# IOP 2014 Joint HEPP & APP Group Meeting

Apr 7 – 9, 2014
Royal Holloway, University of London
Europe/London timezone
Institute of Physics 2014 Joint High Energy Particle Physics and Astro Particle Physics Groups Annual Meeting

## D mixing in multi-body decays

Apr 8, 2014, 5:15 PM
15m
Room B (Windsor Building)

### Room B

#### Windsor Building

contributed talk Flavour Physics and Beyond

### 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.

### Primary author

Samuel Thomas Harnew (University of Bristol (GB))

 Slides