1,040 research outputs found

    The role of sport and physical culture in human life

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    Nowadays, in the time of advanced technology, physical activity has significantly decreased, which has coursed to serious health problems. Phisical training is necessary to people keep good health and successful self-development.В наше время развитых технологий физическая активность значительно уменьшилась, что грозит серьезными проблемами со здоровьем. Занятия физической культурой необходимы для поддержания отличного самочувствия и для успешного саморазвития человека

    Observation of an Excited Bc+ State

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    Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date

    Measurement of CPCP violation in B0Dπ±B^{0}\rightarrow D^{\mp}\pi^{\pm} decays

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    A measurement of the CPCP asymmetries SfS_{f} and SfˉS_{\bar{f}} in B0Dπ±B^0\to D^{\mp}\pi^{\pm} decays is reported. The decays are reconstructed in a dataset collected with the LHCb experiment in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV and corresponding to an integrated luminosity of 3.0fb13.0 \rm{ fb}^{-1}. The CPCP asymmetries are measured to be Sf=0.058±0.020(stat)±0.011(syst)S_{f} = 0.058 \pm 0.020 (\rm{stat}) \pm 0.011(\rm{syst}) and Sfˉ=0.038±0.020(stat)±0.007(syst)S_{\bar{f}} = 0.038\pm 0.020 (\text{stat})\pm 0.007 (\text{syst}). These results are in agreement with, and more precise than, previous determinations. They are used to constrain sin(2β+γ)|\sin\left(2\beta+\gamma\right)| and γ\gamma to intervals that are consistent with the current world-average values.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2018-009.htm

    Evidence for the decay BS0K0μ+μ {B}_S^0\to {\overline{K}}^{\ast 0}{\mu}^{+}{\mu}^{-}

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    International audienceA search for the decay BS0K0μ+μ {B}_S^0\to {\overline{K}}^{\ast 0}{\mu}^{+}{\mu}^{-} is presented using data sets corresponding to 1.0, 2.0 and 1.6 fb1^{−1} of integrated luminosity collected during pp collisions with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, respectively. An excess is found over the background-only hypothesis with a significance of 3.4 standard deviations. The branching fraction of the BS0K0μ+μ {B}_S^0\to {\overline{K}}^{\ast 0}{\mu}^{+}{\mu}^{-} decay is determined to be B(Bs0K0μ+μ)=[2.9±1.0(stat)±0.2(syst)±0.3(norm)]×108 \mathrm{\mathcal{B}}\left({B}_s^0\to {\overline{K}}^{\ast 0}{\mu}^{+}{\mu}^{-}\right)=\left[2.9\pm 1.0\left(\mathrm{stat}\right)\pm 0.2\left(\mathrm{syst}\right)\pm 0.3\left(\mathrm{norm}\right)\right]\times {10}^{-8} , where the first and second uncertainties are statistical and systematic, respectively. The third uncertainty is due to limited knowledge of external parameters used to normalise the branching fraction measurement

    Measurement of the branching fraction and CP asymmetry in B plus . J/.. plus decays

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    The branching fraction and direct C ⁣PC\!P asymmetry of the decay B+J/ψρ+B^{+}\rightarrow J/\psi \rho^{+} are measured using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to a total integrated luminosity of 3\mbox{fb}^{-1}. The following results are obtained: \begin{align} \mathcal{B}(B^{+}\rightarrow J/\psi \rho^{+}) &= (3.81 ^{+0.25}_{-0.24} \pm 0.35) \times 10^{-5}, \nonumber \\ \mathcal{A}^{C\!P} (B^{+}\rightarrow J/\psi \rho^{+}) &= -0.045^{+0.056}_{-0.057} \pm 0.008, \nonumber \end{align} where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2018-036.htm

    Erratum to: Measurement of ϒ production in pp collisions at s√ = 13 TeV

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    Evidence for an ηc(1 S) π- resonance in B0→ ηc(1 S) K+π- decays

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    A Dalitz plot analysis of B0→ηc(1S)K+π- decays is performed using data samples of pp collisions collected with the LHCb detector at centre-of-mass energies of s=7,8 and 13TeV, corresponding to a total integrated luminosity of 4.7fb-1. A satisfactory description of the data is obtained when including a contribution representing an exotic ηc(1 S) π- resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are 4096±20-22+18MeV and 152±58-35+60MeV, respectively. The spin-parity assignments JP= 0 + and JP= 1 - are both consistent with the data. In addition, the first measurement of the B0→ηc(1S)K+π- branching fraction is performed and gives B(B0→ηc(1S)K+π-)=(5.73±0.24±0.13±0.66)×10-4,where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions

    Search for CPCP violation through an amplitude analysis of D0K+Kπ+πD^0 \to K^+ K^- \pi^+ \pi^- decays

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    International audienceA search for CP violation in the Cabibbo-suppressed D0^{0} → K+^{+}K^{−}π+^{+}π^{−} decay mode is performed using an amplitude analysis. The measurement uses a sample of pp collisions recorded by the LHCb experiment during 2011 and 2012, corresponding to an integrated luminosity of 3.0 fb1^{−1}. The D0^{0} mesons are reconstructed from semileptonic b-hadron decays into D0^{0}μ^{−}X final states. The selected sample contains more than 160 000 signal decays, allowing the most precise amplitude modelling of this D0^{0} decay to date. The obtained amplitude model is used to perform the search for CP violation. The result is compatible with CP symmetry, with a sensitivity ranging from 1% to 15% depending on the amplitude considered

    Measurement of the CP asymmetry in B- -&gt; (Ds-D0) and B- -&gt; (D-D0) decays

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    The CP asymmetry in B- -&gt; (Ds-D0) and B- -&gt; (D-D0) decays is measured using LHCb data corresponding to an integrated luminosity of 3.0 fb(-1), collected in pp collisions at centre-of-mass energies of 7 and 8TeV. The results are A(CP) (B- -&gt; (Ds-D0)) = (-0.4 +/- 0.5 +/- 0.5)% and A(CP) (B- -&gt; (D-D0)) = (2.3 +/- 2.7 +/- 0.4)%, where the first uncertainties are statistical and the second systematic. This is the first measurement of A(CP) (B- -&gt; (Ds-D0)) and the most precise determination of A(CP) (B- -&gt; (D-D0)). Neither result shows evidence of CP violation

    Measurement of the time-integrated <i>CP</i> asymmetry in <i>D</i><sup>0</sup> → <i>K <sub>S</sub></i> <sup>0</sup> <i>K <sub>S </sub></i><sup>0</sup> decays

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    A measurement of the time-integrated CPCP asymmetry in D0KS0KS0D^0\rightarrow K^0_S K^0_S decays is reported. The data correspond to an integrated luminosity of about 22 fb1^{-1} collected in 2015-2016 by the LHCb collaboration in pppp collisions at a centre-of-mass energy of 1313 TeV. The D0D^0 candidate is required to originate from a D+D0π+D^{\ast +} \rightarrow D^0 \pi^+ decay, allowing the determination of the flavour of the D0D^0 meson using the pion charge. The D0K+KD^0 \rightarrow K^{+}K^{-} decay, which has a well measured CPCP asymmetry, is used as a calibration channel. The CPCP asymmetry for D0KS0KS0D^0\rightarrow K^0_S K^0_S is measured to be \begin{equation*} \mathcal{A}^{CP}(D^0\rightarrow K^0_S K^0_S) = (4.3\pm 3.4\pm 1.0)\%, \end{equation*} where the first uncertainty is statistical and the second is systematic. This result is combined with the previous LHCb measurement at lower centre-of-mass energies to obtain \begin{equation*} \mathcal{A}^{CP}(D^0\rightarrow K^0_S K^0_S) = (2.3\pm 2.8\pm 0.9)\%. \end{equation*}Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2018-012.htm
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