This paper gives the 2010 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. The 2010 adjustment takes into account the data considered in the 2006 adjustment as well as the data that became available from 1 January 2007, after the closing date of that adjustment, until 31 December 2010, the closing date of the new adjustment. Further, it describes in detail the adjustment of the values of the constants, including the selection of the final set of input data based on the results of least-squares analyses. The 2010 set replaces the previously recommended 2006 CODATA set and may also be found on the World Wide Web at physics.nist.gov/constants.

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CODATA Recommended Values of the Fundamental Physical Constants: 2006

Substantial effort has been placed on developing semiconducting carbon nanotubes and nanowires as building blocks for electronic devices--such as field-effect transistors--that could replace conventional silicon transistors in hybrid electronics or lead to stand-alone nanosystems. Attaching electric contacts to individual devices is a first step towards integration, and this step has been addressed using lithographically defined metal electrodes. Yet, these metal contacts define a size scale that is much larger than the nanometre-scale building blocks, thus limiting many potential advantages. Here we report an integrated contact and interconnection solution that overcomes this size constraint through selective transformation of silicon nanowires into metallic nickel silicide (NiSi) nanowires. Electrical measurements show that the single crystal nickel silicide nanowires have ideal resistivities of about 10 microOmega cm and remarkably high failure-current densities, >10(8) A cm(-2). In addition, we demonstrate the fabrication of nickel silicide/silicon (NiSi/Si) nanowire heterostructures with atomically sharp metal-semiconductor interfaces. We produce field-effect transistors based on those heterostructures in which the source-drain contacts are defined by the metallic NiSi nanowire regions. Our approach is fully compatible with conventional planar silicon electronics and extendable to the 10-nm scale using a crossed-nanowire architecture.

Single-crystal metallic nanowires and metal/semiconductor nanowire heterostructures

http://nuclearmasses.org/resources_folder/Blaum_06.pdf

High-accuracy mass spectrometry with stored ions

The authors combine modern theoretical calculations with evaluated selected experimental data to produce a comprehensive data resource of K- and L-x-ray transition and absorption edge energies for all of the elements from neon to fermium. The theoretical and experimental components of this work are the result of programs of parallel development extending over more than 20 years. At each of several progressively more refined comparisons, it was possible to identify theoretical components whose systematic improvement then led to the next level of refinement in comparisons with an increasingly robust experimental reference data set. We have now reached a certain practical limit in what can be undertaken with reasonable levels of theoretical effort. This limit is not very different from the practical level of accuracy that can be meaningfully associated with the experimental data. For the more prominent diagram lines, experiment and theory are concordant with a zero-centered distribution of residuals whose statistical metrics allow the uncertainties to be estimated. For the light elements $(Zl20)$ and the very heavy elements $(Zg90)$ there are significant difficulties, as is also the case for a few isolated elements and transitions for $20lZl90.$ Overall, the results reported here represent improvements over previously available data compilations not only because of their scope but also because of their attempt to offer internal metrics of the database accuracy. The identified regions of difficulty are areas where further experimental work may be directed to see if there may remain theoretical issues that are still unresolved.

X-ray transition energies: new approach to a comprehensive evaluation

Because classical Maxwellian electromagnetism has been one of the cornerstones of physics during the past century, experimental tests of its foundations are always of considerable interest. Within that context, one of the most important efforts of this type has historically been the search for a rest mass of the photon. The effects of a nonzero photon rest mass can be incorporated into electromagnetism straightforwardly through the Proca equations, which are the simplest relativistic generalization of Maxwell's equations. Using them, it is possible to consider some far-reaching implications of a massive photon, such as variation of the speed of light, deviations in the behaviour of static electromagnetic fields, longitudinal electromagnetic radiation and even questions of gravitational deflection. All of these have been studied carefully using a number of different approaches over the past several decades. This review attempts to assess the status of our current knowledge and understanding of the photon rest mass, with particular emphasis on a discussion of the various experimental methods that have been used to set upper limits on it. All such tests can be most easily categorized in terms of terrestrial and extra-terrestrial approaches, and the review classifies them as such. Up to now, there has been no conclusive evidence of a finite mass for the photon, with the results instead yielding ever more stringent upper bounds on the size of it, thus confirming the related aspects of Maxwellian electromagnetism with concomitant precision. Of course, failure to find a finite photon mass in any one experiment or class of experiments is not proof that it is identically zero and, even as the experimental limits move more closely towards the fundamental bounds of measurement uncertainty, new conceptual approaches to the task continue to appear. The intrinsic importance of the question and the lure of what might be revealed by attaining the next decimal place are as strong a draw on this question as they are in any other aspect of precise tests of physical laws.

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The mass of the photon

The neutron lifetime ${\mathrm{\ensuremath{\tau}}}_{\mathit{n}}$ has been measured by counting decay protons stored in a Penning trap whose magnetic axis coincided with a neutron-beam axis. The result of the measurement is ${\mathrm{\ensuremath{\tau}}}_{\mathit{n}}$=893.6\ifmmode\pm\else\textpm\fi{}5.3 s, which agrees well with the value predicted by precise measurements of the \ensuremath{\beta}-decay asymmetry parameter A and the standard model.

Measurement of the neutron lifetime by counting trapped protons.

A new value for the deuteron binding energy of B(d)=2388 176 8(24)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}3}$ u is reported based on an absolute wavelength determination of the 22-MeV n-p capture \ensuremath{\gamma} ray Derived values of the n-H and n-p mass differences are also given We also derive ${M}_{n}$=1008 664 919(14) u We note that the uncertainties in the neutron-mass data are now dominated by uncertainties arising from mass spectroscopy

New determination of the deuteron binding energy and the neutron mass.

Determination of short lifetimes with ultra high resolution (n, γ) spectroscopy

We describe a method by which existing precision measurements may be used to provide a new laboratory test of the special theory of relativity In this test the speed of light ${\mathit{c}}_{\mathrm{em}}$ is compared to the limiting velocity of massive particles, ${\mathit{c}}_{\mathit{m}}$ Although it is conventionally assumed that ${\mathit{c}}_{\mathrm{em}}$=${\mathit{c}}_{\mathit{m}}$ieqc, this need not be the case in phenomenological alternatives to special relativity Our results impose limits on the quantity (1-${\mathit{c}}_{\mathit{m}}$/${\mathit{c}}_{\mathrm{em}}$) Unlike null tests of special relativity, this limit does not depend on assumptions concerning the motion of the laboratory with respect to a preferred frame

Test of special relativity by a determination of the Lorentz limiting velocity: Does E=mc2?

GAMS4, a double-flat-crystal spectrometer, is operated as a joint NIST/ILL facility at the High Flux Reactor at the Institut Laue-Langevin (ILL) in Grenoble, France. It was designed and has been used successfully for the absolute determination of gamma-ray energies in the region <5 MeV. Such measurements can lead to a unification of the atomic mass scale and the wavelength scale. Recently, new directions of research that exploit details of measured line shapes have been identified. We discuss the status of the absolute wavelength program and these new programs.

G. L. Greene

Papers

Measurement of the neutron lifetime by counting trapped protons.

New determination of the deuteron binding energy and the neutron mass.

Determination of short lifetimes with ultra high resolution (n, γ) spectroscopy

Test of special relativity by a determination of the Lorentz limiting velocity: Does E=mc2?

Fundamental physics using ultrahigh resolution gamma spectroscopy