The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1 of pp collision data collected by the LHCb ...experiment at a centre-of-mass energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x 10^{-5}. The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/- 0.9(syst.))%. Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations.
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 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.
A search for charmless three-body decays of B0 and B0s mesons with a KS0 meson in the final state is performed using the pp collision data, corresponding to an integrated luminosity of 1.0 /fb, ...collected at a centre-of-mass energy of 7 TeV recorded by the LHCb experiment. Branching fractions of the B0(s) -> KS0 h+ h'- decay modes (h(') = \pi, K), relative to the well measured B0 -> KS0 \pi+ \pi- decay, are obtained. First observation of the decay modes B0s -> KS0 K+/- \pi-/+ and B0s -> KS0 \pi+ \pi- and confirmation of the decay B0 -> KS0 K+/- \pi-/+ are reported. The following relative branching fraction measurements or limits are obtained BF(B0 -> KS0 K+/- \pi-/+) / BF(B0 -> KS0 \pi+ \pi-) = 0.128 +/- 0.017 (stat.) +/- 0.009 (syst.), BF(B0 -> KS0 K+ K-) / BF(B0 -> KS0 \pi+ \pi-) = 0.385 +/- 0.031 (stat.) +/- 0.023 (syst.), BF(B0s -> KS0 \pi+ \pi-) / BF(B0 -> KS0 \pi+ \pi-) = 0.29 \pm 0.06 (stat.) +/- 0.03 (syst.) +/- 0.02 (f_s/f_d), BF(B0s -> KS0 K+/- \pi-/+) / BF(B0 -> KS0 \pi+ \pi-) = 1.48 +/- 0.12 (stat.) +/- 0.08 (syst.) +/- 0.12 (f_s/f_d), BF(B0s -> KS0 K+ K-) / BF(B0 -> KS0 \pi+ \pi-) E 0.004;0.068 at 90% CL.
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.
A search for the decays Bs -> mu+ mu- and B0 -> mu+ mu- is performed with 0.37 fb^-1 of pp collisions at sqrt{s} = 7 TeV collected by the LHCb experiment in 2011. The upper limits on the branching ...fractions are BR (Bs -> mu+ mu-) < 1.6 x 10^-8 and BR(B0 -> mu+ mu-) < 3.6 x 10^-9 at 95% confidence level. A combination of these results with the LHCb limits obtained with the 2010 dataset leads to BR (Bs -> mu+ mu-) < 1.4 x 10^-8 and BR (B0 -> mu+ mu-) < 3.2 x 10^-9 at 95% confidence level.
The B^0_s-\bar{B}^0_s oscillation frequency Delta m_s is measured with 36 pb^{-1} of data collected in pp collisions at \sqrt{s} = 7 TeV by the LHCb experiment at the Large Hadron Collider. A total ...of 1381 B^0_s -> D_s^- \pi^+ and \B^0_s -> D_s^- pi^+ pi^- pi^+ signal decays are reconstructed, with average decay time resolutions of 44 fs and 36 fs, respectively. An oscillation signal with a statistical significance of 4.6 sigma is observed. The measured oscillation frequency is Delta m_s = 17.63 \pm 0.11 (stat) \pm 0.02 (syst) ps^{-1}.
A measurement of the effective $B_srightarrow K^+K^-$ lifetime is presented using approximately $37 pb^{-1}$ of data collected by LHCb during 2010. This quantity can be used to put constraints on ...contributions from processes beyond the Standard Model in the $B_s$ meson system and is determined by two complementary approaches as $tau_{B_sto K^+K^-} = 1.440 pm 0.096 (stat) pm 0.008 (syst) pm 0.003 (model) ps$.
The first observation of the decay Bs0 -> K*0 anti-K*0 is reported using 35 pb^{-1} of data collected by LHCb in proton-proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8 \pm 7.5 ...signal events are observed, with a significance of 10.9 sigma. The branching fraction and the CP-averaged K*0 longitudinal polarization fraction are measured to be BR(Bs0 -> K*0 anti-K*0) = (2.81 \pm 0.46 (stat.) \pm 0.45 (syst.) \pm 0.34 (f_s/f_d))x10^{-5} and f_L = 0.31 \pm 0.12 (stat.) \pm 0.04 (syst.).
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