33 research outputs found

    Determination of gamma and-2 beta(s) from charmless two-body decays of beauty mesons

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    Using the latest LHCb measurements of time-dependent CP violation in the B^0_s -> K^+K^- decay, a U-spin relation between the decay amplitudes of B^0_s -> K^+K^- and B^0 -> \pi^+\pi^- decay processes allows constraints to be placed on the angle gamma of the unitarity triangle and on the B^0_s mixing phase -2\beta_s. Results from an extended approach, which uses additional inputs on B^0 -> \pi^0\pi^0 and B^+ -> \pi^+\pi^0 decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value \gamma = ( 63.5 +7.2 -6.7 ) degrees modulo 180 degrees is determined. In an alternative analysis, the value -2\beta_s = -0.12 +0.14 -0.16 rad is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included.Comment: updated to v2 with minor changes after journal revie

    Measurement of the lifetime of the Bc+B_c^+ meson using the Bc+→J/ψπ+B_c^+\rightarrow J/\psi\pi^+ decay mode

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    The difference in total widths between the Bc+B_c^+ and B+B^+ mesons is measured using 3.0fb−1^{-1} of data collected by the LHCb experiment in 7 and 8 TeV centre-of-mass energy proton-proton collisions at the LHC. Through the study of the time evolution of Bc+→J/ψπ+B_c^+ \rightarrow J/\psi \pi^+ and B+→J/ψK+B^+\rightarrow J/\psi K^+ decays, the width difference is measured to be ΔΓ≡ΓBc+−ΓB+=4.46±0.14±0.07mm−1c, \Delta\Gamma \equiv \Gamma_{B_c^+} - \Gamma_{B^+} = 4.46 \pm 0.14 \pm 0.07mm^{-1}c, where the first uncertainty is statistical and the second systematic. The known lifetime of the B+B^+ meson is used to convert this to a precise measurement of the Bc+B_c^+ lifetime, τBc+=513.4±11.0±5.7fs,\tau_{B_c^+} = 513.4 \pm 11.0 \pm 5.7fs, where the first uncertainty is statistical and the second systematic.Comment: 19 pagers, 3 figure

    Measurement of the CP-violating phase ÎČ\beta in B0→J/ψπ+π−B^0\rightarrow J/\psi \pi^+\pi^- decays and limits on penguin effects

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    Time-dependent CP violation is measured in the B0→J/ψπ+π−B^0\rightarrow J/\psi\pi^+\pi^- channel for each π+π−\pi^+\pi^- resonant final state using data collected with an integrated luminosity of 3.0 fb−1^{-1} in pppp collisions using the LHCb detector. The final state with the largest rate, J/ψρ0(770)J/\psi\rho^0(770), is used to measure the CP-violating angle 2ÎČeff2\beta^{\rm eff} to be (41.7±9.6−6.3+2.8)∘(41.7\pm 9.6_{-6.3}^{+2.8})^{\circ}. This result can be used to limit the size of penguin amplitude contributions to CP violation measurements in, for example, Bs0→J/ψϕB_s^0\rightarrow J/\psi\phi decays. Assuming approximate SU(3) flavour symmetry and neglecting higher order diagrams, the shift in the CP-violating phase ϕs\phi_s is limited to be within the interval [−1.05∘-1.05^\circ, +1.18∘1.18^\circ] at 95% confidence level. Changes to the limit due to SU(3) symmetry breaking effects are also discussed.Comment: 18 pages, 6 figures; v2-updated from reviewers comments and added a figur

    Study of the rare B-s(0) and B-0 decays into the pi(+) pi(-) mu(+) mu(-) final state

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    A search for the rare decays Bs0→π+π−Ό+Ό−B_s^0 \to \pi^+\pi^-\mu^+\mu^- and B0→π+π−Ό+Ό−B^0 \to \pi^+\pi^-\mu^+\mu^- is performed in a data set corresponding to an integrated luminosity of 3.0 fb−1^{-1} collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5-1.3 GeV/c2c^2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay Bs0→π+π−Ό+Ό−B_s^0 \to \pi^+\pi^-\mu^+\mu^- and the first evidence of the decay B0→π+π−Ό+Ό−B^0 \to \pi^+\pi^-\mu^+\mu^- are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be B(Bs0→π+π−Ό+Ό−)=(8.6±1.5 (stat)±0.7 (syst)±0.7 (norm))×10−8\mathcal{B}(B_s^0 \to \pi^+\pi^-\mu^+\mu^-)=(8.6\pm 1.5\,({\rm stat}) \pm 0.7\,({\rm syst})\pm 0.7\,({\rm norm}))\times 10^{-8} and B(B0→π+π−Ό+Ό−)=(2.11±0.51 (stat)±0.15 (syst)±0.16 (norm))×10−8\mathcal{B}(B^0 \to \pi^+\pi^-\mu^+\mu^-)=(2.11\pm 0.51\,({\rm stat}) \pm 0.15\,({\rm syst})\pm 0.16\,({\rm norm}) )\times 10^{-8}, where the third uncertainty is due to the branching fraction of the decay B0→J/ψ(→Ό+Ό−)K∗(890)0(→K+π−)B^0\to J/\psi(\to \mu^+\mu^-)K^*(890)^0(\to K^+\pi^-), used as a normalisation.Comment: 21 pages, 3 figures, 2 Table

    Disinfectants prepared in a hospital pharmacy: assessment of their microbiological purity and antimicrobial effectivenes

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    The microbial contamination and antimicrobial effectiveness of seven topical disinfectants prepared at the hospital pharmacy were studied. These products were controlled throughout storage and use. The manufacturing routine investigated was able to deliver larger batch sizes and quality products that allowed increased storage time. The formulations chosen by the pharmacists were effective against bacteria for their intended uses. For chloramine only, loss of effectiveness required reduced storage time. No significant modification in the microbial quality of these products was observed during use in our hospital.Journal ArticleSCOPUS: ar.jFLWNAinfo:eu-repo/semantics/publishe
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