815 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
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