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The decays$$ {\mathrm{B}}_{\mathrm{s}}^0 $$Bs0→ J/ψπ+π−K+K−are studied using a data set corresponding to an integrated luminosity of 9 fb−1, collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8... more
The decays$$ {\mathrm{B}}_{\mathrm{s}}^0 $$Bs0→ J/ψπ+π−K+K−are studied using a data set corresponding to an integrated luminosity of 9 fb−1, collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The decays$$ {\mathrm{B}}_{\mathrm{s}}^0 $$Bs0→$$ \mathrm{J}/{\uppsi \mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0} $$J/ψK∗0K¯∗0and$$ {\mathrm{B}}_{\mathrm{s}}^0 $$Bs0→ χc1(3872)K+K−, where the K+K−pair does not originate from a ϕ meson, are observed for the first time. Precise measurements of the ratios of branching fractions between intermediate χc1(3872)ϕ,$$ \mathrm{J}/{\uppsi \mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0} $$J/ψK∗0K¯∗0, ψ(2S)ϕ and χc1(3872)K+K−states are reported. A structure, denoted as X(4740), is observed in the J/ψϕ mass spectrum and, assuming a Breit-Wigner parameterisation, its mass and width are determined to be$$ {\displaystyle \begin{array}{c}{m}_{\mathrm{X}(4740)}=4741\pm 6\pm 6\kern0.5em \mathrm{...
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From samples of pp collision data collected by the LHCb experiment at $\sqrt{s}$=7, 8 and 13 TeV, corresponding to integrated luminosities of 1.0, 2.0 and 1.5 fb$^{-1}$, respectively, a peak in both the $Λ_b^0 K^-$ and $Ξ_b^0 π^-$... more
From samples of pp collision data collected by the LHCb experiment at $\sqrt{s}$=7, 8 and 13 TeV, corresponding to integrated luminosities of 1.0, 2.0 and 1.5 fb$^{-1}$, respectively, a peak in both the $Λ_b^0 K^-$ and $Ξ_b^0 π^-$ invariant mass spectra is observed. In the quark model, radially and orbitally excited $Ξ_{b}-$ resonances with quark content bds are expected. Referring to this peak as $Ξ_b (6227)^-$, the mass and natural width are measured to be $m_{{Ξ}_{b}{(6227)}}- =6226.9±2.0±0.3±0.2 MeV/c^2$ and $Γm_{{Ξ}_{b}{(6227)}}- = 18.1±5.4±1.8 MeV/c^2$, where the first uncertainty is statistical, the second is systematic, and the third, on $m_{{Ξ}_{b}{(6227)}}-$, is due to the knowledge of the Λb0 baryon mass. Relative production rates of the$m_{{Ξ}_{b}{(6227)}}- \to Λ_b^0 K^-$ and $m_{{Ξ}_{b}{(6227)}}- → Ξ_b^0 π^-$ decays are also reported.
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The ratio of branching fractions ${\cal{R}}(D^{*-})\equiv {\cal{B}}(B^0 \to D^{*-} \tau^+ \nu_{\tau})/{\cal{B}}(B^0 \to D^{*-} \mu^+\nu_{\mu})$ is measured using a data sample of proton-proton collisions collected with the LHCb detector... more
The ratio of branching fractions ${\cal{R}}(D^{*-})\equiv {\cal{B}}(B^0 \to D^{*-} \tau^+ \nu_{\tau})/{\cal{B}}(B^0 \to D^{*-} \mu^+\nu_{\mu})$ is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3$~$fb$^{-1}$. The $\tau$ lepton is reconstructed with three charged pions in the final state. A novel method is used that exploits the different vertex topologies of signal and backgrounds to isolate samples of semitauonic decays of $b$ hadrons with high purity. Using the $B^0 \to D^{*-}\pi^+\pi^-\pi^+$ decay as the normalization channel, the ratio ${\cal{B}}(B^0 \to D^{*-} \tau^+ \nu_{\tau})/{\cal{B}}(B^0 \to D^{*-}\pi^+\pi^-\pi^+)$ is measured to be $1.93 \pm 0.13 \pm 0.18$, where the first uncertainty is statistical and the second systematic. The LHCb measurement of the branching fraction for the normalization channel is used to derive ${\cal{B}}(B^0 \to D^{*-...
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A search for the rare decay is performed using collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. No significant signal of the decay is... more
A search for the rare decay is performed using collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. No significant signal of the decay is observed and an upper limit of at 90% confidence level is set on the branching fraction.
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A measurement of the$$ {\varXi}_{cc}^{++} $$Ξcc++mass is performed using data collected by the LHCb experiment between 2016 and 2018 inppcollisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.6... more
A measurement of the$$ {\varXi}_{cc}^{++} $$Ξcc++mass is performed using data collected by the LHCb experiment between 2016 and 2018 inppcollisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.6 fb−1. The$$ {\varXi}_{cc}^{++} $$Ξcc++candidates are reconstructed via the decay modes$$ {\varXi}_{cc}^{++}\to {\varLambda}_c^{+}{K}^{-}{\pi}^{+}{\pi}^{+} $$Ξcc++→Λc+K−π+π+and$$ {\varXi}_{cc}^{++}\to {\varXi}_c^{+}{\pi}^{+} $$Ξcc++→Ξc+π+. The result, 3621.55±0.23 (stat)±0.30 (syst) MeV/c2, is the most precise measurement of the$$ {\varXi}_{cc}^{++} $$Ξcc++mass to date.
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The CP violation observables S and C in the decay channel B^{0}→D^{+}D^{-} are determined from a sample of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, collected by the LHCb experiment and corresponding to an... more
The CP violation observables S and C in the decay channel B^{0}→D^{+}D^{-} are determined from a sample of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 3 fb^{-1}. The observable S describes CP violation in the interference between mixing and the decay amplitude, and C parametrizes direct CP violation in the decay. The following values are obtained from a flavor-tagged, decay-time-dependent analysis: S=-0.54_{-0.16}^{+0.17}(stat)±0.05(syst), C=0.26_{-0.17}^{+0.18}(stat)±0.02(syst). These values provide evidence for CP violation at a significance level of 4.0 standard deviations. The phase shift due to higher-order standard model corrections is constrained to a small value of Δϕ=-0.16_{-0.21}^{+0.19} rad.
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A precision measurement of the$$ {B}_c^{+} $$Bc+meson mass is performed using proton- proton collision data collected with the LHCb experiment at centre-of-mass energies of 7,8 and 13 TeV, corresponding to a total integrated luminosity of... more
A precision measurement of the$$ {B}_c^{+} $$Bc+meson mass is performed using proton- proton collision data collected with the LHCb experiment at centre-of-mass energies of 7,8 and 13 TeV, corresponding to a total integrated luminosity of 9.0 fb−1. The$$ {B}_c^{+} $$Bc+mesons are reconstructed via the decays$$ {B}_c^{+} $$Bc+→ J/ψπ+,$$ {B}_c^{+} $$Bc+→ J/ψπ+π−π+,$$ {B}_c^{+}\to J/\psi p\overline{p}{\pi}^{+} $$Bc+→J/ψpp¯π+,$$ {B}_c^{+}\to J/\psi {D}_s^{+} $$Bc+→J/ψDs+,$$ {B}_c^{+} $$Bc+→ J/ψ D0K+and$$ {B}_c^{+}\to {B}_s^0{\pi}^{+} $$Bc+→Bs0π+. Combining the results of the individual decay channels, the$$ {B}_c^{+} $$Bc+mass is measured to be 6274.47±0.27 (stat)±0.17 (syst) MeV/c2. This is the most precise measurement of the$$ {B}_c^{+} $$Bc+mass to date. The difference between the$$ {B}_c^{+} $$Bc+and$$ {B}_s^0 $$Bs0meson masses is measured to be 907.75±0.37 (stat)±0.27 (syst) MeV/c.