2010546 SzGeCERN 20210503101901.0 oai:cds.cern.ch:2010546 cerncds:FULLTEXT cerncds:CERN:FULLTEXT cerncds:CERN arXiv oai:arXiv.org:1504.04462 Inspire 1361911 arXiv arXiv:1504.04462 hep-ex eng INSPIRE-00392110 Pescatore, L. Birmingham U. An analysis of $\Lambda_b^0 \rightarrow \Lambda\mu^+\mu^-$ decays at the LHCb experiment 2015 17 Apr 2015 4 p Comments: 4 pages, 6 figures arXiv 4 pages, 6 figures The branching fraction of the rare decay $\Lambda_b^0 \rightarrow \Lambda \mu^+ \mu^-$ is measured as a function of $q^2$, the square of the dimuon invariant mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb$^{-1}$, collected by the LHCb experiment. Evidence of signal is found for the first time in the $q^2$ region below the square of the J/$\psi$ mass. In the $q^2$ intervals where the signal is observed, angular distributions are studied and two forward-backward asymmetries, in the dimuon and hadronic systems, are measured for the first time. arXiv http://arxiv.org/licenses/nonexclusive-distrib/1.0/ arXiv nonexclusive-distrib. 1.0 giva a faire LANL EDS arXiv Particle Physics - Experiment PREPRINT CERN CERN LHC LHCb LANL EDS hep-ex for the LHCb Collaboration http://arxiv.org/pdf/1504.04462.pdf Preprint 1323344 832488 http://cds.cern.ch/record/2010546/files/arXiv:1504.04462.pdf 1323340 23176 http://cds.cern.ch/record/2010546/files/figure8a.png 00004 Forward-backward asymmetries as a function of $q^2$ in the dimuon system (left) and $p\pi^{-}$ system (right) with the SM prediction~\protect\cite{prediction} overlaid. 1323341 22350 http://cds.cern.ch/record/2010546/files/figure8b.png 00005 Forward-backward asymmetries as a function of $q^2$ in the dimuon system (left) and $p\pi^{-}$ system (right) with the SM prediction~\protect\cite{prediction} overlaid. 1323342 24356 http://cds.cern.ch/record/2010546/files/figure7a.png 00002 Distributions of the (left) $\cos \theta_\ell$ and (right) $\cos \theta_h$ angles in data in the $15 < q^2 < 20$ GeV$^2/c^4$ interval with overlaid the total fit function, solid (blue) line, and the background component, dashed (red) line. 1323343 28670 http://cds.cern.ch/record/2010546/files/figure7b.png 00003 Distributions of the (left) $\cos \theta_\ell$ and (right) $\cos \theta_h$ angles in data in the $15 < q^2 < 20$ GeV$^2/c^4$ interval with overlaid the total fit function, solid (blue) line, and the background component, dashed (red) line. 1323345 26535 http://cds.cern.ch/record/2010546/files/figure5.png 00001 (left) Invariant mass of the $\Lambda\mu^+\mu^-$ system in the $15 < q^2 < 20$ GeV$^2/c^4$ interval with the fit function overlaid. (right) Measured differential branching fraction of the rare $\Lambda_b^0 \rightarrow \Lambda \mu^+ \mu^-$ decay as a function of $q^2$ with the SM prediction~\protect\cite{prediction} superimposed. The inner error bar on data points represents the total uncertainty on the relative branching fraction (statistical and systematic); the outer error bar also includes the uncertainties from the branching fraction of the normalisation mode. 1323346 34515 http://cds.cern.ch/record/2010546/files/figure2.png 00000 (left) Invariant mass of the $\Lambda\mu^+\mu^-$ system in the $15 < q^2 < 20$ GeV$^2/c^4$ interval with the fit function overlaid. (right) Measured differential branching fraction of the rare $\Lambda_b^0 \rightarrow \Lambda \mu^+ \mu^-$ decay as a function of $q^2$ with the SM prediction~\protect\cite{prediction} superimposed. The inner error bar on data points represents the total uncertainty on the relative branching fraction (statistical and systematic); the outer error bar also includes the uncertainties from the branching fraction of the normalisation mode. n 201516 11 PREPRINT