22,975 research outputs found
The 2^-+ assignment for the X(3872)
Very recently the BaBar collaboration has put forward a claim that the
X(3872) is not a 1^++ resonance, as most of the phenomenological work on the
subject was relying on, but rather a 2^-+ one. We examine the consequences of
this quantum number assignment for the solution of the X(3872) puzzle. The
molecular interpretation appears less likely, and the conventional charmonium
interpretation should be reconsidered. There are several well-known
difficulties with this interpretation, to which we add a new one: the
production cross section at CDF is predicted to be much smaller than that
observed. We also confirm, using a relativistic string model, the conclusion
from potential models that the mass of the state is not consistent with
expectations. In the tetraquark interpretation the 2^-+ assignment implies a
rich spectrum of partner states, although the X(3872) may be among the few
which are narrow enough to be observable.Comment: 18 pages, 6 figures, 4 tables; minor style corrections. Version to
appear in PR
Cluster Winds Blow along Supercluster Axes
Within Abell galaxy clusters containing wide-angle tailed radio sources,
there is evidence of a ``prevailing wind'' which directs the WAT jets. We study
the alignment of WAT jets and nearby clusters to test the idea that this wind
may be a fossil of drainage along large-scale supercluster axes. We also test
this idea with a study of the alignment of WAT jets and supercluster axes.
Statistical test neighbours indicate no alignment of WAT jets towards nearest
clusters, but do indicate approximately 98% confidence in alignment with the
long axis of the supercluster in which the cluster lies. We find a preferred
scale for such superclusters of order 25 Mpc .Comment: Latex, 5 pages, with 5 postscript figures. To be published in MNRAS.
Slight revisions to coincide with journal text. Linked to color image at
http://kusmos.phsx.ukans.edu/~melott/images/A2634SUW.jp
On equivariant characteristic ideals of real classes
Let be an odd prime, an abelian totally real number field,
its cyclotomic -extension,
We give an explicit description of the equivariant characteristic ideal of
over for all odd by applying M. Witte's formulation of an equivariant main conjecture (or
"limit theorem") due to Burns and Greither. This could shed some light on
Greenberg's conjecture on the vanishing of the -invariant of
$F_\infty/F.
Space station full-scale docking/berthing mechanisms development
One of the most critical operational functions for the space station is the orbital docking between the station and the STS orbiter. The program to design, fabricate, and test docking/berthing mechanisms for the space station is described. The design reflects space station overall requirements and consists of two mating docking mechanism halves. One half is designed for use on the shuttle orbiter and incorporates capture and energy attenuation systems using computer controlled electromechanical actuators and/or attenuators. The mating half incorporates a flexible feature to allow two degrees of freedom at the module-to-module interface of the space station pressurized habitat volumes. The design concepts developed for the prototype units may be used for the first space station flight hardware
The momentum distribution of J/psi in B decays
The discrepancy between theory and data in the momentum distribution of slow
J/psi in B decays has been several times addressed as a puzzle. Using the most
recent results on exclusive B decays into J/psi and heavy kaons or exotic
mesons and reconsidering the non-relativistic-QCD calculation of the color
octet fragmentation component, we show that an improvement in the comparison
between data and theory can be obtained. There is still room for a better fit
to data and this may imply that new exotic mesons of the XYZ kind have yet to
be discovered.Comment: 4 pages, 2 figures, 2 tables. To appear in Physical Review
Investigation of resin systems for improved ablative materials Interim report, 10 Jan. - 1 Jul. 1966
Preparation, and evaluation of polyimide sulfone resins, graphite-silica reinforced polyamide resins, and resin resistance to FLOX- methane, and fluorine-hydrogen fuel
How realistic is the mixed-criticality real-time system model?
23rd International Conference on Real-Time Networks and Systems (RTNS 2015). 4 to 6, Nov, 2015, Main Track. Lille, France. Best Paper Award NomineeWith the rapid evolution of commercial hardware platforms, in most application domains, the industry has shown
a growing interest in integrating and running independently-developed applications of different “criticalities” in the
same multicore platform. Such integrated systems are commonly referred to as mixed-criticality systems (MCS).
Most of the MCS-related research published in the state-of-the-art cite the safety-related standards associated to
each application domain (e.g. aeronautics, space, railway, automotive) to justify their methods and results.
However, those standards are not, in most cases, freely available, and do not always clearly and explicitly specify
the requirements for mixed-criticality systems. This paper addresses the important challenge of unveiling the
relevant information available in some of the safety-related standards, such that the mixed-criticality concept is
understood from an industrialist’s perspective. Moreover, the paper evaluates the state-of-the-art mixed-criticality
real-time scheduling models and algorithms against the safety-related standards and clarifies some
misconceptions that are commonly encountered
Applicability of Three Alternative Instruments for Food Authenticity Analysis: GMO Identification
Ensuring foods are correctly labelled for ingredients derived from genetically modified organisms (GMOs) is an issue facing manufacturers, retailers, and enforcement agencies. DNA approaches for the determination of food authenticitys often use the polymerase chain reaction (PCR), and PCR products can be detected using capillary or gel electrophoresis. This study examines the fitness for purpose of the application of three laboratory electrophoresis instruments (Agilent Bioanalyzer 2100, Lab901 TapeStation, and Shimadzu MCE-202 MultiNA) for the detection of GMOs using PCR based on a previously validated protocol. Whilst minor differences in the performance characteristics of bias and precision were observed, all three instruments demonstrated their applicability in using this protocol for screening of GMO ingredients
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