The first observation of the decay $B^0_s\rightarrow\chi_{c1}\phi$ and a study of $B^0\rightarrow\chi_{c1,2}K^{*0}$ decays are presented. The analysis is performed using a dataset, 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 7 TeV. The following ratios of branching fractions are measured: \begin{equation*} \begin{array}{lll} \dfrac{\cal{B}(B^0_s\rightarrow\chi_{c1}\phi)}{\cal{B}(B^0_s\rightarrow J/\psi\phi)} &=& (18.9 \pm1.8\,(stat)\pm1.3\,(syst)\pm0.8\,(\cal{B})) \times 10^{-2}, \nonumber \\ \noalign{\vskip 3pt} \dfrac{\cal{B}(B^0\rightarrow\chi_{c1}K^{*0})}{\cal{B}(B^0\rightarrow J/\psiK^{*0})} &=& (19.8 \pm1.1\,(stat)\pm1.2\,(syst)\pm0.9\,(\cal{B})) \times 10^{-2}, \nonumber \\ \noalign{\vskip 3pt} \dfrac{\cal{B}(B^0\rightarrow\chi_{c2}K^{*0})}{\cal{B}(B^0\rightarrow\chi_{c 1}K^{*0})} &=& (17.1 \pm5.0\,(stat)\pm1.7\,(syst)\pm1.1\,(\cal{B})) \times 10^{-2}, \nonumber \\ \noalign{\vskip 3pt} \end{array} \end{equation*} \noindent where the third uncertainty is due to the limited knowledge of the branching fractions of ${\chi_{c}\rightarrow J/\psi \gamma}$ modes.
The decay $B_c\rightarrow J/\psi K^+ K^- \pi^+$ 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 $78\pm14$ 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 $0.53\pm 0.10\pm0.05$, where the first uncertainty is statistical and the second is systematic.
A first observation of the decay $B_s^0 \rightarrow \phi \bar{K}^{*0}$ is reported from an analysis based on a data sample, corresponding to an integrated luminosity of 1.0 fb$^{-1}$ of $pp$ ...collisions at sqrt(s) = 7 TeV, collected with the LHCb detector. A yield of $30 \pm 6$ $B_s^0 \rightarrow (KK)(K\pi)$ candidates is found in the mass windows $1012.5 < M(KK) < 1026.5 MeV/c^2$ and $746 < M(K\pi)< 1046 MeV/c^2$, corresponding to a signal significance of 6.1 standard deviations. The candidates are found to be dominated by $B_s^0 \rightarrow \phi \bar{K}^{*0}$ decays, and the branching fraction is measured to be $BF(B_s^0 \rightarrow \phi \bar{K}^{*0}) = (1.10 \pm 0.24 (stat) \pm 0.14 (syst) \pm 0.08 (f_d/f_s)) \times 10^{-6}$, where the uncertainties are statistical, systematic and from the ratio of fragmentation fractions $f_d/f_s$ which accounts for the different production rate of $B^0$ and $B_s^0$ mesons. The fraction of longitudinal polarization in $B_s^0 \rightarrow \phi \bar{K}^{*0}$ decays is found to be $f_0 = 0.51 \pm 0.15 (stat) \pm 0.07 (syst)$.
An angular analysis of the decay $J/\psi \rightarrow \mu^{+} \mu^{-}$ is performed to measure the polarization of prompt $J/\psi$ mesons produced in $pp$ collisions at $\sqrt{s}=7 \mathrm{TeV}$. The ...dataset corresponds to an integrated luminosity of 0.37 fb$^{-1}$ collected with the LHCb detector. The measurement is presented as a function of transverse momentum, $p_\mathrm{T}$, and rapidity, $y$, of the $J/\psi$ meson, in the kinematic region $2 < p_\mathrm{T} < 15 \mathrm{GeV}/c$ and $2.0
A study of $D^+\pi^-$, $D^0 \pi^+$ and $D^{*+}\pi^-$ final states is performed using pp collision data, corresponding to an integrated luminosity of 1.0 $fb^{-1}$, collected at a centre-of-mass ...energy of 7 TeV with the LHCb detector. The $D_1(2420)^0$ resonance is observed in the $D^{*+}\pi^-$ final state and the $D^*_2(2460)$ resonance is observed in the $D^+\pi^-$, $D^0 \pi^+$ and $D^{*+}\pi^-$ final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 2800 MeV. Further structures in the region around 3000 MeV are observed in all the $D^{*+}\pi^-$, $D^+\pi^-$ and $D^0 \pi^+$ final states.
The results of searches for B0(s) -> J/{\psi} p pbar and B+ -> J/{\psi} p pbar {\pi}+ decays are reported. The analysis is based on a data sample, corresponding to an integrated luminosity of 1.0 ...fb^-1 of pp collisions, collected with the LHCb detector. An excess with 2.8 {\sigma} significance is seen for the decay B0s -> J/{\psi} p pbar and an upper limit on the branching fraction is set at the 90 % confidence level: B(B0s -> J/{\psi} p pbar) < 4.8 x 10^-6, which is the first such limit. No significant signals are seen for B0 -> J/{\psi} p pbar and B+ -> J/{\psi} p pbar {\pi}+ decays, for which the corresponding limits are set: B(B0 -> J/{\psi} p pbar) < 5.2 x 10^-7, which significantly improves the existing limit; and B(B+ -> J/{\psi} p pbar {\pi}+) < 5.0 x 10^-7, which is the first limit on this branching fraction.
A key ingredient to searches for physics beyond the Standard Model in $B^{0}_{s}$ mixing phenomena is the measurement of the $B^{0}_{s}$-$\bar{B}^{0}_{s}$ oscillation frequency, which is equivalent ...to the mass difference $\Delta m_{s}$ of the $B^{0}_{s}$ mass eigenstates. Using the world's largest $B^{0}_{s}$ meson sample accumulated in a dataset, corresponding to an integrated luminosity of 1.0 fb$^{-1}$, collected by the LHCb experiment at the CERN LHC in 2011, a measurement of $\Delta m_{s}$ is presented. A total of about 34,000 $B^{0}_{s}\rightarrowD^{-}_{s}\pi^{+}$ signal decays are reconstructed, with an average decay time resolution of 44 fs. The oscillation frequency is measured to be \mbox{$\Delta m_{s}$ = 17.768 $\pm$ 0.023 (stat) $\pm$ 0.006 (syst) ps$^{-1}$}, which is the most precise measurement to date.
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