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A measurement of the QCD colour factors and a limit on the light gluino

  • Experimental Physics
  • Published:
Zeitschrift für Physik C Particles and Fields

Abstract

Using data collected from 1992 to 1995 with the ALEPH detector at LEP, a measurement of the colour factor ratios C A/C F and T F /C F and the strong coupling constant α s = C F α s(MZ)/(2π) has been performed by fitting theoretical predictions simultaneously to the measured differential two-jet rate and angular distributions in four-jet events. The result is found to be in excellent agreement with QCD, {fx4-1} Fixing C A/C F and T F/C F to the QCD values permits a determination of α s(MZ) and η f, the number of active flavours. With this measurement the existence of a gluino with mass below 6.3 GeV/c2 is excluded at 95% confidence level.

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References

  1. D. Barate et al., ALEPH Collaboration, CERN preprint CERN-PPE/96- 186, submitted to Physics Reports, 1996

  2. R. Muñoz-Tapia and W.J. Stirling, Phys. Rev. D49 (1994), 3763

    ADS  Google Scholar 

  3. R.K. Ellis, D.A. Ross, and A.E. Terrano, Nucl. Phys. B178 (1981), 421

    Article  ADS  Google Scholar 

  4. N. Magnoli, P. Nason and R. Rattazzi, Phys. Lett. B252 (1990), 271

    Article  ADS  Google Scholar 

  5. D. Decamp et al., ALEPH Collaboration, Phys. Lett. B257 (1991), 479

    Article  ADS  Google Scholar 

  6. P.D. Acton et al., OPAL Collaboration, Z. Phys. C55 (1992), 1

    ADS  Google Scholar 

  7. S. Catani, L. Trentadue, G. Turnock, and B.R. Webber, Nucl. Phys. B407 (1993), 3

    Article  ADS  Google Scholar 

  8. P.D. Acton et al., OPAL Collaboration, Z. Phys. C59 (1993), 1

    ADS  Google Scholar 

  9. G. Farrar, Phys. Rev. D51 (1995), 3904

    ADS  Google Scholar 

  10. M. Bengtsson and P.M. Zerwas, Phys. Lett. B208 (1988), 306; M. Bengtsson, Z. Phys. C42 (1989), 75; J.G. Körner, G. Schierholz and J. Willrodt, Nucl. Phys. B185 (1981), 365; O. Nachtmann and A. Reiter, Z. Phys. C16 (1982), 45; S. Bethke, A. Richter and P.M. Zerwas, Z. Phys. C49 (1991), 59

    Article  ADS  Google Scholar 

  11. Y.L. Dokshitzer, Workshop on Jets at LEP and HERA, Durham, 1990

    Google Scholar 

  12. S. Catani, Y.L. Dokshitzer, M. Olsson, G. Turnock, and B.R. Webber, Phys. Lett. B269 (1991), 432

    Article  ADS  Google Scholar 

  13. N. Brown and W.J. Stirling, Z. Phys. C53 (1992), 629

    ADS  Google Scholar 

  14. G. Dissertori and M. Schmelling, Phys. Lett. B361 (1995), 167

    Article  ADS  Google Scholar 

  15. D. Decamp et al., ALEPH Collaboration, Phys. Lett. B284 (1992), 163

    Article  ADS  Google Scholar 

  16. P. Abreu et al., DELPHI Collaboration, Phys. Lett. B255 (1991), 466. P. Abreu et al., DELPHI Collaboration, Z. Phys. C59 (1993), 357

    Article  ADS  Google Scholar 

  17. B. Adeva et al., L3 Collaboration, Phys. Lett. B248 (1990), 227

    Article  ADS  Google Scholar 

  18. R. Akers et al., OPAL Collaboration, Z. Phys. C65 (1995), 367

    ADS  Google Scholar 

  19. D. Decamp et al., ALEPH Collaboration, Phys. Lett. B284 (1992), 151

    Article  ADS  Google Scholar 

  20. D. Decamp et al., ALEPH Collaboration, Nucl. Instrum. Methods A294 (1990), 121

    Article  ADS  Google Scholar 

  21. D. Buskulic et al., ALEPH Collaboration, Nucl. Instrum. Methods A360 (1995), 481

    Article  ADS  Google Scholar 

  22. P. Nason, private communication, 1995

  23. T. Sjöstrand, Comput. Phys. Commun. 27 (1982), 243; 28 (1983), 229; T. Sjöstrand and M. Bengtsson, Comput. Phys. Commun. 43 (1987), 367

    Article  ADS  Google Scholar 

  24. G. Marchesini, B.R. Webber, G. Abbiendi, I.G. Knowles, M.H. Seymour, and L. Stanco, Comput. Phys. Commun. 67 (1992), 465

    Article  ADS  Google Scholar 

  25. J.E. Campagne and R. Zitoun, Z. Phys. C43 (1989), 469

    ADS  Google Scholar 

  26. F. James and M. Roos, computer program MINUIT, CERN program library, writeup CERN D506, 1989

  27. B.R. Webber, Hadronic Final States, Plenary talk at the Workshop on Deep Inelastic Scattering and QCD, Paris, April 1995. Yu.L. Dokshitzer, G. Marchesini and B.R. Webber, CERN preprint CERN-TH/95-281, 1995

  28. A. Ballestrero, E. Maina, and S. Moretti, Phys. Lett. B294 (1992), 425

    Article  ADS  Google Scholar 

  29. D. Buskulic et al., ALEPH Collaboration, Phys. Lett. B355 (1995), 381

    Article  ADS  Google Scholar 

  30. L. Dixon and A. Signer, private communication, 1996

  31. R. Akers et al., OPAL Collaboration, Z. Phys. C68 (1995), 519

    ADS  Google Scholar 

  32. M. Schmelling, Status of the strong coupling constant, Plenary talk at the XXVIII International Conference on High Energy Physics, Warsaw, July 1996

    Google Scholar 

  33. P. Fayet, Phys. Lett. B64 (1976), 159

    Article  ADS  Google Scholar 

  34. R.M. Barnett at al., Particle Data Group, Phys. Rev. D54 (1996), 1–720

    ADS  Google Scholar 

  35. M. Schmelling and R. St. Denis, Phys. Lett. B329 (1994), 393

    Article  ADS  Google Scholar 

  36. F. Csikor and Z. Fodor, Phys. Rev. Lett. 78 (1997), 4335

    Article  ADS  Google Scholar 

  37. A. de Gouvêa and Hitoshi Murayama, HEP preprint hep-ph/9606449, LBL-39030, 1996

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ALEPH Collaboration. A measurement of the QCD colour factors and a limit on the light gluino. Z Phys C - Particles and Fields 76, 1–14 (1997). https://doi.org/10.1007/s002880050522

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  • DOI: https://doi.org/10.1007/s002880050522

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