Skip to main content
Log in

First study of the interference between initial and final state radiation at the Z resonance

  • Published:
Zeitschrift für Physik C: Particles and Fields

Abstract

The interference between initial and final state radiation in the processe + e μ + μ at √s≈MZ has been studied by measuring the forward-backward asymmetry as a function of the acoplanarity angle between the final state muons. The interference is expected to be sensitive to the space-time separation of the initial and final state radiation. The measured asymmetry distribution has been compared to theoretical predictions using thekoralz generator, with and without\({\mathcal{O}}(\alpha )\) interference. The magnitude of the interference between initial and final state radiation was found to be of the order predicted and to follow the expected distribution. Using the theoretical predictions, a value of

$$\Gamma _{\rm Z} = 2.50 \pm 0.21 (stat.) \pm 0.06 (syst.) GeV.$$

has been extracted. The interpretation of this result is discussed. There is an additional uncertainty in the estimate ofΓ Z from as yet uncalculated higher order interference terms. By assuming a value ofΓ Z consistent with the world average, the data were used to estimate the size of these uncalculated corrections.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. M. Böhm & W. Hollik, “Forward-backward Asymmetries”, in “Z Physics at LEP 1”, (ed: G. Altarelli, R. Kleiss, C. Verzegnassi), CERN 89-08 (1989) 203;

  2. Z. Was & S. Jadach, Phys. Rev.D41 (1990) 1425;

    ADS  Google Scholar 

  3. S. Jadach, J.H. Kuhn & Z. Was, Z. Phys.C38 (1988) 609.

    ADS  Google Scholar 

  4. S. Jadach & Z. Was, Phys. Lett.B219 (1989) 103.

    ADS  Google Scholar 

  5. S. Jadach & Z. Was, CERN-TH 7232/94 (1994).

  6. D. Schaile, Proceedings of the XXVII International Conference on High Energy Physics, Glasgow, Scotland, UK, 20–27 July 1994, Editors P.J. Bussey and I.G. Knowles, IOP publishing (1995) 27.

  7. S. Jadach, B.F.L. Ward & Z. Was, Comp. Phys. Comm.79 (1994) 503.

    Article  ADS  Google Scholar 

  8. D. Bardinet al., “ZFITTER An Analytical Program for Fermion Pair Production ine + e Annihilation”, hep-ph/9412201 (1994).

  9. DELPHI Collaboration, P. Aarnio et al., Nucl. Inst. Meth.A303 (1991) 233; DELPHI Collaboration, P. Abreu et al., CERN-PPE/95-194, subm. to Nucl. Inst. Meth.A.

    Google Scholar 

  10. DELPHI Collaboration, P. Abreu et al., Nucl. Phys.B418 (1994) 403.

    Article  ADS  Google Scholar 

  11. J.E. Campagne & R. Zitoun, Z. Phys.C43 (1989) 469.

    ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Consortia

Rights and permissions

Reprints and permissions

About this article

Cite this article

DELPHI Collaboration., Abreu, P., Adam, W. et al. First study of the interference between initial and final state radiation at the Z resonance. Z. Phys. C - Particles and Fields 72, 31–38 (1996). https://doi.org/10.1007/BF02909129

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02909129

Keywords

Navigation