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The dependence of the electrochemical characteristics of layered cathode materials LiNi x Mn y Co z O 2 (0.4 ≤ x ≤ 0.6; y = 0.2, 0.3; z = 0.2, 0.4) on the method of applying a protective layer of nanoparticles of lithium-conductive material Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 with NASICON structure onto their surface has been investigated. It is shown that the surface modification reduces the capacity fading during prolonged charge/discharge cycling (up to 15%) and improves the suitability for fast charge/discharge processes.

A bstract Measurements are reported of the central exclusive production of J/ψ and ψ (2 S ) mesons in pp collisions at a centre-of-mass energy of 13 TeV. Backgrounds are significantly reduced compared to previous measurements made at lower energies through the use of new forward shower counters. The products of the cross-sections and the branching fractions for the decays to dimuons, where both muons are within the pseudorapidity range 2 . 0 < η < 4 . 5, are measured to be σ J / ψ → μ + μ − = 435 ± 18 ± 11 ± 17 p b σ ψ 2 S → μ + μ − = 11.1 ± 1.1 ± 0.3 ± 0.4 p b . The first uncertainties are statistical, the second are systematic, and the third are due to the luminosity determination. The cross-sections are also measured differentially for meson rapidities between 2.0 and 4.5. Good agreement is observed with theoretical predictions. Photoproduction cross-sections are derived and compared to previous experiments, and a deviation from a pure power-law extrapolation of lower energy data is observed.

A bstract A measurement of the Ξ cc + + mass is performed using data collected by the LHCb experiment between 2016 and 2018 in pp collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5 . 6 fb − 1 . The Ξ cc + + candidates are reconstructed via the decay modes Ξ cc + + → Λ c + K − π + π + and Ξ cc + + → Ξ c + π + . The result, 3621 . 55 ± 0 . 23 (stat) ± 0 . 30 (syst) MeV/ c 2 , is the most precise measurement of the Ξ cc + + mass to date.

A bstract A precision measurement of the B c + meson mass is performed using proton- proton collision data collected with the LHCb experiment at centre-of-mass energies of 7 , 8 and 13 TeV, corresponding to a total integrated luminosity of 9 . 0 fb − 1 . The B c + mesons are reconstructed via the decays B c + → J/ψπ + , B c + → J/ψπ + π − π + , B c + → J / ψp p ¯ π + , B c + → J / ψ D s + , B c + → J/ψ D 0 K + and B c + → B s 0 π + . Combining the results of the individual decay channels, the B c + mass is measured to be 6274 . 47 ± 0 . 27 (stat) ± 0 . 17 (syst) MeV /c 2 . This is the most precise measurement of the B c + mass to date. The difference between the B c + and B s 0 meson masses is measured to be 907 . 75 ± 0 . 37 (stat) ± 0 . 27 (syst) MeV /c .

A bstract A search is presented for the lepton flavour violating decay B + → K + μ − τ + using a sample of proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV, collected with the LHCb detector and corresponding to a total integrated luminosity of 9 fb − 1 . The τ leptons are selected inclusively, primarily via decays with a single charged particle. The four-momentum of the τ lepton is determined by using B + mesons from B s 2 ∗ 0 → B + K − decays. No significant excess is observed, and an upper limit is set on the branching fraction ℬ( B +  →  K + μ − τ + ) < 3.9 × 10 −5  at 90 %  confidence level. The obtained limit is comparable to the world-best limit.

A bstract The production of B ± mesons is studied in pp collisions at centre-of-mass energies of 7 and 13 TeV, using B ± → J / ψ K ± decays and data samples corresponding to 1.0 fb −1 and 0.3 fb −1 , respectively. The production cross-sections summed over both charges and integrated over the transverse momentum range 0 < p T < 40 GeV/ c and the rapidity range 2.0 < y < 4.5 are measured to be σ pp → B ± X , s = 7 T e V = 43.0 ± 0.2 ± 2.5 ± 1.7 μ b , σ pp → B ± X , s = 13 T e V = 86.6 ± 0.5 ± 5.4 ± 3.4 μ b , where the first uncertainties are statistical, the second are systematic, and the third are due to the limited knowledge of the B ± → J / ψ K ± branching fraction. The ratio of the cross-section at 13 TeV to that at 7 TeV is determined to be 2.02 ± 0.02 (stat) ± 0.12 (syst). Differential cross-sections are also reported as functions of p T and y . All results are in agreement with theoretical calculations based on the state-of-art fixed next-to-leading order quantum chromodynamics.

A search for the doubly charmed baryon Ξ c c + is performed through its decay to the Λ c + K − π + final state, using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. The data correspond to a total integrated luminosity of 9 fb −1 . No significant signal is observed in the mass range from 3.4 to 3.8 GeV/ c 2 . Upper limits are set at 95% credibility level on the ratio of the Ξ c c + production cross-section times the branching fraction to that of Λ c + and Ξ c c + + baryons. The limits are determined as functions of the Ξ c c + mass for different lifetime hypotheses, in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/ c .

The decay-time-dependent CP asymmetry in Bs0→J/ψK+K- decays is measured using proton–proton collision data, corresponding to an integrated luminosity of 1.9fb-1, collected with the LHCb detector at a centre-of-mass energy of 13TeV 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 ϕs is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the Bs0-B¯s0 system, ΔΓs. The difference of the average Bs0 and B0 meson decay widths, Γs-Γd, is determined using in addition a sample of B0→J/ψK+π- decays. The values obtained are ϕs=-0.083±0.041±0.006rad, ΔΓs=0.077±0.008±0.003ps-1 and Γs-Γd=-0.0041±0.0024±0.0015ps-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 Bs0→J/ψπ+π- decays obtained using the same dataset as this analysis, and with previous independent LHCb results.

A bstract This paper presents an analysis of the Λ b 0 → J/ψ Λ angular distribution and the transverse production polarisation of Λ b 0 baryons in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The measurements are performed using data corresponding to an integrated luminosity of 4.9 fb − 1 , collected with the LHCb experiment. The polarisation is determined in a fiducial region of Λ b 0 transverse momentum and pseudorapidity of 1 < p T < 20 GeV/ c and 2 < η < 5, respectively. The data are consistent with Λ b 0 baryons being produced unpolarised in this region. The parity-violating asymmetry parameter of the Λ → pπ − decay is also determined from the data and its value is found to be consistent with a recent measurement by the BES III collaboration.

A bstract A new baryon state is observed in the Λ b 0 π + π − mass spectrum with high significance using a data sample of pp collisions, collected with the LHCb detector at centre-of-mass energies s = 7 , 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb − 1 . The mass and natural width of the new state are measured to be m = 6072.3 ± 2.9 ± 0.6 ± 0.2 MeV , Γ = 72 ± 11 ± 2 MeV , where the first uncertainty is statistical and the second systematic. The third uncertainty for the mass is due to imprecise knowledge of the Λ b 0 baryon mass. The new state is consistent with the first radial excitation of the Λ b 0 baryon, the Λ b (2S) 0 resonance. Updated measurements of the masses and the upper limits on the natural widths of the previously observed Λ b (5912) 0 and Λ b (5920) 0 states are also reported.