Single decay-lepton angular distributions in polarized e+e- --> t tbar and simple angular asymmetries as a measure of CP-violating top dipole couplings

Abstract

In the presence of an electric dipole coupling of t-tbar to a photon, and an analogous "weak" dipole coupling to the Z, CP violation in the process e+e- --> t tbar results in modified polarization of the top and anti-top. This polarization can be analyzed by studying the angular distributions of decay charged leptons when the top or anti-top decays leptonically. Analytic expressions are presented for these distributions when either t or tbar decays leptonically, including O(alpha_s) QCD corrections in the soft-gluon approximation. The angular distributions are insensitive to anomalous interactions in top decay. Two types of simple CP-violating polar-angle asymmetries and two azimuthal asymmetries, which do not need the full reconstruction of the t or tbar, are studied. Independent 90% CL limits that may be obtained on the real and imaginary parts of the electric and weak dipole couplings at a linear collider operating at sqrt{s}=500 GeV with integrated luminosity 500 fb^{-1} and also at sqrt{s}=1000 GeV with integrated luminosity 1000 fb^{-1} have been evaluated. The effect of longitudinal electron and/or positron beam polarizations has been included.

26 pages, latex, figures included as latex files, version appearing in Pramana - Journal of Physics, minor corrections and note added in proof

Cited by in corpus (18)

• The role of polarized positrons and electrons in revealing fundamental interactions at the Linear Collider
• Lepton distribution as a probe of new physics in production and decay of the t quark and its polarization
• CP violating anomalous top-quark couplings at the LHC
• T-odd correlations from CP violating anomalous top-quark couplings revisited
• Improved Measurement of ttZ Couplings at the LHC
• Angular distributions as a probe of anomalous ZZH and gammaZH interactions at a linear collider with polarized beams
• CP violation at a linear collider with transverse polarization
• CP-odd correlations using jet momenta from tt_bar events at the Tevatron
• Transverse beam polarization and CP violation in e+ e- -> gamma Z with contact interactions
• CP violation in tbW couplings at the LHC
• Decay-lepton correlations as probes of anomalous ZZH and gammaZH interactions in e+e- --> ZH with polarized beams
• New physics in e+ e- -> Z gamma with polarized beams
• Charged lepton distributions as a probe of contact e+e-HZ interactions at a linear collider with polarized beams
• Space-time structure of new physics with polarized beams at the linear collider
• Two-particle kinematic distributions from new physics at an electron-positron collider with polarized beams
• Exploring the Top-Higgs FCNC Couplings at Polarized Linear Colliders with Top Spin Observables
• Physics Possibilities at a Linear Collider
• Effective fermion-Higgs interactions at an $e^{+}{e}^{-}$ collider with polarized beams