Physics – High Energy Physics – High Energy Physics - Phenomenology
Scientific paper
2002-02-18
Phys.Rev. D66 (2002) 074008
Physics
High Energy Physics
High Energy Physics - Phenomenology
12 pages, 1 figure
Scientific paper
10.1103/PhysRevD.66.074008
The perturbative expression of the running strong coupling constant \alpha_{\rm s}(Q^{2}) has an unphysical singularity for Q^{2} = \Lambda^{2}_{\rm QCD}. Various modification have been proposed for the infrared region. The effect of some of such proposals on the quark-antiquark spectrum is tested on a Bethe-Salpeter (second order) formalism which was successfully applied in previous papers to an overall evaluation of the spectrum in the light-light, light-heavy and heavy-heavy sectors (the only serious discrepancy with data being for the light pseudoscalar meson masses). In this paper only the {\rm c} \bar{\rm c}, {\rm b} \bar{\rm b} and {\rm q} \bar{\rm q} (q = u or d) cases are considered and fine structure is neglected. It is found that in the {\rm b} \bar{\rm b} and {\rm c} \bar{\rm c} cases the results are little sensitive to the specific choice. In the light-light case the Dokshitzer et al. prescription is again essentially equivalent to the truncation prescription used in the previous calculation and it is consistent with the same a priori fixing of the quark light masses on the typical current values m_{\rm u} = m_{\rm d} = 10 MeV (only the pion mass resulting completely out of scale of about 500 MeV). With the Shirkov-Solovtsov prescription, on the contrary, a reasonable agreement with the data is obtained only at the price of using a phenomenological momentum dependent effective mass for the quark. The use of such an effective mass should amount to a correction of the free quark propagator. It is remarkable that this has also the effect of bringing the pion mass in the correct range.
Baldicchi M.
Prosperi G. M.
No associations
LandOfFree
Infrared behavior of the running coupling constant and bound states in QCD does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Infrared behavior of the running coupling constant and bound states in QCD, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Infrared behavior of the running coupling constant and bound states in QCD will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-161778