CP Conserving and CP Violating Asymmetries in $e^{+}{e}^{-}\to t\bar{t}{\nu }_e{\bar{\nu }}_e$} at the NLC: Application to Determining the Higgs Width

Abstract

The polarization asymmetries of $t$, $\bar{t}$ quarks can be used in the reaction $e^{+}{e}^{-}\to t\bar{t}{\nu }_e{\bar{\nu }}_e$ to measure the Higgs width, in the Standard Model or in its extensions, and to search for non-standard CP violating phases. As an application of the CPT theorem the Higgs width is monitored through a CP-even, $T_N$-odd, polarization asymmetry, $B_y$. CP violation manifests through interference at tree graph level with the resonant Higgs amplitude. Consequently, the asymmetries are all quite sizable and can be in the range of 10--50\% for a wide choice of the Higgs mass.

14 pages; 4 figures