Abstract
The value of the strong coupling constant,\(\alpha _s (M_{Z^0 } )\), is determined from a study of 15 different observables in hadronicZ 0 and τ decays. The study includes global event shape variables, jet production rates, energy correlations, theZ 0 line shape and decay asymmetries and the hadronic branching fraction of τ-leptons. Differences between the αs values from the different observables can be consistently attributed to unknown higher order contributions to the
calculations. These uncertaities may be parametrized by variations of the renormalization scale and of the parton virtuality to which the data are corrected, separately for each observable, resulting in a consistent description of the event shapes, jet rates and energy correlations with the value\(\alpha _s (M_{Z^0 } ) = 0.122_{ - 0.005}^{ + 0.006} \) in
. The error is dominated by the theoretical uncertainties. Application of recent calculations which include the resummation of leading and next-to-leading logarithms to all orders for some observables confirm this result with a reduced sensitivity to renormalization scale variations. TheZ 0 line shapes and τ-lepton branching ratios yield\(\alpha _s (M_{Z^0 } ) = 0.148 \pm 0.021\) and\(\alpha _s (M_{Z^0 } ) = 0.123_{ - 0.007}^{ + 0.006} \), respectively, in
. These measurements and their uncertainties are entirely independent of each other and from event shape and jet observables; the good agreement of the resulting αs values thus constitutes an important consistency check of the reliability of perturbative QCD.
Similar content being viewed by others
References
H. Fritsch, M. Gell-Mann: 16th Int. Conf. on High Energy Physics, Chicago (1972); H. Fritsch, M. Gell-Mann, H. Leutwyler: Phys. Lett. B47 (1973) 365; D. Gross, F. Wilczek: Phys. Rev. Lett. 30 (1973) 1343; H.D. Politzer: Phys. Rev. Lett. 30 (1973) 1346
U. Amaldi et al.: Phys. Lett. B260 (1991) 447; CERN-PPE/91-233; F. Anselmo, L. Cifarelli, A. Petermann, A. Zichini: CERN-PPE/91-123; J. Ellis, S. Kelley, D.V. Nanopoulos: CERN-TH.6140/91
OPAL Coll., M.Z. Akrawy et al.: Phys. Lett. B235 (1991) 389
OPAL Coll., M.Z. Akrawy et al.: Z. Phys. C — Particles and Fields 49 (1991) 375
OPAL Coll., M.Z. Akrawy et al.: Phys. Lett. B252 (1990) 159
OPAL Coll., P.D. Acton et al.: Phys. Lett. B276 (1992) 547
OPAL Coll., P.D. Acton et al.: CERN-PPE/91-189, to appear in Z. Phys. C — Particles and Fields
OPAL Coll., G. Alexander et al.: Z. Phys. C — Particles and Fields 52 (1991) 175
ALEPH Coll., D. Decamp et al.: Phys. Lett. B255 (1991) 623
ALEPH Coll., D. Decamp et al.: Phys. Lett. B257 (1991) 479
ALEPH Coll., D. Decamp et al.: CERN-PPE/91-105
DELPHI Coll., P. Abreu et al.: Phys. Lett. B247 (1990) 167
DELPHI Coll., P. Abreu et al.: Phys. Lett. B252 (1990) 149
DELPHI Coll., P. Abreu et al.: CERN-PPE/91-181/rev., submitted to Z. Phys.
L3 Coll., B. Adeva et al.: Phys. Lett. B248 (1991) 464
L3 Coll., B. Adeva et al.: Phys. Lett. B257 (1991) 469
L3 Coll., B. Adeva et al.: Z. Phys. C — Particles and Fields 51 (1991) 179
L3 Coll., B. Adeva et al.: Phys. Lett. B265 (1991) 451
L3 Coll., B. Adeva et al.: Phys. Lett. B271 (1991) 461
N. Magnoli, P. Nason, R. Rattazzi: Phys. Lett. B252 (1990) 271
OPAL Coll., K. Ahmet et al.: Nucl. Instrum. Methods A305 (1991) 275
OPAL Coll., M. Arignon et al.: Nucl. Instrum. Methods A313 (1992) 103
Particle Data Group: Review of Particle Properties. Phys. Lett. B239 (1990)
Z. Kunszt, P. Nason [conv.]; in: Z. Physics at LEP 1. G. Altarelli, R. Kleiss, C. Verzegnassi (eds.), CERN 89-08 (1989)
R.K. Ellis, D.A. Ross, A.E. Terrano: Nucl. Phys. B178 (1981) 421
T. Sjöstrand: Comput. Phys. Commun. 39 (1986) 347
T. Sjöstrand: Comput. Phys. Commun. 43 (1987) 367
M. Bengtsson, T. Sjöstrand: Nucl. Phys. B289 (1987) 810
G. Marchesini, B.R. Webber: Nucl. Phys. B310 (1988) 461; G. Marchesini, B.R. Webber: Cavendish-HEP-88/7
OPAL Coll., M.Z. Akrawy et al.: Z. Phys. C — Particles and Fields 47 (1990) 505
J. Allison et al.: Comput. Phys. Commun. 47 (1987) 55; D.R. Ward: The OPAL Monte Carlo Program — GOPAL; Proc. MC '91 Workshop, Amsterdam, April 1991; J. Allison et al.: CERN-PPE/91-234 (1991), to appear in Nucl. Instrum. Methods
B. Andersson, G. Gustafson, G. Ingelman, T. Sjöstrand: Phys. Rep. 97 (1983) 31
R. Odorico: Comput. Phys. Commun. 32 (1984) 139; Comput. Phys. Commun. 59 (1990) 527
T. Sjöstrand et al.: QCD Generators: in: Z. Physics at LEP 1, CERN 89-08, vol. 3, G. Altarelli, R. Kleiss, C. Verzegnassi (eds)
P.M. Stevenson: Phys. Rev. D24 (1981) 1622
S.J. Brodsky, G.P. Lepage, P.B. Mackenzie: Phys. Lett. D28 (1983) 228
G. Grunberg: Phys. Lett. B95 (1980) 70
J. Ellis, D.V. Nanopoulos, D.A. Ross: Phys. Lett. B267 (1991) 132
G. Parisi: Phys. Lett. B74 (1978) 65; J.F. Donoghue, F.E. Low, S.Y. Pi: Phys. Rev. D20 (1979) 2759
S. Brandt et al.: Phys. Lett. 12 (1964) 57; E. Fahri: Phys. Rev. Lett. 39 (1977) 1587
Mark J Coll., D.P. Barber et al.: Phys. Rev. Lett. 43 (1979) 830; Phys. Lett. B89 (1979) 139
T. Chandramohan, L. Clavelli: Nucl. Phys. B184 (1981) 365
JADE Coll., W. Bartel et al.: Z. Phys. C — Particles and Fields 33 (1986) 23; JADE Coll., S. Bethke et al.: Phys. Lett. B213 (1988) 235
S. Bethke, Z. Kunszt, D. Soper, W.J. Stirling: Nucl. Phys. B370 (1992) 310
S. Catani et al.: Phys. Lett. B269 (1991) 432
N. Brown, W.J. Stirling: Z. Phys. C — Particles and Fields 53 (1992) 629
S. Catani: CERN-TH.6281/91; S. Catani et al.: Phys. Lett. B269 (1991) 432
C.L. Basham et al.: Phys. Rev. Lett. 41 (1978) 1585; Phys. Rev. D17 (1978) 2298
F. Csikor, G. Pócsik, A. Tóth: Phys. Rev. D31 (1985) 1025
F. Csikor et al.: Phys. Rev. D39 (1989) 713
F. Csikor: Phys. Rev. D40 (1989) 3595
S. Catani, L. Trentadue, G. Turnock, B.R. Webber: Phys. Lett. B263 (1991) 491
S. Catani, G. Turnock, B.R. Webber: Phys. Lett. B272 (1991) 368
G. Turnock: Private communication
S.G. Gorishny, A.L. Kataev, S.A. Larin: Phys. Lett. B259 (1991) 144; L.R. Surguladze, M.A. Samuel: Phys. Rev. Lett. 66 (1991) 560
UA2 Coll., J. Alitti et al.: Phys. Lett. B276 (1992) 354
CDF Coll., F. Abe et al.: Phys. Rev. Lett. 65 (1990) 2243
A. Blondel et al.: Z. Phys. C — Particles and Fields 45 (1990) 361; CHARM Coll., J.V. Allaby et al.: Z. Phys. C — Particles and Fields 36 (1987) 611. The average value for sin2 θ W has been scaled toM t =M H =100 GeV as in: CHARM-II Coll., D. Geiregat et al.: Phys. Lett. B259 (1991) 499
Line shape program ZFITTER, Dubna-Zeuthen radiative correction group: D.Yu. Bardin et al.: Nucl. Phys. B351 (1991) 1; D.Yu. Bardin et al.: Comput. Phys. Commun. 59 (1990) 303; D.Yu. Bardin et al.: Z. Phys. C—Particles and Fields 44 (1989) 493; D.Yu. Bardin et al.: Phys. Lett. B229 (1989) 405
K.G. Chetyrkin, J.H. Kühn: Phys. Lett. B248 (1990) 359
W.J. Marciano: Phys. Rev. D29 (1984) 580
E. Braaten: Phys. Rev. Lett. 60 (1988) 1606
E. Braaten, S. Narison, A. Pich: CERN-TH.6070/91 (1991)
OPAL Coll., G. Alexander et al.: Phys. Lett. B266 (1991) 201
OPAL Coll., M.Z. Akrawy et al.: Phys. Lett. B261 (1991) 334
OPAL Coll., G. Alexander et al.: Phys. Lett. B265 (1991) 462
G. Altarelli: Ann. Rev. Nucl. Part. Sci. Vol. 39 (1989) 357
A.D. Martin, W.J. Stirling, R.G. Roberts: Phys. Lett. B266 (1991) 173
M. Virchaux, A. Milsztajn: Phys. Lett. B274 (1992) 221
T. Hebbeker: Proc. of the LP-HEP91 Conference on High Energy Physics, Geneva 1991; Aachen preprint PITHA 91/17
S. Bethke: Proc. of the EPS conference on Hadronic Structure and Electroweak Interactions, Amsterdam 1991; Heidelberg preprint HD-PY 91/5
Author information
Authors and Affiliations
Consortia
Additional information
On leave from Research Institute for Computer Peripherals, Hangzhou, PRC
Rights and permissions
About this article
Cite this article
OPAL Collaboration., Acton, P.D., Alexander, G. et al. A global determination of\(\alpha _s (M_{Z^0 } )\) at LEP. Z. Phys. C - Particles and Fields 55, 1–24 (1992). https://doi.org/10.1007/BF01558285
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01558285