OVERVIEW OF tanβ DETERMINATION AT A LINEAR e+e− COLLIDER

The ratio of the vacuum expectation value of the two Higgs doublets, tanβ, is an important parameter of the general 2-HiggsDoublet Model (2HDM) and the Minimal Supersymmetric extension of the Standard Model (MSSM). The expected uncertainty on the determination of tanβ at a Linear Collider (LC) of at least 500 GeV center-of-mass energy and high luminosity is reviewed based on studies of neutral and charged Higgs boson production. Presented at the SUSY02 conference, DESY, June 2002; and the LCWS02, Korea, Aug. 2002 OVERVIEW OF tanβ DETERMINATION AT A LINEAR e + e − COLLIDER J. GUNION, T. HAN, J. JIANG, A. SOPCZAK Davis Institute for HEP, U. of California, Davis, CA Dept. of Physics, U. of Wisconsin, Madison, WI Argonne National Laboratory, Chicago, IL Lancaster University, UK Abstract The ratio of the vacuum expectation value of the two Higgs doublets, tanβ, is an important parameter of the general 2-Higgs-Doublet Model (2HDM) and the Minimal Supersymmetric extension of the Standard Model (MSSM). The expected uncertainty on the determination of tanβ at a Linear Collider (LC) of at least 500 GeV center-of-mass energy and high luminosity is reviewed based on studies of neutral and charged Higgs boson production.The ratio of the vacuum expectation value of the two Higgs doublets, tanβ, is an important parameter of the general 2-Higgs-Doublet Model (2HDM) and the Minimal Supersymmetric extension of the Standard Model (MSSM). The expected uncertainty on the determination of tanβ at a Linear Collider (LC) of at least 500 GeV center-of-mass energy and high luminosity is reviewed based on studies of neutral and charged Higgs boson production. Introduction Various methods to determine tan β at a LC exist and they have in common that a physical observable depends on tanβ: • The pseudoscalar Higgs boson, A, could be produced via radiation off a pair of b-quarks: ee → bb̄ → bb̄A → bb̄bb̄. The bb̄A coupling is proportional to tan β and thus the expected production rate is proportional to tan β. • The bb̄bb̄ rate from the pair-production of the heavier scalar, H, in association with the pseudoscalar Higgs boson ee → HA → bb̄bb̄ can be exploited. While the HA production rate is almost independent of tanβ the sensitivity occurs via the variation of the decay branching ratios with tan β.