Abstract The decay-time-dependent $$CP$$ CP asymmetry in $${{B} ^0_{s}} \rightarrow J/\psi {{K} ^+} {{K} ^-} $$ Bs0→J/ψK+K- decays is measured using proton–proton collision data, corresponding to an ...integrated luminosity of $$1.9\,\mathrm{fb}^{-1} $$ 1.9fb-1 , collected with the LHCb detector at a centre-of-mass energy of $$13\,\mathrm {TeV}$$ 13TeV in 2015 and 2016. Using a sample of approximately 117 000 signal decays with an invariant $${{K} ^+} {{K} ^-} $$ K+K- mass in the vicinity of the $$\phi (1020)$$ ϕ(1020) resonance, the $$CP$$ CP -violating phase $$\phi _s$$ ϕs is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the $${{B} ^0_{s}} $$ Bs0 -$${{\overline{B}{}} {}^0_{s}} $$ B¯s0 system, $$\Delta \Gamma _s$$ ΔΓs . The difference of the average $${{B} ^0_{s}} $$ Bs0 and $${{B} ^0} $$ B0 meson decay widths, $$\Gamma _s-\Gamma _d$$ Γs-Γd , is determined using in addition a sample of $${{B} ^0} \rightarrow J/\psi {{K} ^+} {{\pi } ^-} $$ B0→J/ψK+π- decays. The values obtained are $$\phi _s = -0.083\pm 0.041\pm 0.006\mathrm { \,rad} $$ ϕs=-0.083±0.041±0.006rad , $$\Delta \Gamma _s = 0.077 \pm 0.008 \pm 0.003 {\mathrm { \,ps^{-1}}} $$ ΔΓs=0.077±0.008±0.003ps-1 and $$\Gamma _s-\Gamma _d = -0.0041 \pm 0.0024 \pm 0.0015{\mathrm { \,ps^{-1}}} $$ 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 $${{B} ^0_{s}} \rightarrow J/\psi {{\pi } ^+} {{\pi } ^-} $$ Bs0→J/ψπ+π- decays obtained using the same dataset as this analysis, and with previous independent LHCb results.
Abstract A search for the rare leptonic decay $${{{B} ^+}} \!\rightarrow {\mu ^+} {\mu ^-} {\mu ^+} {{\upnu } _\mu } $$ B+→μ+μ-μ+νμ is performed using proton-proton collision data corresponding to an ...integrated luminosity of $$4.7 \, {\hbox {fb}}^{-1}$$ 4.7fb-1 collected by the LHCb experiment. The search is carried out in the region where the lowest of the two $${\mu ^+\mu ^-} $$ μ+μ- mass combinations is below $$980 {\mathrm {\,MeV\!/}c^2} $$ 980MeV/c2 . The data are consistent with the background-only hypothesis and an upper limit of $$1.6 \times 10^{-8}$$ 1.6×10-8 at 95% confidence level is set on the branching fraction in the stated kinematic region.
Abstract The branching fraction and direct $$C\!P$$ CP asymmetry of the decay $${{{B} ^+}} \!\rightarrow {{J /\psi }} {{\rho } ^+} $$ B+→J/ψρ+ are measured using proton-proton collision data ...collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to a total integrated luminosity of 3$$\,\text{ fb }^{-1}$$ fb-1 . The following results are obtained: $$\begin{aligned} \mathcal {B}({{B} ^+} \!\rightarrow {{J /\psi }} {{\rho } ^+} )&= (3.81^{+0.25}_{-0.24} \pm 0.35) \times 10^{-5},\\ \mathcal {A}^{{C\!P}} ({{B} ^+} \!\rightarrow {{J /\psi }} {{\rho } ^+} )&= -0.045^{+0.056}_{-0.057} \pm 0.008, \end{aligned}$$ B(B+→J/ψρ+)=(3.81-0.24+0.25±0.35)×10-5,ACP(B+→J/ψρ+)=-0.045-0.057+0.056±0.008, where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date.
A search for B+ → Ds+K+K− decays is performed using pp collision data corresponding to an integrated luminosity of 4.8 fb−1, collected at centre-of-mass energies of 7, 8 and 13 TeV with the LHCb ...experiment. A significant signal is observed for the first time and the branching fraction is determined to beℬB+→Ds+K+K−=7.1±0.5±0.6±0.7×10−6,where the first uncertainty is statistical, the second systematic and the third due to the uncertainty on the branching fraction of the normalisation mode B+→Ds+D¯0. A search is also performed for the pure annihilation decay B+ → Ds+ϕ. No significant signal is observed and a limit ofℬB+→Ds+ϕ<4.9×10−74.2×10−7is set on the branching fraction at 95% (90%) confidence level.
A search for CP violation in Λb0→pK− and Λb0→pπ− decays is presented using a sample of pp collisions collected with the LHCb detector and corresponding to an integrated luminosity of 3.0fb−1. The CP ...-violating asymmetries are measured to be ACPpK−=−0.020±0.013±0.019 and ACPpπ−=−0.035±0.017±0.020, and their difference ACPpK−−ACPpπ−=0.014±0.022±0.010, where the first uncertainties are statistical and the second systematic. These are the most precise measurements of such asymmetries to date.
The decay Λb0→Λc+pp‾π− is observed using pp collision data collected with the LHCb detector at centre-of-mass energies of s=7 and 8 Tev, corresponding to an integrated luminosity of 3 fb−1. The ratio ...of branching fractions between Λb0→Λc+pp‾π− and Λb0→Λc+π− decays is measured to beB(Λb0→Λc+pp‾π−)B(Λb0→Λc+π−)=0.0540±0.0023±0.0032. Two resonant structures are observed in the Λc+π− mass spectrum of the Λb0→Λc+pp‾π− decays, corresponding to the Σc(2455)0 and Σc⁎(2520)0 states. The ratios of branching fractions with respect to the decay Λb0→Λc+pp‾π− areB(Λb0→Σc0pp‾)×B(Σc0→Λc+π−)B(Λb0→Λc+pp‾π−)=0.089±0.015±0.006,B(Λb0→Σc⁎0pp‾)×B(Σc⁎0→Λc+π−)B(Λb0→Λc+pp‾π−)=0.119±0.020±0.014. In all of the above results, the first uncertainty is statistical and the second is systematic. The phase space is also examined for the presence of dibaryon resonances. No evidence for such resonances is found.
A search for the CP-violating strong decays η→π+π− and η′(958)→π+π− has been performed using approximately 2.5×107 events of each of the decays D+→π+π+π− and Ds+→π+π+π−, recorded by the LHCb ...experiment. The data set corresponds to an integrated luminosity of 3.0 fb−1 of pp collision data recorded during LHC Run 1 and 0.3 fb−1 recorded in Run 2. No evidence is seen for D(s)+→π+η(′) with η(′)→π+π−, and upper limits at 90% confidence level are set on the branching fractions, B(η→π+π−)<1.6×10−5 and B(η′→π+π−)<1.8×10−5. The limit for the η decay is comparable with the existing one, while that for the η′ is a factor of three smaller than the previous limit.
Abstract The Λ b 0 $$ {\Lambda}_b^0 $$ → D + D − Λ decay is observed for the first time using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, ...corresponding to an integrated luminosity of 5.3 fb −1. Using the B 0 → D + D − K S 0 $$ {D}^{+}{D}^{-}{K}_S^0 $$ decay as a reference channel, the product of the relative production cross-section and decay branching fractions is measured to be R = σ Λ b 0 σ B 0 = B Λ b 0 → D + D − Λ B B 0 → D + D − K S 0 = 0.179 ± 0.022 ± 0.014 , $$ \mathcal{R}=\frac{\sigma_{\Lambda_b^0}}{\sigma_{B^0}}=\frac{\mathcal{B}\left({\Lambda}_b^0\to {D}^{+}{D}^{-}\Lambda \right)}{\mathcal{B}\left({B}^0\to {D}^{+}{D}^{-}{K}_{\textrm{S}}^0\right)}=0.179\pm 0.022\pm 0.014, $$ where the first uncertainty is statistical and the second is systematic. The known branching fraction of the reference channel, B B 0 → D + D − K S 0 $$ \mathcal{B}\left({B}^0\to {D}^{+}{D}^{-}{K}_{\textrm{S}}^0\right) $$ , and the cross-section ratio, σ Λ b 0 / σ B 0 $$ {\sigma}_{\Lambda_b^0}/{\sigma}_{B^0} $$ , previously measured by LHCb are used to derive the branching fraction of the Λ b 0 $$ {\Lambda}_b^0 $$ → D + D − Λ decay B Λ b 0 → D + D − Λ = 1.24 ± 0.15 ± 0.10 ± 0.28 ± 0.11 × 10 − 4 , $$ \mathcal{B}\left({\Lambda}_b^0\to {D}^{+}{D}^{-}\Lambda \right)=\left(1.24\pm 0.15\pm 0.10\pm 0.28\pm 0.11\right)\times {10}^{-4}, $$ where the third and fourth contributions are due to uncertainties of B B 0 → D + D − K S 0 $$ \mathcal{B}\left({B}^0\to {D}^{+}{D}^{-}{K}_{\textrm{S}}^0\right) $$ and σ Λ b 0 / σ B 0 $$ {\sigma}_{\Lambda_b^0}/{\sigma}_{B^0} $$ , respectively. Inspection of the D +Λ and D + D − invariant-mass distributions suggests a rich presence of intermediate resonances in the decay. The Λ b 0 $$ {\Lambda}_b^0 $$ → D *+ D − Λ decay is also observed for the first time as a partially reconstructed component in the D + D − Λ invariant mass spectrum.
Abstract A search for the fully reconstructed B s 0 $$ {B}_s^0 $$ → μ + μ − γ decay is performed at the LHCb experiment using proton-proton collisions at s $$ \sqrt{s} $$ = 13 TeV corresponding to an ...integrated luminosity of 5.4 fb −1. No significant signal is found and upper limits on the branching fraction in intervals of the dimuon mass are set B B s 0 → μ + μ − γ < 4.2 × 10 − 8 , m μ + μ − ∈ 2 m μ 1.70 GeV / c 2 , B B s 0 → μ + μ − γ < 7.7 × 10 − 8 , m μ + μ − ∈ 1.70, 2.88 GeV / c 2 , B B s 0 → μ + μ − γ < 4.2 × 10 − 8 , m μ + μ − ∈ 3.92 m B s 0 GeV / c 2 , $$ {\displaystyle \begin{array}{cc}\mathcal{B}\left({B}_s^0\to {\mu}^{+}{\mu}^{-}\gamma \right)<4.2\times {10}^{-8},& m\left({\mu}^{+}{\mu}^{-}\right)\in \left2{m}_{\mu },1.70\right\textrm{GeV}/{c}^2,\\ {}\mathcal{B}\left({B}_s^0\to {\mu}^{+}{\mu}^{-}\gamma \right)<7.7\times {10}^{-8},&\ m\left({\mu}^{+}{\mu}^{-}\right)\in \left\textrm{1.70,2.88}\right\textrm{GeV}/{c}^2,\\ {}\mathcal{B}\left({B}_s^0\to {\mu}^{+}{\mu}^{-}\gamma \right)<4.2\times {10}^{-8},& m\left({\mu}^{+}{\mu}^{-}\right)\in \left3.92,{m}_{B_s^0}\right\textrm{GeV}/{c}^2,\end{array}} $$ at 95% confidence level. Additionally, upper limits are set on the branching fraction in the 2m μ , 1.70 GeV/c 2 dimuon mass region excluding the contribution from the intermediate ϕ(1020) meson, and in the region combining all dimuon-mass intervals.
A search is made for the highly-suppressed B meson decays B+→K+K+π− and B+→π+π+K− using a data sample corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb experiment in ...proton–proton collisions at centre-of-mass energies of 7 and 8 TeV. No evidence is found for the decays, and upper limits at 90% confidence level are determined to be B(B+→K+K+π−)<1.1×10−8 and B(B+→π+π+K−)<4.6×10−8.
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