Observation of the $varLambda^0_b to varLambda^+_c K^+ K^- pi^-$ decay

The $varLambda^0_b to varLambda^+_c K^+ K^- pi^-$ decay is observed for the first time using a data sample of proton-proton collisions at centre-of-mass energies of $sqrt{s}=7$ and 8 $rm{TeV}$ collected by the $mbox{LHCb}$ detector, corresponding to an integrated luminosity of $3{rm{fb}^{-1}}$. The ratio of branching fractions between the $varLambda^0_b to varLambda^+_c K^+ K^- pi^-$ and the $varLambda^{0}_{b}tovarLambda^{+}_{c}D^{-}_{s}$ decays is measured to be begin{equation*} frac{mathcal{B} ( varLambda^0_b to varLambda^+_c K^+ K^- pi^-) } {mathcal{B} ( varLambda^0_b to varLambda^+_c D^-_s)} = (9.26 pm 0.29 pm 0.46 pm 0.26)times10^{-2}, end{equation*} where the first uncertainty is statistical, the second systematic and the third is due to the knowledge of the $D^-_s to K^+ K^- pi^-$ branching fraction. No structure on the invariant mass distribution of the $varLambda^+_c K^+$ system is found, consistent with no open-charm pentaquark signature.

Observation of Bs -> J/psi f2(1525) in J/psi K+K- final states

The decay Bs -> J/psi K+ K- is investigated using 0.16/fb of data collected with the LHCb detector using 7 TeV pp collisions. Although the J/psi phi channel is well known, final states at higher K+K- masses have not previously been studied. In the K+K- mass spectrum we observe a significant signal in the f2(1525) region as well as a non-resonant component. After subtracting the non-resonant component, we find B(Bs->J/psi f_2(1525))/B(Bs->J/psi phi)=(26.4 +/- 2.7 +/- 2.4)%.

Observation of new resonances decaying to $J/psi K^+$ and $J/psi phi$

The first observation of exotic states with a new quark content $c bar{c} u bar{s}$ decaying to the $J/psi K^+$ final state is reported with high significance from an amplitude analysis of the $B^+ to J/psi phi K^+$ decay. The analysis is carried out using proton-proton collision data corresponding to a total integrated luminosity of 9 fb$^{-1}$ collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV. The most significant state, $Z_{cs}(4000)^+$, has a mass of $4003pm6,^{+,phantom{0}4}_{-,14}$ MeV, a width of $131pm15pm26$ MeV, and spin-parity $J^P=1^+$, where the quoted uncertainties are statistical and systematic, respectively. A new $1^+$ $X(4685)$ state decaying to the $J/psi phi$ final state is also observed with high significance. In addition, the four previously reported $J/psi phi$ states are confirmed and two more exotic states, $Z_{cs}(4220)^+$ and $X(4630)$, are observed with significance exceeding five standard deviations.

Observation of the $varXi^{-}_{b}to J/psivarLambda K^{-}$ decay

The observation of the decay $varXi^{-}_{b}to J/psivarLambda K^{-}$ is reported, using a data sample corresponding to an integrated luminosity of $3~mathrm{fb}^{-1}$, collected by the LHCb detector in $pp$ collisions at centre-of-mass energies of $7$ and $8~mathrm{TeV}$. The production rate of $varXi_{b}^{-}$ baryons detected in the decay $varXi_{b}^{-}to J/psivarLambda K^{-}$ is measured relative to that of $varLambda_{b}^{0}$ baryons using the decay $varLambda_{b}^{0}to J/psi varLambda$. Integrated over the $b$-baryon transverse momentum $p_{rm T}<25~mathrm{GeV/}c $ and rapidity $2.0<y<4.5$, the measured ratio is begin{equation*} frac{f_{varXi_{b}^{-}}}{f_{varLambda_{b}^{0}}}frac{mathcal{B}(varXi_{b}^{-}to J/psivarLambda K^{-})}{mathcal{B}(varLambda_{b}^{0}to J/psi varLambda)}=(4.19pm 0.29~(mathrm{stat})pm0.15~(mathrm{syst}))times 10^{-2}, end{equation*}where $f_{varXi_{b}^{-}}$ and $f_{varLambda_{b}^{0}}$ are the fragmentation fractions of $btovarXi_{b}^{-}$ and $btovarLambda_{b}^{0}$ transitions, and $mathcal{B}$ represents the branching fraction of the corresponding $b$-baryon decay. The mass difference between $varXi_{b}^{-}$ and $varLambda_{b}^{0}$ baryons is measured to be begin{equation*} M(varXi_{b}^{-})-M(varLambda_{b}^{0})=177.08pm0.47~(mathrm{stat})pm0.16~(mathrm{syst} )~mathrm{MeV/}c^{2}. end{equation*}

First observation of the decay $B_{c}^{+}to J/psi K^+$

The decay $B_c^+to J/psi K^+$ is observed for the first time using a data sample, corresponding to an integrated luminosity of 1.0 ${,fb}^{-1}$, collected by the LHCb experiment in $pp$ collisions at a centre-of-mass energy of $7mathrm{,Tekern -0.1em V}$. A yield of $46pm12$ events is reported, with a significance of 5.0 standard deviations. The ratio of the branching fraction of $B_c^+to J/psi K^+$ to that of $B_c^+to J/psipi^+$ is measured to be $0.069pm0.019pm0.005$, where the first uncertainty is statistical and the second is systematic.