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1.
R. Akers G. Alexander J. Allison N. Altekamp K. Ametewee K. J. Anderson S. Anderson S. Arcelli S. Asai D. Axen et al. 《Zeitschrift fur Physik C Particles and Fields》1995,67(3):365-378
The forward-backward asymmetry of
has been measured using approximately 2.15 million hadronicZ
0 decays collected at the LEP e+e– collider with the OPAL detector. A lifetime tag technique was used to select an enriched
event sample. The measurement of the
asymmetry was then performed using a jet charge algorithm to determine the direction of the primary quark. Values of:
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2.
D. J. Broadhurst N. Gray K. Schilcher 《Zeitschrift fur Physik C Particles and Fields》1991,52(1):111-122
We calculate theon-shell fermion wave-function renormalization constantZ
2 of a general gauge theory, to two loops, inD dimensions and in an arbitrary covariant gauge, and find it to be gauge-invariant. In QED this is consistent with the dimensionally regularized version of the Johnson-Zumino relation: d logZ
2/da
0=i(2)–D
e
0
2
d
D
k/k
4=0. In QCD it is, we believe, a new result, strongly suggestive of the cancellation of the gauge-dependent parts of non-abelian UV and IR anomalous dimensions to all orders. At the two-loop level, we find that the anomalous dimension
F
of the fermion field in minimally subtracted QCD, withN
L light-quark flavours, differs from the corresponding anomalous dimension
of the effective field theory of a static quark by the gauge-invariant amount
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