The oscillation frequency, Formula: see text, of Formula: see text mesons is measured using semileptonic decays with a Formula: see text or Formula: see text meson in the final state. The data sample ...corresponds to 3.0Formula: see text of
collisions, collected by the LHCb experiment at centre-of-mass energies Formula: see text = 7 and 8Formula: see text. A combination of the two decay modes gives Formula: see text, where the first uncertainty is statistical and the second is systematic. This is the most precise single measurement of this parameter. It is consistent with the current world average and has similar precision.
The production of the Formula: see text state in proton-proton collisions is probed via its decay to the Formula: see text final state with the LHCb detector, in the rapidity range Formula: see text ...and in the meson transverse-momentum range Formula: see text. The cross-section for prompt production of Formula: see text mesons relative to the prompt Formula: see text cross-section is measured, for the first time, to be Formula: see text at a centre-of-mass energy Formula: see text using data corresponding to an integrated luminosity of 0.7 fbFormula: see text, and Formula: see text at Formula: see text using 2.0 fbFormula: see text. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the Formula: see text and Formula: see text decays to the Formula: see text final state. In addition, the inclusive branching fraction of Formula: see text-hadron decays into Formula: see text mesons is measured, for the first time, to be Formula: see text, where the third uncertainty includes also the uncertainty on the Formula: see text inclusive branching fraction from Formula: see text-hadron decays. The difference between the Formula: see text and Formula: see text meson masses is determined to be Formula: see text.
The resonant substructure of B(s)(0) → D(0)K(-)π(+) decays is studied using a data sample corresponding to an integrated luminosity of 3.0 fb(-1) of pp collision data recorded by the LHCb detector. ...An excess at m(D(0)K(-))≈ 2.86 GeV/c(2) is found to be an admixture of spin-1 and spin-3 resonances. Therefore, the D(sJ)*(2860)(-) state previously observed in inclusive e(+)e(-) → D(0)K(-)X and pp → D(0)K(-)X processes consists of at least two particles. This is the first observation of a heavy flavored spin-3 resonance, and the first time that any spin-3 particle has been seen to be produced in B decays. The masses and widths of the new states and of the D(s2)*(2573)(-) meson are measured, giving the most precise determinations to date.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract A measurement of the inclusive W arrow right muν production cross-section using data from pp collisions at a ...centre-of-mass energy of ... TeV is presented. The analysis is based on an integrated luminosity of about 1.0 fb-1 recorded with the LHCb detector. Results are reported for muons with a transverse momentum greater than 20 GeV/c and pseudorapidity between 2.0 and 4.5. The W + and W - production cross-sections are measured to be ... ... where the first uncertainty is statistical, the second is systematic and the third is due to the luminosity determination. Cross-section ratios and differential distributions as functions of the muon pseudorapidity are also presented. The ratio of W + to W - cross-sections in the same fiducial kinematic region is determined to be ... where the uncertainties are statistical and systematic, respectively. Results are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. Figure not available: see fulltext.
The ratio of the B_{s}^{0} and B^{+} fragmentation fractions f_{s} and f_{u} is studied with B_{s}^{0}→J/ψϕ and B^{+}→J/ψK^{+} decays using data collected by the LHCb experiment in proton-proton ...collisions at 7, 8, and 13 TeV center-of-mass energies. The analysis is performed in bins of B-meson momentum, longitudinal momentum, transverse momentum, pseudorapidity, and rapidity. The fragmentation-fraction ratio f_{s}/f_{u} is observed to depend on the B-meson transverse momentum with a significance of 6.0σ. This dependency is driven by the 13 TeV sample (8.7σ), while the results for the other collision energies are not significant when considered separately. Furthermore, the results show a 4.8σ evidence for an increase of f_{s}/f_{u} as a function of collision energy.
A measurement of the time-dependent CP-violating asymmetry in Bs0→ϕϕ\ {B}_s^0\to \phi \phi \ decays is presented. Using a sample of proton-proton collision data corresponding to an integrated ...luminosity of 5.0 fb−1 collected by the LHCb experiment at centre-of-mass energies s\ \sqrt{s} \ = 7 TeV in 2011, 8 TeV in 2012 and 13 TeV in 2015 and 2016, a signal yield of around 9000 Bs0→ϕϕ\ {B}_s^0\to \phi \phi \ decays is obtained. The CP-violating phase ϕsss¯s\ {\phi}_s^{s\overline{s}s} \ is measured to be −0.073 ± 0.115(stat) ± 0.027(syst) rad, under the assumption it is independent of the helicity of the ϕϕ decay. In addition, the CP-violating phases of the transverse polarisations under the assumption of CP conservation of the longitudinal phase are measured. The helicity-independent direct CP-violation parameter is also measured, and is found to be |λ| = 0.99 ± 0.05(stat) ± 0.01(syst). In addition, T-odd triple-product asymmetries are measured. The results obtained are consistent with the hypothesis of CP conservation in b¯→s¯ss¯s\ \overline{b}\to \overline{s}s\overline{s}s \ transitions. Finally, a limit on the branching fraction of the B0 → ϕϕ decay is determined to be BB0→ϕϕ<2.7×10−8\ \mathcal{B}\left({B}^0\to \phi \phi \right)<2.7\times {10}^{-8} \ at 90 % confidence level.
Using proton-proton collision data, collected with the LHCb detector and corresponding to 1.0, 2.0 and 1.9 fb−1 of integrated luminosity at the centre-of-mass energies of 7, 8, and 13 TeV, ...respectively, the decay Λb0→χc1\ {\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}1} \(3872)pK− with χc1(3872) → J/ψ π+π− is observed for the first time. The significance of the observed signal is in excess of seven standard deviations. It is found that (58 ± 15)% of the decays proceed via the two-body intermediate state χc1(3872)Λ(1520). The branching fraction with respect to that of the Λb0\ {\Lambda}_{\mathrm{b}}^0 \ → ψ(2S)pK− decay mode, where the ψ(2S) meson is reconstructed in the J/ψ π+π− final state, is measured to be:βΛb0→χc13872pK−βΛb0→ψ2SpK−×βχc13872→J/ψπ+π−βψ2S→J/ψπ+π−=5.4±1.1±0.2×10−2,\ \frac{\beta \left({\Lambda}_{\mathrm{b}}^0\to {\upchi}_{\mathrm{c}1}(3872){\mathrm{pK}}^{-}\right)}{\beta \left({\Lambda}_{\mathrm{b}}^0\to \uppsi \left(2\mathrm{S}\right){\mathrm{pK}}^{-}\right)}\times \frac{\beta \left({\upchi}_{\mathrm{c}1}(3872)\to \mathrm{J}/\uppsi {\uppi}^{+}{\uppi}^{-}\right)}{\beta \left(\uppsi \left(2\mathrm{S}\right)\to \mathrm{J}/\uppsi {\uppi}^{+}{\uppi}^{-}\right)}=\left(5.4\pm 1.1\pm 0.2\right)\times {10}^{-2}, \where the first uncertainty is statistical and the second is systematic.
A time-dependent analysis of the B_{s}^{0}→ϕγ decay rate is performed to determine the CP -violating observables S_{ϕγ} and C_{ϕγ} and the mixing-induced observable A_{ϕγ}^{Δ}. The measurement is ...based on a sample of pp collision data recorded with the LHCb detector, corresponding to an integrated luminosity of 3 fb^{-1} at center-of-mass energies of 7 and 8 TeV. The measured values are S_{ϕγ}=0.43±0.30±0.11, C_{ϕγ}=0.11±0.29±0.11, and A_{ϕγ}^{Δ}=-0.67_{-0.41}^{+0.37}±0.17, where the first uncertainty is statistical and the second systematic. This is the first measurement of the observables S and C in radiative B_{s}^{0} decays. The results are consistent with the standard model predictions.
The radiative decay Λ_{b}^{0}→Λγ is observed for the first time using a data sample of proton-proton collisions corresponding to an integrated luminosity of 1.7 fb^{-1} collected by the LHCb ...experiment at a center-of-mass energy of 13 TeV. Its branching fraction is measured exploiting the B^{0}→K^{*0}γ decay as a normalization mode and is found to be B(Λ_{b}^{0}→Λγ)=(7.1±1.5±0.6±0.7)×10^{-6}, where the quoted uncertainties are statistical, systematic, and systematic from external inputs, respectively. This is the first observation of a radiative decay of a beauty baryon.
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