1,211 research outputs found
Determination of and heavy quark masses from recent measurements of
In this paper we compare recent experimental data for the total cross section
with the up-to-date theoretical prediction of
perturbative QCD for those energies where perturbation theory is reliable. The
excellent agreement suggests the determination of the strong coupling
from the measurements in the continuum. The precise data from the
charm threshold region, when combined with the recent evaluation of moments
with three loop accurracy, lead to a direct determination of the short distance
charm quark mass. Our result for the strong coupling constant
corresponds to
, for the charmed quark mass we
find . Applying the same approach to the bottom quark we
obtain GeV. Whereas our result for serves
as a useful cross check for other more precise determinations, our values for
the charm and bottom quark masses are more accurate than other recent analyses.Comment: 16 pages, minor change in numerical result for mb(mb
Massive Quark Production in Electron Positron Annihilation to Order
Recent analytical and numerical results for the three-loop polarization
function allow to present a phenomenological analysis of the cross section for
massive quark production in electron positron annihilation to order
. Numerical predictions based on fixed order perturbation theory
are presented for charm and bottom production above 5 and 11.5 GeV,
respectively. The contribution from these energy regions to ,
the running QED coupling constant at scale M_Z, are given. The dominant terms
close to threshold, i.e. in an expansion for small quark velocity , are
presented.Comment: 26 pages (Latex), 16 figures (Postscript
137Cs in the meat of wild boars: a comparison of the impacts of Chernobyl and Fukushima
The impact of Chernobyl on the 137Cs activities found in wild boars in Europe, even in remote locations from the NPP, has been much greater than the impact of Fukushima on boars in Japan. Although there is great variability within the 137Cs concentrations throughout the wild boar populations, some boars in southern Germany in recent years exhibit higher activity concentrations (up to 10,000 Bq/kg and higher) than the highest 137Cs levels found in boars in the governmental food monitoring campaign (7900 Bq/kg) in Fukushima prefecture in Japan. The levels of radiocesium in boar appear to be more persistent than would be indicated by the constantly decreasing 137Cs inventory observed in the soil which points to a food source that is highly retentive to 137Cs contamination or to other radioecological anomalies that are not yet fully understood.CDC NIOSH Mountain and Plains Education and Research Center/T42OH009229-07NRC/NRC-HQ-12-G-38-004
The Demographic Characteristics of 1860 New Ulm, Minnesota, Germans
Demand for an increase in ethnically oriented course materials led to this study of the 1860 New Ulm (Minnesota) German community as an example of ethnic migration and community establishment. The New Ulm German community was defined for the purposes of this study as the 698 German-born adult migrants living in New Ulm and its functionally connected area in 1860. Detailed information concerning the specific places of origin, migratory routes and sequences of intervening stops, and organizational networks of support was collected. A series of maps and graphs represents the migration patterns
Surface Monitoring by Combination of an Optical Sensor and an Ultrasonic Scanning System
Nondestructive testing is a vital tool in the effort to ensure the quality of mechanically highly-loaded aero-engine parts. Nondestructive testing methods, such as eddy current and dye penetrant, are used to verify the surface condition of components, this condition greatly affecting operational safety and service life. Yet while these methods will readily detect small cracks, they fail to show the gradual changes in surface topology commonly associated with service wear
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