tanβdetermination from heavy Higgs boson production at linear colliders

We study the production at future $e^{+}{e}^{-}$ linear colliders of the heavy neutral Higgs bosons H and A of the minimal supersymmetric standard model in association with top and bottom quarks. The cross sections have a strong dependence on the parameter $\tan \beta ,$ and thus provide a good way to determine it. At a linear collider with $\sqrt{s}=0.5\mathrm{}$–1 TeV and expected integrated luminosities, we find significant sensitivities for determining $\tan \beta .$ In the supergravity scenario, the sensitivity is particularly strong for $\tan \beta \gtrsim 10,$ reaching a $15\%$ or better measurement. In the general MSSM scenario, the interplay between the $4b$ and $4t$ channels results in a good determination for $\tan \beta \lesssim 10,$ while the sensitivity is weakened for higher values of $\tan \beta .$