Strong coupling constant from the photon structure function

ELSEVIER

Nuclear

Physics

B (Proc.

Suppl.)

121 (2003)

73

www.elsevier.com/locate/npe

Strong Coupling Constant from the Photon Structure Function * * Simon

Albinot

“II. Institut Germany bFNAL,

a, Michael

Klasen

fiir Theoretische

a and Stefan

Physik,

Sdldner-Rembold

Universitat

P.O. Box 500, MS 357, Batavia,

IL 60510,

Hamburg,

b Luruper

Chaussee

149, D-22761

Hamburg,

USA

We extract the value of the strong coupling constant ays from a single-parameter pointlike fit to the photon structure function Fz at large z and Q2 and from a first five-parameter full (pointlike and hadronic) fit to the complete F,7 data set taken at PETRA, TRISTAN, and LEP. In next-to-leading order and the MS renormalization and factorization schemes, we obtain o,(ms) = 0.1183 f O.O050(exp.)‘8:8~~~(theor.) [pointlike] and (~~(rnz) = 0.1198 f 0.0028(exp.)f0.0034 0,0046(theor.) [pointlike and hadronic]. We demonstrate that the data taken at LEP have reduced the experimental error by about a factor of two, so that a competitive determination of cr. from F; is now

possible

REFERENCES 13. K. Ackerstaff et al., Phys. Lett. B 411 (1997) 387. 14. K. Ackerstaff et al., Z. Phys. C 74 (1997) 33. 15. G. Abbiendi et al., Eur. Phys. J. C 18 (2000) 15. 16. G. Abbiendi et al., arXiv:hep-ex/0202035. 17. H. Aihara et al., Phys. Rev. Lett. 58 (1987) 97. 18. H. Aihara et al., Z. Phys. C 34 (1987) 1. 19. M.Gliick, E.Reya, A.Vogt, Phys. Rev. D 46 (1992) 1973. 20. P. Aurenche, M. Fontannaz and J. P. Guillet, Z. Phys. C 64 (1994) 621. 21. G. Schuler and T. Sjijstrand, Z. Phys. C 68 (1995) 607. 22. M. Gliick, E. R.eya and I. Schienbein, Phys. Rev. D 60 (1999) 054019; 62 (1999) 019902(E). 23. C. Adloff et al., Phys. Lett. B 483 (2000) 36. 24. K. Hagiwara et al., Phys. Rev. D 66 (2002) 010001.

1.

V. Budnev, I. Ginzburg, G. Meledin and V. Serbo, Phys. Rept. 15 (1974) 181. 2. J.Kiihn, M.Steinhauser, Nucl. Phys. B 619 (2001) 588. 3. M.Ghick, E.Reya, A.Vogt, Phys. Rev. D 45 (1992) 3986. 4. W. Bartel et al., Z. Phys. C 24 (1984) 231. 5. C. Berger et al., Phys. Lett. B 142 (1984) 111; Nucl. Phys. B 281 (1987) 365. 6. M. Althoff et al., Z. Phys. C 31 (1986) 527. 7. S. Sahu et al., Phys. Lett. B 346 (1995) 208. 8. T. Kojima et al., Phys. Lett. B 400 (1997) 395. 9. K. Muramatsu et al., Phys. Lett. B 332 (1994) 477. 10. R. Barate et al., Phys. Lett. B 458 (1999) 152. 11. P. Abreu et al., Z. Phys. C 69 (1996) 223. 12. M. Acciarri et al., Phys. Lett. B 436 (1998) 403; ibid., 447 (1999) 147; ibid., 483 (2000) 373.

*Presented t Speaker

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* A full length version published in Acta Phys.

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of this paper has been published Polon. B33 (2002) 2939-2945.

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