Search for the doubly heavy baryon <i>Ξ⁺_bc</i> decaying to<i> J|ΨΞ⁺_c^*</i>

A first search for the ?bc+ ? J/??c+ decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9 fb-1 recorded at centre-of-mass energies of 7, 8, and 13 TeV. Two peaking structures are seen with a local (global) significance of 4.3(2.8) and 4.1(2.4) standard deviations at masses of 6571 and 6694 MeV/c2, respectively. Upper limits are set on the ?bc+ baryon production cross-section times the branching fraction relative to that of the B+c ? J/?D+s decay at centre-of-mass energies of 8 and 13 TeV, in the ?bc+ and in the B+c rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to 20 GeV/c, respectively. Upper limits are presented as a function of the ?bc+ mass and lifetime

Search for CP violation using T ^ -odd correlations in B⁰ → pp¯ K⁺Π^- decays

A search for CP and P violation in charmless four-body B0?pp¯K+p- decays is performed using triple-product asymmetry observables. It is based on proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 8.4 fb-1. The CP- and P-violating asymmetries are measured both in the integrated phase space and in specific regions. No evidence is seen for CP violation. P-parity violation is observed at a significance of 5.8 standard deviations

Measurement of lepton universality parameters in B+ ?k+l+l- and B0 ?k*0l+l- decays

A simultaneous analysis of the B+?K+l+l- and B0?K*0l+l- decays is performed to test muon-electron universality in two ranges of the square of the dilepton invariant mass, q2. The measurement uses a sample of beauty meson decays produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb-1. A sequence of multivariate selections and strict particle identification requirements produce a higher signal purity and a better statistical sensitivity per unit luminosity than previous LHCb lepton universality tests using the same decay modes. Residual backgrounds due to misidentified hadronic decays are studied using data and included in the fit model. Each of the four lepton universality measurements reported is either the first in the given q2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model

Measurement of the mass difference and relative production rate of the ?b- and ?b- baryons

The mass difference between the ?b- and ?b- baryons is measured using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb-1, and is found to be m(?b-)-m(?b-)=248.54±0.51(stat)±0.38(syst) MeV/c2. The mass of the ?b- baryon is measured to be m(?b-)=6045.9±0.5(stat)±0.6(syst) MeV/c2. This is the most precise determination of the ?b- mass to date. In addition, the production rate of ?b- baryons relative to that of ?b- baryons is measured for the first time in pp collisions, using an LHCb dataset collected at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 6 fb-1. Reconstructing beauty baryons in the kinematic region 2&lt;?&lt;6 and pT&lt;20 GeV/c with their decays to a J/? meson and a hyperon, the ratio f?b-f?b-×B(?b-?J/??-)B(?b-?J/??-)=0.120±0.008(stat)±0.008(syst), is obtained, where f?b- and f?b- are the fragmentation fractions of b quarks into ?b- and ?b- baryons, respectively, and B represents the branching fractions of their respective decays

Identification of charm jets at LHCb

The identification of charm jets is achieved at LHCb for data collected in 2015-2018 using a method based on the properties of displaced vertices reconstructed and matched with jets. The performance of this method is determined using a dijet calibration dataset recorded by the LHCb detector and selected such that the jets are unbiased in quantities used in the tagging algorithm. The charm-tagging efficiency is reported as a function of the transverse momentum of the jet. The measured efficiencies are compared to those obtained from simulation and found to be in good agreement