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Updated: Jun 8, 2026

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
Direct mass limits for chiral fourth-generation quarks in all mixing scenarios
Christian J Flacco1, Daniel Whiteson, Tim M P Tait
1Department of Physics and Astronomy, University of California, Irvine, California 92697, USA. cflacco@mac.com
Abstract:
Present limits on chiral fourth-generation quark masses mb' and mt' are broadly generalized and strengthened by combining both t' and b' decays and considering a full range of t' and b' flavor-mixing scenarios with the lighter generations (to 1-‖V44‖2≈10(-13)). Various characteristic mass-splitting choices are considered. With mt'>mb' we find that CDF Collaboration limits on the b' mass vary by no more than 10%-20% with any choice of flavor mixing, while for the t' mass, we typically find stronger bounds, in some cases up to mt'>430 GeV. For mb'>mt', we find mb'>380-430 GeV, depending on the flavor mixing and the size of the mt'-mb' mass splitting.
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