Grand Unified Theories without Superheavy Magnetic Monopoles

  • Paul Langacker
Part of the Lie Groups: History, Frontiers and Applications book series (LGR, volume 11)


Grand unified theories have many very attractive features, such as the approximately correct prediction of the Weinberg angle, the prediction of proton decay, and the possible explanation of the baryon asymmetry of the universe. However, one serious problem that has received much attention recently1–6 is that many grand unified theories predict the existence of superheavy magnetic monopoles. These monopoles may have been produced prolifically soon after the big bang and could very well contribute too much to the energy density of the universe. In this talk I will briefly review the subject and then describe a model that I have developed in collaboration with S.-Y. Pi6 in which the superheavy monopoles would never have been produced.


Gauge Boson Proton Decay Grand Unify Theory Magnetic Monopole Baryon Asymmetry 
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  1. 1.
    Zel’dovich, Ya. B., and M.Y. Khlopov, Phys. Lett. 79B, 239 (1979).ADSGoogle Scholar
  2. 2.
    Preskill, J.P., Phys. Rev. Lett. 43, 1365 (1979).ADSCrossRefGoogle Scholar
  3. 3.
    Einhorn, M.B., D.L. Stein, and D. Toussaint, Michigan Preprint UM HE 80-1.Google Scholar
  4. 4.
    Guth, A.H., and S.-H.H. Tye, SLAC-PUB-2448.Google Scholar
  5. 5.
    Lazarides, G., and Q. Shafi, CERN TH 2821.Google Scholar
  6. 6.
    Langacker, P., and S.-Y. Pi, IAS Preprint.Google Scholar
  7. 7.
    ’t Hooft, G., Nucl. Phys. B79, 276 (1974); A.M. Polyakov, Pis’ma Eksp. Teor. Fiz. 20, 430 (1974) [JETP Lett. 20, 194 (1974)]. For an introduction, see S. Coleman in New Phenomena in Subclear Physios, Part A, A. Zichichi (ed.), Plenum, New York, 1977, p. 297.MathSciNetADSCrossRefGoogle Scholar
  8. 8.
    Georgi, H., and S.L. Glashow, Phys. Rev. Lett. 32, 438 (1974). See also A. Buras et al., Nucl. Phys. B135, 66 (1978).ADSCrossRefGoogle Scholar
  9. 9.
    Annihilations could produce2 a small enough density if mm < 1011 GeV, but this would lead to an unacceptably short proton lifetime in the standard model. A small unification mass could be tolerated in theories with a stable proton (which can still generate a baryon asymmetry). See P. Langacker, G. Segre, and H.A. Weldon, Phys. Lett. 73B, 87 (1978) and Phys. Rev. D18, 552 (1978); M. Gell-Mann, P. Ramond, and R. Slansky, Rev. Mod. Phys. 50, 721 (1978); G. Segre and H.A. Weldon, Penn. Preprint UPR-0147T.ADSGoogle Scholar
  10. 10.
    Steigman, G., private communication.Google Scholar
  11. 11.
    A small density could be obtained for an unacceptably large scalar self interaction.Google Scholar
  12. 12.
    Guth, A., to be published.Google Scholar
  13. 13.
    Bardeen, J., private communication.Google Scholar
  14. 14.
    Except for models with a stable proton (Ref. 9).Google Scholar
  15. 15.
    Kirzhnits, D.A., and A.D. Linde, Phys. Lett. 42B, 471 (1972) and Ann. Phys. 101, 195 (1976).ADSGoogle Scholar
  16. 16.
    Weinberg, S., Phys. Rev. D9, 3357 (1974).ADSGoogle Scholar
  17. 17.
    Dolan, L., and R. Jackiw, Phys. Rev. D9, 3320 (1974).ADSGoogle Scholar
  18. 18.
    Mohapatra, R.N., and G. Senjanovic, Phys. Rev. Lett. 42, 1651 (1979); Phys. Rev. D20, 3390 (1979); CCNY Preprint HEP-7916.ADSCrossRefGoogle Scholar
  19. 19.
    Zee, A., Phys. Rev. Lett. 44, 703 (1980).ADSCrossRefGoogle Scholar
  20. 20.
    Lee, B.W., H. Thacker, and C. Quigg, Phys. Rev. D16, 1519 (1977), and references therein.ADSGoogle Scholar
  21. 21.
    Cheng, T.P., E. Eichten, and L.-F. Li, Phys. Rev. D9, 2259 (1974).ADSGoogle Scholar
  22. 22.
    The solutions tend to diverge for large momenta if the initial values are too large. See L. Maiani, G. Parisi, and R. Petronzio, Nucl. Phys. B136, 115 (1978) and N. Cabibbo et al., CERN Preprint TH 2683. It might be possible to avoid this problem by fine tuning parameters, introducing more Higgs fields (with smaller σij ), or by invoking higher order contributions to the equations.ADSCrossRefGoogle Scholar
  23. 23.
    See, for example, G. Steigman, in Ann. Rev. Nucl. Sci., Vol. 29.Google Scholar
  24. 24.
    We thank S. Barr for this comment.Google Scholar
  25. 25.
    Lyttleton, R.A., and H. Bondi, Proc. Roy. Soo. London A252, 313 (1959).MathSciNetADSCrossRefGoogle Scholar
  26. 26.
    Barnes, A., Ast. Journal 227, 1 (1979).ADSCrossRefGoogle Scholar
  27. 27.
    We thank G. Kane for this comment.Google Scholar

Copyright information

© Robert Hermann 1980

Authors and Affiliations

  • Paul Langacker
    • 1
    • 2
  1. 1.Institute for Advanced StudyPrincetonUSA
  2. 2.University of PennsylvaniaPhiladelphiaUSA

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