Large (g-2)-mu in SU(5) x U(1) supergravity models

Aug, 1993
14 pages
Published in:
  • Phys.Rev.D 49 (1994) 366-372
e-Print:
Report number:
  • CERN-TH-6986-93,
  • CTP-TAMU-44-93,
  • ACT-17-93

Citations per year

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Abstract:
We compute the supersymmetric contribution to the anomalous magnetic moment of the muon within the context of SU(5)×U(1)SU(5)\times U(1) supergravity models. The largest possible contributions to a susyμa~{susy}_\mu occur for the largest allowed values of tanβ\tan\beta and can easily exceed the present experimentally allowed range, even after the LEP lower bounds on the sparticle masses are imposed. Such tanβ\tan\beta enhancement implies that a susyμa~{susy}_\mu can greatly exceed both the electroweak contribution (1.95×10 9\approx1.95\times10~{-9}) and the present hadronic uncertainty (±1.75×10 9\approx\pm1.75\times10~{-9}). Therefore, the new E821 Brookhaven experiment (with an expected accuracy of 0.4×10 90.4\times10~{-9}) should explore a large fraction (if not all) of the parameter space of these models, corresponding to slepton, chargino, and squarks masses as high as 200, 300, and 1000 GeV respectively. Moreover, contrary to popular belief, the a susyμa~{susy}_\mu contribution can have either sign, depending on the sign of the Higgs mixing parameter μ\mu: a susyμ>0(<0)a~{susy}_\mu>0\,(<0) for μ>0\mu>0 (μ<0\mu<0). The present aμa_\mu constraint excludes chargino masses in the range 45-120\GeV depending on the value of tanβ\tan\beta, although there are no constraints for \tan\beta\lsim8. We also compute a susyτa~{susy}_\tau and find |a~{susy}_\tau|\approx(m_\tau/m_\mu)~2\,|a~{susy}_\mu|\lsim10~{-5} and briefly comment on its possible observability.
  • supergravity: SU(5) x U(1)
  • muon: magnetic moment
  • magnetic moment: muon
  • supersymmetry
  • sparticle: mass
  • mass: sparticle
  • postulated particle: dilaton
  • numerical calculations
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