Naturalness bounds on weak scale supersymmetry in the context of radiative breaking of the electroweak symmetry are analyzed. In the case of minimal supergravity it is found that for low tanβ and for low values of fine-tuning Φ, where Φ is defined essentially by the ratio μ2/MZ2 where μ is the Higgs mixing parameter and MZ is the Z boson mass, the allowed values of the universal scalar parameter m₀, and the universal gaugino mass m1/2 lie on the surface of an ellipsoid with radii fixed by Φ leading to tightly constrained upper bounds ∼√Φ. Thus for tanβ<~2(1/2. Effects of nonuniversalities in the Higgs boson sector and in the third generation sector on naturalness bounds are also analyzed and it is found that nonuniversalities can significantly affect the upper bounds. It is also found that achieving the maximum Higgs boson mass allowed in supergravity unified models requires a high degree of fine-tuning. Thus a heavy sparticle spectrum is indicated if the Higgs boson mass exceeds 120 GeV. The prospect for the discovery of supersymmetry at the Fermilab Tevatron and at the CERN LHC in view of these results is discussed.


Originally published in Physical Review D v.58 (1998): 096004. DOI: 10.1103/PhysRevD.58.096004


naturalness, weak scale supersymmetry, Fermilab Tevatron, CERN LHC

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Higgs bosons, Supersymmetry, Supergravity




American Physical Society

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Copyright (1998) American Physical Society

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American Physical Society

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