a simple and pedagogical explanation, using a two-level system, which shows how the basic TDDFT formalism for excitation energies works. There is currently an intense effort underway to develop TDDFT methodologies for the charge and spin dynamics in extended systems,...

Source: http://arxiv.org/abs/0808.2021v1

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Sep 20, 2013
09/13

by
Sylvain Maillot

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We give a sufficient condition for an open 3-manifold to admit a decomposition along properly embedded open annuli and tori, generalizing the toric splitting of Jaco-Shalen and Johannson.

Source: http://arxiv.org/abs/0802.1447v1

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Sep 23, 2013
09/13

by
Hong Yao; Shou-Cheng Zhang; Steven A. Kivelson

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We have proposed an exactly solvable quantum spin-3/2 model on a square lattice. Its ground state is a quantum spin liquid with a half integer spin per unit cell. The fermionic excitations are gapless with a linear dispersion, while the topological "vison" excitations are gapped. Moreover, the massless Dirac fermions are stable. Thus, this model is, to the best of our knowledge, the first exactly solvable model of half-integer spins whose ground state is an "algebraic spin...

Source: http://arxiv.org/abs/0810.5347v1

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Sep 21, 2013
09/13

by
Hans Jockers; Masoud Soroush

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For compact Calabi-Yau geometries with D5-branes we study N=1 effective superpotentials depending on both open- and closed-string fields. We develop methods to derive the open/closed Picard-Fuchs differential equations, which control D5-brane deformations as well as complex structure deformations of the compact Calabi-Yau space. Their solutions encode the flat open/closed coordinates and the effective superpotential. For two explicit examples of compact D5-brane Calabi-Yau hypersurface...

Source: http://arxiv.org/abs/0808.0761v2

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Sep 22, 2013
09/13

by
J. A. Hoyos

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The effects of quenched disorder on nonequilibrium phase transitions in the directed percolation universality class are revisited. Using a strong-disorder energy-space renormalization group, it is shown that for any amount of disorder the critical behavior is controlled by an infinite-randomness fixed point in the universality class of the random transverse-field Ising models. The experimental relevance of our results are discussed.

Source: http://arxiv.org/abs/0805.2211v3

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Sep 20, 2013
09/13

by
Eunan J. McEniry; Thomas Frederiksen; Tchavdar N. Todorov; Daniel Dundas; Andrew P. Horsfield

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A dynamical method for inelastic transport simulations in nanostructures is compared with a steady-state method based on non-equilibrium Green's functions. A simplified form of the dynamical method produces, in the steady state in the weak-coupling limit, effective self-energies analogous to those in the Born Approximation due to electron-phonon coupling. The two methods are then compared numerically on a resonant system consisting of a linear trimer weakly embedded between metal electrodes....

Source: http://arxiv.org/abs/0802.4174v1

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Sep 22, 2013
09/13

by
Hongquan Xu; Frederick K. H. Phoa; Weng Kee Wong

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Nonregular fractional factorial designs such as Plackett-Burman designs and other orthogonal arrays are widely used in various screening experiments for their run size economy and flexibility. The traditional analysis focuses on main effects only. Hamada and Wu (1992) went beyond the traditional approach and proposed an analysis strategy to demonstrate that some interactions could be entertained and estimated beyond a few significant main effects. Their groundbreaking work stimulated much of...

Source: http://arxiv.org/abs/0812.3000v1

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Sep 17, 2013
09/13

by
P. Fraser; K. Amos; L. Canton; G. Pisent; S. Karataglidis; J. P. Svenne; D. van der Knijff

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How does the scattering cross section change when the colliding bound-state fragments are allowed particle-emitting resonances? This question is explored in the framework of a multi-channel algebraic scattering method of determining nucleon-nucleus cross sections at low energies. Two cases are examined, the first being a gedanken investigation in which n + carbon-12 scattering is studied with the target states assigned artificial widths. The second is a study of neutron scattering from...

Source: http://arxiv.org/abs/0807.2914v1

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Sep 21, 2013
09/13

by
CDF Collaboration; T. Aaltonen

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We use the three lepton and missing energy "trilepton" signature to search for chargino-neutralino production with 2.0 inverse femtobarns of integrated luminosity collected by the CDF II experiment at the Tevatron ppbar collider. We expect an excess of approximately 11 supersymmetric events for a choice of parameters of the mSUGRA model, but our observation of 7 events is consistent with the standard model expectation of 6.4 events. We constrain the mSUGRA model of supersymmetry and...

Source: http://arxiv.org/abs/0808.2446v3

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Sep 23, 2013
09/13

by
U. Munari; A. Siviero; P. Ochner; S. Dallaporta; C. Simoncelli

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We obtained BVIc photometry of IRC-10443 on 85 different nights distributed over two years, and in addition low resolution absolute spectro- photometry and high resolution Echelle spectroscopy. Our data show that IRC-10443, which was never studied before in any detail, is a SRa variable, characterized by Delta(B)=1.27, Delta(V)=1.14 and Delta(I)=0.70 mag amplitudes and mean values =13.75, =11.33 and =6.18 mag. Two strong periodicities are simultaneously present: a principal one of 85.5 (+/-0.2)...

Source: http://arxiv.org/abs/0810.1375v1

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Sep 23, 2013
09/13

by
Sophie Schlunk; Adela Marian; Wieland Schoellkopf; Gerard Meijer

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We study the dynamic behavior of ultracold neutral atoms in a macroscopic ac electric trap. Confinement in such a trap is achieved by switching between two saddle-point configurations of the electric field. The gradual formation of a stably trapped cloud is observed and the trap performance is studied versus the switching frequency and the symmetry of the switching cycle. Additionally, the electric field in the trap is mapped out by imaging the atom cloud while the fields are still on. Finally,...

Source: http://arxiv.org/abs/0801.3362v2

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Sep 20, 2013
09/13

by
James H. Degnan

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Consensus methods provide a useful strategy for combining information from a collection of gene trees. An important application of consensus methods is to combine gene trees to estimate a species tree. To investigate the theoretical properties of consensus trees that would be obtained from large numbers of loci evolving according to a basic evolutionary model, we construct consensus trees from independent gene trees that occur in proportion to gene tree probabilities derived from coalescent...

Source: http://arxiv.org/abs/0802.2355v1

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Sep 23, 2013
09/13

by
Tran Minh-Tien

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Statistics of the local density of states in the two-dimensional Falicov-Kimball model with local disorder is studied by employing the statistical dynamical mean-field theory. Within the theory the local density of states and its distributions are calculated through stochastic self-consistent equations. The most probable value of the local density of states is used to monitor the metal-insulator transition driven by correlation and disorder. Nonvanishing of the most probable value of the local...

Source: http://arxiv.org/abs/0801.0852v1

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Sep 22, 2013
09/13

by
M. D. Kapetanakis; I. E. Perakis

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We address the role of correlations between spin and charge degrees of freedom on the dynamical properties of ferromagnetic systems governed by the magnetic exchange interaction between itinerant and localized spins. For this we introduce a general theory that treats quantum fluctuations beyond the Random Phase Approximation based on a correlation expansion of the Green's function equations of motion. We calculate the spin susceptibility, spin--wave excitation spectrum, and magnetization...

Source: http://arxiv.org/abs/0805.1320v2

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Sep 23, 2013
09/13

by
Ignasi Rosell

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Within Resonance Chiral Theory and in the context of QCD current correlators at next-to-leading order in 1/N(C), we have analyzed the two-body form factors which include resonances as a final state . The short-distance constraints have been studied. One of the main motivations is the estimation of the chiral low-energy constants at subleading order, that is, keeping full control of the renormalization scale dependence. As an application we show the resonance estimation of some coupling,...

Source: http://arxiv.org/abs/0810.3592v1

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Sep 18, 2013
09/13

by
A. Sheykhi; M. Allahverdizadeh

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In this paper, with an appropriate combination of three Liouville-type dilaton potentials, we obtain the higher dimensional charged slowly rotating dilaton black hole solution for asymptotically anti-de Sitter spacetime. The angular momentum and the gyromagnetic ratio of such a black hole are determined for the arbitrary values of the dilaton coupling constant. It is shown that the dilaton field modifies the gyromagnetic ratio of the rotating dilaton black holes.

Source: http://arxiv.org/abs/0809.1131v2

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Sep 20, 2013
09/13

by
Luiz Gustavo Cancado; Ryan Beams; Lukas Novotny

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This paper reports the experimental determination of the phase-breaking length L of conduction electrons in graphene using Raman spectroscopy. Based on the double-resonance model, we extract L from the spatial dependence of the D band susceptibility near the graphene edge. By using prior knowledge of sample properties and the excitation point-spread function we are able to determine the spatial variation of the Raman susceptibilities with high accuracy, and the results reveal a phase-breaking...

Source: http://arxiv.org/abs/0802.3709v1

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Sep 22, 2013
09/13

by
Antonio De Maio; Marco Lops; Luca Venturino

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In this work, a MIMO detection problem is considered. At first, we derive the Generalized Likelihood Ratio Test (GLRT) for arbitrary transmitted signals and arbitrary time-correlation of the disturbance. Then, we investigate design criteria for the transmitted waveforms in both power-unlimited and power-limited systems and we study the interplay among the rank of the optimized code matrix, the number of transmit diversity paths and the amount of energy integrated along each path. The results...

Source: http://arxiv.org/abs/0805.0740v1

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Sep 18, 2013
09/13

by
George Miloshevich; Ramaz Khomeriki; Stefano Ruffo

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We consider a damped $\beta$-Fermi-Pasta-Ulam chain, driven at one boundary subjected to stochastic noise. It is shown that, for a fixed driving amplitude and frequency, increasing the noise intensity, the system's energy resonantly responds to the modulating frequency of the forcing signal. Multiple peaks appear in the signal to noise ratio, signalling the phenomenon of stochastic resonance. The presence of multiple peaks is explained by the existence of many stable and metastable states that...

Source: http://arxiv.org/abs/0809.3604v1

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Sep 22, 2013
09/13

by
Sean Hallgren; Aram W. Harrow

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The first separation between quantum polynomial time and classical bounded-error polynomial time was due to Bernstein and Vazirani in 1993. They first showed a O(1) vs. Omega(n) quantum-classical oracle separation based on the quantum Hadamard transform, and then showed how to amplify this into a n^{O(1)} time quantum algorithm and a n^{Omega(log n)} classical query lower bound. We generalize both aspects of this speedup. We show that a wide class of unitary circuits (which we call dispersing...

Source: http://arxiv.org/abs/0805.0007v2

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Sep 18, 2013
09/13

by
I. Froehlich

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The HADES experiment, installed at GSI, Darmstadt, measures di-electron production in A+A, p/pi+N and p/pi+A collisions. Here, the pi0 and eta Dalitz decays have been reconstructed in the exclusive p+p reaction at 2.2 GeV to form a reference cocktail for long-lived di-electron sources. In the C+C reaction at 1 and 2 GeV/u, these long-lived sources have been subtracted from the measured inclusive e+e- yield to exhibit the signal from the early phase of the collision. The results suggest that...

Source: http://arxiv.org/abs/0809.2764v1

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Sep 22, 2013
09/13

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A. M. G. Cox; David Hobson; Jan Obłój

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We develop a class of pathwise inequalities of the form $H(B_t)\ge M_t+F(L_t)$, where $B_t$ is Brownian motion, $L_t$ its local time at zero and $M_t$ a local martingale. The concrete nature of the representation makes the inequality useful for a variety of applications. In this work, we use the inequalities to derive constructions and optimality results of Vallois' Skorokhod embeddings. We discuss their financial interpretation in the context of robust pricing and hedging of options written on...

Source: http://arxiv.org/abs/math/0702173v2

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Sep 18, 2013
09/13

by
Ching-Ming Chen; Tianjun Li; Dimitri V. Nanopoulos

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We study the flux parameter spaces for semi-realistic supersymmetric Pati-Salam models in the AdS vacua on Type IIA orientifold and realistic supersymmetric Pati-Salam models in the Minkowski vacua on Type IIB orientifold. Because the fluxes can be very large, we show explicitly that there indeed exists a huge number of semi-realistic Type IIA and realistic Type IIB flux models. In the Type IIA flux models, in the very large flux limit, the theory can become weakly coupled and the AdS vacua can...

Source: http://arxiv.org/abs/0806.0192v1

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Sep 21, 2013
09/13

by
A. V. Lebedev; G. Blatter

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Adopting the frame of mesoscopic physics, we describe a Bell type experiment involving time-delayed two-particle correlation measurements. The indistinguishability of quantum particles results in a specific interference between different trajectories. We show how the non-locality in the time-delayed correlations due to the indistinguishability of the quantum particles manifests itself in the violation of a Bell inequality, where the degree of violation is related to the accuracy of the...

Source: http://arxiv.org/abs/0706.3437v2

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Sep 18, 2013
09/13

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J. -Y. P. Delannoy; A. G. Del Maestro; M. J. P. Gingras; P. C. W. Holdsworth

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We study the ground state quantum spin fluctuations around the N\'eel ordered state for the one-band ($t,U$) Hubbard model on a site-diluted square lattice. An effective spin Hamiltonian, $H_{\rm s}^{(4)}$, is generated using the canonical transformation method, expanding to order $t(t/U)^3$. $H_{\rm s}^{(4)}$ contains four-spin ring exchange terms as well as second and third neighbor bilinear spin-spin interactions. Transverse spin fluctuations are calculated to order $1/S$ using a numerical...

Source: http://arxiv.org/abs/0806.4934v1

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Sep 23, 2013
09/13

by
M. Rengel; P. Hartogh; C. Jarchow

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We present submillimeter observations of 12CO J=3-2 and J=2-1, and 13CO J = 2-1 lines of the Venusian mesosphere and lower thermosphere with the Heinrich Hertz Submillimeter Telescope (HHSMT) taken around the second MESSENGER flyby of Venus on 5 June 2007. The observations cover a range of Venus solar elongations with different fractional disk illuminations. Preliminary results like temperature and CO abundance profiles are presented.These data are part of a coordinated observational campaign...

Source: http://arxiv.org/abs/0810.2899v1

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Sep 23, 2013
09/13

by
S. Meda; P. Sjogren; M. Vallarino

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We prove that if q is in (1,\infty), Y is a Banach space and T is a linear operator defined on the space of finite linear combinations of (1,q)-atoms in R^n which is uniformly bounded on (1,q)-atoms, then T admits a unique continuous extension to a bounded linear operator from H^1(R^n) to Y. We show that the same is true if we replace (1,q)-atoms with continuous (1,\infty)-atoms. This is known to be false for (1,\infty)-atoms.

Source: http://arxiv.org/abs/0801.1745v1

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Sep 18, 2013
09/13

by
R. Granier de Cassagnac

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Quarkonia were predicted to be suppressed in the "hot" deconfined matter known as the Quark Gluon Plasma (QGP), but they were also seen to suffer from "cold" nuclear matter effects (parton shadowing, nuclear absorption...). Both at SPS and RHIC, suppression beyond nuclear effects was observed, but the rapidity dependence of the RHIC result is not easy to interpret. I review here the current status of these results, their possible interpretations and the new measurements that...

Source: http://arxiv.org/abs/0806.0046v3

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Sep 18, 2013
09/13

by
Sudip Bhattacharyya

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We report the detection of a point source CXO J172337.5-373442 in a Chandra field with a high significance (26.7 sigma), and the discovery (4 sigma) of a 48" long X-ray tail emanating from the point source. The X-ray spectra of both the point source and the tail are well described with a single absorbed powerlaw, and the tail is harder (powerlaw index Gamma = 0.14^{+0.59}_{-0.68}) than the point source (Gamma = 1.78^{+0.13}_{-0.11}). From this first detailed spatial, spectral and timing...

Source: http://arxiv.org/abs/0809.4962v1

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Sep 22, 2013
09/13

by
T. Sakuma; for the RHIC Spin collaboration

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We report on recent results of the longitudinal double-spin asymmetry A_LL from the STAR and PHENIX experiments. Data were collected in longitudinally polarized proton-proton collisions at a center-of-mass energy of 200 GeV. The results added new constraints to the polarized gluon distribution function g(x) with the probed x range of 0:02 < x < 0:3. The results lead to the importance of probing small x.

Source: http://arxiv.org/abs/0805.3692v1

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Sep 22, 2013
09/13

by
Monique Lejeune-Jalabert; Ana J. Reguera

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We prove that, if X is a variety over an uncountable algebraically closed field k of characteristic zero, then any irreducible exceptional divisor E on a resolution of singularities of X which is not uniruled, belongs to the image of the Nash map, i.e. corresponds to an irreducible component of the space of arcs on X centered in Sing X. This reduces the Nash problem of arcs to understanding which uniruled essential divisors are in the image of the Nash map, more generally, how to determine the...

Source: http://arxiv.org/abs/0811.2421v1

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Sep 22, 2013
09/13

by
D. Blume

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We consider population-imbalanced two-component Fermi gases under external harmonic confinement interacting through short-range two-body potentials with diverging s-wave scattering length. Using the fixed-node diffusion Monte Carlo method, the energies of the "normal state" are determined as functions of the population-imbalance and the number of particles. The energies of the trapped system follow, to a good approximation, a universal curve even for fairly small systems. A simple...

Source: http://arxiv.org/abs/0805.2130v1

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Sep 22, 2013
09/13

by
V. Shklyar; H. Lenske

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We show that the gauge-invariant coupling suggested by Pascalutsa removes non-pole terms from a spin-$\fth$ propagator only for a specific choice of free parameter. For the general case the problem can be solved by including higher order derivatives of spin-$\fth$ fields or by modifying the original coupling. In the latter case the obtained Lagrangian depends on one free parameter pointing to the freedom in choosing an 'off-shell' content of the theory. However, the physical observables must...

Source: http://arxiv.org/abs/0812.4435v1

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Sep 22, 2013
09/13

by
Olexei I. Motrunich; Ashvin Vishwanath

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Using Monte Carlo simulations, we study a Higgs transition in several three-dimensional lattice realizations of the noncompact CP$^1$ model (NCCP$^1$), a gauge theory with two complex matter fields with SU(2) invariance. By comparing with a one-component theory, which is well understood and has continuous transition in the inverted XY universality class, we argue that the two-component case also has continuous Higgs transition with a larger correlation length exponent (i.e., it is ``more...

Source: http://arxiv.org/abs/0805.1494v1

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Sep 21, 2013
09/13

by
W. Bietenholz; N. Cundy; M. Gockeler; R. Horsley; H. Perlt; D. Pleiter; P. E. L. Rakow; G. Schierholz; A. Schiller; J. M. Zanotti

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Lattice calculations could boost our understanding of Deep Inelastic Scattering by evaluating moments of the Nucleon Structure Functions. To this end we study the product of electromagnetic currents between quark states. The Operator Product Expansion (OPE) decomposes it into matrix elements of local operators (depending on the quark momenta) and Wilson coefficients (as functions of the larger photon momenta). For consistency with the matrix elements, we evaluate a set of Wilson coefficients...

Source: http://arxiv.org/abs/0808.3637v1

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Sep 20, 2013
09/13

by
Saharon Shelah

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Suppose we are given a family of choice functions on pairs from a given finite set (with at least three elements) closed under permutations of the given set. The set is considered the set of alternatives (say candidates for an office). The question is, what are the choice functions c on pairs of this set of the following form: for some (finite) family of ``voters'', each having a preference, i.e., a choice from each pair from the given family, c{x,y} is chosen by the preference of the majority...

Source: http://arxiv.org/abs/math/0405119v3

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Sep 21, 2013
09/13

by
Volker Becker; Heiko Briesen

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Recently, Pantina and Furst (Phys. Rev. Lett., 94(13), 138301, 2005) experimentally demon- strated that there are tangential forces between bonded colloidal particles and that bonds between colloidal particles are capable of supporting bending moments. We introduce a model to be used in computer simulations that describes these tangential interactions. We show how the model parame- ters can be determined from experimental data. Simulations using the model are able to reproduce the measurement...

Source: http://arxiv.org/abs/0808.3108v2