Speaker
Prof.
Rohini Godbole
(IISC Bangalore)
Description
We analyse the associated production of the Higgs boson with a top quar pair,
${e^-e^+ \to t\bar t\Phi}$, in the most general case where the coupling
is a mixture of scalar and pseudoscalar components, $g_{\Phi t \bar t} \propto
(a+i b \gamma_5)$. We have calculated the individual helicity amplitudes for
the process and obtained the corresponding cross sections for each helicity
state; we have also constructed the top quark polarization asymmetries with
polarized and unpolarized initial $e^\pm$ beams. The sensitivity of the
pseudoscalar component of the coupling $b$ to the cross section and
polarization asymmetry has been investigated. We find that although neither
of these observables is very sensitive to the parameter $b$ except for values
close to unity, both can clearly distinguish a purely CP--even Higgs state
from a purely CP--odd state. Finally, we have constructed an up--down
asymmetry for the produced top quark which allows to probe the CP mixing of
the Higgs state $\Phi$.
Primary author
Prof.
Rohini Godbole
(IISC Bangalore)
