Measurement of the differential branching fraction of the decay $Λ_b^0\rightarrowΛμ^+μ^-$

Journal article

The differential branching fraction of the decay $\Lambda_b^0\rightarrow\Lambda\mu^+\mu^-$ is measured as a function of the square of the dimuon invariant mass, $q^2$. A yield of $78\pm12$ $\Lambda_b^0\rightarrow\Lambda\mu^+\mu^-$ decays is observed using data, corresponding to an integrated luminosity of 1.0\,fb$^{-1}$, collected by the LHCb experiment at a centre-of-mass energy of 7\,TeV. A significant signal is found in the $q^2$ region above the square of the $J/\psi$ mass, while at lower-$q^2$ values upper limits are set on the differential branching fraction. Integrating the differential branching fraction over $q^2$, while excluding the $J/\psi$ and $\psi(2S)$ regions, gives a branching fraction of $\BF($\Lambda_b^0\rightarrow\Lambda\mu^+\mu^-$)=(0.96\pm 0.16\stat\pm 0.13\syst\pm 0.21 (\mathrm{norm}))\times 10^{-6}$, where the uncertainties are statistical, systematic and due to the normalisation mode, $$\Lambda_b^0\rightarrow J/psi\Lambda$, respectively.

Authors: collaboration, L; Aaij, R; Adeva, B; Adinolfi, M; Adrover, C

• Publication status: Published
• Journal: Phys. Lett. B
• Volume: 725
• Issue: 1-3
• Pages: 25
• Publication date: 2013-06-11
• DOI: 10.1016/j.physletb.2013.06.060
• ISSN: 0370-2693
• Language: English
• Keywords: hep-ex