B. Gaissmaier | Searcharxiv

arXiv2003

Analysis of CP Violation in Neutralino Decays to Tau Sleptons

In the minimal supersymmetric standard model, tau sleptons $\tilde τ_{1,2}$ and neutralinos $\tilde χ^0_{1,2}$ are expected to be among the lightest supersymmetric particles that can be produced copiously at future $e^+e^-$ linear colliders. We analyze $\tilde τ$ pair and $\tilde χ_1^0 \tilde χ_2^0$ production under the assumption $m_{\tilde χ_1^0} < m_{\tilde τ_1} < m_{\tilde χ_2^0}$, allowing the relevant parameters of the SUSY Lagrangian to have complex phases. We show that the transverse and normal components of the polarization vector of the $τ$ lepton produced in $\tilde χ_2^0$ decays offer sensitive probes of these phases.

hep-ph↗

arXiv2002

CP-odd phases at NLC: a project outline

Low-energy results from measurements of leptonic dipole operators are used to derive constraints on phases of the MSSM. After rediscovering older bounds on these phases, we try to investigate the impact of these possibly non-vanishing CP-odd phases on the measurement of CP-even cross-sections at the next leptonic collider.

hep-ph↗

arXiv2001

CP Violation in Tau Slepton Pair Production at Muon Colliders

We discuss in detail signals for CP violation in the Higgs boson and tau-slepton sectors through the production processes $μ^+μ^- \to \tildeτ_i^- \tildeτ_j^+$, where $i,j=1,2$ label the two $τ$ slepton mass eigenstates in the minimal supersymmetric standard model. We assume that the soft breaking parameters of third generation sfermions contain CP violating phases, which induce CP violation in the Higgs sector through quantum corrections. We classify all the observables for probing CP violation in the Higgs boson and $τ$ slepton sectors. These observables depend on the initial muon beam polarization, where we include transverse polarization states. If the heavy Higgs bosons can decay into tau slepton pairs, a complete determination of the CP properties of the neutral Higgs boson and $τ$--slepton systems is possible. The interference between the Higgs boson and gauge boson contributions could also provide a powerful method for probing CP violation, if transversely polarized muon beams are available. We show in detail how to directly measure CP violation in the tau slepton system, under the assumption that the neutral Higgs mixing angles are determined through the on--shell production of the neutral Higgs bosons.

hep-ph↗