Can the flyby anomaly be attributed to earth-bound dark matter?

We make preliminary estimates to assess whether the recently reported flyby anomaly can be attributed to dark matter interactions. We consider both elastic and exothermic inelastic scattering from dark matter constituents; for isotropic dark matter velocity distributions, the former decrease, while the latter increase, the final flyby velocity. The fact that the observed flyby velocity anomaly shows examples with both positive and negative signs, requires the dominance of different dark matter scattering processes along different flyby trajectories. The magnitude of the observed anomalies requires dark matter densities many orders of magnitude greater than the galactic halo density. Such a large density could result from an accumulation cascade, in which the solar system-bound dark matter density is much higher than the galactic halo density, and the earth-bound density is much higher than the solar system-bound density. We discuss a number of strong constraints on the hypothesis of a dark matter explanation for the flyby anomaly. These require dark matter to be non-self-annihilating, with the dark matter scattering cross section on nucleons much larger, and the dark matter mass much lighter, than usually assumed.Comment: Latex, 21 pages. v3: substantially revised and expanded; v4: version to appear in Phys. Rev.

Squeezed gluon vacuum and the global colour model of QCD

We discuss how the vacuum model of Celenza and Shakin with a squeezed gluon condensate can explain the existence of an infrared singular gluon propagator frequently used in calculations within the global colour model. In particular, it reproduces a recently proposed QCD-motivated model where low energy chiral parameters were computed as a function of a dynamically generated gluon mass. We show how the strength of the confining interaction of this gluon propagator and the value of the physical gluon condensate may be connected.Comment: 13 pages, LaTe

Gathering experience in trust-based interactions

As advances in mobile and embedded technologies coupled with progress in adhoc networking fuel the shift towards ubiquitous computing systems it is becoming increasingly clear that security is a major concern. While this is true of all computing paradigms, the characteristics of ubiquitous systems amplify this concern by promoting spontaneous interaction between diverse heterogeneous entities across administrative boundaries [5]. Entities cannot therefore rely on a specific control authority and will have no global view of the state of the system. To facilitate collaboration with unfamiliar counterparts therefore requires that an entity takes a proactive approach to self-protection. We conjecture that trust management is the best way to provide support for such self-protection measures

Explorer 12 magnetometer records, 16 August - 6 December 1961

Explorer XII magnetometer record

Can a Logarithmically Running Coupling Mimic a String Tension?

It is shown that a Coulomb potential using a running coupling slightly modified from the perturbative form can produce an interquark potential that appears nearly linear over a large distance range. Recent high-statistics SU(2) lattice gauge theory data fit well to this potential without the need for a linear string-tension term. This calls into question the accuracy of string tension measurements which are based on the assumption of a constant coefficient for the Coulomb term. It also opens up the possibility of obtaining an effectively confining potential from gluon exchange alone.Comment: 13 pages, LaTeX, two figures not included, available from author. revision - Line lengths fixed so it will tex properl

From treebank resources to LFG F-structures

We present two methods for automatically annotating treebank resources with functional structures. Both methods define systematic patterns of correspondence between partial PS configurations and functional structures. These are applied to PS rules extracted from treebanks, or directly to constraint set encodings of treebank PS trees

Vacuum Condensates in the Global Color Symmetry Model

Based on the quark propagator in the instanton dilute liquid approximation, we calculate analytically the quark condensate , the mixed quark gluon condensate $g_{s}$ and the four quark condensate at the mean field level in the framework of global color symmetry model. The numerical calculation shows that the values of these condensates are compatible with the ranges determined by other nonperturbative approaches. Moreover, we find that for nonlocal four quark condensate the previous vacuum saturation assumption is not a good approximation even at the mean field level.Comment: 8 latex pages, no figure, Submitted to Phys. Rev.

Progress on the hybrid gun project at UCLA

UCLA/INFN-LNF/Univ. Rome has been developing the hybrid gun which has an RF gun and a short linac for velocity bunching in one structure. After the cavity was manufactured at INFN-LNF in 2012, tests of the gun was carried out at UCLA. The field in the standing wave part was 20 % smaller than the simulation but the phase advance was fine. The cavity was commissioned successfully up to 13 MW. The beam test was performed at 11.5 MW and demonstrated the bunch compression