Abstract: The doubly Cabibbo- suppressed decay Xi(+)(c) -> p phi with ! K+K is observed for the fi rst time, with a statistical signi fi cance of more than fi fteen standard deviations. The data sample used in this analysis corresponds to an integrated luminosity of 2 fb recorded with the LHCb detector in pp collisions at a centre- of- mass energy of 8TeV. The ratio of branching fractions between the decay + c ! p and the singly Cabibbo- suppressed decay + c ! pK is measured to be B (Xi(+)(c) -> p phi) B (Xi(+)(c) -> p phi) = (19 : 8 0 : 7 0 : 9 0 : 2) 10 where the fi rst uncertainty is statistical, the second systematic and the third due to the knowledge of the Xi(+)(c) -> pK(+)pi(+) branching fraction.

Abstract: The first untagged decay-time-integrated amplitude analysis of B 0 s ! K 0 S K decays is performed using a sample corresponding to 3: 0 fb of pp collision data recorded with the LHCb detector during 2011 and 2012. The data are described with an amplitude model that contains contributions from the intermediate resonances K 9892) 0;+, K 2 91430) 0;+ and K 0 91430) 0;+, and their charge conjugates. Measurements of the branching fractions of the decay modes B 0 s ! K 9892) K and B 0 s ! K 9892) 0 K 0 are in agreement with, and more precise than, previous results. The decays B 0 s ! K 0 91430) K and B 0 s ! K 0 91430) 0 K 0 are observed for the fi rst time, each with signi fi cance over 10 standard deviations.

Abstract: Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb, collected with the LHCb detector between 2011 and 2018, a new narrow charmonium state, the X(3842) resonance, is observed in the decay modes X(3842) ! D0 D 0 and X(3842) ! D+D. The mass and the natural width of this state are measured to be where the fi rst uncertainty is statistical and the second is systematic. The observed mass and narrow natural width suggest the interpretation of the new state as the unobserved spin-3 3 1 3 D 3 charmonium state. In addition, prompt hadroproduction of the (3770) and 2 (3930) states is observed for the fi rst time, and the parameters of these states are measured to be m (3770) = 3778 : 1 0 : 7 0 : 6MeV where the first uncertainty is statistical and the second is systematic.

Abstract: A search for the rare leptonic decay B +. μ+ μ- μ+.mu is performed using proton- proton collision data corresponding to an integrated luminosity of 4.7 fb – 1 collected by the LHCb experiment. The search is carried out in the region where the lowest of the two μ+ μ- mass combinations is below 980 MeV/ c2. The data are consistent with the background- only hypothesis and an upper limit of 1.6x10 – 8 at 95% confidence level is set on the branching fraction in the stated kinematic region.

Abstract: The decay-time-dependent CP asymmetry in B0 s. J/. 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 f( 1020) resonance, the CP-violating phase fs is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the B0 s-B0s system, s. The difference of the average B0 s and B0 meson decay widths, s-d, is determined using in addition a sample of B0. J/. K + p-decays. The values obtained are fs =-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 B0 s. J/. p + p-decays obtained using the same dataset as this analysis, and with previous independent LHCb results.