3,907 research outputs found
Running coupling constant and masses in QCD, the meson spectrum
In line with some previous works, we study in this paper the meson spectrum
in the framework of a second order quark-antiquark Bethe-Salpeter formalism
which includes confinement. An analytic one loop running coupling constant
alpha_s(Q), as proposed by Shirkov and Sovlovtsov, is used in the calculations.
As for the quark masses, the case of a purely phenomenological running mass for
the light quarks in terms of the c. m. momentum is further investigated.
Alternatively a more fundamental expression m_P(Q) is introduced for light and
strange quarks, combining renormalization group and analyticity requirements
with an approximate solution of the Dyson-Schwinger equation. The use of such
running coupling constant and masses turns out to be essential for a correct
reproduction of the the light pseudoscalar mesons.Comment: 10 pages, 2 figures, conference: Quark Confinement and the Hadron
Spectrum VI, Villasimius, Cagliari, Ital
B_{c} meson and the light-heavy quarkonium spectrum
We compute the c \bar{b} spectrum from a first principle Salpeter equation
obtained in a preceding paper. For comparison we report also the heavy-light
quarkonium spectrum and the hyperfine separations previously presented only in
a graphical form. Notice that all results are parameter free.Comment: 7 pages. Minor changes; references added. Accepted for publication on
Phys. Rev.
Infrared behavior of the running coupling constant and quarkonium spectrum
We study the effect of the infrared behavior of the running coupling constant
on the quark-antiquark spectrum.Comment: 3 pages. 1 figure, talk given at the 5th International Conference
"Quark Confinement and the Hadron Spectrum", September 10-14, 2002. Gargnano
sul Garda (BS) Ital
Indirect Effects of Eco-labelling of agricultural products on Natural Resources
The implementation of eco-labelling schemes for agricultural and food products may represent an opportunity to enhance production technologies compatible with the sustainable economic approach. The paper presents an attempt to design a comprehensive methodological framework in which the consumer behaviour change is the driving force for redirecting the market, the production, and the international trade. This approach focuses on the specification of the most relevant variables necessary to implement a simplified, but comprehensive analysis, from which it is possible to proceeding to a broad estimate of the changes in terms of consumption patterns, revenue distribution, import and export, and natural resources consumption. On a theoretical basis, the framework highlights that the most relevant conservation effect on natural resources, occurs when the eco-labelling schemes are enforced by two countries, under a market regime of free trade. On the contrary, if only one country adopts the schemes, then the effect is negligible.environmental labelling, natural resources conservation, international trade, Food Consumption/Nutrition/Food Safety, Resource /Energy Economics and Policy,
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