Transverse polarisation measurement of Λ\Lambda hyperons in ppNe collisions at sNN\sqrt{s_{NN}}=68.4 GeV with the LHCb detector

A measurement of the transverse polarization of the $\Lambda$ and $\bar{\Lambda}$hyperons in $p$Ne fixed-target collisions at $\sqrt{s_{NN}}$=68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay $\Lambda \rightarrow p \pi^-$ together with its charge conjugated process, the integrated values measured are $$P_{\Lambda} = 0.029 \pm 0.019 \, (\rm{stat}) \pm 0.012 \, (\rm{syst}) \, ,$$ $$P_{\bar{\Lambda}} = 0.003 \pm 0.023 \, (\rm{stat}) \pm 0.014 \,(\rm{syst}) \,$$ Furthermore, the results are shown as a function of the Feynman $x$ variable, transverse momentum, pseudorapidity and rapidity of the hyperons, and are compared with previous measurements.A measurement of the transverse polarization of the $\Lambda$ and $\bar{\Lambda}$ hyperons in $p$Ne fixed-target collisions at $\sqrt{s_{NN}}$ = 68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay $\Lambda \rightarrow p \pi^-$ together with its charge conjugated process, the integrated values measured are $$P_{\Lambda} = 0.029 \pm 0.019 \, (\rm{stat}) \pm 0.012 \, (\rm{syst}) \, ,$$ $$P_{\bar{\Lambda}} = 0.003 \pm 0.023 \, (\rm{stat}) \pm 0.014 \,(\rm{syst}) \,.$$ Furthermore, the results are shown as a function of the Feynman~$x$~variable, transverse momentum, pseudorapidity and rapidity of the hyperons, and are compared with previous measurements

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

A comprehensive study of the local and nonlocal amplitudes contributing to the decay $B^0\rightarrow K^{*0}(\to K^+\pi^-) \mu^+\mu^-$ is performed by analysing the phase-space distribution of the decay products. The analysis is based on $pp$ collision data corresponding to an integrated luminosity of 8.4fb$^{-1}$ 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 $C_9$, responsible for vector dimuon currents, exhibits a $2.1\sigma$ deviation from the Standard Model expectation. The Wilson Coefficients $C_{10}$, $C_{9}'$ and $C_{10}'$ are all in better agreement than $C_{9}$ with the Standard Model and the global significance is at the level of $1.5\sigma$. The model used also accounts for nonlocal contributions from $B^{0}\to K^{*0}\left[\tau^+\tau^-\to \mu^+\mu^-\right]$ rescattering, resulting in the first direct measurement of the $b s\tau\tau$ vector effective-coupling $C_{9\tau}$.A comprehensive study of the local and nonlocal amplitudes contributing to the decay $B^0\rightarrow K^{*0}(\to K^+\pi^-) \mu^+\mu^-$ 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$^{-1}$ 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 $C_9$, responsible for vector dimuon currents, exhibits a $2.1\sigma$ deviation from the Standard Model expectation. The Wilson Coefficients $C_{10}$, $C_{9}'$ and $C_{10}'$ are all in better agreement than $C_{9}$ with the Standard Model and the global significance is at the level of $1.5\sigma$. The model used also accounts for nonlocal contributions from $B^{0}\to K^{*0}\left[\tau^+\tau^-\to \mu^+\mu^-\right]$ rescattering, resulting in the first direct measurement of the $b s\tau\tau$ vector effective-coupling $C_{9\tau}$

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

Decays of $\Xi_{b}^{-}$ and $\Omega_{b}^{-}$ baryons to $\Lambda_{c}^{+} h^- h^{\prime -}$ final states, with $h^- h^{\prime -}$ being $\pi^{-}\pi^{-}$, $K^{-}\pi^{-}$ and $K^{-}K^{-}$ meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of $8.7 \rm fb^{-1}$ of $pp$ collisions collected at centre-of-mass energies $\sqrt{s} = 7$, $8$ and $13 \rm TeV$. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the $B^{-} \rightarrow \Lambda_{c}^{+} \bar{p} \pi^{-}$ mode, are measured, with $\Xi_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} \pi^{-}$, $\Xi_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} K^{-}$ and $\Omega_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} K^{-}$ decays being observed at over $5\,\sigma$ significance. The $\Xi_{b}^{-} \rightarrow\Lambda_{c}^{+} K^{-} \pi^{-}$ mode is also used to measure the $\Xi_{b}^{-}$ production asymmetry, which is found to be consistent with zero. In addition, the $B^{-} \rightarrow \Lambda_{c}^{+} \bar{p} K^{-}$ decay is observed for the first time, and its branching fraction is measured relative to that of the $B^{-} \rightarrow \Lambda_{c}^{+} \bar{p} \pi^{-}$ mode.Decays of $\Xi_b^-$ and $\Omega_b^-$ baryons to $\Lambda_c^+ h^- h^{\prime -}$ final states, with $h^- h^{\prime -}$ being $\pi^-\pi^-$, $K^-\pi^-$ and $K^-K^-$ meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of $8.7\,\mathrm{fb}^{-1}$ of $pp$ collisions collected at centre-of-mass energies $\sqrt{s} = 7$, $8$ and $13\,\mathrm{Te\kern -0.1em V}$. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the $B^- \to \Lambda_c^+ \overline{p} \pi^-$ mode, are measured, with $\Xi_{b}^- \to\Lambda_{c}^+ K^- \pi^-$, $\Xi_{b}^- \to\Lambda_{c}^+ K^- K^-$ and $\Omega_{b}^- \to\Lambda_{c}^+ K^- K^-$ decays being observed at over $5\,\sigma$ significance. The $\Xi_{b}^- \to\Lambda_{c}^+ K^- \pi^-$ mode is also used to measure the $\Xi_{b}^-$ production asymmetry, which is found to be consistent with zero. In addition, the $B^- \to \Lambda_{c}^+ \overline{p} K^-$ decay is observed for the first time, and its branching fraction is measured relative to that of the $B^- \to \Lambda_{c}^+ \overline{p} \pi^-$ mode