Abstract: A branching fraction measurement of the B0 -> Ds+</mml:msubsup>pi- decay is presented using proton-proton collision data collected with the LHCb experiment, corresponding to an integrated luminosity of 5.0<mml:mspace width=“0.166667em”></mml:mspace>fb-1. The branching fraction is found to be B(B0 -> Ds+</mml:msubsup>pi-)=(19.4 +/- 1.8 +/- 1.3 +/- 1.2)x10-6, where the first uncertainty is statistical, the second systematic and the third is due to the uncertainty on the B0 -> D-pi+, Ds+</mml:msubsup>-> K+K-pi+ and D--> K+pi-pi- branching fractions. This is the most precise single measurement of this quantity to date. As this decay proceeds through a single amplitude involving a b -> u charged-current transition, the result provides information on non-factorisable strong interaction effects and the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element <mml:msub>Vub. Additionally, the collision energy dependence of the hadronisation-fraction ratio <mml:msub>fs/<mml:msub>fd is measured through B<overbar></mml:mover>s0 -> Ds+pi- and B0 -> D-pi <mml:mo>+ decays.

Abstract: The inclusive b (b) over bar- and c (c) over bar -dijet production cross-sections in the forward region of pp collisions are measured using a data sample collected with the LHCb detector at a centre-of-mass energy of 13TeV in 2016. The data sample corresponds to an integrated luminosity of 1.6 fb(-1). Differential cross-sections are measured as a function of the transverse momentum and of the pseudorapidity of the leading jet, of the rapidity difference between the jets, and of the dijet invariant mass. A fiducial region for the measurement is defined by requiring that the two jets originating from the two b or c quarks are emitted with transverse momentum greater than 20 GeV/c, pseudorapidity in the range 2.2 < eta < 4.2, and with a difference in the azimuthal angle between the two jets greater than 1.5. The integrated b (b) over bar -dijet cross-section is measured to be 53.0 +/- 9.7 nb, and the total c (c) over bar -dijet cross-section is measured to be 73 +/- 16 nb. The ratio between c (c) over bar- and b (b) over bar -dijet cross-sections is also measured and found to be 1.37 +/- 0.27. The results are in agreement with theoretical predictions at next-to-leading order.

Abstract: An angular analysis of the B-0 -> K*(0)e(+)e(-) decay is performed using a data sample corresponding to an integrated luminosity of 9 fb(-1) of pp collisions collected with the LHCb experiment. The analysis is conducted in the very low dielectron mass squared (q(2)) interval between 0.0008 and 0.257 GeV2, where the rate is dominated by the B-0 -> K*(0)gamma transition with a virtual photon. The fraction of longitudinal polarisation of the K*(0) meson, F-L, is measured to be F-L = (4.4 +/- 2.6 +/- 1.4)%, where the first uncertainty is statistical and the second systematic. The A(T)(Re) observable, which is related to the lepton forward-backward asymmetry, is measured to be A(T)(Re) = -0.06 +/- 0.08 +/- 0.02. The A(T)((2)) and A(T)(Im) transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be A(T)((2)) = 0.11 +/- 0.10 +/- 0.02 and A(T)(Im) = 0.02 +/- 0.10 +/- 0.01. The results are consistent with Standard Model predictions and provide the world's best constraint on the b -> s gamma photon polarisation.

Abstract: A search for the doubly heavy Xi bc0 baryon using its decay to the D(0)pK(-) final state is performed using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment between 2016 and 2018, corresponding to an integrated luminosity of 5.4 fb(-1). No significant signal is found in the invariant mass range from 6.7 to 7.2 GeV/c(2). Upper limits are set at 95% credibility level on the ratio of the Xi bc0 production cross-section times its branching fraction to D(0)pK(-) relative to that of the Lambda b0 -> D0pK- decay. The limits are set as a function of the Xi bc0 mass and lifetime hypotheses, in the rapidity range from 2.0 to 4.5 and in the transverse momentum region from 5 to 25 GeV/c. Upper limits range from 1.7 x 10(-2) to 3.0 x 10(-1) for the considered Xi bc0 mass and lifetime hypotheses.

Abstract: The only anticipated resonant contributions to B+ -> D+D-K+ decays are charmonium states in the D+D- channel. A model-independent analysis, using LHCb proton-proton collision data taken at centerof-mass energies of root s = 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb(-1), is carried out to test this hypothesis. The description of the data assuming that resonances only manifest in decays to the D+D- pair is shown to be incomplete. This constitutes evidence for a new contribution to the decay, potentially one or more new charm-strange resonances in the D-K+ channel with masses around 2.9 GeV/c(2).