rho nu decay > We demonstrate that a measurement of the impact parameter in one-prong
tau decay can be useful for the determination of the Higgs boson
parity in the H/A –> tau tau; tau –> rho nu decay chain. We
have estimated that for a detection set-up such as TESLA, use of the
information from the tau impact parameter can improve the significance
of the measurement of the parity of the Standard Model 120 GeV Higgs
boson to 4.5 sigma, and in general by factor of about 1.5 with respect
to the method where this information is not used.
We also show that the variation in the assumption on the precision of the
measurement of the impact parameter and/or pi's momenta does not affect
the sensitivity of the method. This is because the method remains
limited by the type of twofold ambiguity in reconstructing the tau
momentum.
