Studies of charmed states in amplitude analyses at LHCb

Amplitude analysis is a powerful tool to study the properties of intermediate resonances produced in the decays of B mesons. At LHCb we have studied B+ decays to X(3872) K+, where X(3872) decays to J/psi pi+ pi-, to determine the quantum numbers of the X(3872), and B+ decays to proton anti-proton K+ to learn more about (charm anti-charm) to proton anti-proton transitions. We also exploit the spin of the J/psi to perform amplitude analyses of the decays B0_s to J/psi pi+ pi-, B0_s to J/psi K+ K-, B0 to J/psi pi+ pi-, and B0 to J/psi K+ K-. Our results use 1.0 inverse femtobarn of data taken in 2011 from 7 TeV proton-proton collisions, provided by the LHC.Comment: 9 pages, 3 figures, to appear in the proceedings of The 6th International Workshop on Charm Physics (CHARM 2013

Searches for CP Violation in charm at LHCb

LHCb has collected the world's largest sample of charmed hadrons. This sample is used to search for direct and indirect CP Violation in charm. Recent and updated measurements from several decay modes are presented.Comment: To be published in the proceedings of CHARM-2015, Detroit, MI, 18-22 May 201

Novel sources of correlated D0D‾0{{{D}^{0}}{\overline{{D}}{}^{0}}} for c/b{c/b} physics and tests of T/CPT{T/CPT}

Decays of charmonia(-like) particles with definite $J^{PC}$ (e.g. ${{\chi_{c{\rm 1}}}(3872)}$), to a ${{D}^{0}}{\overline{{D}}{}^{0}}$ system and any combination of $C$-definite decay particles, are sources of quantum-correlated ${{D}^{0}}{\overline{{D}}{}^{0}}$ systems with $C = P = \pm 1$. Several $b$-hadron decays also produce ${{D}^{0}}{\overline{{D}}{}^{0}}$ systems, which may be quantum-correlated or isolated in a $C = \pm 1$ component. Methods to separate the $C = \pm 1$ ${{D}^{0}}{\overline{{D}}{}^{0}}$ components from ${{\chi_{c{\rm 1}}}(3872)}$ decay samples are presented. Studying $T$ and $CPT$ conservation in $C = +1$ ${{D}^{0}}{\overline{{D}}{}^{0}}$ systems allows a final state reconstructibility advantage. Several production mechanisms offering opportunities to collect $C = \pm 1$ ${{D}^{0}}{\overline{{D}}{}^{0}}$ systems are described.Comment: 40 pages, 6 figure

Rare Strange and Charm Decays at LHCb

Thanks to the large cross-section for the production of strange and charm mesons at the Large Hadron Collider, LHCb has recently performed several new explorations of rare transitions that are highly suppressed or forbidden by the Standard Model: mostly flavour changing neutral current decays, but also lepton flavour violating decays. Physics beyond the Standard Model could contribute at tree and loop levels.Comment: Presented at the 12th Workshop on the CKM Unitarity Triangle, 18-22 September 2023, Santiago de Compostel

Model-independent determination of the strong phase difference between D0D^0 and Dˉ0→π+π−π+π−\bar{D}^0 \to\pi^+\pi^-\pi^+\pi^- amplitudes

For the first time, the strong phase difference between $D^0$ and $\bar{D}^0\to\pi^+\pi^-\pi^+\pi^-$ amplitudes is determined in bins of the decay phase space. The measurement uses $818\,\mathrm{pb}^{-1}$ of $e^+e^-$ collision data that is taken at the $\psi(3770)$ resonance and collected by the CLEO-c experiment. The measurement is important for the determination of the $C P$-violating phase $\gamma$ in $B^{\pm}\to D K^{\pm}$ (and similar) decays , where the $D$ meson (which represents a superposition of $D^0$ and $\bar{D}^0$) subsequently decays to $\pi^+\pi^-\pi^+\pi^-$. To obtain optimal sensitivity to $\gamma$, the phase space of the $D \to \pi^+\pi^-\pi^+\pi^-$ decay is divided into bins based on a recent amplitude model of the decay. Although an amplitude model is used to define the bins, the measurements obtained are model-independent. The $CP$-even fraction of the $D \to \pi^+\pi^-\pi^+\pi^-$ decay is determined to be $F_{+}^{4\pi} = 0.769 \pm 0.021 \pm 0.010$, where the uncertainties are statistical and systematic, respectively. Using simulated $B^{\pm}\to D K^{\pm}, D \to \pi^+\pi^-\pi^+\pi^-$ decays, it is estimated that by the end of the current LHC run, the LHCb experiment could determine $\gamma$ from this decay mode with an uncertainty of $(\pm10\pm7)^\circ$, where the first uncertainty is statistical based on estimated LHCb event yields, and the second is due to the uncertainties on the parameters determined in this paper