CP Violation in Correlated Production and Decay of Unstable Particles

Abstract

We study resonant CP-violating Einstein--Podolsky--Rosen correlations that may take place in the production and decay of unstable scalar particles at high-energy colliders. We show that as a consequence of unitarity and CPT invariance of the S-matrix, in 2 --> 2 scatterings mediated by mixed scalar particles, at least three linearly independent decay matrices associated with the unstable scalar states are needed to obtain non-zero CP-odd observables that are also odd under C-conjugation. Instead, for the correlated production and decay of two unstable particle systems in 2 --> 4 processes, we find that only two independent decay matrices are sufficient to induce a net non-vanishing CP-violating phenomenon. As an application of this theorem, we present numerical estimates of CP asymmetries for the correlated production and decay of supersymmetric scalar top--anti-top pairs at the LHC, and demonstrate that these could reach values of order one. As a byproduct of our analysis, we develop a novel spinorial trace technique, which enables us to efficiently evaluate lengthy expressions of squared amplitudes describing the resonant scalar transitions.

19 pages, 6 figures, version to appear in NPB, comment on the accessibility of the asymmetry at the LHC added, references added

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Cited by in corpus (10)

• Heavy Scalar Top Quark Decays in the Complex MSSM: A Full One-Loop Analysis
• Nearly degenerate heavy sterile neutrinos in cascade decay: mixing and oscillations
• Heavy Scalar Tau Decays in the Complex MSSM: A Full One-Loop Analysis
• Space-time evolution of heavy sterile neutrinos in cascade decays
• Some exact results on CP and CPT violations in a $C=-1$ entangled pseudoscalar neutral meson pair
• Comparison of neutralino and sneutrino dark matter in a model with spontaneous CP violation
• CP and CPT Violating Parameters Determined from the Joint Decays of $C=+1$ Entangled Neutral Pseudoscalar Mesons
• Momentum asymmetries as CP violating observables
• Effective field theory of particle mixing
• Field mixing in a thermal medium: A quantum master equation approach