Observation of the Bc+ → J/ψπ+π0 decay

The first observation of the Bc+→J/ψπ+π0 decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of 9 fb−1, collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV. The ratio of its branching fraction relative to the Bc+→J/ψπ+ channel is measured to beBBc+→J/ψπ+π0BBc+→J/ψπ+=2.80±0.15±0.11±0.16, where the first uncertainty is statistical, the second systematic and the third related to imprecise knowledge of the branching fractions for B+ → J/ψK*+ and Bc+→J/ψπ+ decays, which are used to determine the π0 detection efficiency. The π+π0 mass spectrum is found to be consistent with the dominance of an intermediate ρ+ contribution in accordance with a model based on QCD factorisation

Measurement of the branching fraction of B0 → J/ψπ 0 decays

The ratio of branching fractions between B0 → J/ψπ0 and B+ → J/ψK*+ decays is measured with proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. The measured value isBB0→J/ψπ0BB+→J/ψK∗+=1.153±0.053±0.048×10−2, where the first uncertainty is statistical and the second is systematic. The branching fraction for B0 → J/ψπ0 decays is determined using the branching fraction of the normalisation channel, resulting inBB0→J/ψπ0=1.670±0.077±0.069±0.095×10−5, where the last uncertainty corresponds to that of the external input. This result is consistent with the current world average value and competitive with the most precise single measurement to date

Measurement of the branching fraction of B0 → J/ψπ0 decays

Abstract The ratio of branching fractions between B0 → J/ψπ0 and B+ → J/ψK*+ decays is measured with proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. The measured value is$$\frac{{\mathcal{B}}_{B^0\to J/\psi {\pi}^0}}{{\mathcal{B}}_{B^{+}\to J/\psi {K}^{\ast +}}}=\left(1.153\pm 0.053\pm 0.048\right)\times {10}^{-2},$$ B B 0 → J / ψ π 0 B B + → J / ψ K ∗ + = 1.153 ± 0.053 ± 0.048 × 10 − 2 , where the first uncertainty is statistical and the second is systematic. The branching fraction for B0 → J/ψπ0 decays is determined using the branching fraction of the normalisation channel, resulting in$${\mathcal{B}}_{B^0\to J/\psi {\pi}^0}=\left(1.670\pm 0.077\pm 0.069\pm 0.095\right)\times {10}^{-5},$$ B B 0 → J / ψ π 0 = 1.670 ± 0.077 ± 0.069 ± 0.095 × 10 − 5 , where the last uncertainty corresponds to that of the external input. This result is consistent with the current world average value and competitive with the most precise single measurement to date.</jats:p

Observation of the Bc+→J/ψπ+π0 {B}_c^{+}\to J/\psi {\pi}^{+}{\pi}^0 decay

Abstract The first observation of the $${B}_c^{+}\to J/\psi {\pi}^{+}{\pi}^0$$ B c + → J / ψ π + π 0 decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of 9 fb−1, collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV. The ratio of its branching fraction relative to the $${B}_c^{+}\to J/\psi {\pi}^{+}$$ B c + → J / ψ π + channel is measured to be$$\frac{{\mathcal{B}}_{B_c^{+}\to J/\psi {\pi}^{+}{\pi}^0}}{{\mathcal{B}}_{B_c^{+}\to J/\psi {\pi}^{+}}}=2.80\pm 0.15\pm 0.11\pm 0.16,$$ B B c + → J / ψ π + π 0 B B c + → J / ψ π + = 2.80 ± 0.15 ± 0.11 ± 0.16 , where the first uncertainty is statistical, the second systematic and the third related to imprecise knowledge of the branching fractions for B+ → J/ψK*+ and $${B}_c^{+}\to J/\psi {\pi}^{+}$$ B c + → J / ψ π + decays, which are used to determine the π0 detection efficiency. The π+π0 mass spectrum is found to be consistent with the dominance of an intermediate ρ+ contribution in accordance with a model based on QCD factorisation.</jats:p

Measurement of the Branching Fraction of B0→J/ψπ0B^{0} \rightarrow J/\psi \pi^{0} Decays

International audienceThe ratio of branching fractions between $B^{0} \rightarrow J/\psi \pi^{0}$ and $B^{+} \rightarrow J/\psi K^{*+}$ decays is measured with proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb$^{-1}$. The measured value is $\frac{\mathcal{B}_{B^{0} \rightarrow J/\psi \pi^{0}}}{\mathcal{B}_{B^{+} \rightarrow J/\psi K^{*+}}} = (1.153 \pm 0.053 \pm 0.048 ) \times 10^{-2}$, where the first uncertainty is statistical and the second is systematic. The branching fraction for $B^{0} \rightarrow J/\psi \pi^{0}$ decays is determined using the branching fraction of the normalisation channel, resulting in $\mathcal{B}_{B^{0} \rightarrow J/\psi \pi^{0}} = (1.670 \pm 0.077 \pm 0.069 \pm 0.095) \times 10^{-5}$, where the last uncertainty corresponds to that of the external input. This result is consistent with the current world average value and competitive with the most precise single measurement to date

Transverse polarisation measurement of Λ\Lambda hyperons in ppNe collisions at sNN\sqrt{s_{NN}}=68.4 GeV with the LHCb detector

A measurement of the transverse polarization of the $\Lambda$ and $\bar{\Lambda}$hyperons in $p$Ne fixed-target collisions at $\sqrt{s_{NN}}$=68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay $\Lambda \rightarrow p \pi^-$ together with its charge conjugated process, the integrated values measured are $$P_{\Lambda} = 0.029 \pm 0.019 \, (\rm{stat}) \pm 0.012 \, (\rm{syst}) \, ,$$ $$P_{\bar{\Lambda}} = 0.003 \pm 0.023 \, (\rm{stat}) \pm 0.014 \,(\rm{syst}) \,$$ Furthermore, the results are shown as a function of the Feynman $x$ variable, transverse momentum, pseudorapidity and rapidity of the hyperons, and are compared with previous measurements.A measurement of the transverse polarization of the $\Lambda$ and $\bar{\Lambda}$ hyperons in $p$Ne fixed-target collisions at $\sqrt{s_{NN}}$ = 68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay $\Lambda \rightarrow p \pi^-$ together with its charge conjugated process, the integrated values measured are $$P_{\Lambda} = 0.029 \pm 0.019 \, (\rm{stat}) \pm 0.012 \, (\rm{syst}) \, ,$$ $$P_{\bar{\Lambda}} = 0.003 \pm 0.023 \, (\rm{stat}) \pm 0.014 \,(\rm{syst}) \,.$$ Furthermore, the results are shown as a function of the Feynman~$x$~variable, transverse momentum, pseudorapidity and rapidity of the hyperons, and are compared with previous measurements