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Using data collected with the LHCb detector in proton–proton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays B¯s0→Ds*Xμ-v¯ and B¯s0→D0K+Xμ-v¯ are detected. Two structures are observed in the D0K+ mass spectrum at masses consistent with the known Ds1+(2536) and Ds2*(2573)+ mesons. The measured branching fractions relative to the total B¯s0 semileptonic rate are B(B¯s0→Ds2*+Xμ-v¯)/B(B¯s0→D0→Xμ-v¯)=(3.3±1.0±0.4)%, B(B¯s0→Ds1*+Xμ-v¯)/B(B¯s0→D0→Xμ-v¯)= (5.4±1.2±0.5)%, where the first uncertainty is statistical and the secon...
We present a measurement of the time-dependent CP-violating asymmetry in Bs0→J/ψϕ decays, using data collected with the LHCb detector at the LHC. The decay time distribution of Bs0→J/ψϕ is characterized by the decay widths ΓH and ΓL of the heavy and light mass eigenstates, respectively, of the Bs0-B̅ s0 system and by a CP-violating phase ϕs. In a sample of about 8500 Bs0→J/ψϕ events isolated from 0.37  fb-1 of pp collisions at √s=7  TeV, we measure ϕs=0.15±0.18(stat)±0.06(syst)  rad. We also find an average Bs0 decay width Γs≡(ΓLH)/2=0.657±0.009(stat)±0.008(syst)  ps-1 and a decay width difference ΔΓs≡ΓLH=0.123±0.029(stat)±0.011(syst)  ps-1. Our measurement is insensitive to the transformation (ϕs,ΔΓs)...
So far only the channel has been used. Here we report on a measurement using an LHCb data sample of 0.41 fb−1, in the CP odd eigenstate J/ψf0(980), where f0(980)→π+π−. A time-dependent fit of the data with the lifetime and the difference in widths of the heavy and light eigenstates constrained to the values obtained from yields a value of the CP violating phase of −0.44±0.44±0.02 rad, consistent with the Standard Model expectation.
A search for the decays View the MathML source and B0→μ+μ− is performed with 0.37 fb−1 of pp collisions at View the MathML source collected by the LHCb experiment in 2011. The upper limits on the branching fractions are View the MathML source and B(B0→μ+μ−)<3.6×10−9 at 95% confidence level. A combination of these results with the LHCb limits obtained with the 2010 dataset leads to View the MathML source and B(B0→μ+μ−)<3.2×10−9 at 95% confidence level.
A model-independent search for direct CP violation in the Cabibbo-suppressed decay D+→K-K+π+ in a sample of approximately 370 000 decays is carried out. The data were collected by the LHCb experiment in 2010 and correspond to an integrated luminosity of 35  pb-1. The normalized Dalitz plot distributions for D+ and D- are compared using four different binning schemes that are sensitive to different manifestations of CP violation. No evidence for CP asymmetry is found.
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