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Register a new userObservation of the decay $B_c^+ to psi(2S)pi^+$
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The decay $B_c^+ to psi(2S)pi^+$ with $psi(2S) to mu^+mu^-$ is observed with a significance of $5.2,sigma$ using $pp$ collision data corresponding to an integrated luminosity of $1.0,invfb$ collected by the LHCb experiment. The branching fraction of $B_c^+ to psi(2S)pi^+$ decays relative to that of the $B_c^+ to J/psipi^+$ mode is measured to be begin{equation*} frac{mathcal{B}(B_c^+ to psi(2S)pi^+)}{mathcal{B}(B_c^+ to J/psipi^+)} = 0.250 pm 0.068 ,text{stat} pm 0.014 ,text{syst} pm 0.006 ,(mathcal{B}). end{equation*} The last term is the uncertainty on the ratio $mathcal{B}(psi(2S) to mu^+mu^-)/mathcal{B}(J/psi to mu^+mu^-)$.
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The decay $B_crightarrow J/psi K^+ K^- pi^+$ is observed for the first time, using proton-proton collisions collected with the LHCb detector corresponding to an integrated luminosity of 3fb$^{-1}$. A signal yield of $78pm14$ decays is reported with a significance of 6.2 standard deviations. The ratio of the branching fraction of $B_c rightarrow J/psi K^+ K^- pi^+$ decays to that of $B_c rightarrow J/psi pi^+$ decays is measured to be $0.53pm 0.10pm0.05$, where the first uncertainty is statistical and the second is systematic.
Using $pp$ collision data collected by LHCb at center-of-mass energies $sqrt{s}$ = 7 TeV and 8 TeV, corresponding to an integrated luminosity of 3 fb$^{-1}$, the ratio of the branching fraction of the $B_c^+ rightarrow psi(2S)pi^+$ decay relative to that of the $B_c^+ rightarrow J/psipi^+$ decay is measured to be 0.268 $pm$ 0.032 (stat) $pm$ 0.007 (syst) $pm$ 0.006 (BF). The first uncertainty is statistical, the second is systematic, and the third is due to the uncertainties on the branching fractions of the $J/psi rightarrow mu^+mu^-$ and $psi(2S) rightarrow mu^+mu^-$ decays. This measurement is consistent with the previous LHCb result, and the statistical uncertainty is halved.
Measurements of $B_c^+$ production and mass are performed with the decay mode $B_c^+ to J/psi pi^+$ using 0.37 fb$^{-1}$ of data collected in $pp$ collisions at $sqrt{s}=7$ TeV by the LHCb experiment. The ratio of the production cross-section times branching fraction between the $B_c^+ to J/psi pi^+$ and the $B^+ to J/psi K^+$ decays is measured to be $(0.68 pm 0.10,({rm stat.}) pm 0.03,({rm syst.}) pm 0.05,({rm lifetime}))$% for $B_c^+$ and $B^+$ mesons with transverse momenta $p_{rm T}>4 $GeV/$c$ and pseudorapidities $2.5<eta<4.5$. The $B_c^+$ mass is directly measured to be $6273.7 pm 1.3,({rm stat.}) pm 1.6 ,({rm syst.})$ MeV/$c^2$, and the measured mass difference with respect to the $B^+$ meson is $M(B_c^+)-M(B^+) = 994.6 pm 1.3,({rm stat.}) pm 0.6,({rm syst.})$ MeV/$c^2$.
The decay $overline{B}_s^0 rightarrow psi(2S) K^+ pi^-$ is observed using a data set corresponding to an integrated luminosity of $3.0fb^{-1}$ collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies of 7 and 8 TeV. The branching fraction relative to the $B^0rightarrow psi(2S) K^+ pi^-$ decay mode is measured to be begin{equation} frac{{cal B}(overline{B}^0_s rightarrow psi(2S) K^+ pi^-)}{{cal B}(B^0 rightarrow psi(2S) K^+ pi^-)} = 5.38 pm 0.36 (stat) pm 0.22 (syst) pm 0.31 , (f_s/f_d) , %, onumber end{equation} where $f_s/f_d$ indicates the uncertainty due to the ratio of probabilities for a $b$ quark to hadronise into a $B_s^0$ or $B^0$ meson. Using an amplitude analysis, the fraction of decays proceeding via an intermediate $K^*(892)^0$ meson is measured to be $0.645 pm 0.049 (stat) pm 0.049 (syst)$ and its longitudinal polarisation fraction is $0.524 pm 0.056 (stat) pm 0.029 (syst)$. The relative branching fraction for this component is determined to be begin{equation} frac{{cal B}(overline{B}^0_s rightarrow psi(2S) K^*(892)^0)}{{cal B}(B^0 rightarrow psi(2S) K^*(892)^0)} = 5.58 pm 0.57 (stat) pm 0.40 (syst) pm 0.32 , (f_s/f_d) , %. onumber end{equation} In addition, the mass splitting between the $B_s^0$ and $B^0$ mesons is measured as begin{equation} M(B^0_s) - M(B^0) = 87.45 pm 0.44 (stat) pm 0.07 (syst) MeV/c^2. onumber end{equation}
The decay Bc+ --> J/psi pi+pi-pi+ is observed for the first time, using 0.8 fb-1 of pp collisions at sqrt{s}=7 TeV collected by the LHCb experiment. The ratio of branching fractions BR(Bc+ --> J/psi pi+pi-pi+)/BR(B_c+ --> J/psi pi+) is measured to be 2.41+-0.30+-0.33, where the first uncertainty is statistical and the second systematic. The result is in agreement with theoretical predictions.
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