Observation of $CP$ violation in $B^0\to J/\psi \rho (770{)}^0$ decays

Abstract

The time-dependent $CP$ asymmetry in $B^0\to J/\psi \rho (770{)}^0$ decays is measured using proton-proton collision data corresponding to an integrated luminosity of $6{\text{fb}}^{-1}$, collected with the LHCb detector at a center-of-mass energy of $13\text{TeV}$ during the years 2015-2018. The $CP$-violation parameters for this process are determined to be $2{\beta }_{c\bar{c}d}^{\mathrm{eff}}=0.710\pm 0.084\pm 0.051\text{rad}$ and $|\lambda |=1.019\pm 0.034\pm 0.024$, where the first uncertainty is statistical and the second systematic. This constitutes the first observation of time-dependent $CP$ violation in $B^0\to J/\psi \rho (770{)}^0$ decays. Assuming approximate SU(3) flavor symmetry, these results are combined with the previous consistent LHCb measurement to set the most stringent constraint on the penguin contribution, $\Delta {\varphi }_s$, to the $CP$-violating phase ${\varphi }_s$ in $B_s^0\to J/\psi \varphi (1020)$ decays, yielding $\Delta {\varphi }_s=5.0\pm 4.6\text{mrad}$.

All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://lbfence.cern.ch/alcm/public/analysis/full-details/1620/ (LHCb public pages)

References in corpus (16)

• PYTHIA 6.4 Physics and Manual
• Current status of the Standard Model CKM fit and constraints on $\Delta F=2$ New Physics
• Opposite-side flavour tagging of B mesons at the LHCb experiment
• Measurement of the CP-violating phase $\beta$ in $B^0\to J/\psi {\pi }^{+}{\pi }^{-}$ decays and limits on penguin effects
• A Roadmap to Control Penguin Effects in $B_d^0\to J/\psi K_{\mathrm{S}}^0$ and $B_s^0\to J/\psi \varphi$
• The mass of the sigma pole
• Measurement of the $CP$-violating phase ${\varphi }_s$ in $B_s^0\to J/\psi \varphi$ decays in ATLAS at 13 TeV
• Parameter uncertainties in weighted unbinned maximum likelihood fits
• In Pursuit of New Physics with $B_d^0\to J/\psi K^0$ and $B_s^0\to J/\psi \varphi$ Decays at the High-Precision Frontier
• Search for time-dependent $CP$ violation in $D^0\to K^{+}{K}^{-}$ and $D^0\to {\pi }^{+}{\pi }^{-}$ decays
• Time-dependent Dalitz-plot formalism for B_q -> J/ψ h+ h-
• Measurement of CP violation in $B^0\to \psi (\to {\ell }^{+}{\ell }^{-})K_S^0(\to {\pi }^{+}{\pi }^{-})$ decays
• Improved measurement of $CP$ violation parameters in $B_s^0\to J/\psi K^{+}{K}^{-}$ decays in the vicinity of the $\varphi (1020)$ resonance
• How to tame penguins: Advancing to high-precision measurements of ${\varphi }_d$ and ${\varphi }_s$
• Observation of time-dependent $CP$ violation and measurement of the branching fraction of $B^0\to J/\psi {\pi }^0$ decays
• First evidence for mixing-induced $CP$ violation in B${}_{\mathrm{s}}^0$ $\to$ J/$\psi \varphi$(1020) decays in pp collisions at $\sqrt{s}=$ 13 TeV