CP-violating scattering processes in the minimal supersymmetric standard model

2012

Nuclear Physics B

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-antitop 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.

Section: Beyond the Two-particle Mixingmentioning

confidence: 58%

“…It now proves useful to define the Hermitian matrix 12) for the production vertex, including an analogous definition T βγ B for the decay vertex. In terms of these matrices, the squared amplitude for the s-channel resonant process A → S α → B takes on the simple form:…”

Section: Formalism For Scalar Particle Mixingmentioning

confidence: 99%

CP violation in correlated production and decay of unstable particles

Kittel

2012

Nuclear Physics B

“…This is also evident from (2.6) and (2.7). Writing the fields Φ 1 and Φ 2 in the form 9) and collecting quadratic terms in the components of Φ i we get, after diagonalizing the mass matrices, the following mass eigenstates 12) where sin x ≡ s x and cos x ≡ c x . In eq.…”

Section: The Cp-violating Two-higgs Doublet Modelmentioning

confidence: 99%

“…Usually, such phases arise from the calculation of absorptive parts of higher order diagrams [11]. Here, we do that in an effective way by introducing complex BW propagators for the Higgs bosons similar to [12]. We, of course, assume that at least one of the Higgs masses is bigger than 2m t .…”

Section: The Cp-violating Two-higgs Doublet Modelmentioning

confidence: 99%

See 1 more Smart Citation

CP-ODD NEUTRAL HIGGS EFFECTS IN $t\bar t$ PRODUCTION

Nowakowski

1994

Int. J. Mod. Phys. A

Self Cite

We study CP violation in the process e + e − → ttνν at an e + e − -TeV collider. As the source of CP violation we assume a two-Higgs doublet model with an explicitly CP -noninvariant Higgs potential. Sizeable CP -odd observables originating from the subprocess reaction, W + W − → tt, may arise as a result of finite width effects of the neutral Higgs particles. CP T constraints due to final (initial) state interactions are also taken into account. Numerical estimates of the CP asymmetry are given. *

On gauge invariance of Breit-Wigner propagators

Nowakowski

Z. Phys. C - Particles and Fields

1993

Self Cite

We present an approach to bosonic (Z 0 , W ± ) as well as fermionic (top-quark) Breit-Wigner propagators which is consistent with gauge invariance arguments. In particular, for the Z 0 -boson propagator we extend previous analyses and show that the part proportional to k µ k ν /M 2 must be modified near the resonance. We derive a mass shift which agrees with results obtained elsewhere by different methods. The modified form of a resonant heavy fermion propagator is also given.