The $π^2$ terms in the s-channel QCD observables
| dc.creator | Shirkov, D. V. | |
| dc.date | 2000-09-10 | |
| dc.date | 2001-01-23 | |
| dc.date.accessioned | 2026-07-07T03:42:33Z | |
| dc.date.available | 2026-07-07T03:42:33Z | |
| dc.description | We analyze the effect of $π^2$-terms in the QCD perturbative expansions for the s-channel effective coupling and observables, the effect known from the 80s. We remind that these terms can be collected into specific functions -- strong s-channel coupling $\tildaα_s$ and its effective powers ${\mathfrak A}(s)$ free of ghost singularities. Further on, we study the structure of perturbation theory for observables and its reformulation in terms of nonpower perturbation expansion over the set $\{\mathfrak A}(s)\}.$\par values of $α_s$ as extracted from experiments. The main result is that the common two-loop (NLO, NLLA) approximation widely used in the five-quark ($10 \GeV\lesssim \sqrt{s}\lesssim 170 \GeV$) region for a shape analysis contains a systematic negative error of a 1-2 per cent order of magnitude for the extracted $\barα_s^{(2)}$. Our physical conclusion is that the $α_s(M_Z)$ value averaged over the f=5 data $<α_s(M_Z)>_{f=5} \simeq 0.124$ appreciably differs from the currently accepted "world average" (=0.118).} | |
| dc.description | 12 pages, LaTeX2e | |
| dc.identifier | https://arxiv.org/abs/hep-ph/0009106 | |
| dc.identifier | http://arxiv.org/abs/hep-ph/0009106 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/39935 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | The $π^2$ terms in the s-channel QCD observables | |
| dc.type | text |