CP Violating Anomalous Couplings at a 500 GeV e+ e- Linear Collider

Abstract

We study the sensitivity of a 500 GeV $e^+e^-$ Linear Collider to $CP$ violating anomalous couplings. We find that with 50~fb$^{-1}$, and taking only one non-zero coupling at a time, the process $e^+e^-\to W^+ W^-$ can be used to place the 95% confidence level bounds $|\tilde\kappa_\gamma|\leq0.1$, $|\tilde\kappa_Z|\leq 0.1$ and $|g_4^Z|\leq 0.1$ from CP even observables. By studying certain distributions in the process $e^+e^-\to \mu^+\mu^-\nu\bar{\nu}$ one of the bounds can be improved to $|g_4^Z| \leq 0.06$. This process also allows the construction of a CP odd observable which can be used to place bounds on CP violating new physics. At the 95% confidence level we find $|\tilde\kappa_\gamma|\leq 0.3$, $|\tilde\kappa_Z|\leq 0.2$ and a much weaker bound for $|g_4^Z|$.