International Linear Collider Workshop - LCWS 2007/ILC 2007

CP properties of the Higgs boson via ttbar Higgs

1 Jun 2007, 09:50

25m

SemRm FLA (DESY Hamburg)

LCWS: Top/ QCD

Speaker

Prof. Rohini Godbole (IISC Bangalore)

Description

We analyse the associated production of the Higgs boson with a top quar pair, $e^{-}{e}^{+}\to t\overline{t}\mathrm{\Phi }$, in the most general case where the coupling is a mixture of scalar and pseudoscalar components, $g_{\mathrm{\Phi }t\overline{t}}\propto (a+ib{\gamma }_5)$. 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 $\mathrm{\Phi }$.

Presentation materials

Slides

talk_LCWS07_godbole1.pdf