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The results of an amplitude analysis of the charmless three-body decay B þ → π þ π þ π − , in which CP-violation effects are taken into account, are reported. The analysis is based on a data sample corresponding to an integrated luminosity of 3 fb −1 of pp collisions recorded with the LHCb detector. The most challenging aspect of the analysis is the description of the behavior of the π þ π − S-wave contribution, which is achieved by using three complementary approaches based on the isobar model, the K-matrix formalism, and a quasi-model-independent procedure. Additional resonant contributions for all three methods are described using a common isobar model, and include the ρð770Þ 0 , ωð782Þ and ρð1450Þ 0 resonances in the π þ π − P-wave, the f 2 ð1270Þ resonance in the π þ π − D-wave, and the ρ 3 ð1690Þ 0 resonance in the π þ π − F-wave. Significant CP-violation effects are observed in both Sand D-waves, as well as in the interference between the Sand P-waves. The results from all three approaches agree and provide new insight into the dynamics and the origin of CP-violation effects in B þ → π þ π þ π − decays.

Observations are reported of different sources of CP violation from an amplitude analysis of B þ → π þ π þ π − decays, based on a data sample corresponding to an integrated luminosity of 3 fb −1 of pp collisions recorded with the LHCb detector. A large CP asymmetry is observed in the decay amplitude involving the tensor f 2 ð1270Þ resonance, and in addition significant CP violation is found in the π þ π − S wave at low invariant mass. The presence of CP violation related to interference between the π þ π − S wave and the P wave B þ → ρð770Þ 0 π þ amplitude is also established; this causes large local asymmetries but cancels when integrated over the phase space of the decay. The results provide both qualitative and quantitative new insights into CP-violation effects in hadronic B decays.

The decay-time-dependent CP asymmetry in B 0 s → J/ψ K + K − decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 1.9 fb −1 , collected with the LHCb detector at a centre-ofmass energy of 13 TeV in 2015 and 2016. Using a sample of approximately 117 000 signal decays with an invariant K + K − mass in the vicinity of the φ(1020) resonance, the CP-violating phase φ s is measured, along with the difference in decay widths of the light and heavy mass eigenstatesThe values obtained are φ s = −0.083 ± 0.041 ± 0.006 rad, s = 0.077 ± 0.008 ± 0.003 ps −1 and s − d = −0.0041 ± 0.0024 ± 0.0015 ps −1 , where the first uncertainty is statistical and the second systematic. These are the most precise single measurements of these quantities to date and are consistent with expectations based on the Standard Model and with a previous LHCb analysis of this decay using data recorded at centre-of-mass energies 7 and 8 TeV. Finally, the results are combined with recent results from B 0 s → J/ψ π + π − decays obtained using the same dataset as this analysis, and with previous independent LHCb results. Detector and simulationThe LHCb detector [35,36] is a single-arm forward spectrometer covering the pseudorapidity range 2 < η < 5, designed for the study of particles containing b or c quarks. The detector includes a high-precision tracking system consisting of a silicon-strip vertex detector surrounding the pp interaction region, a large-area silicon-strip detector located upstream of a dipole magnet with a bending power of about 4 Tm, and three stations of silicon-strip detectors and straw drift tubes placed downstream of the magnet. The tracking system provides a measurement of the momentum, p,

Random access memory is an indispensable device for classical information technology. Analog to this, for quantum information technology, it is desirable to have a random access quantum memory with many memory cells and programmable access to each cell. We report an experiment that realizes a random access quantum memory of 105 qubits carried by 210 memory cells in a macroscopic atomic ensemble. We demonstrate storage of optical qubits into these memory cells and their read-out at programmable times by arbitrary orders with fidelities exceeding any classical bound. Experimental realization of a random access quantum memory with many memory cells and programmable control of its write-in and read-out makes an important step for its application in quantum communication, networking, and computation.