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Volumn 49, Issue 1, 1994, Pages 437-450

Optimization of Re+e- and freezing of the QCD couplant at low energies

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EID: 33845797789     PISSN: 05562821     EISSN: None     Source Type: Journal    
DOI: 10.1103/PhysRevD.49.437     Document Type: Article
Times cited : (188)

References (102)
  • 5
    • 84931516933 scopus 로고    scopus 로고
    • These questions were originally posed by P. M. Stevenson (private communication to Dr. Gorishny, Dr. Kataev, and Dr. Larin, 1988), before the original Resup+e- calculation was completed.
  • 31
    • 84931516931 scopus 로고    scopus 로고
    • Two schemes, which for the same μ value are related by a′ = a(1 + v1 a + cdots), have tilde{Λ} parameters which are related by ln( tilde{Λ}′/ tilde{Λ}) = v1/b. This relation is exact, Ref. 19, Ref. 3
  • 32
    • 84931516932 scopus 로고    scopus 로고
    • The choice of Λ overlineMS as the free parameter of QCD is an arbitrary choice, but a harmless one since the Λ of any other ``reference scheme'' could be related exactly to Λ overlineMS (see, Ref. 20, above). Thus, this choice affects only how the predictions are parametrized, and not their content. For complications related to flavor thresholds, see Appendix B.
  • 34
    • 84931516935 scopus 로고    scopus 로고
    • Some authors use a different definition: tilde{ρ}2 = ρ2 + 1 / 4 c2.
  • 40
    • 84931516936 scopus 로고    scopus 로고
    • Fixed point behavior will also be found in RS's which are sufficiently close to the ``optimized'' scheme. This is the case, for instance, in the ``fastest apparent convergence'' (FAC) or ``effective charge'' scheme (the RS in which r1=r2=0). However, this scheme gives an asup * that is 64 % larger than ours, for Nf=2.
  • 41
    • 4243375814 scopus 로고
    • The αs3 corrections to the Bjorken sum rule for polarized electroproduction and to the Gross-Llewellyn Smith sum rule
    • The π2 term in r2, Ref. 2, gives a substantial negative contribution to ρ2. Another timelike process, hadronic decay of the Higgs boson, also has a sizable, negative ρ2: see, Ref. 9, and references therein. In a spacelike case, deep inelastic scattering, the third order QCD corrections to the Gross Llewellyn Smith, and Bjorken sum rules give ρ2's that are negative only for Nf ge 4 or 5. [See,] It may be that in this case fixed point behavior will extend to fewer flavors only in higher orders. Alternatively, might be that there is a real difference in behavior between spacelike and timelike processes. Another possibility is that exponentiation of some of the π2 contributions is important. See, e.g., 90B, 295, G. Parisi, Phys. Lett.
    • (1980) Physics Letters B , vol.259 , pp. 345
    • Larin, S.A.1    Vermaseren, J.A.M.2
  • 43
    • 0011564712 scopus 로고
    • It is noteworthy that the fixed point values all lie comfortably below the classical critical value 9 / 8π = 0.358 of
    • (1977) Phys. Lett. , vol.67 B , pp. 175
    • Mandula, J.1
  • 44
    • 84931516948 scopus 로고    scopus 로고
    • Obviously, the procedure may be repeated with different trial values of Λ overlineMS if one seeks to determine the value that gives the best fit to the Resup+e- data.
  • 58
    • 84931516950 scopus 로고    scopus 로고
    • Crystal Ball Collaboration, C. Edwards et al., SLAC Report No. SLAC PUB 5160, 1990 (unpublished).
  • 60
    • 84931516951 scopus 로고    scopus 로고
    • p. III.7A;
  • 78
    • 84931516952 scopus 로고    scopus 로고
    • Sec. 5.
  • 88
    • 84931516953 scopus 로고    scopus 로고
    • We thank Dr. R. S. Fletcher for helpful correspondence on this issue.
  • 89
    • 84931516954 scopus 로고    scopus 로고
    • Yu. L. Dokshitzer, V. A. Khoze, and S. I. Troyan, Lund Report No. LU TP 92 10 (unpublished).
  • 90
    • 84931516955 scopus 로고    scopus 로고
    • V. Khoze, in Proceedings of the XXVIth International Conference on High Energy Physics, Dallas, Texas, 1992, edited by J. Sanford, AIP Conf. Proc. No. 272 (AIP, New York, 1993).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.