2 research outputs found

    Comprehensive analysis of local and nonlocal amplitudes in the B0→K∗0ÎŒ+Ό−B^0 \to K^{*0} \mu^+\mu^- decay

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    A comprehensive study of the local and nonlocal amplitudes contributing to the decay B0→K∗0(→K+π−)ÎŒ+Ό−B^0\rightarrow K^{*0}(\to K^+\pi^-) \mu^+\mu^- is performed by analysing the phase-space distribution of the decay products. The analysis is based on pppp collision data corresponding to an integrated luminosity of 8.4fb−1^{-1} collected by the LHCb experiment. This measurement employs for the first time a model of both one-particle and two-particle nonlocal amplitudes, and utilises the complete dimuon mass spectrum without any veto regions around the narrow charmonium resonances. In this way it is possible to explicitly isolate the local and nonlocal contributions and capture the interference between them. The results show that interference with nonlocal contributions, although larger than predicted, only has a minor impact on the Wilson Coefficients determined from the fit to the data. For the local contributions, the Wilson Coefficient C9C_9, responsible for vector dimuon currents, exhibits a 2.1σ2.1\sigma deviation from the Standard Model expectation. The Wilson Coefficients C10C_{10}, C9â€ČC_{9}' and C10â€ČC_{10}' are all in better agreement than C9C_{9} with the Standard Model and the global significance is at the level of 1.5σ1.5\sigma. The model used also accounts for nonlocal contributions from B0→K∗0[τ+τ−→Ό+Ό−]B^{0}\to K^{*0}\left[\tau^+\tau^-\to \mu^+\mu^-\right] rescattering, resulting in the first direct measurement of the bsττb s\tau\tau vector effective-coupling C9τC_{9\tau}.A comprehensive study of the local and nonlocal amplitudes contributing to the decay B0→K∗0(→K+π−)ÎŒ+Ό−B^0\rightarrow K^{*0}(\to K^+\pi^-) \mu^+\mu^- is performed by analysing the phase-space distribution of the decay products. The analysis is based on \proton\proton collision data corresponding to an integrated luminosity of 8.4fb−1^{-1} collected by the LHCb experiment. This measurement employs for the first time a model of both one-particle and two-particle nonlocal amplitudes, and utilises the complete dimuon mass spectrum without any veto regions around the narrow charmonium resonances. In this way it is possible to explicitly isolate the local and nonlocal contributions and capture the interference between them. The results show that interference with nonlocal contributions, although larger than predicted, only has a minor impact on the Wilson Coefficients determined from the fit to the data. For the local contributions, the Wilson Coefficient C9C_9, responsible for vector dimuon currents, exhibits a 2.1σ2.1\sigma deviation from the Standard Model expectation. The Wilson Coefficients C10C_{10}, C9â€ČC_{9}' and C10â€ČC_{10}' are all in better agreement than C9C_{9} with the Standard Model and the global significance is at the level of 1.5σ1.5\sigma. The model used also accounts for nonlocal contributions from B0→K∗0[τ+τ−→Ό+Ό−]B^{0}\to K^{*0}\left[\tau^+\tau^-\to \mu^+\mu^-\right] rescattering, resulting in the first direct measurement of the bsττb s\tau\tau vector effective-coupling C9τC_{9\tau}

    Study of b−b-hadron decays to Λc+h−hâ€Č−\Lambda_c^+h^-h^{\prime -} final states

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    Decays of Ξb−\Xi_{b}^{-} and Ωb−\Omega_{b}^{-} baryons to Λc+h−hâ€Č−\Lambda_{c}^{+} h^- h^{\prime -} final states, with h−hâ€Č−h^- h^{\prime -} being π−π−\pi^{-}\pi^{-}, K−π−K^{-}\pi^{-} and K−K−K^{-}K^{-} meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of 8.7fb−18.7 \rm fb^{-1} of pppp collisions collected at centre-of-mass energies s=7\sqrt{s} = 7, 88 and 13TeV13 \rm TeV. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the B−→Λc+pˉπ−B^{-} \rightarrow \Lambda_{c}^{+} \bar{p} \pi^{-} mode, are measured, with Ξb−→Λc+K−π−\Xi_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} \pi^{-}, Ξb−→Λc+K−K−\Xi_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} K^{-} and Ωb−→Λc+K−K−\Omega_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} K^{-} decays being observed at over 5 σ5\,\sigma significance. The Ξb−→Λc+K−π−\Xi_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} \pi^{-} mode is also used to measure the Ξb−\Xi_{b}^{-} production asymmetry, which is found to be consistent with zero. In addition, the B−→Λc+pˉK−B^{-} \rightarrow \Lambda_{c}^{+} \bar{p} K^{-} decay is observed for the first time, and its branching fraction is measured relative to that of the B−→Λc+pˉπ−B^{-} \rightarrow \Lambda_{c}^{+} \bar{p} \pi^{-} mode.Decays of Ξb−\Xi_b^- and Ωb−\Omega_b^- baryons to Λc+h−hâ€Č−\Lambda_c^+ h^- h^{\prime -} final states, with h−hâ€Č−h^- h^{\prime -} being π−π−\pi^-\pi^-, K−π−K^-\pi^- and K−K−K^-K^- meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of 8.7 fb−18.7\,\mathrm{fb}^{-1} of pppp collisions collected at centre-of-mass energies s=7\sqrt{s} = 7, 88 and 13 TeV13\,\mathrm{Te\kern -0.1em V}. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the B−→Λc+p‟π−B^- \to \Lambda_c^+ \overline{p} \pi^- mode, are measured, with Ξb−→Λc+K−π−\Xi_{b}^- \to\Lambda_{c}^+ K^- \pi^-, Ξb−→Λc+K−K−\Xi_{b}^- \to\Lambda_{c}^+ K^- K^- and Ωb−→Λc+K−K−\Omega_{b}^- \to\Lambda_{c}^+ K^- K^- decays being observed at over 5 σ5\,\sigma significance. The Ξb−→Λc+K−π−\Xi_{b}^- \to\Lambda_{c}^+ K^- \pi^- mode is also used to measure the Ξb−\Xi_{b}^- production asymmetry, which is found to be consistent with zero. In addition, the B−→Λc+p‟K−B^- \to \Lambda_{c}^+ \overline{p} K^- decay is observed for the first time, and its branching fraction is measured relative to that of the B−→Λc+p‟π−B^- \to \Lambda_{c}^+ \overline{p} \pi^- mode
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