The standard model of particle physics currently provides our best description of fundamental particles and their interactions. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Previous measurements have shown that a wide range of particle decays are consistent with this principle of lepton universality. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton–proton collision data collected with the LHCb detector at CERN’s Large Hadron Collider. The measurements are of processes in which a beauty meson transforms into a strange meson with the emission of either an electron and a positron, or a muon and an antimuon. If confirmed by future measurements, this violation of lepton universality would imply physics beyond the standard model, such as a new fundamental interaction between quarks and leptons.

A combination of measurements sensitive to the CKM angle γ from LHCb is performed. The inputs are from analyses of time-integrated B + → DK + , B 0 → DK * 0 , B 0 → DK + π − and B + → DK + π + π − tree-level decays. In addition, results from a time-dependent analysis of B 0 s → D ∓ s K ± decays are included. The combination yields γ = (72.2 +6.8 −7.3 ) • , where the uncertainty includes systematic effects. The 95.5% confidence level interval is determined to be γ ∈ [55.9, 85.2] • . A second combination is investigated, also including measurements from B + → Dπ + and B + → Dπ + π − π + decays, which yields compatible results.

In the original paper Phys. Rev. D 95, 052004 (2017), "Measurements of charm mixing and CP violation using D 0 → K AE π ∓ decays," the systematic uncertainties reported in Table II regarding the doubly tagged (DT) only result for ðx 0þ Þ 2 and y 0þ were swapped in both the "no direct CPV" and "all CPV allowed" fits. All other reported values are correct. The corrected table is shown below in Table II.

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The production of J=ψ mesons in jets is studied in the forward region of proton-proton collisions using data collected with the LHCb detector at a center-of-mass energy of 13 TeV. The fraction of the jet transverse momentum carried by the J=ψ meson, zðJ=ψÞ ≡ p T ðJ=ψÞ=p T ðjetÞ, is measured using jets with p T ðjetÞ > 20 GeV in the pseudorapidity range 2.5 < ηðjetÞ < 4.0. The observed zðJ=ψÞ distribution for J=ψ mesons produced in b-hadron decays is consistent with expectations. However, the results for prompt J=ψ production do not agree with predictions based on fixed-order nonrelativistic QCD. This is the first measurement of the p T fraction carried by prompt J=ψ mesons in jets at any experiment.