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Register a new userObservation of the decay $Lambda^0_brightarrowpsi(2S)ppi^-$
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The Cabibbo-suppressed decay $Lambda^0_brightarrowpsi(2S)ppi^-$ is observed for the first time using a data sample collected by the LHCb experiment in proton-proton collisions corresponding to 1.0, 2.0 and 1.9fb$^{-1}$ of integrated luminosity at centre-of-mass energies of 7, 8 and 13TeV, respectively. The $psi(2S)$ mesons are reconstructed in the $mu^+mu^-$ final state. The~branching fraction with respect to that of the $Lambda^0_brightarrowpsi(2S)pK^-$ decay mode is measured to be $$frac{mathcal{B}left(Lambda^0_brightarrowpsi(2S)ppi^- right)} {mathcal{B}left(Lambda^0_brightarrowpsi(2S)pK^-right)}=left(11.4 pm 1.3 pm 0.2right)!%,,$$ where the first uncertainty is statistical and the second is systematic. The $psi(2S)p$ and $psi(2S)pi^-$ mass spectra are investigated and no evidence for exotic resonances is found.
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The suppressed decay $Lambda^{0}_{b}rightarrow ppi^{-}mu^{+}mu^{-}$, excluding the $J/psi$ and $psi(2S)rightarrow mu^{+}mu^{-}$ resonances, is observed for the first time with a significance of 5.5 standard deviations. The analysis is performed with proton-proton collision data corresponding to an integrated luminosity of $3mathrm{fb}^{-1}$ collected with the LHCb experiment. The $Lambda^{0}_{b}rightarrow ppi^{-}mu^{+}mu^{-}$ branching fraction is measured relative to the $Lambda^{0}_{b}rightarrow J/psi(rightarrow mu^{+}mu^{-})ppi^{-}$ branching fraction giving begin{align} onumber frac{mathcal{B}(Lambda^{0}_{b}rightarrow ppi^{-}mu^{+}mu^{-})}{mathcal{B}({Lambda^{0}_{b}rightarrow J/psi(rightarrow mu^{+}mu^{-})ppi^{-}})} &= 0.044pm0.012pm0.007, end{align} where the first uncertainty is statistical and the second is systematic. This is the first observation of a $brightarrow d$ transition in a baryonic decay.
The Cabibbo-suppressed decay $Lambda_b^0rightarrowchi_{c1}ppi^-$ is observed for the first time using data from proton-proton collisions corresponding to an integrated luminosity of 6fb$^{-1}$, collected with the LHCb detector at a centre-of-mass energy of 13TeV. Evidence for the $Lambda_b^0rightarrowchi_{c2}ppi^-$ decay is also found. Using the $Lambda_b^0rightarrowchi_{c1}pK^-$ decay as normalisation channel, the ratios of branching fractions are measured to be $$begin{array}{rcl} frac{ mathcal{B} (Lambda_b^0rightarrowchi_{c1}ppi^-)}{mathcal{B} (Lambda_b^0rightarrowchi_{c1}pK^-)} & = & (6.59 pm 1.01 pm 0.22 ) times 10^{-2} ,, frac{mathcal{B} (Lambda_b^0rightarrowchi_{c2}ppi^-)}{mathcal{B} (Lambda_b^0rightarrowchi_{c1}ppi^-)} & = & 0.95 pm 0.30 pm 0.04 pm 0.04 ,, frac{mathcal{B} (Lambda_b^0rightarrowchi_{c2}pK^-)}{mathcal{B} (Lambda_b^0rightarrowchi_{c1}pK^-)} & = & 1.06 pm 0.05 pm 0.04 pm 0.04 ,,end{array}$$ where the first uncertainty is statistical, the second is systematic and the third is due to the uncertainties in the branching fractions of $chi_{c1,2}rightarrow J/psigamma$ decays.
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 $mathcal{B}(psi(2S) to mu^+mu^-)/mathcal{B}(J/psi to mu^+mu^-)$.
We report a measurement of the $B^0rightarrowpsi(2S)pi^0$ branching fraction based on the full $Upsilon(4S)$ data set of $772times10^{6}$ $Bbar{B}$ pairs collected by the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We obtain $B(B^0rightarrowpsi(2S)pi^0) = (1.17pm0.17text{(stat)}pm0.08text{(syst)})times10^{-5}$. The result has a significance of 7.2 standard deviations and is the first observation of the decay $B^0rightarrowpsi(2S)pi^0$.
We report the observation of $Upsilon(2S)togammaeta_{b}(1S)$ decay based on analysis of the inclusive photon spectrum of $24.7$ fb$^{-1}$ of $e^+ e^-$ collisions at the $Upsilon(2S)$ center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We measure a branching fraction of $mathcal{B}(Upsilon(2S)togammaeta_{b}(1S))=(6.1^{+0.6+0.9}_{-0.7-0.6})times 10^{-4}$, and derive an $eta_{b}(1S)$ mass of $9394.8^{+2.7+4.5}_{-3.1-2.7}$ MeV/$c^{2}$, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.
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