Speaker
Samuel Thomas Harnew
(University of Bristol (GB))
Description
Although mixing in neutral K and B systems has long been established, mixing in neutral D mesons has only recently been observed. In fact, in 2012 LHCb published the first single observation of D mixing in $D^{0}
\to K^{-}\pi^{+}$ decays.
LHCb has now collected enough data to study D mixing in multi-body D decays such as $D^{0} \to K^{+}\pi^{-}\pi^{0}$ and $D^{0} \to K^{+}\pi^{-}\pi^{+}\pi^{-}$. Whilst these decay modes do not necessarily provide as much sensitivity to mixing, they provide us with another exciting opportunity.
D mixing results in a time dependent superposition of $D^{0}$ and $\bar{D}^{0}$ states. This superposition is defined by the dimensionless mixing parameters $x$ and $y$. With knowledge of $x$ and $y$ from other analyses, we can now use D mixing to investigate the interference effects betweek $D^{0}$ and $\bar{D}^{0}$ amplitudes, including information on their relative phase.
In particular, one can constrain the coherence factor, $R_{K\pi\pi\pi}$, and average strong phase difference $\delta_{ K \pi\pi\pi }$. These two parameters provide important input to extracting the CP violating phase $\gamma$ in $B^{\pm}\to DK^{\pm}$ decays.
Author
Samuel Thomas Harnew
(University of Bristol (GB))
